By ~3.5 cal ka BP Pinus increased under cooling conditions, and Picea gradually rebounded to form the mixed conifer forest present today. Picea-dominated forests prevailed from ~8.0 to 5.0 cal ka BP, after which time a more open Picea parkland developed. By ~9.0 cal ka BP Picea began to expand in response to early Holocene summer warming and enhanced winter moisture. Our results show that at the end of the Younger Dryas, Silver Lake was surrounded by open Pinus/Picea parkland mixed with Artemisia subalpine steppe. Here we present a Holocene record of upper montane forest-parkland dynamics from Silver Lake in Big Cottonwood Canyon, Wasatch Range, on the Great Basin’s eastern margin. Available records suggest that western North American subalpine forest-parkland ecosystems responded to Holocene climate in various ways at different places. Understanding long-term responses of subalpine forest-parklands to Holocene climate variability in local context is critical for better managing those ecosystems under future climate change. Accommodating for complicating factors, long-term vegetation and hydrologic histories line up quite well through much of the Quaternary, and during the last glacial cycle in particular, on both orbital and millennial scales of climatic flux. Given these potential pitfalls, the fact that paleolake history–vegetation history comparisons work as well as they do is rather remarkable. Further complicating the interpretation of past vegetation patterns in relation to climatic factors are elements of considerable local climatic heterogeneity, differences in responses and spatiotemporal averaging of different proxy paleovegetation data sources, and chronometric uncertainties. Vegetation and constituent taxa respond to fluctuations in temperature, precipitation, seasonality, and other factors in a complex and mutually interactive interplay.
#Packrat salina kansas drivers
Lake history and vegetation history complement each other in identifying key climate drivers of these interacting systems for that reason comparing the two histories in the Bonneville basin has long held considerable research interest. The ultimate outcome is a clear case of how long-term oscillations in climate can repeatedly motivate change in foraging societies in a marginal environmental setting.
Results show a striking consistency in human-occupation intensity and oscillations between cool, mesic and warm, arid climate, specifically high occupation intensity during relatively cool times, and low intensity d even abandonment d during extended periods of drought. Here, we report and analyze one of the largest datasets (n ¼ 247) of radiocarbon ages yet amassed from a single archaeological site in the Americas d Bonneville Estates Rockshelter, Nevada d to investigate human-environment interaction in this desert setting since 13,000 years ago. In the Great Salt Lake desert (USA), a detailed record of paleoenvironmental change has been developed for the last 15,000 years, but a similarly complete chronicle of human occupation and adaptation is less secure. The extent to which long-term climate change has influenced cultural evolution among hunter-gatherers has long been debated. Pinus percentages then decreased and Artemisia became codominant, suggesting drier and perhaps colder conditions from ~ 21 to ~ 15 cal ka, when Lake Bonneville was at or near its highest levels. The pollen percentages of Pinus and subalpine conifers were high from ~ 25 to 21.5 cal ka, indicating cool and moist conditions during the Stansbury oscillation and for much of the rise toward the Bonneville shoreline. Vegetation changed during this time span, albeit not always with the same direction or amplitude as the lake. Lake Bonneville oscillated near the Stansbury shoreline between ~ 26 and ~ 24 cal ka, rose to the Bonneville shoreline by ~ 18 cal ka, and then fell to the Provo shoreline, which it occupied until ~ 15 cal ka.
As Lake Bonneville began to rise (from ~ 30 to 28 cal ka), Pinus and subalpine conifer pollen percentages increased and Artemisia declined, suggesting the onset of wetter conditions. Initially, the coring site was covered by a shallow saline lake and surrounded by Artemisia steppe or steppe-tundra under a cold and dry climate. Sediment cores from Great Salt Lake (GSL) provide the basis for reconstructing changes in lakes, vegetation, and climate for the last ~ 40 cal ka.
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