Theory predicts that geographically complex regions should harbor exceptional biological diversity, and that past Earth history events such as climatic fluctuations will affect the diversification and maintenance of genetic variation. The island of Madagascar represents one such complex region. Only four groups of native terrestrial mammals exist on Madagascar; each colonized Madagascar a single time and then diversified to exhibit spectacular morphological and ecological variation. This proposal focuses on the small insectivore-like mammals, especially on those species distributed throughout Madagascar's mountainous, humid-forest belt. The project will use DNA sequences from multiple genes to determine how many genetically distinct sets of populations exist within each species, and to provide an estimate of how long ago they diverged. The researchers will use Geographic Information Systems (GIS) to model the niche of each species using climatic data sets to estimate the species' current ranges and to reconstruct their distributions during past glacial cycles.
Understanding the forces that shape regional biodiversity is one of the key goals of modern biology. This project will illuminate the importance of past climatic events in shaping present-day patterns of biodiversity. It will reveal the extent of small-mammal diversity in Madagascar's humid forests and identify areas containing unexpected genetic variation, providing critical information for designing protected areas and conservation strategies in one of the world?s foremost biodiversity hotspots. The researchers will train undergraduate and graduate students in DNA sequencing and analysis and GIS, including students from groups underrepresented in science.