New Harvard Forest Publications: Postdoctoral Fellows Publish On Species Turnover and Tree Migration

Harvard Forest Postdoctoral Fellow Robert McDonald, along with collaborators at the University of North Carolina at Chapel Hill, tested the effectiveness of ecoregions, a common conservation tool that divides the world into discrete regions by their ecology, in representing variation in species composition for mammals, trees, and birds. Their results show that, for any particular taxonomic group, most ecoregion boundaries do not represent zones of higher than average turnover. This result has implications for conservation planning, and suggests that utilizing a set of ecoregions designed for one purpose for a different purpose will often be far from optimal.

McDonald, R., M. Mcknight, D. Weiss, E. Selig, M. O'Connor, C. Violin, A. Moody. 2005. Species compositional similarity and ecoregions: Do ecoregion boundaries represent zones of high species turnover? Biological Conservation 126: 24–40

Tree species are at risk of extinction if their ability to expand northwards is too slow to keep up with anticipated climate warming. With colleagues at Duke University, Jason McLachlan showed that previous estimates of range expansion at the end of the last ice age were too fast. Surveys of molecular markers indicate that rates of spread in beech and red maple may be severely constrained by factors such as limited seed dispersal in the face of rapid climate change.

J.S. McLachlan, J.S. Clark and P.S. Manos. 2005. Molecular indicators of tree migration capacity under rapid climate change. Ecology 86: 2088-2098.