PARENT SESSION
Oral Session # 2: Paleoecology.
Presiding: B Lynch
Monday, August 4. 8:00 AM to 11:30 AM, SITCC Meeting Room 101.

Conservation lessons from the Last Glacial Maximum.

McLachlan, Jason^*,1, Clark, James¹, Manos, Paul¹, ¹ Biology, Durham, NC

ABSTRACT- Some places, like Brazil's Atlantic Forests, are hotspots of local species endemism. In other places, like Amazonia, many rare species have geographically extensive overlapping ranges. Global conservation efforts increasingly focus on regions with the former kind of rarity, because species there are thought to be more prone to extinction. The end of the last ice age provides an interesting contrast to the modern extinction crisis because most species did not go extinct, despite rapid environmental change. Many currently common temperate tree taxa were rare at the last glacial maximum (LGM) and it would be useful to know if their survival was aided by extensive diffuse populations. The consensus of the paleoecological community, though not unanimous, is that rapid expansion from isolated southern refugia (ice age 'hotspots') was common in Europe and in North America. We show that reconstructions of LGM refugia using the fossil record have suffered from systematic bias against the detection of widespread diffuse populations. Molecular data and a reanalysis of fossil pollen data from eastern North America show that temperate hardwood species thought to be restricted to isolated refugia during the late glacial, were, in fact, widely distributed, though rare. Large ranges may have helped rare species survive rapid environmental change in the past, as conservation biologists hope they will today.

Key words: conservation, molecular ecology, biodiversity, fossil pollen