Climate change as an ecosystem architect: implications to rare plant ecology, conservation, and restoration

Abstract

Recent advances in earth system sciences have revealed significant new information relevant to rare plant ecology and conservation. Analysis of climate change at high resolution with new and precise proxies of paleotemperatures reveals a picture over the past two million years of oscillatory climate change operating simultaneously at multiple timescales. Low-frequency oscillations are paced by cycles of the earth’s orbit around the sun and the resulting solar heat that earth receives. These control multi-millennial cycles of glacial (~90,000 year) and interglacial (~10,000 year – the Holocene is one of many) periods with 10-15°C average differences. Despite the long duration of these cycles, transitions between periods have been abrupt, on the order of years to millennial climate oscillations, paced primarily by cycles in solar activity. These occur in quasi-1300 year periods and also have abrupt decades. Nested within the glacial/interglacial cycles are century-transitions between states, e.g., >8°C mean change in ten years. Further within these cycles are high-frequency interannual to decadal fluctuations, with mechanisms generated by ocean/atmosphere dynamics. Climate change thus functions as an important recurring agent of ecological and evolutionary change, with each scale of historic climate cycling tracked by changes in vegetation. Primary responses at multi-millennial scales are major migrations, range shifts, and population extirpations and colonizations (up to 1500 m elevation and across hundreds of km). Similar types of change but smaller magnitudes characterize mid-frequency climate variability, while annual and decadal climate oscillations provoke primarily changes in productivity and abundance of plants. The nature of climate change and the vegetation response have conservation implications on the nature of rarity, transience of native ranges andMillar Climate Change and Conservation 2 plant associations, significance of population declines and increases, development of targets and references for restoration, and strategies for global warming

Citation

Millar, Constance I. 2003. Climate change as an ecosystem architect: implications to rare plant ecology, conservation, and restoration. Sierra Nevada Research Center USDA Forest Service, Pacific Southwest Research Station