KERRY N. RABENOLD

   One of the greatest issues of our time is the massive erosion of the variety of life in our local landscapes and globally. Researchers should be able to test and develop biological principles for their own sake while also asking questions that have application to conservation. Since the tropical latitudes of our planet harbor the most exuberant life, this is where ecological research is most needed. We have studied the behavioral ecology of tropical birds, particularly the selective forces favoring cooperative society in wrens of the Venezuelan savanna. We are currently focusing on the implications of dispersal for both individual fitness and population viability. Our team ("equipo cucarachero") has combined intensive field observations, field experiments, molecular analysis of genetic relatedness within and between populations, and modeling of population dynamics. We have also studied the very different sociality of brown jays in Costa Rica, and comparison between these species defines the range of cooperative breeding in birds, and their range of sexual bias in dispersal as well. We have also maintained long-term projects investigating diversity and stability of natural communities in Costa Rica, the southern Appalachians of the US, and in Indiana. Locally, we have documented long-term decline in flowering dogwood populations associated with natural change in the composition of the forest canopy. Costa Rican mountain rainforests support diverse bird communities that change substantially between narrow altitudinal zones, and these communities are threatened by climate change. Many species specialized for life in these forests are endemics whose populations are dwindling, so that it is important to understand their habitat requirements. We are studying the factors that determine change in species composition along local environmental gradients and the biogeography of species richness and turnover across Central America. We are also studying communities in the Great Smoky Mountains to compare "beta diversity" of birds along altitudinal gradients in the tropics to that of the temperate zone, and to understand the resilience of high-elevation communities to chemical and biological pollution. Running through these diverse projects is the fundamental issue of measuring the effectiveness of protected areas in conserving biological diversity and the processes that sustain it.