Abstract

Climate change in the next century is expected to drive disequilibrium dynamics in biotic communities, particularly for long-lived species such as trees, that may exhibit lagged responses. In many systems, we are already beginning to see the fingerprints of historic and ongoing climate change or other anthropogenic impacts, and so many communities that appear to be in equilibrium may actually be in a transient state. As a result, conservation strategies that rely on static restoration or management targets are unlikely to be successful. The paleoecological record may provide a promising way forward in understanding disequilibrium dynamics, as the increased spatiotemporal resolution of pollen data now allows us to reconstruct vegetation dynamics at sub-centennial scales. Plant associations without a modern analog are a well-recognized feature of late glacial landscapes, and their formation has been attributed to no-analog climates and the extinction of Pleistocene herbivores. While the establishment of no-analog plant communities took less than a century, the interval of high vegetation dissimilarity lasted nearly 1000 years, providing an opportunity to explore community dynamics in tree assemblages in response to climate change and megafaunal extinction.