Pacific Southwest Research Station

Pacific Southwest Research Station
800 Buchanan Street
West Annex Building
Albany, CA 94710-0011

(510) 559-6300

Research Topics Ecosystem Processes

Title

Quaternary Biogeography of Pacific Southwest Tree Species

Implications of climate cycling to population ecology and genetics, conservation and land management

Research Project Summary

The Research

Current research in paleoclimatology documents the magnitude of climate variability and its quasi-cyclic nature at decadal to multi-millennial scales over the past 2-3 million years. Similarly, many studies worldwide indicate that historic vegetation responses have been strongly correlated to abrupt as well as gradual climate changes, and that not only does vegetation change over time but physical forces change as well ("a variable chasing a variable"). Despite the abundant information of this nature, conceptual implications to ecology, evolution, and conservation of Quaternary climate as a recurring natural evolutionary force, and of the non-stationarity of ecological regimes, have been little integrated or adopted. We use available literature on paleoecological abundance and distribution to reconstruct range shifts and population levels likely to have prevailed throughout the Quaternary, and analyze dynamics over several timescales. With these examples, we interpret new conceptual approaches to conservation, restoration, and land management.

Objectives

Using available literature, reconstruct spatially and temporally explicit with attention to low-frequency (glacial/interglacial), medium-frequency (millennial to century), and high-frequency (decadal) fluctuations, especially to periods of abrupt change.

Assess the role of climate variability and other disturbances (fire/geomorphologic change) as an ecological and evolutionary force at several timescales.

Interpret the importance of climate forcing to restoration and conservation strategies and applications.

Location

Pacific Southwest region, USA.

Lead Scientists/Collaborators

1) Millar, C.I. 2) Skinner, C. N. 3) Swetnam, T.W., 3) Falk, D., and 4) Woolfenden, W.

1) USDA Forest Service, PSW Research Station
Sierra Nevada Research Center
800 Buchanan St., Albany, CA 94706 USA
ph: 510-559-6300

2) USDA Forest Service, PSW Research Station, Redding, CA

3) Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ

4) USDA Forest Service, Mountain Heritage Associates, Lee Vining, CA

Publications and Reports

• Millar, C.I. Quaternary biogeography of oaks in the California region, USA. In preparation for Journal of Biogeography.
• Millar, C.I., W.B. Woolfenden. 2001. Integrating Quaternary science research in land management, restoration, and conservation. Quaternary Times 31(1): 1-9.
• Millar, C.I. 2000. Historical variability in ecosystem management. Past Global Changes 8(3): 2-4.
• Millar, C.I. 1999. Evolution and biogeography of Pinus radiata with a proposed revision of its Quaternary history. New Zealand Journal of Forest Science. 29(3): 335-365.
• Millar, C.I. and W.B. Woolfenden. 1999. The role of climate change in interpreting historic variability. Ecological Applications 9(4): 1207-1216.
• Millar, C.I. and W.B. Woolfenden. 1999. Sierra Nevada forests: Where did they come from? Where are they going? What does it mean? Pages 206-236 in R.McCabe and S. Loos (eds.), Natural Resource Management: Perceptions and Realities. Transactions of the 64th North American Wildlife and Natural Resource Conference. March 26-30, 1999. San Francisco-Burlingame. Wildlife Management Institute, Washington D.C.
• Millar, C.I. 1999. Genetic diversity. Pages 460-494 in M.L. Hunter (ed.), Managing Biodiversity in Forest Ecosystems. Oxford University Press.
• Millar, C.I. 1998. Reconsidering the conservation of Monterey pine. Fremontia 26(3): 12-16.