A Holocene record of climate, Ž re and vegetation regimes was reconstructed for Siesta Lake, Yosemite National Park, California, using fossil pollen and charcoal from lake sediments. These reconstructions were generated to provide a long-term perspective on drought in the Sierra Nevada. The sedimentary record is in agreement with other long-term records of climate and vegetation from the Sierra...

We present the results of pollen analysis performed on an ice core recovered from Nevado Sajama, Bolivia, dated to 25 ka BP. Low pollen concentrations from 25 to 15 ka BP are consistent with the scenario of an expanded ice cap surrounded by sparse vegetation and cold conditions on the Altiplano during the Last Glacial Maximum. After 15 ka BP, more pollen is present and percentages show vegetati...

The changes in diatom species composition in a sediment core from Crevice Lake, Yellowstone National Park, spanning the past 2550 yr, were used to reconstruct long-term limnological and ecological conditions that may be related to late Holocene climate variability. Planktic forms dominate the fossil diatom assemblages throughout this record, but changes in species dominance indicate varying nut...

The Russian treeline is a dynamic ecotone typified by steep gradients in summer temperature and regionally variable gradients in albedo and heat flux. The location of the treeline is largely controlled by summer temperatures and growing season length. Temperatures have responded strongly to twentieth-century global warming and will display a magnified response to future warming. Dendroecologica...

The Late Holocene was characterized by several centennial-scale climate oscillations including the Roman Warm Period, Dark Ages Cold Medieval Period and Little Ice Age. detection investigation of such anomalies requires paleoclimate archives with an accurate chronology as well a high temporal resolution. Here, we present 230Th/U-dated high-resolution multi-proxy records (?13C, ?18O trace elemen...

a r t i c l e i n f o A sediment core spanning ∼ 7000 cal yr BP recovered from Stella Lake, a small sub-alpine lake located in Great Basin National Park, Nevada, was analyzed for subfossil chironomids (non-biting midges), diatoms, and organic content (estimated by loss-on-ignition (LOI)). Subfossil chironomid analysis indicates that Stella Lake was characterized by a warm, middle Holocene, foll...