Ecologists put some life into models of a changing world.

In the spring of 1993, two groups of scientists will unite general circulation models with computer models of forests, grasslands, and swamps. The models will map changes in vegetation that occur as a result of climate changes. One model, BIOME, assigns 14 types of vegetation to 60 km square grids and tracks changes in vegetation patterns in response to changes in minimum temperature, degree days, and moisture. The other model, DOLY, works much the same way. Changes in vegetation cover will then drive the climate to a new equilibrium. Other ecologists are developing bottom-up models that try to describe how species mixture and other complex factors that vary on small scales influence an ecosystems response to changes in climate. Hopefully the modelers will pool their strategies on an international network based at the University of Virginia. Also, large-scale field experiments are being conducted to study the interplay between natural ecosystems and climatic factors such as CO[sub 2]. Future projects will also attempt to account for changes caused by human activities such as deforestation.