137. Archibald, SB; Mathewes, RW; Aase, A. (2023) Eocene giant ants, Arctic intercontinental dispersal, and hyperthermals revisited: discovery of fossil Titanomyrma (Hymenoptera: Formicidae: Formiciinae) in the cool uplands of British Columbia, Canada.Can. Entomol. 155 Eocene giant ants, Arctic intercontinental dispersal, and hyperthermals revisited: discovery of fossil <i>Titanomyrma</i> (Hymenoptera: Formicidae: Formiciinae) in the cool uplands of British Columbia, Canada
We examine the implications for intercontinental dispersal of the extinct ant genus, Titanomyrma Archibald et al. (Hymenoptera: Formicidae: Formiciinae), following the discovery of its first fossil in Eocene temperate upland Canada. Modern Holarctic distributions of plants and animals were in part formed by dispersals across Late Cretaceous through early Eocene Arctic land bridges. Mild winters in a microthermal Arctic would allow taxa today restricted to the tropics by cold intolerance to cross, with episodic hyperthermal events allowing tropical taxa requiring hot climates to cross. Modern ants with the largest queens inhabit low latitudes of high temperature and mild coldest months, whereas those with smaller queens inhabit a wide variety of latitudes and climates. Gigantic and smaller formiciine ants (Titanomyrma and Formicium Westwood) are known from Europe and North America in the Eocene. The new Canadian Titanomyrma inhabited a cooler upland. It is incomplete, indistinctly preserved, and distorted in fossilisation, and so we do not assign it to a species or erect a new one for it. The true size of this fossil is unclear by this distortion: small size would support gigantism in Titanomyrma requiring hot climates and dispersal during hyperthermals; if it was large, it may have been cold-winter intolerant and able to have crossed during any time when the land bridge was present. DOI
136.Mathewes, RW. (2023) Plant macrofossils as indicators of vegetation and climate change in the Northern Black Forest of Germany during the last millennium-with focus on the Little Ice Age.Veg. Hist. Archaeobot. 32: 111-123 Plant macrofossils as indicators of vegetation and climate change in the Northern Black Forest of Germany during the last millennium-with focus on the Little Ice Age
Conifer needle flux; Wildsee am Ruhestein; Pollen analysis; Little Ice Age; Climatic cooling; Black Forest National Park
In order to better understand the potential effects of climatic change on forest cover during and after the Little Ice Age (ad 1550 to 1880), a high-elevation cirque Lake (Wildsee am Ruhestein) was cored and analysed using continuous plant macrofossil analysis, supplemented by standard pollen analysis. The plant macrofossil record provides local information for climate changes not clearly seen in regional pollen records for the Northern Black Forest. Abundant deposition of white fir (Abies alba) needles is restricted to the Little Ice Age, suggesting reaction to climatic cooling. Human impacts, particularly forest clearing, are well documented historically during the past millennium, but discrete peaks in needle flux are only recorded at Wildsee once Little Ice Age cooling begins. The first needle flux event at 39-42 cm depth has a median modelled age of ad 1650, at the start of the Maunder Minimum, recognized as a particularly cold interval. Also of climatic significance is the flux of 19 immature Abies needles recovered from the 30-33 cm layer, dated around ad 1720. This finding is interpreted as clear evidence of severe spring frosts during the Little Ice Age, discrete events that are well-recorded in historical observations. Pollen analysis also supports cooling, beginning at a depth of 54 cm, modelled at ad 1560 during the beginning of the Little Ice Age. A decline in oak (Quercus) pollen begins around ad 1560 at the start of pollen zone IV, which also includes the lowest total pollen accumulation rates seen, suggesting a climatic influence. The significant forest dieback (Waldsterben) events that were observed during the late 1970 and 1980 s could not be identified in our pollen and macrofossil data. The combined approach of using pollen and detailed macrofossil analysis provides a better reconstruction of forest history than either technique in isolation, and the combination is potentially important for management of protected areas such as the Black Forest National Park. DOI
135.Mathewes, RW; Greenwood, DR; Reichgelt, T. (2023) PLANT MEGAFOSSILS, PALYNOMORPHS, AND PALEOENVIRONMENT FROM THE LATE MIDDLE TO LATE EOCENE BURNABY MOUNTAIN FLORA, HUNTINGDON FORMATION, BRITISH COLUMBIA, CANADA.Int. J. Plant Sci.PLANT MEGAFOSSILS, PALYNOMORPHS, AND PALEOENVIRONMENT FROM THE LATE MIDDLE TO LATE EOCENE BURNABY MOUNTAIN FLORA, HUNTINGDON FORMATION, BRITISH COLUMBIA, CANADA
British Columbia; Eocene; megaflora; palynology; paleoclimate
Premise of research. The Eocene fossil flora of the area around Vancouver, British Columbia, is poorly known despite work beginning in the 1890s to 1920s. The floristic character of the previously unstudied Burnaby Mountain flora from the Huntingdon Formation in British Columbia is reconstructed using plant megafossils and palynology. This site offers insight into the terrestrial vegetation and paleoclimate during the late middle to late Eocene of the Pacific Northwest of North America in a coastal setting during a global cooling trend. Methodology. Megaflora and microflora were identified, and the combined flora was compared with that of coeval floras from northwestern Washington. Paleoclimate was reconstructed from leaf morphology using the Climate Leaf Analysis Multivariate Program, leaf margin analysis, and leaf area analysis. A probabilistic nearest-living-relative approach was used to reconstruct paleoclimate independently of leaf morphology, using taxonomic identifications from both mega- and microfossils. These data were combined in an ensemble approach. Pivotal results. The Burnaby Mountain fossil flora is late middle Eocene to late Eocene in age and shares key plant taxa with the coeval Upper Ravenian flora of the Puget Group and the upper Chumstick Formation of northwestern Washington. The fossil flora contained a mix of subtropical and temperate forest elements, including rare palm and possible cycad leaf fragments, rare conifer pollen, and a diversity of broad-leaved trees. Conclusions. The reconstructed paleoclimate suggests humid warm-temperate to marginally subtropical conditions in coastal British Columbia during the late middle Eocene to late Eocene. An ensemble paleoclimate approach provided a most parsimonious mean annual temperature estimate of 16.2 degrees C +/- 3.1 degrees C for the Burnaby Mountain fossils and mean annual precipitation of 134 +/- 56 cm. A modern climatic analog is present on the East Coast of the United States in North Carolina, where palms are part of the native flora. DOI
134. Monteath, AJ; Kuzmina, S; Mahony, M; Calmels, F; Porter, T; Mathewes, R; Sanborn, P; Zazula, G; Shapiro, B; Murchie, TJ; Poinar, HN; Sadoway, T; Hall, E; Hewitson, S; Froese, D. (2023) Relict permafrost preserves megafauna, insects, pollen, soils and pore- ice isotopes of the mammoth steppe and its collapse in central Yukon.Quat. Sci. Rev. 299 Relict permafrost preserves megafauna, insects, pollen, soils and pore- ice isotopes of the mammoth steppe and its collapse in central Yukon
Pleistocene; Paleoclimatology; North America; Sedimentology; Loess; Mammoth steppe; Steppe-tundra; Beringia; Pleistocene-holocene transition; Palaeoecology
In eastern Beringia (unglaciated Alaska and western Yukon), the Pleistocene-Holocene transition was characterised by rapid changes in plant, insect and mammal communities as the mammoth steppe ecosystem was replaced, first by shrub tundra and later boreal forest. These changes indicate a transition from well drained terrain with deep active layers to wetter, cooler soils, to which steppe-tundra vege-tation was poorly adapted. The nature and precise timing of these events is not well resolved, particularly in central Yukon where regional climate may have been strongly affected by the retreating Cordilleran-Laurentide ice sheet complex. Resolving this uncertainty is not only important for understanding past ecosystems, but also provides a long-term perspective for contemporary environmental change and shrub expansion that affects large areas of northern high-latitudes today. Here, we report chronology (41 radiocarbon dates), stratigraphy, pore-ice d2H/d18O measurements, pollen data, megafauna remains and fossil insect assemblages from a permafrost-preserved loessal sequence in central Yukon, named Lucky Lady. The site spans the interval from ca. 17,000 to 8000 cal yr BP (calibrated years before C.E. 1950) and records the Pleistocene-Holocene transition in exceptional resolution. Full glacial environments (ca. 16,500 cal yr BP) supported elements of steppe-tundra vegetation and an insect fauna dominated by Connatichela artemisiae -an endemic weevil indicating warm soil temperatures. The collapse of the mammoth steppe ecosystem began with slowing of loess accumulation and development of paleosol ca. 13,480 cal yr BP. At this time, C. artemisiae remains become infrequent and Artemisia pollen decline to be replaced by Cyperaceae (ca. 13,220), before mesic, shrub taxa (likely dwarf Betula and Salix) becomes dominant ca. 13,210 cal yr BP. The establishment of shrub tundra is associated with rapid changes in d2H/ d18O measurements, suggesting that ecological turnover coincided with a shift in atmospheric conditions and moisture availability. Finally, boreal vegetation communities became established ca. 10,680 cal yr BP. The replacement of steppe-tundra vegetation in central Yukon lagged other areas of eastern Beringia by as much as 1000 years and coincided with rapid deglaciation during the Bolling-Allerod time-period (14,600-12,90 0 cal yr BP). Turnover in insect and vegetation communities took place in ca. 40 years as shrub tundra became dominant. This rapid turnover has parallels with contemporary Arctic greening and re-emphasises the sensitivity of high-latitude environments to climate change.(c) 2022 Elsevier Ltd. All rights reserved. DOI
133. Archibald, SB; Gu, JJ; Mathewes, RW. (2022) The Palaeorehniidae (Orthoptera, Ensifera, "Zeuneropterinae"), and new taxa from the early Eocene Okanagan Highlands, western North America.Zootaxa 5100: 559-572 The Palaeorehniidae (Orthoptera, Ensifera, "Zeuneropterinae"), and new taxa from the early Eocene Okanagan Highlands, western North America
Hagloidea; Stenopelmatoidea; Ypresian; Cenozoic; Quilchena; Republic
We revise the subfamily Zeuneropterinae (Orthoptera, Ensifera) and treat it as the family Palaeorehniidae Zeuner stat. nov. We restore the late Eocene Palaeorehnia Cockerell from Florissant, Colorado, USA to the taxon and describe two new genera and species in it: Ypopteron nicola n. gen., n. sp. from Quilchena, British Columbia, Canada and Republicopteron douseae n. gen., n. sp. from Republic, Washington, USA. Given current knowledge, Palaeorehniidae appears intermediate between the Stenopelmatoidea and the Hagoidea (s.s.). DOI PubMed
132. Archibald, SB; Cannings, RA; Erickson, RJ; Bybee, SM; Mathewes, RW. (2021) The Cephalozygoptera, a new, extinct suborder of Odonata with new taxa from the early Eocene Okanagan Highlands, western North America.Zootaxa 4934: 1-133 The Cephalozygoptera, a new, extinct suborder of Odonata with new taxa from the early Eocene Okanagan Highlands, western North America
Ypresian; Republic; McAbee; Driftwood Canyon; Sieblosiidae; Zygoptera
We describe the Cephalozygoptera, a new, extinct suborder of Odonata, composed of the families Dysagrionidae and Sieblosiidae, previously assigned to the Zygoptera, and possibly the Whetwhetaksidae n. fam. The Cephalozygoptera is close to the Zygoptera, but differs most notably by distinctive head morphology. It includes 59 to 64 species in at least 19 genera and one genus-level parataxon. One species is known from the Early Cretaceous (Congqingia rhora Zhang), possibly three from the Paleocene, and the rest from the early Eocene through late Miocene. We describe new taxa from the Ypresian Okanagan Highlands of British Columbia, Canada and Washington, United States of America: 16 new species of Dysagrionidae of the existing genus Dysagrion (D. pruettae); the new genera Okanagrion (O. threadgillae, O. hobani, O. beardi, O. lochmum, O. angustum, O. dorrellae, O. liquetoalatum, O. worleyae, all new species); Okanopteryx (O. jeppesenorum, O. fraseri, O. macabeensis, all new species); Stenodiafanus (S. westersidei, new species); the new genus-level parataxon Dysagrionites (D. delinei new species, D. sp. A, D. sp. B, both new); and one new genus and species of the new family Whetwhetaksidae (Whetwhetaksa millerae). DOI PubMed
131. Kubiak, C; Mathewes, R; Grimes, V; Van Biesen, G; Richards, MP. (2021) Evidence of a significant marine plant diet in a Pleistocene caribou from Haida Gwaii, British Columbia, through compound-specific stable isotope analysis.Paleogeogr. Paleoclimatol. Paleoecol. 564 Evidence of a significant marine plant diet in a Pleistocene caribou from Haida Gwaii, British Columbia, through compound-specific stable isotope analysis
Northwest Coast; Antler collagen; Amino acids; Seaweed; MIS 3
The Northwest Coast of Canada was likely an important location for glacial refugia in the Late Pleistocene. Recently, a caribou (Rangifer tarandus) antler fragment was reported from Graham Island dating prior to the Fraser Glaciation (MIS 3; 48,200-45,200 cal yr BP). The high carbon and nitrogen stable isotope values found in the bulk collagen samples of this caribou prompted further investigation into its diet and palaeoecological context. Today, caribou in British Columbia face rapid population and range decline, and have been placed on threatened and endangered species lists by both the U.S. and Canadian governments. Further insights into this species and its responses to changing environmental conditions can both improve our understanding of the Late Pleistocene ecosystems of the Northwest Coast and add relevant data to modern conservation issues. We employed compound-specific carbon and nitrogen stable isotope analysis to the individual amino acids of antler collagen to better understand the isotopic signal of this specimen. Our results suggest a significant marine plant contribution to the caribou's spring-summer diet, potentially reflecting an intensive foraging behavior observed in some modern-day Rangifer tarandus populations under conditions of terrestrial resource restriction. DOI
130. Makarkin, VN; Archibald, SB; Mathewes, RW. (2021) New Protosmylinae (Neuroptera: Osmylidae) from the early Eocene of western North America, with taxonomic remarks.Zootaxa 4980: 142-156 New Protosmylinae (Neuroptera: Osmylidae) from the early Eocene of western North America, with taxonomic remarks
Neuroptera; Osmylidae; Protosmylinae; Okanagan Highlands; Green River Formation; Baltic amber; Eocene
The osmylid subfamily Protosmylinae is revised based on our emended diagnosis: Petrushevskia Martynova, 1958 and Mesosmylidus Jepson et al., 2012 are excluded (both considered Osmylidae incertae sedis), and Sogjuta Martynova, 1958 is transferred to it from the Mesosmylininae. The late Eocene genus Protosmylus Kruger, 1913 is considered a junior synonym of Osmylidia Cockerell, 1908 based on a distinct apomorphy (deeply forked MA in the hind wing), syn. nov. Three new species of Osmylidia from the early Eocene of North America are described: O. donnae sp. nov. from Quilchena, O. glastrai sp. nov. from Republic, Washington, USA, and an unnamed species of Osmylidia is reported from Driftwood Canyon Provincial Park, British Columbia (all localities of the Okanagan Highlands series), and O. taliae sp. nov. from the Green River Formation of Colorado, USA. DOI PubMed
129.Mathewes, R; Archibald, SB; Lundgren, A. (2021) Tips and identification of early Eocene Fraxinus L. samaras from the Quilchena locality, Okanagan Highlands, British Columbia, Canada.Rev. Palaeobot. Palynology 293 Tips and identification of early Eocene Fraxinus L. samaras from the Quilchena locality, Okanagan Highlands, British Columbia, Canada
Fraxinus samaras; Early Eocene; Fraxinus eoemarginata sp. nov; Quilchena B.C
A large collection (49 specimens) of early Eocene Fraxinus (ash) samaras enabled us to evaluate whether or not more than one species was present at the Quilchena fossil site. Analysis of living ashes indicates that morphology of the samara tips is sometimes cited as a taxonomic criterion, and sometimes assumed to be due to intraspecific variation. Two shale slabs with multiple samaras, some still attached to their fruiting panicle, have been recovered, and in each case all samaras were either emarginate at the tip, or entire, indicating a degree of fidelity of tip type, and the possibility that more than one species may be represented. Analysis of 27 dispersed samaras with notched tips, involving measurements of overall length, width, venation, and seed morphology, reveal differences with unnotched samaras from the same site, with width significantly greater (p < 0.05) for the notched samaras. Together with other differences that are not statistically significant, the larger size for notched specimens encouraged us to describe a new species, Fraxinus eoemarginata sp. nov. Quilchena is well dated to the early Eocene at 51.5 million years, making it the oldest radiometrically documented site for diversification of Fraxinus species. (C) 2021 Elsevier B.V. All rights reserved. DOI
128.Mathewes, RW; Greenwood, DR; Love, RL. (2020) The Kanaka Creek fossil flora (Huntingdon Formation), British Columbia, Canada - paleoenvironment and evidence for Paleocene age using palynology and macroflora.Can. J. Earth Sci. 57: 348-365 The Kanaka Creek fossil flora (Huntingdon Formation), British Columbia, Canada - paleoenvironment and evidence for Paleocene age using palynology and macroflora
Paleocene; paleobotany; palynology; paleoclimate; Huntingdon Formation; Kanaka Creek
Paleogene sediments of the Huntingdon Formation, a correlative to the Chuckanut Formation of neighbouring Washington State, USA, are exposed in the Greater Vancouver area, British Columbia, Canada. Palynology and plant macrofossils suggest the Kanaka Creek section is Paleocene rather than Eocene in age. Detrital zircon dating is less decisive, yet indicates the Kanaka rocks are no older than Maastrichtian. Analyses of plant macro- and micro-fossils suggest an early to middle Paleocene age for the Kanaka fossil flora. Paleocene indicators include macrofossils such as Platanus bella, Archeampelos, Hamamelites inequalis, and Ditaxocladus, and pollen taxa such as Paraalnipollenites, Triporopollenites mullensis, and Duplopollis. Paleogene taxa such as Woodwardia maxonii, Macclintockia, and Glyptostrobus dominate the flora. Fungal spores including the Late Cretaceous Pesavis parva and the Paleogene Pesavis tagluensis are notable age indicators. Physiognomy of 41 angiosperm leaf morphotypes from Kanaka Creek yields mean annual temperatures in the microthermal to lower mesothermal range (11.2 +/- 4.3 to 14.6 +/- 2.7 degrees C from leaf margin analysis; 14.8 +/- 2.1 degrees C from Climate Leaf Analysis Multivariate Program), with mild winters (cold month mean temperature 3.9 +/- 3.4 degrees C). Paleoclimate was cooler than the upper Paleocene and Eocene members of the Chuckanut Formation. Mean annual precipitation is estimated at similar to 140 cm with large uncertainties. The Kanaka paleoflora is reconstructed as a mixed conifer-broadleaf forest, sharing common taxa with other western North American Paleocene floras and growing in a temperate moist climate. Kanaka Creek is a rare coastal Paleocene plant locality that provides new insights into coastal vegetation and climate prior to the Paleocene-Eocene Thermal Maximum. DOI
127.Mathewes, RW; Lacourse, T; Helmer, EF; Howarth, CR; Fedje, DW. (2020) Late Pleistocene vegetation and sedimentary charcoal at Kilgii Gwaay archaeological site in coastal British Columbia, Canada, with possible proxy evidence for human presence by 13,000 cal bp.Veg. Hist. Archaeobot. 29: 297-307 Late Pleistocene vegetation and sedimentary charcoal at Kilgii Gwaay archaeological site in coastal British Columbia, Canada, with possible proxy evidence for human presence by 13,000 cal bp
Haida Gwaii; Charcoal; Pollen analysis; Archaeology; Kilgii Gwaay; Peopling of Americas
Kilgii Gwaay is an early Holocene archaeological wet site located in the intertidal zone of Ellen Island in the southern Haida Gwaii archipelago of coastal British Columbia, Canada. The Kilgii site includes one of the oldest shell middens in western North America and provides evidence of early maritime adaptations by humans. Radiocarbon-dated cultural deposits that surround a small palaeopond (Kilgii Pond) include hearth features, abundant lithic, bone and wood artifacts, and a diverse fossil fauna and flora. The known occupation dates between 10,800 and 10,500 cal bp, when relative sea level was 1-3 m lower than today. The site was submerged and capped by marine deposits by 10,500 cal bp as relative sea level rose. We conducted multi-proxy palaeoenvironmental analyses (magnetic susceptibility, pollen, charcoal, macrofossils) on Kilgii Pond sediments from a core taken beneath the coarse intertidal deposits. Pollen analysis indicates establishment of herb-shrub tundra by 14,500 cal bp, followed by pine-dominated communities after 13,800 cal bp and spruce forest with abundant ferns from about 13,250 cal bp. Macroscopic charcoal in the core is most abundant during the period of confirmed human occupation; however, significant peaks in charcoal abundance are present well below the known occupation horizon. Since lightning and natural forest fires are infrequent in this wet hypermaritime setting, we consider that the charcoal peaks from Kilgii Pond may serve as a proxy for human presence, potentially as early as 13,000 cal bp, approximately 2,200 years earlier than indicated by the AMS-dated cultural deposits and artifacts. DOI
126.Mathewes, RW; Richards, M; Reimchen, TE. (2019) Late Pleistocene age, size, and paleoenvironment of a caribou antler from Haida Gwaii, British Columbia.Can. J. Earth Sci. 56: 688-692 Late Pleistocene age, size, and paleoenvironment of a caribou antler from Haida Gwaii, British Columbia
Haida Gwaii; caribou; fossil antler; accelerator mass spectrometry dating; paleoecology; MIS 3
The basal portion of a fossil caribou antler from Graham Island is the only evidence of large terrestrial vertebrates older than the Fraser (late-Wisconsin) glaciation on Haida Gwaii. This antler has been radiocarbon dated three times by different laboratories and all ages fall within the mid-Wisconsin Olympia Interglaciation (Marine Isotope Stage 3, MIS 3). We suggest that the latest date, using ultrafiltration of bone collagen, is closest to the true age at 43 200 +/- 650 years BP (48 200 - 45 200 cal BP). Previous paleoecological analysis from Graham Island reconstructed a vegetation cover during MIS 3 consisting of mixed coniferous forest with nonforested openings, similar to cool subalpine forests of today. These conditions are consistent with environments that support woodland caribou and the related extinct Dawson caribou. Morphometric comparison of antlers from woodland and Dawson caribou suggest that they are more similar than previously interpreted and raise questions about the inferred differences between the mainland and island subspecies. DOI
125. Mayr, G; Archibald, SB; Kaiser, GW; Mathewes, RW. (2019) Early Eocene (Ypresian) birds from the Okanagan Highlands, British Columbia (Canada) and Washington State (USA).Can. J. Earth Sci. 56: 803-813 Early Eocene (Ypresian) birds from the Okanagan Highlands, British Columbia (Canada) and Washington State (USA)
aves; diagenesis; fossil birds; systematics; taxonomy
We survey the known avian fossils from Ypresian (early Eocene) fossil sites of the North American Okanagan Highlands, mainly in British Columbia (Canada). All specimens represent taxa that were previously unknown from the Eocene of far-western North America. Wings from the McAbee site are tentatively referred to the Caviiformes and would constitute the earliest fossil record of this group of birds. A postcranial skeleton from Driftwood Canyon is tentatively assigned to the Songziidae, a taxon originally established for fossils from the Ypresian of China. Two skeletons from Driftwood Canyon and the McAbee site are tentatively referred to Coliiformes and Zygodactylidae, respectively, whereas three further fossils from McAbee, Blakeburn, and Republic (Washington, USA) are too poorly preserved for even a tentative assignment. The specimens from the Okanagan Highlands inhabited relatively high paleoaltitudes with microthermal climates (except Quilchena: lower mesothermal) and mild winters, whereas most other Ypresian fossil birds are from much warmer lowland paleoenvironments with upper mesothermal to megathermal climates. The putative occurrence of a gaviiform bird is particularly noteworthy because diving birds are unknown from other lacustrine Ypresian fossil sites of the Northern Hemisphere. The bones of the putative zygodactylid show a sulphurous colouration, and we hypothesize that this highly unusual preservation may be due to the metabolic activity of sulphide-oxidizing bacteria. DOI
124. Archibald, SB; Rasnitsyn, AP; Brothers, DJ; Mathewes, RW. (2018) Modernisation of the Hymenoptera: ants, bees, wasps, and sawflies of the early Eocene Okanagan Highlands of western North America.Can. Entomol. 150: 205-257 Modernisation of the Hymenoptera: ants, bees, wasps, and sawflies of the early Eocene Okanagan Highlands of western North America
Trigonalidae
Most major modern families of Hymenoptera were established in the Mesozoic, but the diversifications within ecologically key trophic guilds and lineages that significantly influence the character of modern terrestrial ecosystems - bees (Apiformes), ants (Formicidae), social Vespidae, parasitoids (Ichneumonidae), and phytophagous Tenthredinoidea - were previously known to occur mostly in the middle to late Eocene. We find these changes earlier, seen here in the early Eocene Okanagan Highlands fossil deposits of western North America. Some of these may have occurred even earlier, but have been obscured by taphonomic processes. We provide an overview of the Okanagan Highlands Hymenoptera to family level and in some cases below that, with a minimum of 25 named families and at least 30 when those tentatively assigned or distinct at family level, but not named are included. Some are poorly known as fossils (Trigonalidae, Siricidae, Peradeniidae, Monomachidae), and some represent the oldest confirmed occurrences (Trigonalidae, Pompilidae, Sphecidae sensu stricto, Peradeniidae, Monomachidae, and possibly Halictidae). Some taxa previously thought to be relictual or extinct by the end of the Cretaceous (Angarosphecidae, Archaeoscoliinae, some Diapriidae) are present and sometimes abundant in the early Eocene. Living relatives of some taxa are now present in different climate regimes or on different continents. DOI
123.Mathewes, RW; Clague, JJ. (2017) Paleoecology and ice limits of the early Fraser glaciation (Marine Isotope Stage 2) on Haida Gwaii, British Columbia, Canada.Quat. Res. 88: 277-292 Paleoecology and ice limits of the early Fraser glaciation (Marine Isotope Stage 2) on Haida Gwaii, British Columbia, Canada
Fraser glaciation; Glacial geology; Last glacial maximum; MIS 2; Stratigraphy; Paleoecology; Refugia; Geochronology; Haida Gwaii; British Columbia
Our study combines new geological and paleoecological information to reconstruct the glacial history and terrestrial paleoenvironments on Haida Gwaii during the advance phase of the Fraser glaciation (Marine Isotope Stage 2). At Cape Ball on eastern Graham Island, five accelerator mass spectrometry radiocarbon ages ranging from 23,200 +/- 280 to 26,650 +/- 390 C-14 yr BP (ca. 27,000-31,400 cal yr BP) record the earliest approach of mainland glaciers to Haida Gwaii. Abundant marine dinoflagellate cysts indicate isostatic depression by glacial ice in Hecate Strait to the east. At Mary Point on the north coast of Graham Island, similar outwash of a piedmont lobe advancing westward along Dixon Entrance preserves plant remains dated from 19,270 +/- 360 to 23,740 +/- 300 C-14 yr BP (22,500-28,600 cal yr BP). These sediments also contain marine indicators. Plant macrofossils, pollen, and invertebrates support the geological evidence of a proglacial environment under a colder-than-present macroclimate. Although some trees were likely present on Graham Island at this time, tundra-like plant communities dominated low-lying areas. A large area that appears to have been ice-free during this time is a portion of the continental shelf off the east coast of Moresby Island, referred to provisionally as the "Hecate Refugium." DOI
122. Zazula, GD; Hall, E; Hare, PG; Thomas, C; Mathewes, R; La Farge, C; Martel, AL; Heintzman, PD; Shapiro, B. (2017) A middle Holocene steppe bison and paleoenvironments from the Versleuce Meadows, Whitehorse, Yukon, Canada.Canadian Journal of Earth Sciences 54: 1138-1152 A middle Holocene steppe bison and paleoenvironments from the Versleuce Meadows, Whitehorse, Yukon, Canada
A partial skeleton of a bison was recovered during residential house construction in Whitehorse, Yukon, Canada. The specimen represents a young (estimated 6 year old) bison individual that died, was partially scavenged by carnivores, and subsequently buried by calcareous silt sediment in a pond or small lake during the middle Holocene, similar to 5400 years ago. Palaeoenvironmental data, including molluscs, pollen, vascular plant, and bryophyte macrofossils demonstrate that the small waterbody was surrounded by white spruce dominated boreal forest. Morphometric analysis of the skeleton reveals that its taxonomic affinity is ambiguous, likely owing to it representing an ontogenetically young individual, though it does share some cranial and horn core characteristics of named species such as Bison occidentalis or Bison priscus. Mitochondrial genomic data confirm that this bison belongs to Clade 2A (northern clade), which represents Pleistocene steppe bison (B. cf. priscus) in Beringia through the Holocene and is not represented in living bison species. These data further demonstrate that northern steppe bison population survived the late Pleistocene extinction event, persisted locally in southern Yukon into the Holocene, and are best characterized as a species with a high degree of morphological variability and ecological flexibility. DOI
120.Mathewes, RW; Greenwood, DR; Archibald, SB. (2016) Paleoenvironment of the Quilchena flora, British Columbia, during the Early Eocene Climatic Optimum.Canadian Journal of Earth Sciences 53: 574-590 Paleoenvironment of the Quilchena flora, British Columbia, during the Early Eocene Climatic Optimum
The Quilchena fossil locality is dated (51.5 +/- 0.4 Ma) to the Early Eocene Climatic Optimum, and this locality is reconstructed as the warmest and wettest of the Early Eocene upland sites from the Okanagan Highlands of British Columbia and northern Washington State. Mean annual temperature (MAT) is estimated from leaf margin analysis, using 55 dicot morphotypes, as 16.2 +/- 2.1 degrees C/14.6 +/- 4.8 degrees C. Using bioclimatic analysis of 45 nearest living relatives, a moist mesothermal climate is indicated (MAT 12.7-16.6 degrees C; cold month mean temperature (CMMT) 3.5-7.9 degrees C; mean annual precipitation (MAP) 103-157 cm/year. Leaf size analysis estimates MAP at 121 +/- 39 cm/year. Estimates from the climate leaf analysis multivariate program corroborate these results, although with a slightly cooler MAT (13.3 +/- 2.1 degrees C). Plants that support an interpretation of warm winters with minimal or no frost include Azolla, Glyptostrobus, Taxodium, Keteleeria, Pseudolarix, Eucommia, Dipteronia, Hovenia, Ternstroemia, and others. These thermophilous elements occur together with temperate genera such as Alnus, Betula, Ulmus, Calocedrus, and Fraxinus. Palynological assemblages at Quilchena are dominated by bisaccate conifers and Cupressaceae. Common angiosperms include Ulmus type, triporates, Pterocarya, and Alnus. Insect fossils at Quilchena that today inhabit tropical and subtropical regions also support warm and equable climate without significant frost, and include obligate palm-feeding beetles (Pachymerina), which indicate CMMT perhaps as high as 8 degrees C. These are found together with temperate aphids, wasps, giant lacewings, brown lacewings, and a panorpoid scorpionfly, supporting an interpretation of equable climatic conditions during the Early Eocene Climatic Optimum. DOI
119.Mathewes, RW; Lian, OB; Clague, JJ; Huntley, MJW. (2015) Early Wisconsinan (MIS 4) glaciation on Haida Gwaii, British Columbia, and implications for biological refugia.Canadian Journal of Earth Sciences 52: 939-951 Early Wisconsinan (MIS 4) glaciation on Haida Gwaii, British Columbia, and implications for biological refugia
Sea cliffs at Cape Ball on Graham Island, British Columbia, expose a thick sequence of Pleistocene sediments deposited during at least two glaciations. In sequence, from the base of the section, the units are (1) stony mud, (2) till, (3) silt, sand, and peat, (4) stony mud, (5) laminated sand and silt, (6) cross-bedded sand, and (7) till. Of special interest is unit 4, a massive to weakly stratified mud containing scattered stones that was deposited during the penultimate Pleistocene glaciation (marine isotope stage (MIS) 4). This unit contains wood and marine shell fragments that have yielded non-finite radiocarbon ages. Sand and silt with thin stringers of peat (unit 3) directly underlie this stony mud, and returned an optical age of 57.3 +/- 5.7 ka. The stony mud is unconformably overlain by ponded sediments (unit 5) and advance outwash (unit 6) and till (unit 7) deposited during the Fraser Glaciation (MIS 2). The optically dated unit and a correlative peat and silty sand unit at a nearby exposure have pollen spectra with almost 100% non-arboreal pollen. Very low values of tree pollen, coupled with high frequencies of sedges, grasses, composites, Ericales, and the arctic-alpine indicator Koenigia islandica, indicate tundra vegetation and a cold climate. Abundant coprophilous Sporormiella (69%-91%) and Sordaria type (14%-47%) fungal spores in the peat samples indicate the former presence of grazing mammals at Cape Ball during MIS 4. During the MIS 3 interstade, subalpine forest existed at low elevations on Graham Island, providing environments suitable for the development of genetically distinct bird and mammal populations that survived in lowland refugia during the Fraser Glaciation. DOI
118. Pellatt, MG; Mccoy, MM; Mathewes, RW. (2015) Paleoecology and fire history of Garry oak ecosystems in Canada: implications for conservation and environmental management.Biodiversity and Conservation 24: 1621-1639 Paleoecology and fire history of Garry oak ecosystems in Canada: implications for conservation and environmental management
British Columbia; Eco-cultural landscapes; Environmental change; Fire history; Garry oak; Indigenous people land practices; Paleoecology; Pollen analysis; Charcoal analysis
Garry oak (Quercus garryana) ecosystems are listed as "at-risk" or endangered throughout their global range. In Canada, they are an umbrella for over one hundred species that are endangered to some degree. In order to effectively recover or allow these species to persist where possible, understanding of the ecological processes essential to their ongoing survival is needed. Fire suppression, aboriginal land-use, climate change, and post-colonial development have lead to drastic changes in the structure and amount of Garry oak ecosystems in North America. This paper presents new data using pollen and charcoal analysis to reconstruct past vegetation change and disturbance regimes for Garry oak and coastal Douglas-fir ecosystems over the past 500 years. Significant change in vegetation at the study sites has occurred with the greatest change in community structure and decline in Garry oak ecosystems occurring after the end of the Little Ice Age and as the impacts of western colonization occurred in the mid to late 19th century. Understanding mean fire return intervals (MFRI), ecosystem dynamics over time, and the role of people in this ecosystem structure is critical to the success of conservation efforts that are designed to ensure the long-term survival of these communities. The MFRI, inferred from charcoal analysis, ranges from 26 to 41 years on Vancouver and Pender Islands, Canada. Our results indicate that fire suppression, cessation of aboriginal land-use, climate change, western colonization and subsequent intensification of land-use has greatly altered Garry oak ecosystems. This study illustrates the utility of using paleoecological investigations to help in the development of land management strategies and prescribed burn plans. DOI
117. Archibald, SB; Kehlmaier, C; Mathewes, RW. (2014) Early Eocene big headed flies (Diptera: Pipunculidae) from the Okanagan Highlands, western North America.Canadian Entomologist 146: 429-443 Early Eocene big headed flies (Diptera: Pipunculidae) from the Okanagan Highlands, western North America
Three new species of Pipunculidae (Diptera) are described (one named), from the early Eocene (Ypresian) Okanagan Highlands of British Columbia, Canada and Washington State, United States of America: Metanephrocerus belgardeae new species from Republic, Washington; and Pipunculidae species A and Pipunculinae species A from Quilchena, British Columbia. We re-describe the late Eocene (Priabonian) species Protonephrocerus florissantius Carpenter and Hull from Florissant, Colorado, United States of America, and assign it to a new genus proposed here, Priabona new genus. Pipunculinae species A is the oldest known member of the family whose wing lacks a separated M-2 vein; previously this had been known in species only as old as Miocene Dominican amber. This is a presumably derived character state that is predominant in modern species. Molecular analysis indicates an origin of the Pipunculidae in the Maastrichtian; the morphological and taxonomic diversity seen here in the Ypresian is consistent with an early radiation of the family. This is concordant with the radiation of Auchenorrhyncha, upon which they mostly prey, which is in turn associated with the early Paleogene diversification of angiosperm-dominated forests recovering from the K-Pg extinction event. DOI
116. Archibald, SB; Morse, GE; Greenwood, DR; Mathewes, RW. (2014) Fossil palm beetles refine upland winter temperatures in the Early Eocene Climatic Optimum.Proceedings of the National Academy of Sciences of the United States of America 111: 8095-8100 Fossil palm beetles refine upland winter temperatures in the Early Eocene Climatic Optimum
palm bruchines; paleoclimate; Okanagan Highlands; palm pollen
Eocene climate and associated biotic patterns provide an analog system to understand their modern interactions. The relationship between mean annual temperatures and winter temperatures-temperature seasonality-may be an important factor in this dynamic. Fossils of frost-intolerant palms imply low Eocene temperature seasonality into high latitudes, constraining average winter temperatures there to >8 degrees C. However, their presence in a paleo-community may be obscured by taphonomic and identification factors for macrofossils and pollen. We circumvented these problems by establishing the presence of obligate palm-feeding beetles (Chrysomelidae: Pachymerina) at three localities (a fourth, tentatively) in microthermal to lower mesothermal Early Eocene upland communities in Washington and British Columbia. This provides support for warmer winter Eocene climates extending northward into cooler Canadian uplands. DOI PubMed
115. Czarnecki, JM; Dashtgard, SE; Pospelova, V; Mathewes, RW; MacEachern, JA. (2014) Palynology and geochemistry of channel-margin sediments across the tidal-fluvial transition, lower Fraser River, Canada: Implications for the rock record.Marine and Petroleum Geology 51: 152-166 Palynology and geochemistry of channel-margin sediments across the tidal-fluvial transition, lower Fraser River, Canada: Implications for the rock record
Dinoflagellate cyst; Pollen; Carbon isotopes; Estuary; Delta; Marginal-marine; McMurray Formation
In the tidally influenced Fraser River, Canada, palynological and carbon isotope (delta C-13(org)) signatures of channel-margin sediments are compared to environmental parameters (e.g., grain size, water salinity) to establish how the signatures vary across the tidal-fluvial transition. Palynological assemblages in the Fraser River are dominated by tree pollen, which constitutes between 85% and 95% of all assemblages. Dinocyst abundances do not exceed 2% of the total palynological assemblage, and the number and diversity of dinocysts gradually decreases landward. The calculated landward limit for dinocysts is at approximately 83 river km, which is relatively close to the upstream limit of the tidal backwater (at similar to 100 km). delta C-13(org) values show minimal variability across the tidal fluvial transition, and the average value is approximately -26 parts per thousand. The delta C-13(org) signature of river sediments indicates a dominance of terrestrially sourced organic matter regardless of brackish-water and tidal influence on sediment deposition. Six palynological and geochemical trends are identified as relevant to the rock record. 1) In deltaic environments, palynological and geochemical characteristics are less useful than sedimentological and ichnological characteristics for establishing depositional conditions. 2) In marginal-marine settings, low abundances and low species diversities of dinocysts, coupled with a "terrestrial" geochemical signature (delta C-13(org) < -25 parts per thousand.) do not necessarily indicate deposition in a terrestrial environment. 3) Dinocyst abundances above 1% of the total palynomorph population can indicate a significant marine influence on sediment deposition. 4) Mud beds, preferably bioturbated, should be preferentially sampled in order to maximize palynomorph recovery. 5) Marine palynomorphs can occur, albeit in very low concentrations, to the landward limit of the tidal-backwater zone. 6) Palynological and geochemical data should be compared across the paleo-depositional environment in order to establish general trends and remove local variations caused by biases such as grain size. (C) 2013 Elsevier Ltd. All rights reserved. DOI
110. Archibald, SB; Greenwood, DR; Mathewes, RW. (2013) Seasonality, montane beta diversity, and Eocene insects: Testing Janzen's dispersal hypothesis in an equable world.Palaeogeography Palaeoclimatology Palaeoecology 371: 1-8 Seasonality, montane beta diversity, and Eocene insects: Testing Janzen's dispersal hypothesis in an equable world
HIGHLANDS BRITISH-COLUMBIA; OKANAGAN HIGHLANDS; WASHINGTON-STATE; NORTH-AMERICA; LATITUDINAL GRADIENT; OLIGOCENE TRANSITION; RAPID ASSESSMENT; MOUNTAIN PASSES; THERMAL MAXIMUM; PLANT DIVERSITY
We test Janzen's (1967) hypothesis that the low temperature seasonality in the modern tropics accounts for increased local species turnover (beta diversity) across montane landscapes relative to those of the more seasonal Temperate Zone. In the Eocene, low seasonality extended beyond the hot tropics to Polar Regions, therefore, its effects on montane dispersal ability should have been decoupled from low latitude. We sampled fossil insect communities across the Okanagan Highlands: a thousand kilometer transect of temperate, low temperature seasonality, higher mid-latitude Eocene uplands of far-western North America. We find high species turnover, supporting a prime role of temperature fluctuation in controlling montane beta diversity. This high upper mid-latitude montane endemism is consistent with greater Eocene global biodiversity. (C) 2012 Elsevier B.V. All rights reserved. DOI
109. Archibald, SB; Mathewes, RW; Greenwood, DR. (2013) THE EOCENE APEX OF PANORPOID SCORPIONFLY FAMILY DIVERSITY.Journal of Paleontology 87: 677-695 THE EOCENE APEX OF PANORPOID SCORPIONFLY FAMILY DIVERSITY
PLANT-INSECT ASSOCIATIONS; HIGHLANDS BRITISH-COLUMBIA; OKANAGAN HIGHLANDS; WASHINGTON-STATE; PANORPIDAE MECOPTERA; CANADA; PALEOCENE; EXTINCTION; PATAGONIA; DYNAMICS
The scorpionfly (Mecoptera) superfamily Panorpoidea underwent an Eocene radiation, replacing the extinct Mesozoic orthophlebiid grade and reaching its greatest family-level diversity: Panorpidae, Panorpodidae, Austropanorpidae, Holcorpidae, Dinopanorpidae, and a new family proposed here, the Eorpidae. Only the Panorpidae and Panorpodidae survived the Eocene and persist to the present day. This cluster of family extinctions is exceptional within Cenozoic insects. The Eorpidae includes at least one new genus and three new species described here from four localities of the early Eocene Okanagan Highlands of British Columbia, Canada, and Washington, U.S.A.: Eorpa ypsipeda n. gen. n. sp. (McAbee and possibly Falkland, BC, Canada; and Republic, WA, U.S.A.), Eorpa elverumi n. gen. n. sp. (Republic), and Eorpa jurgeni n. gen. n. sp. (Quilchena, BC). Some of the other fragmentary and poorly preserved specimens might represent further new species. We propose that the apex of Panorpoid family diversity ended by pressures from post-Eocene icehouse world climatic stress and the rise to ecological dominance of ants, some of which would have provided strong competition in scavenging for dead arthropods. DOI
108. Goring, S; Lacourse, T; Pellatt, MG; Mathewes, RW. (2013) Pollen assemblage richness does not reflect regional plant species richness: a cautionary tale.Journal of Ecology 101: 1137-1145 Pollen assemblage richness does not reflect regional plant species richness: a cautionary tale
WESTERN NORTH-AMERICA; TEMPERATE RAIN-FOREST; PALYNOLOGICAL RICHNESS; FLORISTIC DIVERSITY; TAXONOMIC RICHNESS; BRITISH-COLUMBIA; BIODIVERSITY; CLIMATE; RESOLUTION; DYNAMICS
1. Palaeoecological records of species richness spanning time intervals over which climate variables have shifted relative to one another can help reduce issues of colinearity that might affect our understanding of patterns of species richness. 2. Fossil pollen assemblages have the potential to serve as a proxy for past plant richness because they record the presence of plant taxa. However, pollen assemblages are typically limited by low taxonomic resolution and taphonomic processes (pollen production, transport, deposition and preservation), which may degrade the degree to which pollen accurately represents vegetation communities. 3. We combined pollen assemblages from modern lake sediments (n=546; n=167 in British Columbia, Canada) in the Pacific Northwest, with a detailed data base (n=16071) of plant presence across the province and a published record of gamma richness to test the accuracy of pollen assemblages as a proxy for regional patterns of plant richness. 4. A generalized linear model using plant richness resolved at multiple taxonomic levels suggests taxonomic differences between plant and pollen taxa may reduce the ability of pollen richness to predict plant richness at the site level, but that this relationship is still recoverable, albeit with broad confidence intervals. 5. Spatially explicit analysis using a generalized additive model shows that predicted plant richness has no relationship with raw pollen assemblage richness at all taxonomic levels. 6. The taxonomic composition of the region (i.e. the ratio of wind-pollinated to insect-pollinated species) and/or the morphological specificity of the dominant pollen types in the region may play a role in limiting the reconstruction of plant richness from pollen richness. Nonetheless, we believe this study is the first to empirically test the relationship between plant and pollen richness, and fails to find a significant relationship. 7. Synthesis. Palynological richness in itself cannot be considered a universally reliable proxy for inferring plant richness; however, broad spatial and temporal patterns of change in richness have been reported in the literature. Our findings suggest that more work is needed to understand previously reported patterns of pollen assemblage richness through time and in space. We suggest the use of functional diversity or phylogenetically based analysis may help link pollen richness to plant community richness. DOI
107. Huntley, MJW; Mathewes, RW; Shotyk, W. (2013) High-resolution palynology, climate change and human impact on a late Holocene peat bog on Haida Gwaii, British Columbia, Canada.Holocene 23: 1572-1583 High-resolution palynology, climate change and human impact on a late Holocene peat bog on Haida Gwaii, British Columbia, Canada
ELEVATED ATMOSPHERIC CO2; ENVIRONMENTAL-CHANGE; TEMPERATURE VARIABILITY; POLLEN PRODUCTION; COAST MOUNTAINS; BOREAL FOREST; ALASKA; RESPONSES; RECORDS; TOOL
Haida Gwaii (formerly Queen Charlotte Islands) is an archipelago on the outer central coast of British Columbia. Drizzle Bog on Graham Island is a Sphagnum-dominated peatland selected for a multiproxy palaeoecological analysis using pollen, spores and other microfossils to see whether climatic changes such as the Mediaeval Climate Anomaly' (MCA), Little Ice Age' (LIA) and post-LIA warming could be detected in this hypermaritime region. A 90-cm-long Wardenaar peat core was sliced into 1-cm-thick subsamples and dated using Pb-210 back to ad 1892, and four accelerator mass spectrometry (AMS) radiocarbon dates back to 1800 cal. yr BP. Low pollen accumulation rates between similar to ad 1600 and 1875 support cool growing seasons during the LIA. At 34 cm (similar to 1875), total pollen and spore accumulation rates increased dramatically, coinciding with the end of the LIA based on evidence from glacier recession in the Coast Mountains of British Columbia. We suggest that the increased pollen production is likely a reflection of climatic warming and increased vegetation productivity following the LIA. Direct human impact is only apparent above 12 cm depth (similar to 1958) correlated with road building across the southwestern edge of the wetland. DOI
106. Lacourse, T; Delepine, JM; Hoffman, EH; Mathewes, RW. (2012) A 14,000 year vegetation history of a hypermaritime island on the outer Pacific coast of Canada based on fossil pollen, spores and conifer stomata.Quaternary Research 78: 572-582 A 14,000 year vegetation history of a hypermaritime island on the outer Pacific coast of Canada based on fossil pollen, spores and conifer stomata
Pollen; Conifer stomata; Lake sediments; Temperate rainforest; Species arrival; Population expansion; Paleoecology; Haida Gwaii; British Columbia
Pollen and conifer stomata analyses of lake sediments from Hippa Island on the north coast of British Columbia were used to reconstruct the vegetation history of this small hypermaritime island. Between 14,000 and 13,230 cal yr BP, the island supported diverse herb-shrub communities dominated by Cyperaceae, Artemisia and Salix. Pinus contorta and Picea sitchensis stomata indicate that these conifers were present among the herb-shrub communities, likely as scattered individuals. Transition to open P. contorta woodland by 13,000 cal yr BP was followed by increases in Alnus viridis, Alnus rubra and P. sitchensis. After 12,000 cal yr BP, Pinus-dominated communities were replaced by dense P. sitchensis and Tsuga heterophylla forest with Lysichiton americanus and fern understory. Thuja plicata stomata indicate that this species was present by 8700 cal yr BP, but the pollen record suggests that its populations did not expand to dominate regional rainforests, along with Tsuga and Picea, until after 6600 cal yr BP. Conifer stomata indicate that species may be locally present for hundreds to thousands of years before pollen exceed thresholds routinely used to infer local species arrival. When combined, pollen and conifer stomata can provide a more accurate record of paleovegetation than either when used alone. (c) 2012 University of Washington. Published by Elsevier Inc. All rights reserved. DOI
105. Speller, CF; Spalding, KL; Buchholz, BA; Hildebrand, D; Moore, J; Mathewes, R; Skinner, MF; Yang, DY. (2012) Personal Identification of Cold Case Remains Through Combined Contribution from Anthropological, mtDNA, and Bomb-Pulse Dating Analyses.Journal of Forensic Sciences 57: 1354-1360 Personal Identification of Cold Case Remains Through Combined Contribution from Anthropological, mtDNA, and Bomb-Pulse Dating Analyses
forensic science; forensic anthropology; mitochondrial DNA; ancient DNA; short tandem repeat; cold case; bomb-pulse; dental enamel; accelerator mass spectrometry; interdisciplinary
In 1968, a child's cranium was recovered from the banks of a northern Canadian river and held in a trust until the cold case was reopened in 2005. The cranium underwent reanalysis at the Centre for Forensic Research, Simon Fraser University, using recently developed anthropological analysis, bomb-pulse radiocarbon analysis, and forensic DNA techniques. Craniometrics, skeletal ossification, and dental formation indicated an age-at-death of 4.4 +/- 1 year. Radiocarbon analysis of enamel from two teeth indicated a year of birth between 1958 and 1962. Forensic DNA analysis indicated the child was a male, and the obtained mitochondrial profile matched a living maternal relative to the presumed missing child. These multidisciplinary analyses resulted in a legal identification 41 years after the discovery of the remains, highlighting the enormous potential of combining radiocarbon analysis with anthropological and mtDNA analyses in producing confident personal identifications for forensic cold cases dating to within the last 60 years. DOI
104. Archibald, SB; Greenwood, DR; Smith, RY; Mathewes, RW; Basinger, JF. (2011) Great Canadian Lagerstatten 1. Early Eocene Lagerstatten of the Okanagan Highlands (British Columbia and Washington State).Geoscience Canada 38: 155-164 Great Canadian Lagerstatten 1. Early Eocene Lagerstatten of the Okanagan Highlands (British Columbia and Washington State)
The Early Eocene Okanagan Highlands series of lacustrine shale and coal deposits, in far western North America, constitutes a significant group of fossil sites with exceptional preservation of a diverse suite of organisms (Lagerstatten). With contemporaneous basins arrayed across about 1000 kilometres of southern British Columbia and northern Washington, these sites offer a unique opportunity to examine the paleoecology of terrestrial communities spanning a temperate, low-seasonality landscape in a montane setting during a time of generally warm temperatures across the globe. The Okanagan Highlands sites provide an unparalleled comparative framework within which to examine this major turning point in terrestrial community development during the emergence of their broad modern character.
103. Archibald, SB; Johnson, KR; Mathewes, RW; Greenwood, DR. (2011) Intercontinental dispersal of giant thermophilic ants across the Arctic during early Eocene hyperthermals.Proceedings of the Royal Society B-Biological Sciences 278: 3679-3686 Intercontinental dispersal of giant thermophilic ants across the Arctic during early Eocene hyperthermals
Formicidae; Formiciinae; Titanomyrma; Holarctic dispersal; hyperthermals
Early Eocene land bridges allowed numerous plant and animal species to cross between Europe and North America via the Arctic. While many species suited to prevailing cool Arctic climates would have been able to cross throughout much of this period, others would have found dispersal opportunities only during limited intervals when their requirements for higher temperatures were met. Here, we present Titanomyrma lubei gen. et sp. nov. from Wyoming, USA, a new giant (greater than 5 cm long) formiciine ant from the early Eocene (approx. 49.5 Ma) Green River Formation. We show that the extinct ant subfamily Formiciinae is only known from localities with an estimated mean annual temperature of about 20 degrees C or greater, consistent with the tropical ranges of almost all of the largest living ant species. This is, to our knowledge, the first known formiciine of gigantic size in the Western Hemisphere and the first reported cross-Arctic dispersal by a thermophilic insect group. This implies intercontinental migration during one or more brief high-temperature episodes (hyperthermals) sometime between the latest Palaeocene establishment of intercontinental land connections and the presence of giant formiciines in Europe and North America by the early middle Eocene. DOI
102. Zazula, GD; Froese, DG; Elias, SA; Kuzmina, S; Mathewes, RW. (2011) Early Wisconsinan (MIS 4) Arctic ground squirrel middens and a squirrel-eye-view of the mammoth-steppe.Quaternary Science Reviews 30: 2220-2237 Early Wisconsinan (MIS 4) Arctic ground squirrel middens and a squirrel-eye-view of the mammoth-steppe
Fossil arctic ground squirrel (Spermophilus parryii) middens were recovered from ice-rich loess sediments in association with Sheep Creek-Klondike and Dominion Creek tephras (ca 80 ka) exposed in west-central Yukon. These middens provide plant and insect macrofossil evidence for a steppe-tundra ecosystem during the Early Wisconsinan (MIS 4) glacial interval. Midden plant and insect macrofossil data are compared with those previously published for Late Wisconsinan middens dating to similar to 25-29(14)C ka BP (MIS 3/2) from the region. Although multivariate statistical comparisons suggest differences between the relative abundances of plant macrofossils, the co-occurrence of steppe-tundra plants and insects (e.g., Elymus trachycaulus, Kobresia myosuroides, Artemisia frigida, Phlox hoodii, Connatichela artemisiae) provides evidence for successive reestablishment of the zonal steppe-tundra habitats during cold stages of the Late Pleistocene. Arctic ground squirrels were well adapted to the cold, arid climates, steppe-tundra vegetation and well-drained loessal soils that characterize cold stages of Late Pleistocene Beringia. These glacial conditions enabled arctic ground squirrel populations to expand their range to the interior regions of Alaska and Yukon, including the Klondike, where they are absent today. Arctic ground squirrels have endured numerous Quaternary climate oscillations by retracting populations to disjunct "interglacial refugia" during warm interglacial periods (e.g., south-facing steppe slopes, well-drained arctic and alpine tundra areas) and expanding their distribution across the mammoth-steppe biome during cold, arid glacial intervals. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved. DOI
101. Goring, S; Lacourse, T; Pellatt, MG; Walker, IR; Mathewes, RW. (2010) Are pollen-based climate models improved by combining surface samples from soil and lacustrine substrates?Review of Palaeobotany and Palynology 162: 203-212 Are pollen-based climate models improved by combining surface samples from soil and lacustrine substrates?
pollen databases; depositional environment; lacustrine; terrestrial; palynology; climate models; weighted averaging; randomForest; modern analogue technique; partial least squares; non-metric-multidimensional-scaling
Differences between pollen assemblages obtained from lacustrine and terrestrial surface sediments may affect the ability to obtain reliable pollen-based climate reconstructions. We test the effect of combining modern pollen samples from multiple depositional environments on various pollen-based climate reconstruction methods using modern pollen samples from British Columbia, Canada and adjacent Washington, Montana, Idaho and Oregon states. This dataset includes samples from a number of depositional environments including soil and lacustrine sediments. Combining lacustrine and terrestrial (soil) samples increases root mean squared error of prediction (RMSEP) for reconstructions of summer growing degree days when weighted-averaging partial-least-squares (WAPLS), weighted-averaging (WA) and the non-metric-multidimensional-scaling/generalized-additive-models (NMDS/GAM) are used but reduces RMSEP for randomForest, the modern analogue technique (MAT) and the Mixed method, although a slight increase occurs for MAT at the highest sample size. Summer precipitation reconstructions using MAT, randomForest and NMDS/GAM suffer from increased RMSEP when both lacustrine and terrestrial samples are used, but WA, WAPLS and the Mixed method show declines in RMSEP. These results indicate that researchers interested in using pollen databases to reconstruct climate variables need to consider the depositional environments of samples within the analytical dataset since pooled datasets can increase model error for some climate variables. However, since the effects of the pooled datasets will vary between climate variables and between pollen-based climate reconstruction methods we do not reject the use of mixed samples altogether. We finish by proposing steps to test whether significant reductions in model error can be obtained by splitting or combining samples from multiple substrates. (C) 2010 Elsevier B.V. All rights reserved. DOI
99. Goring, S; Pellatt, MG; Lacourse, T; Walker, IR; Mathewes, RW. (2009) A new methodology for reconstructing climate and vegetation from modern pollen assemblages: an example from British Columbia.Journal of Biogeography 36: 626-638 A new methodology for reconstructing climate and vegetation from modern pollen assemblages: an example from British Columbia
HOLOCENE PRECIPITATION; FOREST HOLLOWS; MODERN ANALOGS; SOURCE AREA; CANADA; SPECTRA; ORDINATION; PALEOECOLOGY; CALIBRATION; REGRESSION
We used modern pollen assemblages to develop a method for climate reconstruction that reduces the spatial autocorrelation of residuals and accounts for the strong topographic and climatic variation that occurs in British Columbia, Canada. British Columbia, Canada, including sites both on the mainland and on adjacent islands (Queen Charlotte Islands and Vancouver Island). New pollen assemblages from surface-sediment samples collected in British Columbia were combined with other published and unpublished samples (n = 284). Multivariate rank-distances between sample sites and a randomized set of sites within the province were calculated for climate parameters to determine whether gaps in the current network of present-day pollen sample sites exist. Lacustrine surface-sediment pollen assemblages (n = 145) were ordinated using non-metric multidimensional scaling (NMDS), and a generalized additive model (GAM) was used to reconstruct modern mean warmest month temperature (MWMT) and mean annual precipitation (MAP) from the NMDS ordination. The results were compared with standard climate reconstruction techniques, including the modern analogue technique, partial least squares, weighted averaging, weighted averaging-partial least squares and factor analysis. Reconstructions of MWMT and MAP using NMDS and GAM were comparable to those of existing models. When reconstructing MWMT, the NMDS/GAM method had a lower root-mean-squared error of prediction (RMSEP), lower spatial autocorrelation and higher correlation with observed temperature values than the other methods tested. When reconstructing MAP, the partial least squares method performed better than the NMDS/GAM method for RMSEP and correlation with observed values; however, the NMDS/GAM method had a lower spatial autocorrelation of residuals. NMDS reveals strong relationships among modern pollen assemblages, vegetation and climate parameters. Climate models using NMDS and GAM are comparable to other palaeoecological reconstruction models, but provide lower spatial autocorrelation of residuals for both parameters tested. An inverse distance-weighted surface of multivariate rank-climate distances generated from the network of pollen sample sites indicates that greater sampling intensity in north-western and central-interior British Columbia is required in order to obtain an accurate representation of climatic and vegetation diversity in the province. DOI
98. Hayden, B. and R. Mathewes. (2009) The rise and fall of complex large villages on the British Columbian Plateau: a geoarchaeological controversy.Canadian Journal of Archaeology 33: 281-29 The rise and fall of complex large villages on the British Columbian Plateau: a geoarchaeological controversy.
In a series of publications, Prentiss et al. (2003, 2005, 2007, 2008) have argued for a very late, abrupt, and brief emergence of large villages and large corporate residences in the mid-Fraser region of British Columbia ( 1600-800 cal B.P.) and an even later abrupt emergence of socioeconomic complexity ( 1200-800 cal B.P.). They postulate that climatic changes were responsible for both of these events as well as the collapse of the large villages. We question their interpretations on several grounds including: inappropriate methods for dating these developments; data from Keatley Creek indicating a longer developmental trajectory; incomplete interpretation of paleoclimate trends for the region; and internal contradictions in their own climate-driven explanations for changes. The combined evidence of geochronology and paleoecology (some not previously considered) together with archaeological evidence favors an interpretation of earlier emergence of large villages and socioeconomic complexity than suggested by Prentiss et al. (2003, 2005, 2007, 2008).Website
97. Arsenault, TA; Clague, JJ; Mathewes, RW. (2007) Late Holocene vegetation and climate change at Moraine Bog, Tiedemann Glacier, southern Coast Mountains, British Columbia.Can. J. Earth Sci. 44: 707-719 Late Holocene vegetation and climate change at Moraine Bog, Tiedemann Glacier, southern Coast Mountains, British Columbia
Moraine Bog lies just outside the outermost lateral moraine of Tiedemann Glacier in the southern Coast Mountains of British Columbia. A sediment core taken from the wetland was analyzed for pollen, magnetic susceptibility, and loss on ignition to reconstruct changes in vegetation and climate during the late Holocene. Vegetation changed little between about 3500 and 2400 C-14 years BP. A period of local disturbance marked by deposition of a silty clay bed and increases in Alnus pollen, likely reflecting cooler moister conditions, coincides with an extensive Holocene advance of Tiedemann Glacier about 2400 C-14 years BP. Warm dry conditions between about 1900 and 1500 C-14 years BP are suggested by peak values of Pseudotsuga pollen and increasing Nuphar sclereids; the latter suggests lowered water levels. This period coincides with a time of drought and increased fire frequency in the southernmost Coast Mountains. About 1300 C-14 years BP, the forest became more coastal in composition with abundant Tsuga heterophylla and Abies. An increase in Tsuga mertensiana pollen suggests the onset of cool and wet conditions by ca. 500 C-14 years BP, coincident with the Little Ice Age. The record of inferred climate change at Moraine Bog is broadly synchronous with other paleoclimate records from the Coast Mountains and, at the centennial scale, with records elsewhere in the world. DOI
96. Lacourse, T; Mathewes, RW; Hebda, RJ. (2007) Paleoecological analyses of lake sediments reveal prehistoric human impact on forests at Anthony island UNESCO world heritage site, Queen Charlotte islands (Haida Gwaii), Canada.Quaternary Research 68: 177-183 Paleoecological analyses of lake sediments reveal prehistoric human impact on forests at Anthony island UNESCO world heritage site, Queen Charlotte islands (Haida Gwaii), Canada
pollen analysis; plant macrofossils; Thuja plicata; western red cedar; haida; aboriginal peoples; human impact; disturbance; British Columbia
Pollen and plant macrofossil analyses of lake sediments from Anthony Island in the southern Queen Charlotte Islands (Haida Gwaii), British Columbia, reveal 1800 yr of relatively stable temperate rainforest vegetation. Cupressaccae (cedar) pollen percentages and accumulation rates decline about 1000 cal yr BP, coincident with occupation of the island by Haida peoples, who use Thuja plicata (western red cedar) almost exclusively for house construction, dugout canoes, monumental poles, and many other items. Anthropogenic disturbance offers the most likely explanation for the decline of T plicata. (c) 2007 University of Washington. All rights reserved. DOI
95. Zazula, GD; Froese, DG; Elias, SA; Kuzmina, S; Mathewes, RW. (2007) Arctic ground squirrels of the mammoth-steppe: paleoecology of Late Pleistocene middens (similar to 24000-29450 C-14 yr BP), Yukon Territory, Canada.Quaternary Science Reviews 26: 979-1003 Arctic ground squirrels of the mammoth-steppe: paleoecology of Late Pleistocene middens (similar to 24000-29450 C-14 yr BP), Yukon Territory, Canada
This paper presents paleoecological analyses of 48 fossil arctic ground squirrel (Spermophilus parryii) middens (nests and caches) recovered from ice-rich loess sediments in the Klondike region of west-central Yukon Territory. AMS radiocarbon dates and stratigraphic association of middens with Dawson tephra (similar to 25 300 C-14 yr BP), indicate these paleoecological data reflect the onset of glacial conditions of early Marine Isotope Stage (MIS) 2 and terminal MIS 3 (similar to 24000-29 450 14C yr BP). Plant macrofossils include at least 60 plant taxa, including diverse graminoids (Poa, Elymus trachycaulus, Kobresia myosuroides), steppe forbs (Penstemon gormanii, Anemone patens var. multifida, Plantago cf. canescens), tundra forbs (Draba spp., Bistorta vivipara), dwarf shrubs (Salix cf. arctica, S. cf. polaris), sage (Artemisia frigida) and rare trees (Picea mariana). Many of these taxa identified in the middens represent the first recorded fossils for these plants in Eastern Beringia and add to our knowledge of the floristic composition of Pleistocene vegetation and biogeography in this region. Fossil beetles include typical members of the Eastern Beringian steppe-tundra fauna (Lepidophorus lineaticollis and Connatichela artemisiae) and others suggesting predominantly dry, open habitats. Cache forage selection is suggested by some plant taxa which were particularly frequent and abundant in the middens (Bistorta vivipara, Kobresia myosuroides, Ranunculus spp., Potentilla, Erysimum cf. cheiranthoides, Poa, Carex and Draba). Factors such as proximity of vegetation to burrows and abundance of fruits and seeds per plant were probably important in cache selection. Glacial conditions enabled arctic ground squirrels to form widespread and dense populations in regions such as the Klondike in which they are rare or absent at present. This fossil midden record supports previous hypotheses that suggest arctic ground squirrels evolved in and are well-adapted to the open, steppe-tundra vegetation, loessal soils and glacial climates of the mammoth-steppe biome. (c) 2007 Elsevier Ltd. All rights reserved. DOI
94. Barley, EM; Walker, IR; Kurek, J; Cwynar, LC; Mathewes, RW; Gajewski, K; Finney, BP. (2006) A northwest North American training set: distribution of freshwater midges in relation to air temperature and lake depth.Journal of Paleolimnology 36: 295-314 A northwest North American training set: distribution of freshwater midges in relation to air temperature and lake depth
chironomidae; transfer function; Beringia; air temperature; lake depth; canonical correspondence analysis; paleoclimate
Freshwater midges, consisting of Chironomidae, Chaoboridae and Ceratopogonidae, were assessed as a biological proxy for palaeoclimate in eastern Beringia. The northwest North American training set consists of midge assemblages and data for 17 environmental variables collected from 145 lakes in Alaska, British Columbia, Yukon, Northwest Territories, and the Canadian Arctic Islands. Canonical correspondence analyses (CCA) revealed that mean July air temperature, lake depth, arctic tundra vegetation, alpine tundra vegetation, pH, dissolved organic carbon, lichen woodland vegetation and surface area contributed significantly to explaining midge distribution. Weighted averaging partial least squares (WA-PLS) was used to develop midge inference models for mean July air temperature (r boot 2 = 0.818, RMSEP = 1.46°C), and transformed depth (ln (x+1); r boot 2 = 0.38, and RMSEP = 0.58).Website DOI
93.Mathewes, RW. (2006) Forensic palynology in Canada: An overview with emphasis on archaeology and anthropology.Forensic Sci Int 163: 198-203 Forensic palynology in Canada: An overview with emphasis on archaeology and anthropology
pollen analysis; native land claims; Delgamuukw case; British Columbia
Palynological analysis is shown from published and unpublished Canadian examples to be a useful tool in forensic investigation, although the technique is almost unknown and therefore under-utilized, by forensic investigators. The techniques of pollen and spore identification and interpretation are continually improving, indicating that the potential for forensic applications is real. Focus in this paper is on an updated interpretation of palynological data that was presented during a trial involving a scientific test of oral history as part of a claim for aboriginal title to a large area of British Columbia (BC) (Delgamuukw versus the Queen). Although the original decision in British Columbia Supreme Court was decided in favor of the government defendants, an appeal to the Supreme Court of Canada overturned the original decision, and established new principles and rights for aboriginal peoples. (c) 2006 Elsevier Ireland Ltd. All rights reserved.
92. Zazula, GD; Froese, DG; Elias, SA; Kuzmina, S; La Farge, C; Reyes, AV; Sanborn, PT; Schweger, CE; Smith, CAS; Mathewes, RW. (2006) Vegetation buried under Dawson tephra (25,300 C-14 years BP) and locally diverse late Pleistocene paleoenvironments of Goldbottom Creek, Yukon, Canada.Palaeogeogr Palaeoclimatol 242: 253-286 Vegetation buried under Dawson tephra (25,300 C-14 years BP) and locally diverse late Pleistocene paleoenvironments of Goldbottom Creek, Yukon, Canada
Beringia; paleoecology; tephra; klondike
Paleoecological research at Goldbottom Creek in the Klondike region of Yukon Territory (NW Canada) documents an in situ riparian grassy meadow that was buried during the winter or early spring by Dawson tephra, near the onset of Marine Isotope Stage (MIS) 2, ca. 25,300 C-14 years BP. Analyses of vascular plant macrofossils, bryophytes, pollen, insects and paleosols from the riparian meadow contrast with evidence for well-drained, upland steppe-tundra habitats obtained from fossil arctic ground squirrel middens within the same valley. The mesic valley bottom vegetation consisted of grasses (Deschampsia caespitosa, Alopecurus), sedges (Carex), horsetail (Equisetum cf. palustre), diverse bryophytes and few forbs. Upland habitats with dry loessal soils along the valley slopes contained graminoids (Elymus, Festuca, Kobresia myosuroides), sage (Artemisia frigida) and diverse steppe and tundra forbs (Phlox hoodii, Plantago cf. canescens, Anemone patens var. muiltifida.. Bistorta vivipara, Draba). These paleoecological data highlight the effect of topographic position and moisture on substrates and their control on local-scale habitat variability. This study represents the first recorded in situ riparian surface from the unglaciated Pleistocene refugium of Beringia and provides well-documented evidence for local habitat heterogeneity and ecosystem structure within the mammoth-steppe biome. Other radiocarbon dated paleoecological data from our study sites indicate that full-glacial steppe-tundra habitats in west-central Yukon Territory were established during the later stages of the MIS 3 interstadial, by 29,000 C-14 years BP. The diverse data obtained through integration of multiple palcoecological methods at the site demonstrate the efficacy of interdisciplinary research in furthering our understanding of Beringian glacial environments. (c) 2006 Elsevier B.V. All rights reserved.
91. Zazula, GD; Mathewes, RFW; Harestad, AS. (2006) Cache selection by Arctic ground squirrels inhabiting boreal-steppe meadows of southwest Yukon territory, Canada.Arct Antarct Alp Res 38: 631-638 Cache selection by Arctic ground squirrels inhabiting boreal-steppe meadows of southwest Yukon territory, Canada
We examined food items cached by arctic ground squirrels (Spermophilus parryii) from boreal-steppe meadows of southwest Yukon Territory, Canada. Caches recovered from two sites are dominated by fruits and seeds of either northern comandra (Geocaulon lividum) or prickly rose (Rosa acicularis). These two taxa are relatively rare in the local flora at the study sites (Site 1: >= 32 available taxa, and Site 2: >= 39 available taxa), suggesting they are selectively cached as preferred items. Cache selectivity may be related to perishability, fruit size/seed abundance, and predation risk. These caches are of significantly different composition than caches from present tundra sites and Pleistocene fossil arctic ground squirrel nests and caches (middens) recovered from central Yukon. These findings suggest that although arctic ground squirrels evolved in open tundra, they can subsist on a variety of cache items and may have the ability to adapt to and select a profitable cache within a variety of boreal and tundra habitats.
90. Zazula, GD; Telka, AM; Harington, CR; Schweger, CE; Mathewes, RW. (2006) New spruce (Picea spp.) macrofossils from Yukon Territory: Implications for Late Pleistocene refugia in Eastern Beringia.Arctic 59: 391-400 New spruce (Picea spp.) macrofossils from Yukon Territory: Implications for Late Pleistocene refugia in Eastern Beringia
spruce; refugia; Beringia; Yukon Territory; macrofossils; paleoecology
New radiocarbon-dated plant macrofossils provide evidence for black spruce (Picea mariana) and white spruce (Picea glauca) within the unglaciated Yukon Territory at the onset of glacial conditions during the Marine Isotope Stage 3/2 transition, between about 26000 and 24500 C-14 yr BP. These data indicate that spruce trees were able to reproduce sexually and Grow to maturity within a glacial environment characterized by widespread steppe-tundra vegetation, loess aggradation, and ice-wedge formation. These trees may have been restricted to rare valley-bottom habitats that provided adequate shelter and moisture similar to those at the present latitudinal tree line. Previously published hypotheses suggest that low Picea frequencies in regional Beringian pollen data point to the local persistence of spruce trees through the last glaciation. Although our data provide evidence for local spruce trees at the onset of the last glaciation, the available macrofossil record is inconclusive regarding the survival of spruce through the Last Glacial Maximum in Eastern Beringia. These new plant macrofossil data require palynologists to re-examine the relationship between Picea pollen frequency and local trees and highlight the importance of integrated pollen- and macrofossil-based paleoecological reconstructions.
86. Lepofsky, D; Lertzman, K; Hallett, D; Mathewes, R. (2005) Climate change and culture change on the Southern Coast of British Columbia 2400-1200 CAL. BP: An hypothesis.American Antiquity 70: 267-293 Climate change and culture change on the Southern Coast of British Columbia 2400-1200 CAL. BP: An hypothesis
The Marpole phase of the Gulf of Georgia, SW British Columbia (2400-1200 cal BY) is recognized by many archaeologists as a significant period of culture change. Concurrent with this cultural phase is a climatic regime characterized by a substantial increase in forest fires associated with persistent summer drought: the Fraser Valley Fire Period (FVFP). Culturally, the Marpole phase is characterized by the widespread appearance of large houses, standardized art forms, and elaborate burials. Interactions among people of this region intensfied and were, as today, economically, socially, and ideologically linked to the lower Fraser River system. Ecologically, the FVFP likely resulted in a regional decline in salmon abundance and/or predictability, especially in small streams and offshore areas, but also more berries and wildlife, and easier overland access via trail networks. The ecological diversity of the lower Fraser region, both terrestrial and riverine, resulted in both more abundant and more predictable resources than surrounding areas during this period of changing climate. We hypothesize that social and economic networks throughout the Gulf of Georgia were solidified during the Marpole phase to ensure access to Fraser resources and allow social buffering of resource uncertainty We suggest that the differential availability of resources also allowed and encouraged individuals who had access to Fraser Valley resources to gain relatively greater prestige.
84. Clague, JJ; Wohlfarth, B; Ayotte, J; Eriksson, M; Hutchinson, I; Mathewes, RW; Walker, IR; Walker, L. (2004) Late Holocene environmental change at treeline in the Northern Coast Mountains, British Columbia, Canada.Quat. Sci. Rev. 23: 2413-2431 Late Holocene environmental change at treeline in the Northern Coast Mountains, British Columbia, Canada
An integrated stratigraphic, paleoecological, and geochronological study of lake and fen sediments just beyond the terminus of Berendon Glacier provides insights into late Holocene climate, vegetation, and glacier change in the northern Coast Mountains of British Columbia. Cores collected from two small lakes in the foreland of Berendon Glacier and pits dug in a nearby fen record Little lee Age and older glacier advances. The first Little Ice Age advance in this area began more than 500 years ago and peaked in the early 17th century. An earlier Neoglacial advance began about 2800-3000 cal yr ago and may have lasted for hundreds of years. There is also evidence for an intervening advance of even smaller magnitude around 1200-1300 cal yr ago. The advances are broadly synchronous with those in other parts of western North America, indicating that they were caused by regional, possibly global, changes in climate. Plant communities within the study area did not change dramatically during the late Holocene. The ranges of some plants, however, likely retracted or extended near treeline in response to changes in mean temperatures of perhaps 1-2degreesC, as A well as changes in summer snow cover. The greatest changes in vegetation occurred within and just beyond the forefields of Berendon, Frank Mackie, and other nearby glaciers. The largest climate shifts of the last 3000 years took place during the late Little Ice Age and the last century. Climate warmed about 1-2degreesC during the 20th century, accompanied by a rise in treeline, an increase in coniferous tree cover in the subalpine zone, and an increase in the temperature and biological productivity of ponds. These trends are likely to continue if climate, as expected, continues to warm. (C) 2004 Elsevier Ltd. All rights reserved. DOI
80. Blais-Stevens, A; Clague, JJ; Mathewes, RW; Hebda, RJ; Bornhold, BD. (2003) Record of large, Late Pleistocene outburst floods preserved in Saanich Inlet sediments, Vancouver Island, Canada.Quat. Sci. Rev. 22: 2327-2334 Record of large, Late Pleistocene outburst floods preserved in Saanich Inlet sediments, Vancouver Island, Canada
Two anomalous, gray, silty clay beds are present in ODP cores collected from Saanich Inlet, Vancouver Island, British Columbia, Canada. The beds, which date to about 10,500 C-14 yr BP (11,000 calendar years BP), contain Tertiary pollen derived from sedimentary rocks found only in the Fraser Lowland, on the mainland of British Columbia and Washington just east of the Strait of Georgia. Abundant illite-muscovite in the sediments supports a Fraser Lowland provenance. The clay beds are probably distal deposits of huge floods that swept through the Fraser Lowland at the end of the Pleistocene. Muddy overflow plumes from these floods crossed the Strait of Georgia and entered Saanich Inlet, where the sediment settled from suspension and blanketed diatom-rich mud on the fiord floor. The likely source of the floods is Late Pleistocene, ice-dammed lakes in the Fraser and Thompson valleys, which are known to have drained at about the time the floods occurred. (C) 2003 Elsevier Ltd. All rights reserved. DOI
79. Hallett, DJ; Lepofsky, DS; Mathewes, RW; Lertzman, KP. (2003) 11 000 years of fire history and climate in the mountain hemlock rain forests of southwestern British Columbia based on sedimentary charcoal.Can. J. For. Res.-Rev. Can. Rech. For. 33: 292-312 11 000 years of fire history and climate in the mountain hemlock rain forests of southwestern British Columbia based on sedimentary charcoal
Little is known about the role of fire in the mountain hemlock (Tsuga mertensiana (Bong.) Carriere) rain forests of southern British Columbia. High-resolution analysis of macroscopic charcoal from lake sediment cores, along with 102 accelerator mass spectrometry (AMS) ages on soil charcoal, was used to reconstruct the long-term fire history around two subalpine lakes in the southern Coast and North Cascade Mountains. AMS ages on soil charcoal provide independent evidence of local fire around a lake and support the interpretation of peaks in lake sediment charcoal as distinct fire events during the Holocene. Local fires are rare, with intervals ranging from centuries to several millennia at some sites. Overall fire frequency varied continuously throughout the Holocene, suggesting that fire regimes are linked to climate via large-scale atmospheric circulation patterns. Fires were frequent between I 1000 and 8800 calendar years BP during the warm and dry early Holocene. The onset of humid conditions in the mid-Holocene, as rain forest taxa established in the region, produced a variable fire period until 3500 calendar years BP. A synchronous decrease in fire frequency from 3500 to 2400 calendar years BP corresponds to Neoglacial advances in the region and cool humid climate. A return of frequent fire between 2400 and 1300 calendar years BP suggests that prolonged summer drought occurred more often during this interval, which we name the Fraser Valley Fire Period. The present-day fire regime was established after 1300 calendar years BP. DOI
77. Hughes, JF; Mathewes, RW. (2003) A modern analogue for plant colonization of palaeotsunami sands in Cascadia, British Columbia, Canada.Holocene 13: 877-886 A modern analogue for plant colonization of palaeotsunami sands in Cascadia, British Columbia, Canada
pollen analysis; plant zonation; salt marsh; modern analogue; tsunami; palaeotsunami; particle size; pioneer vegetation; Cascadia earthquake; British Columbia; Canada
The sediment stratigraphy of a modern analogue for pioneer-plant colonization of palaeotsunami sands near Tofino, British Columbia, Canada, shows that a sand outcrop is continuous with a buried sand stratum deposited by tsunamis of the ad 1700 Cascadia earthquake. Plants growing on the sand outcrop form a low-marsh community that includes Triglochin maritimum, Salicornia virginica, Spergularia canadensis, Puccinellia pumila and Plantago maritima. In contrast, low marshes on muddy substrates include only Carex lyngbyei. Although Carex lyngbyei colonizes low marsh on mud, it is restricted to middle marsh or higher-elevation communities on sand. With two-way indicator species analysis (TWINSPAN) and detrended correspondence analysis (DCA), plant cover-abundance clearly distinguishes sandy from muddy low marsh, a finding that suggests that particle size influences plant colonization. TWINSPAN and DCA show that pollen spectra of the sandy marsh surface resemble fossil pollen of sediments that immediately overlie buried sand deposits. Grain size of intertidal deposits influences primary plant succession, and species on sand respond to relative sea-level change just as those on mud. Pollen assemblages in surface sediments reflect plants growing nearby, and taphonomic distortion of the pollen spectrum is minimal at this locality. These observations suggest that past co-seismic subsidence can be estimated by use of pollen assemblages as proxy indicators of elevation relative to sea level. DOI
73. Hughes, JF; Mathewes, RW; Clague, JJ. (2002) Use of pollen and vascular plants to estimate coseismic subsidence at a tidal marsh near Tofino, British Columbia.Paleogeogr. Paleoclimatol. Paleoecol. 185: 145-161 Use of pollen and vascular plants to estimate coseismic subsidence at a tidal marsh near Tofino, British Columbia
earthquake; pollen; tidal marsh; sea-level change; transfer functions; British Columbia
We use botanical data to estimate coseismic subsidence produced by the 1700 Cascadia earthquake at a tidal marsh near Tofino, British Columbia. Association indices for Cyperaceae (0.3), Triglochin-type (0.4), Poaceae (0.7), Potentilla-type (0.6), Achillea-type (0.6), and Ericales (0.6) pollen reveal that high-marsh-taxa have greater fidelity and, therefore, greater value as indicators of elevation than low-marsh-taxa. Pollen taxa that are abundant and have narrow elevation ranges include Poaceae, Potentilla-type, Achillea-type and Triglochin-type. Vegetation and surface pollen define four marsh zones: low, middle, high, and forest-edge transition. Deposits beneath the marsh include a buried peat capped by tsunami sand. The sand is abruptly overlain by peaty mud, which grades into peaty soil of the modern marsh. The buried peat contains pollen indicative of a high to forest-edge transition marsh. Pollen assemblages from the top of the buried peat and the overlying tsunami sand are similar, probably because the tsunami entrained litter as it moved over the marsh surface. Sediments above the tsunami sand yielded pollen characteristic of a low-to middle-marsh-environment, including abundant Cyperaceae, Triglochin-type, Poaceae, and Chenopodiaceae. We calibrated fossil pollen data to elevation using partial least squares, weighted averaging partial least squares, weighted averaging, and weighted averaging with tolerance downweighting. The last of these methods explains the largest amount of variance (root mean square error of prediction = 0.3, r(2) = 0.85) and yielded values of coseismic subsidence at three sites of 0.65 +/- 0.3, 0.69 +/- 0.3, and 0.50 +/- 0.3 m (average = 0.6 +/- 0.3 m). These values agree with previously published estimates of coseismic subsidence near Tofino, based on foraminifera. (C) 2002 Elsevier Science B.V. All rights reserved. DOI
72. Lertzman, K; Gavin, D; Hallett, D; Brubaker, L; Lepofsky, D; Mathewes, R. (2002) Long-term fire regime estimated from soil charcoal in coastal temperate rainforests.Conservation Ecology 6: issue 2 article 5 Long-term fire regime estimated from soil charcoal in coastal temperate rainforests
Clayoquot Sound, Fraser Valley, coastal temperate rainforests, fire intervals, long-term fire regime, soil carbon storage, soil charcoal, sub-alpine forest, time-since-fire.
http://www.ecologyandsociety.org/vol6/iss2/art5/
Coastal temperate rainforests from southeast Alaska through to southern Oregon are ecologically distinct from forests of neighboring regions, which have a drier, or more continental, climate and disturbance regimes dominated by fires. The long-term role of fire remains one of the key outstanding sources of uncertainty in the historical dynamics of the wetter and less seasonal forests that dominate the northerly two thirds of the rainforest region in British Columbia and Alaska. Here, we describe the long-term fire regime in two forests on the south coast of British Columbia by means of 244 AMS radiocarbon dates of charcoal buried in forest soils. In both forests, some sites have experienced no fire over the last 6000 years and many other sites have experienced only one or two fires during that time. Intervals between fires vary from a few centuries to several thousand years. In contrast to other conifer forests, this supports a model of forest dynamics where fires are of minor ecological importance. Instead, forest history is dominated by fine-scale processes of disturbance and recovery that maintain an ubiquitous late-successional character over the forest landscape. This has significant implications for ecosystem-based forest management and our understanding of carbon storage in forest soils.
71. Pellatt, MG; Mathewes, RW; Clague, JJ. (2002) Implications of a late-glacial pollen record for the glacial and climatic history of the Fraser Lowland, British Columbia.Paleogeogr. Paleoclimatol. Paleoecol. 180: 147-157 Implications of a late-glacial pollen record for the glacial and climatic history of the Fraser Lowland, British Columbia
pollen; climate change; paleoecology; late glacial; Younger Dryas; Holocene; British Columbia
Late-glacial sediments at Mike Lake in the Fraser Lowland of southwestern British Columbia shed light on the timing and significance of the Younger Dryas and Sumas events on the west coast of Canada. Five pollen zones span the period from about 11 700 to 9700 radiocarbon years before present (yr BP) or 13 700 to 11 200 calibrated calendar years before present (cal BP). Climate during this interval is inferred to have ranged from cool continental to warm and dry. Changes in pollen assemblages, lithology, and loss on ignition in Mike Lake sediments deposited prior to 11 000 yr BP (13 000 cal BP) may signal the Sumas glacial advance, which has been dated elsewhere in the Fraser Lowland to this time. Palynologic and sedimentological data indicate that there was much climatic and ecological variability in southwestern British Columbia during the Younger Dryas chronozone. Detrended correspondence analysis of modern pollen from lake-sediment surface samples collected throughout British Columbia is used to compare Mike Lake fossil pollen assemblages to modern vegetation zones. The inferred vegetation assemblage during most of the Younger Dryas chronozone indicates a progressively warming climate with a cool interval between 10 400 and 10 000 yr BP. The pollen assemblage in this interval is similar to that of present subalpine forests on the west coast of Canada. The cooling coincides with the later part of the Younger Dryas chronozone and occurred too late to be the driving mechanism for the final Sumas advance, which peaked around 11 300 C-14 yr BP (13 200 cat BP). (C) 2002 Elsevier Science B.V. All rights reserved. DOI
69. Heinrichs, Markus L.; Walker, Ian R.; Mathewes, Rolf W. (2001) Chironomid-based paleosalinity records in southern British Columbia, Canada: A comparison of transfer functions.Journal of Paleolimnology 26: 147-159 Chironomid-based paleosalinity records in southern British Columbia, Canada: A comparison of transfer functions.
Chironomidae [Palaeontological techniques / / Past lake salinity reconstruction modelling & comparisons of transfer functions] [Fossil assemblages / / ] [Environmental indicators / / ] [Lake / / Past salinity reconstruction modelling & comparisons of transfer functions] [Salinity / / ] [British Columbia / 100 Mile House, Big Lake / ].
Chironomid remains from Big Lake, British Columbia were analysed and paleosalinities were estimated using a pre-existing transfer function and several developed using new regression methods. A two component partial-least-squares model (PLS-2) had the highest coefficient of determination (R(Jackknifed)2=0.75) and lowest root-mean-squared error-of-prediction (RMSEP). As compared to the pre-existing model, it was also less sensitive to the influence of rare taxa. Nevertheless, the marginally larger R(Jackknifed)2 and lower RMSEP do not clearly identify a single best model. The models were applied to Big, Mahoney and Kilpoola lakes, revealing the sensitivity of paleosalinity inferences to model selection. A synopsis of chironomid-based paleosalinities in British Columbia and their correspondence with other paleoclimatic data are presented and discussed.
65. Archibald, SB; Mathewes, RW. (2000) Early eocene insects from Quilchena, British Columbia, and their paleoclimatic implications.Can. J. Zool.-Rev. Can. Zool. 78: 1441-1462 Early eocene insects from Quilchena, British Columbia, and their paleoclimatic implications
Fossil insects were examined from the Early Eocene lacustrine shale at Quilchena, British Columbia. Insects of 10 orders (Blattodea, Dermaptera, Orthoptera, Hemiptera, Neuroptera, Coleoptera, Mecoptera, Diptera, Trichoptera, Hymenoptera) were identified, bringing the known number at this site to 11. These were placed in 26 families, 22 of which are new occurrences for this locality. Specimens include early occurrences of bees and ants. Three fossils of leaves with galls were examined. Thirteen of the families are new to British Columbia, and 9 of these (Blaberidae, Haglidae, Cixiidae, Dinidoridae, Cydnidae, Staphylinidae, Panorpidae, Pipunculidae, Halictidae) are new to the region of the Okanagan Highlands. A number of taxa are earliest known occurrences. Several insects in this fauna are larger than their modern relatives and some are larger than their relatives from other Eocene locales. The presence of insects including March flies, diplopterine cockroaches, dinidorid bugs, and seed weevils confirm and perhaps exceed paleobotanical indications that in the Eocene, British Columbia was much warmer than it is today. DOI
64. Pellatt, MG; Smith, MJ; Mathewes, RW; Walker, IR; Palmer, SL. (2000) Holocene treeline and climate change in the subalpine zone near Stoyoma Mountain, Cascade Mountains southwestern British Columbia, Canada.Arct. Antarct. Alp. Res. 32: 73-83 Holocene treeline and climate change in the subalpine zone near Stoyoma Mountain, Cascade Mountains southwestern British Columbia, Canada
Multiproxy paleoecological investigation of a small lake in the high subalpine zone near Stoyoma Mountain, northern Cascade Mountains of British Columbia, reveals significant change in vegetation, limnic conditions, and inferred climate throughout the Holocene (last 10,000 radiocarbon years). Three zones of distinct pollen, plant macrofossil, and chironomid assemblages are apparent in the sediment core from 3M Pond (informal name). A dry, sparsely vegetated spruce parkland and a warm-adapted chironomid community existed in and around the study sites in the early Holocene (ca. 10,000 to 7000 C-14 yr BP). Between 7000 and 3500 C-14 Yr BP, Engelmann spruce-subalpine fir forest conditions established and then declined around 3M Pond leading to modern subalpine parkland conditions from 3500 C-14 yr BP to present. Chironomid communities at 3M Pond between 7000 and 3500 C-14 yr BP are indicative of warmer waters than present, but show a transition to modern assemblages. Three climatic regimes are identified near Stoyoma Mountain: (1) the early Holocene xerothermic period (10,000 to 7000 C-14 yr BP, (2) a period of climatic transition in the mid-Holocene (7000 to 3500 C-14 yr BP), and (3) cool, modern neoglacial conditions (after 3500 C-14 yr BP). These findings confirm vegetation and inferred climate changes identified at Cabin Lake, British Columbia (a nearby lake in the subalpine forest). Changes in treeline position, plant communities, chironomid communities, and inferred climate are nearly synchronous and validate the multiproxy approach for paleoecological reconstruction Chironomid-based paleotemperature reconstructions confirm earlier evidence that the early Holocene was significantly warmer than present, with estimated summer water surface temperatures up to 4 degrees C higher than today. DOI
63. Clague, JJ; Hutchinson, I; Mathewes, RW; Patterson, RT. (1999) Evidence for late Holocene tsunamis at Catala Lake, British Columbia.J. Coast. Res. 15: 45-60 Evidence for late Holocene tsunamis at Catala Lake, British Columbia
tsunamis; paleoseismology; earthquakes; sedimentology; pollen; diatoms; foraminifera; Cascadia subduction zone; British Columbia
Thin sheets of sand and gravel occur within a sequence of fine organic-rich sediments at Catala Lake, off the west coast of Vancouver Island, British Columbia. The uppermost of these coarse sheets thins and fines landward away from the lake outlet, consistent with deposition by a tsunami. This coarse sediment sheet has been radiocarbon dated to some time after AD 1655; we suggest that it was deposited in 1700 by the tsunami of the last great earthquake at the Cascadia subduction zone. Abundant plant macrofossils, derived from nearby forest, are present within and on top of the sand and gravel layer, suggesting that the tsunami transported forest-floor litter, mosses, and seeds into Catala Lake. Deposition coincided with abrupt changes in diatom and foraminifera communities in the lake. The post-tsunami diatom assemblage is more marine in character than the immediate pre-tsunami assemblage, and the foraminifera community became more diverse after the tsunami. These changes are due either to coseismic subsidence or erosion of the outlet by the tsunami, which increased tidal exchange between the sea and the lagoon that was the precursor to Catala Lake. Older coarse sediment layers in cores from Catala Lake and the bordering marsh may also be tsunami deposits. One of these layers is about 1,000 years old and dates to the time of the penultimate great Cascadia earthquake.
62. Heinrichs, ML; Walker, IR; Mathewes, RW; Hebda, RJ. (1999) Holocene chironomid-inferred salinity and paleovegetation reconstruction from Kilpoola Lake, British Columbia.Geogr. Phys. Quat. 53: 211-221 Holocene chironomid-inferred salinity and paleovegetation reconstruction from Kilpoola Lake, British Columbia
Salinity fluctuations in lakes of semi-arid regions have been recognised as indicators of paleoclimatic change and have provided a valuable line of evidence in paleoclimatic reconstruction. However, factors other than climate, including sedimentologic events, may also affect salinity. At Kilpoola Lake, early postglacial freshwater chironomids (Microtendipes, Sergentia, and Heterotrissocladius) occur in the basal sediments and yield a chironomid-inferred salinity of <0.03 g/l. Higher salinities, ranging from 1.0 to 3.5 g/l, with Cricotopus/Orthocladius and Tanypus (chironomids typical of saline environments) follow and, persist for most of the remainder of the Holocene. An inferred 450% salinity increase (from 1.6 to 7.3 g/l) occurred in the sediment above the Mount Mazama tephra, followed by a return to the pre- Mount Mazama salinity. The early Holocene pollen spectra are typical of open steppe, but the post- Mazama Artemisia pollen percentages are exceptionally high and are associated with silty clays. Pollen spectra following this Artemisia peak represent steppe communities and are consistent with regional trends. We suggest that the changes in chironomid communities and vegetation after deposition of the Mazama ash do not reflect a rapid shift to warmer or drier climate and evaporation, but rather an increased ionic concentration due to solutes derived from the freshly deposited tephra and perhaps in-washed silts and clays. DOI
61. Hicock, SR; Lian, OB; Mathewes, RW. (1999) 'Bond cycles' recorded in terrestrial Pleistocene sediments of southwestern British Columbia, Canada.J. Quat. Sci. 14: 443-449 'Bond cycles' recorded in terrestrial Pleistocene sediments of southwestern British Columbia, Canada
Heinrich events; Younger Dryas; deformable beds; till
Recent data from exposures of terrestrial Pleistocene sediments in the Fraser Lowland of southwestern British Columbia reveal at least two 'Bond cycles' within Oxygen Isotope Stage 2. The maximum of the Coquitlam Stade coincides with the timing of Heinrich event H2, the Port Moody Interstade with Dansgaard-Oeschger (D-O) interstade 2, the maximum of the Vashon Stade with H1, and the Fort Langley interval with D-O interstade 1. The Sumas Stade apparently preceded H0 (Younger Dryas) but could have been in response to the same climatic signal. The timing of Sumas advances may be explained by a combination of glacio-isostatic rebound, destabilisation of the ice margin, and rapid movement over a short distance on soft muddy beds of a rising sea floor, thereby leading the timing of North Atlantic events by hundreds of years. In contrast, Coquitlam and Vashon advances were mainly over permeable glaciofluvial sediments and because of this their maxima probably did not precede the timing of H2 and H1. The Port Moody Interstade coincided with the global Last Glacial Maximum, due in part to the moderating effect of moist summer storms in a southward-shifted jet stream that influenced the Fraser Lowland at that time. Copyright (C) 1999 John Wiley & Sons, Ltd.
59. Pellatt, MG; Smith, MJ; Mathewes, RW; Walker, IR. (1998) Palaeoecology of postglacial treeline shifts in the northern Cascade Mountains, Canada.Paleogeogr. Paleoclimatol. Paleoecol. 141: 123-138 Palaeoecology of postglacial treeline shifts in the northern Cascade Mountains, Canada
palaeoclimate; pollen analysis; chironomids; treeline; Cascade Mountains; British Columbia; vegetation history
Postglacial changes in vegetation and chironomid communities at a subalpine lake in the Engelmann Spruce-Subalpine Fir zone in the northern Cascade Mountains, British Columbia, indicate patterns of treeline and climate fluctuation during the Holocene. In late-glacial sediments of Cabin Lake, pollen assemblages representative of alpine vegetation and cold-stenothermous chironomids indicate cold conditions prior to the Holocene. In the early Holocene (10,090 to 7000 C-14 yr BP) co-occurrence of spruce-fir parkland and a warm-adapted chironomid community indicates a warm and probably dry climate. In the mid-Holocene, inferred forest closure suggests that precipitation increased, and a mixture of warm- and cold-adapted chironomids indicates temperatures warmer than present, but cooler than in the early Holocene. This period between 7000 and 3200 C-14 yl. BP represents a transitional climate in which temperature gradually declined, culminating in cool neoglacial conditions. This transitional interval may correspond with the 'mesothermic period' proposed for lowland sites in southern British Columbia. Palaeobotanical evidence suggests that moist subalpine forest began to establish around 4800 C-14 yr BP with minimum temperatures and maximum precipitation between 2435 and ca. 1700 C-14 yr BP, corresponding with neoglacial advances throughout the northern Cordillera. A cool late Holocene (3200 C-14 yr BP to present) is also supported by a further decline in warm-adapted chironomids. Comparisons with other study sites in the Pacific Northwest reveal that regional climatic changes were a major factor in driving biotic changes in this area. (C) 1998 Elsevier Science B.V. All rights reserved. DOI
58. Smith, MJ; Pellatt, MG; Walker, IR; Mathewes, RW. (1998) Postglacial changes in chironomid communities and inferred climate near treeline at Mount Stoyoma, Cascade Mountains, southwestern British Columbia, Canada.J. Paleolimn. 20: 277-293 Postglacial changes in chironomid communities and inferred climate near treeline at Mount Stoyoma, Cascade Mountains, southwestern British Columbia, Canada
chironomid; Holocene; paleoclimate; paleolimnology; treeline; lake sediment; British Columbia
Analysis of the distributions of chironomid (midge) and other dipteran subfossils from two high elevation lake sediment cores in the Cascade Mountains reveals changes in midge communities and inferred climate since the late-glacial. Cabin Lake and 3M Pond are located near treeline in the subalpine Engelmann Spruce/Subalpine Fir biogeoclimatic zone of British Columbia. In Cabin Lake, chironomid head capsule assemblages depict a typical late-glacial community, and three distinct Holocene communities. In Cabin Lake, the late-glacial community is composed of cold-stenothermous taxa dominated by Stictochironomus, Mesocricotopus, Heterotrissocladius, Parakiefferiella nigra, Protanypus and Paracladius, whereas warm water midges are absent or rare, indicating cold conditions. A late-glacial chironomid community was not found in 3M Pond. In both lakes the early Holocene is dominated by a diverse warm-adapted assemblage, corresponding to the warm climatic conditions of the xerothermic period. Cabin Lake's mid-Holocene zone records a decrease in relative abundance of the warm water types and is accompanied by an increase in cold-stenotherms. At 3M Pond this period shows a dramatic loss in diversity of warm-adapted taxa, as the temperate genus Dicrotendipes dominates. This zone corresponds to Hebda's (1995) mesothermic period. Further cooling in the late Holocene (to modem conditions) is inferred from continued reduction of warm water midges and persistence (at Cabin Lake) or appearance (at 3M Pond) of a cold-stenothermal community. This late Holocene cooling is similar in timing to Neoglacial advances in the Coast, Cascade, and Rocky Mountains of southern British Columbia. Similarities in the timing of chironomid and vegetation community changes at these high elevation sites, along with the more rapid response time of the Chironomidae, support the sensitivity of midges to postglacial climatic change at high elevation sites. DOI
57. Clague, JJ; Mathewes, RW; Guilbault, JP; Hutchinson, I; Ricketts, BD. (1997) Pre-Younger Dryas resurgence of the southwestern margin of the Cordilleran ice sheet, British Columbia, Canada.Boreas 26: 261-277 Pre-Younger Dryas resurgence of the southwestern margin of the Cordilleran ice sheet, British Columbia, Canada
A lobe of the Cordilleran ice sheet readvanced into the central Fraser Lowland, southwestern British Columbia, Canada, on at least two occasions near the end of the last glaciation. This ice also flowed into the previously deglaciated, lower reaches of mountain valleys adjacent to the Fraser Lowland and into Washington state. The first of these advances occurred before about 11 900 BP end Ended with glacier retreat and the establishment of lodgepole pine forest on newly deglaciated terrain. Parts of this forest were overridden by ice during a second advance, shortly after 11 300 BP. The younger advance is most likely older than the Younger Dryas Chronozone (11 000-10 000 BP) and may correlate with an intra-Allerod cooling event (the Killarney-Gerzensee oscillation). The older advance may have occurred during the Oldest Dryas or Older Dryas cold period. Non-climatic factors could also be involved, as emergence of the Fraser Lowland before the older advance greatly reduced or eliminated calving at the glacier margin and thus altered the mass balance of the ice lobe.
56. Heinrichs, Mark L.; Wilson, Susan E.; Walker, Ian R.; Smol, John P.; Mathewes, Rolf W.; Hall, Kenneth J. (1997) Midge- and diatom-based palaeosalinity reconstructions for Mahoney Lake, Okanagan Valley, British Columbia, Canada.International Journal of Salt Lake Research 6 Midge- and diatom-based palaeosalinity reconstructions for Mahoney Lake, Okanagan Valley, British Columbia, Canada.
Chironomidae [Fossil assemblages / / Palaeosalinity relations; palaeoclimate reconstruction; Salt lake] [Environmental indicators / / ] [Habitat / / ] [Salinity / / Palaeosalinity; fossil assemblage relations] [Climate and weather / / fossil assemblage indicators] [British Columbia / / Okanagan Valley; Mahoney Lake] [Quaternary / / ].
DOI
55. Hutchinson, I; Clague, JJ; Mathewes, RW. (1997) Reconstructing the Tsunami record on an emerging coast: A case study of Kanim Lake, Vancouver Island, British Columbia, Canada.J. Coast. Res. 13: 545-553 Reconstructing the Tsunami record on an emerging coast: A case study of Kanim Lake, Vancouver Island, British Columbia, Canada
Cascadia subduction zone; diatoms; lakes; relative sea level; tsunami deposits; Vancouver island
A pilot study was conducted at Kanim Lake on the emerging coast of western Vancouver Island, British Columbia, to assess the efficacy of using lake sediments to determine tsunami run-up and recurrence. Sediment sequences in lakes near the coast can complement tsunami records derived from deposits underlying intertidal marshes. Marshes on emerging coasts are uncommon, of limited areal extent, and, most importantly, their deposits have a short Lifespan. Tsunami deposits in lakes are less susceptible to bioturbation and erosion and, generally, can be more accurately dated than similar deposits in marshes and other terrestrial settings. An inferred tsunami deposit in Kanim Lake has distinctive lithological characteristics and contains marine and brackish-water microfossils. Kanim Lake also illustrates some of the limitations in using lakes to reconstruct tsunami run-up and recurrence. Although the lake has been in the potential run-up zone for tsunamis triggered by great earthquakes on the nearby Cascadia subduction zone for the last 3,500-4,000 years, it apparently has been inundated by only one tsunami in this period. This event probably occurred about 2,800 years ago. Tsunamis since that time have failed to reach Kanim Lake as the lake basin has continued to rise through the ran-up zone and the distance to the sea has increased. The development of dense forest stands on the progressively widening reach between the sea and the lake has probably been the most important factor in limiting tsunami access to the site.
54. Pellatt, MG; Mathewes, RW. (1997) Holocene tree line and climate change on the Queen Charlotte Islands, Canada.Quat. Res. 48: 88-99 Holocene tree line and climate change on the Queen Charlotte Islands, Canada
Palynological study of two subalpine ponds on the Queen Charlotte Islands reveals changes in tree line and climate during the Holocene. The findings agree with previous reconstructions, from nearby Louise Pond on the Queen Charlotte Islands, that suggest a warmer-than-present climate and higher-than-present tree lines in the early Holocene (ca. 9600-6600 C-14 yr B.P.). Basal ages at SC1 Pond and Shangri-La Bog indicate that the basins did not hold permanent water before 7200 C-14 yr B.P., consistent with a warmer and drier early Holocene previously inferred from Louise Pond. Pollen and plant macrofossils indicate the initial establishment of subalpine conditions by 6090 +/- 90 C-14 yr B.P., Similar to the 5790 +/- 130 C-14 yr B.P. age for cooling inferred from Louise Pond. Conditions similar to present were established at SCI Pond by 3460 +/- 100 C-14 yr B.P., confirming the previous estimate of 3400 C-14 yr B.P. at Louise Pond. This 3400 C-14 yr B.P. vegetation shift on the Queen Charlotte Islands corresponds with the beginning of the Tiedemann glacial advance in the south-coastal mountains of British Columbia (ca. 3300 C-14 yr B.P.), the Peyto and Robson glacial advances between 3300 and 2800 C-14 yr B.P. in the Rocky Mountains, and climatic cooling inferred from palynological studies throughout southern British Columbia, northern Washington, and southeast Alaska. These findings confirm that changes in regional climate influenced changes in vegetation in coastal British Columbia. (C) 1997 University at Washington. DOI
53. Pellatt, MG; Mathewes, RW; Walker, IR. (1997) Pollen analysis and ordination of lake sediment-surface samples from coastal British Columbia, Canada.Can. J. Bot.-Rev. Can. Bot. 75: 799-814 Pollen analysis and ordination of lake sediment-surface samples from coastal British Columbia, Canada
modern pollen analysis; vegetation; ordination; multivariate statistical analysis; biogeoclimatic zones; British Columbia
Surficial sediment samples from 42 lakes, distributed from sea level to alpine elevations of coastal British Columbia and northwest Washington, were analyzed for pollen and spores. Pollen analysis revealed characteristic differences among the assemblages of the Coastal Western Hemlock, Mountain Hemlock, and Engelmann Spruce - Subalpine Fir biogeoclimatic zones (the Alpine zone is less clearly identifiable). Cluster analysis and detrended correspondence analysis (DCA) correctly group the sites according to their biogeoclimatic zones and also by geographic origin. DCA indicates a high correlation between the biogeoclimatic zones of the sample sites and annual precipitation (-0.89), January temperature (-0.77), annual temperature (-0.64), and growing-season precipitation (-0.68). Further analysis of the samples and eight environmental gradients using canonical correspondence analysis groups the pollen assemblages from the study sites into biogeoclimatic zones in relation to annual precipitation, growing-season precipitation, annual snowfall, annual temperature, and growing degree-days. These data are useful for testing whether or not postglacial pollen assemblages have modern analogues. DOI
52. Clague, JJ; Mathewes, RW. (1996) Neoglaciation, glacier-dammed lakes, and vegetation change in northwestern British Columbia, Canada.Arct. Alp. Res. 28: 10-24 Neoglaciation, glacier-dammed lakes, and vegetation change in northwestern British Columbia, Canada
An integrated geomorphic, stratigraphic, paleoecological, and geochronological study of a system of linked valley glaciers and ice-dammed lakes has provided insights into the Neoglacial history and climate of the northern Coast Mountains of British Columbia. Cores collected fi om a small lake in the glacier foreland of Berendon Glacier and pits dug in a nearby fen record Little Ice Age and earlier Neoglacial advances. AMS and conventional radiocarbon dating of fossil plant material from these sites, supplemented by dendrochronological data, indicate that the Little Ice Age began more than 500 yr ago and peaked in the early 17th century. A middle Neoglacial advance of comparable extent occurred about 2200 to 2800 yr ago. The chronology of Neoglacial advances is generally similar to that at other sites in western Canada, although the Little Ice Age may have peaked as much as 100 yr earlier in our study area than elsewhere. The Little Ice Age advances are also broadly synchronous with those in other parts of the world, suggesting that they were caused by global changes in climate. DOI
51. MATHEWES, RW; CLAGUE, JJ. (1994) DETECTION OF LARGE PREHISTORIC EARTHQUAKES IN THE PACIFIC-NORTHWEST BY MICROFOSSIL ANALYSIS.Science 264: 688-691 DETECTION OF LARGE PREHISTORIC EARTHQUAKES IN THE PACIFIC-NORTHWEST BY MICROFOSSIL ANALYSIS
Geologic and palynological evidence for rapid sea level change similar to 3400 and similar to 2000 carbon-14 years ago (3600 and 1900 calendar years ago) has been found at sites up to 110 kilometers apart in southwestern British Columbia. Submergence on southern Vancouver Island and slight emergence on the mainland during the older event are consistent with a great (magnitude M greater than or equal to 8) earthquake on the Cascadia subduction zone. The younger event is characterized by submergence throughout the region and may also record a plate-boundary earthquake or a very large crustal or intraplate earthquake. Microfossil analysis can detect small amounts of coseismic uplift and subsidence that leave little or no lithostratigraphic signature. DOI PubMed
50. Pellatt, MG; Mathewes, RW. (1994) Paleoecology of postglacial tree line fluctuations on the Queen Charlotte Islands, Canada.Ecoscience 1: 71-81 Paleoecology of postglacial tree line fluctuations on the Queen Charlotte Islands, Canada
paleoclimate; plant macrofossil; pollen analysis; Queen Charlotte Islands; tree line; vegetation history
Plant macrofossil and pollen analyses of sediments from a high elevation lake on the Queen Charlotte Islands, British Columbia, reveal changes in vegetation and inferred climate during the Holocene. Pollen and macrofossil zones at Louise Pond correlate well during the early Holocene, showing that vegetation changes recorded in the fossil diagrams occurred near the lake basins. Paleobotanical evidence for local presence of western hemlock (Tsuga heterophylla [Raf.] Sarg. trees between ca 9 600 and 8 700 +/- 150 yr BP indicates a warmer climate than today in the early Holocene. Declining western hemlock and increasing mountain hemlock (Tsuga mertensiana Bong.) fossils suggest some lowering of tree line at Louise Pond between about 8 700 +/- 150 and ca 7 300 yr BP. Radiocarbon dates from Shangri-La Bog and SC-1 Pond (7 190 +/- 100 yr BP and 7 180 +/- 110 yr BP respectively) show that climatic deterioration was occurring regionally by this time on the Queen Charlotte Islands. The development of upper subalpine mountain hemlock forest similar to today began around 3 400 yr BP and may correspond with climatic deterioration that caused the Tiedemann glacial advance (3 300 - 1 900 yr BP) in the south-coastal mountains of British Columbia. Plant macrofossil analysis in small lakes is shown to be useful in interpreting vegetation shifts in subalpine areas where lowland pollen rain interferes with interpretation of the local palynological record. DOI
49. VANCE, RE; MATHEWES, RW. (1994) DEPOSITION OF MODERN POLLEN AND PLANT MACROREMAINS IN A HYPERSALINE PRAIRIE LAKE BASIN.Can. J. Bot.-Rev. Can. Bot. 72: 539-548 DEPOSITION OF MODERN POLLEN AND PLANT MACROREMAINS IN A HYPERSALINE PRAIRIE LAKE BASIN
SALINE LAKES; GREAT PLAINS; POLLEN; PALEOBOTANY; PALEOHYDROLOGY; ENVIRONMENTAL RECONSTRUCTION
Comparisons between current vegetation patterns and deposition of modern pollen and plant macroremains in a saline lake basin on the northern Great Plains are used to assess the value of plant remains as indicators of past local vegetation dynamics and lake-level changes. Results indicate that both modern pollen spectra and assemblages of plant macroremains reflect clearly the composition of the local vegetation, whereas plant macroremains best reflect lake size. Cactaceae pollen and seeds are confined to upland prairie deposits. Liguliflorae (Compositae) and Leguminosae pollen, Selaginella densa microspores, and Euphorbia and Cruciferae seeds are more abundant in prairie upland deposits than in shoreline or lacustrine environments. An abundance (> 50%) of Ruppia pollen distinguishes near-shore lake sediments, indicating that this taxon is a useful marker of shallow shoreline environments in saline lakes. Seeds of Chenopodiaceae, Erigeron, Cruciferae, and Cyperaceae, as well as Chara oogonia, are more abundant in near-shore lacustrine sediments than in the central lake area, suggesting that they too are indicators of shoreline proximity. These data are useful for paleobotanical reconstructions of past lake-level dynamics. DOI
48. MATHEWES, RW. (1993) EVIDENCE FOR YOUNGER DRYAS-AGE COOLING ON THE NORTH PACIFIC COAST OF AMERICA.Quat. Sci. Rev. 12: 321-331 EVIDENCE FOR YOUNGER DRYAS-AGE COOLING ON THE NORTH PACIFIC COAST OF AMERICA
A review of the Palynological evidence from the Olympic Peninsula of Washington State north to the Alaska Panhandle strongly supports the existence of a climatic oscillation similar in timing and effect to the Younger Dryas cooling (11-10 ka BP) of Europe and eastern North America. The evidence includes many late-glacial pollen peaks of mountain hemlock (Tsuga mertensiana), an indicator of cool and moist climate, reversals from forest to non-aboreal vegetation, and paleoclimate analysis using pollen-climate transfer functions on the Queen Charlotte Islands. Evidence of cooler ocean waters, based on fossil foraminifera in cores from the continental shelf, also supports an interpretation of a Younger Dryas-age climatic reversal. On the other hand, geological evidence of glacier readvances during the Younger Dryas chronozone is weak and poorly dated. Although more and better-constrained (AMS) dates are needed to confirm the timing of the Pacific Northwest cold oscillation, results so far point to maximum cooling and increased moisture between ca. 10.7-10 ka BP, followed by rapid warming in the early Holocene. Additional late-glacial sites need to be investigated in detail to confirm the geographical pattern of vegetation and climate change during this interval, which is best expressed in hypermaritime and maritime climate regions, similar to the Younger Dryas event around the North Atlantic. These results suggest that the search for causal mechanisms to drive the Younger Dryas cooling cannot be limited to events in the North Atlantic region, but should focus on possible hemispheric or global processes. DOI
47. MATHEWES, RW; HEUSSER, LE; PATTERSON, RT. (1993) EVIDENCE FOR A YOUNGER DRYAS LIKE COOLING EVENT ON THE BRITISH-COLUMBIA COAST.Geology 21: 101-104 EVIDENCE FOR A YOUNGER DRYAS LIKE COOLING EVENT ON THE BRITISH-COLUMBIA COAST
Two independent paleoclimatic records from the Pacific coast of Canada indicate that a late-glacial warming trend was interrupted by a return to colder conditions between about 11,000 and 10,200 radiocarbon yr B.P., correlative with the classical Younger Dryas chronozone of the North Atlantic region. Fossil benthic foraminifera from three cores from the continental shelf dated by accelerator mass spectrometry show peak abundances of the cold-water indicator species Cassidulina reniforme at this time. Fossil-pollen spectra from two sites on the Queen Charlotte Islands record a shift from forest to open, herb-rich vegetation after 11,100 yr B.P., probably in response to colder and wetter conditions identified by pollen-climate transfer functions. These preliminary data for a cold oscillation between ca. 11 000 and 10 000 yr ago in the northeast Pacific argue that this deglacial phenomenon was not restricted to the North Atlantic, but was a hemispheric-and possibly global-event. DOI
46. CLAGUE, JJ; MATHEWES, RW; BUHAY, WM; EDWARDS, TWD. (1992) EARLY HOLOCENE CLIMATE AT CASTLE PEAK, SOUTHERN COAST MOUNTAINS, BRITISH-COLUMBIA, CANADA.Paleogeogr. Paleoclimatol. Paleoecol. 95: 153-167 EARLY HOLOCENE CLIMATE AT CASTLE PEAK, SOUTHERN COAST MOUNTAINS, BRITISH-COLUMBIA, CANADA
New palynological, radiocarbon, and stable isotope data from Castle Peak in the southern Coast Mountains indicate that the early Holocene climate of southern British Columbia was warmer and perhaps drier than today. Fossil wood fragments are common above timberline at Castle Peak and have yielded 13 radiocarbon ages ranging from 9.1 ka to 8.1 ka. This evidence for higher timberline during the early Holocene is in agreement with pollen data indicating a warmer and possibly longer summer growing season in this area during the early Holocene, and is consistent with theoretical considerations based on Milankovitch forcing of climate change. The oxygen and hydrogen stable isotope composition of fossil wood cellulose is similar to that of living trees in the same area. Growing season relative humidity values derived from the isotopic data provide some support for episodes of dryness at times of elevated timberline, although the majority of paleohumidity estimates fall within the range of modern moisture levels. DOI
45. VANCE, RE; MATHEWES, RW; CLAGUE, JJ. (1992) 7000 YEAR RECORD OF LAKE-LEVEL CHANGE ON THE NORTHERN GREAT-PLAINS - A HIGH-RESOLUTION PROXY OF PAST CLIMATE.Geology 20: 879-882 7000 YEAR RECORD OF LAKE-LEVEL CHANGE ON THE NORTHERN GREAT-PLAINS - A HIGH-RESOLUTION PROXY OF PAST CLIMATE
Mineralogical and paleobotanical characteristics of the sedimentary fill in a shallow, saline lake in southeastern Alberta indicate that drought intervals are aperiodic and that climatic extremes unprecedented in historic time occurred earlier during the Holocene, when century-long intervals of repeated, intense droughts alternated with long periods when droughts were rare. Low-water intervals (signifying periods of drought) are recorded by carbonate-rich laminae containing abundant plant fossils indicative of hypersalinity. In contrast, highstands of relatively fresh water (outlining moist periods) are represented by massive, silicate-rich sediment with lower numbers of halophytic indicators. DOI
43. GOTTESFELD, AS; GOTTESFELD, LMJ. (1991) HOLOCENE DEBRIS FLOWS AND ENVIRONMENTAL HISTORY, HAZELTON AREA, BRITISH-COLUMBIA.Can. J. Earth Sci. 28: 1583-1593 HOLOCENE DEBRIS FLOWS AND ENVIRONMENTAL HISTORY, HAZELTON AREA, BRITISH-COLUMBIA
Debris flow deposits of Chicago Creek and the sediment, pollen, and macrofossil records of Seeley Lake were studied to elucidate the Holocene history of the northwest flank of the Rocher Deboule Range near Hazelton, British Columbia. The Chicago Creek drainage has experienced numerous rockfalls, debris slides, and debris flows. A large debris flow covering approximately 300 ha occurred about 3580 +/- 150 BP. This flow was two to three orders of magnitude larger than historic debris flows in this drainage. It traveled about 3 km down Chicago Creek and dammed the outlet stream of Seeley Lake. A debris deposit along lower Chicago Creek is interpreted as the product of debris torrents that formed during or soon after the damming of Seeley Lake. Its surface exhibits soil development (rubification and profile development) comparable to that on the large debris flow, suggesting equivalent age. Pollen and plant macrofossils are described from a core taken in Seeley Lake. This core spans the period from ca. 9200 BP to the present. A disturbance event in 3380 +/- 110 BP, correlative with the large Chicago Creek debris flow, is recorded by a clastic sediment layer and changes in the microfossil and macrofossil assemblages. The Chicago Creek debris flow and debris torrent ca. 3500 BP may be the catastrophic event recorded in the story of the Medeek, an oral history or "ada'ok" of the Gitksan people of Hazelton. DOI
42. MATHEWES, RW. (1991) CLIMATIC CONDITIONS IN THE WESTERN AND NORTHERN CORDILLERA DURING THE LAST GLACIATION - PALEOECOLOGICAL EVIDENCE.Geogr. Phys. Quat. 45: 333-339 CLIMATIC CONDITIONS IN THE WESTERN AND NORTHERN CORDILLERA DURING THE LAST GLACIATION - PALEOECOLOGICAL EVIDENCE
In the southern Cordillera, paleoecological evidence suggests that climate was variable, from cooler than present by up to 3-degrees-C, to possibly similar to modern during the Olympia non-glacial interval (> 59 TO 25-29 ka). The development of open subalpine parkland vegetation in lowlands after 25 ka reflects slow cooling to glacial conditions. Assumptions about continuously cold and dry glacial conditions are tested and disputed. Between 18-19 ka, pollen, plant macrofossil and beetle evidence suggest relatively warm and moist conditions in the Fraser/Puget Lowlands. A tentative correlation can be inferred with the recently defined "Hanging Lake thermal event" around 18-22 ka in the unglaciated Yukon. Further work should be done to test this inference. Paleobotanical data suggest that increasing moisture, rather than increased cooling, was responsible for the late Vashon ice advance in the southwestern Cordillera. The controversy regarding the nature of the vegetation cover in eastern Beringia, north of the main Cordilleran ice sheet, is not yet settled, although evidence to date favours a complex mosaic of tundra and "Steppe-tundra" plant communities supporting a greater diversity of grazing large mammals than exist in the area today. DOI
34. Walker, I.R.; Mathewes, R.W. (1989) Early postglacial chironomid succession in southwestern British Columbia, Canada, and its paleoenvironmental significance.Journal of Paleolimnology 2 Early postglacial chironomid succession in southwestern British Columbia, Canada, and its paleoenvironmental significance.
Chironomidae [Fossil assemblages / / Environmental indicator] [Succession in habitats / / Stratigraphical] [Environmental indicators / / Faunal assemblages & stratigraphical succession] [Lake / / ] [British Columbia / / South west; lake faunal assemblages & succession] [Holocene / / ].
Chironomids typical of cold, well-oxygenated, oligotrophic environments are common in late-Pleistocene deposits, but these taxa are rare in Holocene sediments of most small temperate lakes. Hypotheses to explain the demise of these taxa include variations in climate, lake trophic state, lake levels, terrestrial vegetation, and/or sediment composition. In southwestern British Columbia, this demise correlates with palynological evidence for a lodgepole pine decline, and for rapid climatic amelioration, at about 10,000 yr B.P. Faunal change are poorly correlated with lithological boundaries. The similar timing of the declines among lakes suggests that a regional influence, climate, has possibly been the principal determinant of early chironomid faunal succession. DOI
33. Walker, I.R.; Mathewes, R.W. (1989) Much ado about dead Diptera.Journal of Paleolimnology 2 Much ado about dead Diptera.
Chironomidae [Fossil assemblages / / Climatic indicator use; comments] [Environmental indicators / / Faunal assemblages use as climatic indicator] [Lake / / Faunal assemblages use as environmental indicator] [Climate and weather / / ] [British Columbia / / South west; lake faunal assemblages; environmental indicator] [Holocene / / Lake faunal assemblages use as environmental indicator].
DOI
32. Walker, I.R.; Mathewes, R.W. (1989) Chironomidae (Diptera) remains in surficial lake sediments from the Canadian Cordillera: analysis of the fauna across an altitudinal gradient.Journal of Paleolimnology 2 Chironomidae (Diptera) remains in surficial lake sediments from the Canadian Cordillera: analysis of the fauna across an altitudinal gradient.
Chironomidae [Geographical variation / / Altitudinal; lakes] [Fossil assemblages / / Altitudinal variation & climatic indicator] [Environmental indicators / / ] [Lake / / ] [Climate and weather / / Faunal assemblages as indicator] [British Columbia / / South; lake faunal assemblages] [Holocene / / ].
The altitudinal distribution of Chironomidae (Diptera) in the southern Canadian Cordillera was analyzed by means of head capsules preserved in surficial sediments of 30 lakes. Taxa characteristic of late-glacial deposits of southern, coastal British Columbia are extant at high elevations, particularly in the Rocky Mountains, and in large, deep, low-elevation lakes. Many chironomid taxa common at low elevations in the southern Canadian Cordillera were not found in alpine and upper subalpine lakes. These faunal differences are probably climatically related. The differences in fauna between high and low-elevation lakes parallel differences between arctic and temperate lakes. DOI
