Katherine H. Anderson

Modern pollen/climate calibration for southern South America

Abstract Using the response surface technique a modern pollen/climate calibration is presented for the mid-latitudes in southern South America between latitudes 39°S and 44°S, extending from the west coast in Chile across the Andes into the Patagonian steppe region. The climate parameters identified that relate to the present-day pollen distribution of the nine most important pollen types ( Nothofagus dombeyi -type, Nothofagus obliqua -type, Podocarpus , Weinmannia , Caldcluvia / Eucryphia -type, Cupressaceae, Myrtaceae, Misodendrum and steppe-types) are summer precipitation, summer and winter temperatures. Using the modern pollen/climate data set, three fossil pollen records (Mallin Aguado and Lago Moreno, east of the Andes, and Caunahue, west of the Andes) are interpreted in terms of these three seasonal climate parameters. Despite intervals of no-analog fossil pollen assemblages, the reconstruction shows similar climate trends on both sides of the Andes during the last 21 000 cal. yr BP (17 000 yr BP), with summer precipitation as low or markedly lower than today prior to 17 000 cal. yr BP (14 500 yr BP), as high or higher than today between 15 000 and 12 500 cal. yr BP (12 500 and 10 500 yr BP), and again lower than today between 12 500 and 8000 cal. yr BP (10 500 and 7200 yr BP). Summer and winter temperatures were low (or high) when summer precipitation was high (or low).

Late Wisconsin climate in northeastern USA and southeastern Canada, reconstructed from fossil beetle assemblages

Mean July and January temperatures are reconstructed from radiocarbon-dated fossil beetle assemblages, yielding a synthesis of palaeoclimatic history of the regions south of the Laurentide Ice Sheet in North America from 35 000 to 8500 yr BP. Mean July temperatures close to the last glacial maximum were 11–12°C colder than present; mean January temperatures were possibly 10–19°C colder. Mutual climatic range analyses of the beetle assemblages show warming of mean summer temperatures as early as 13.7 kyr, although ice-proximal sites were consistently about 5°C cooler than ice-distal sites. Late-glacial mean summer temperatures peaked between 12 and 11 kyr, then remained fairly constant through the early Holocene. Mean winter temperatures did not reach modern values until after 10 kyr.

Insights on the Climatic Constraints on the Beetle Fauna of Coastal Alaska, U.S.A., Derived from the Mutual Climatic Range Method of Paleoclimate Reconstruction

The Mutual Climatic Range (MCR) method of paleoclimate reconstruction uses the climatic parameters associated with the modern range of species to produce climate envelopes for taxa found in fossil ...

Quaternary vegetation and climate change in the western United States: Developments, perspectives, and prospects

Publisher Summary This chapter explores the strengths and shortcomings of the major sources of data on Quaternary vegetation and climate change and discusses the use of models as a means to explore past and potential future environmental changes. The flora and major vegetation types of the western United States are present for several million years. Ongoing changes in atmospheric chemistry, climate, and human activities may lead to major vegetation changes over the coming decades to centuries. The combination of observations from the paleoenvironmental record, modern ecological studies, and modeling now permit assessments of the magnitude of potential future changes in the context of natural variability. They also provide opportunities for hypothesis testing and identification of the processes driving past changes in vegetation and climate. Understanding the dynamics of paleoenvironmental change can contribute to current conservation and natural resource management efforts and will help conservation and natural resource managers anticipate the potential rate, magnitude, and complexity of future vegetation change.