Why are some places more species-rich than others is an enduring question in ecology and evolution. Tropics generally harbor a greater diversity of life than temperate regions and many hypotheses have been proposed to explain this observation. One set of hypotheses, rooted in ecological niche theory, is based on the premise that tropics are more productive because they are warmer and wetter and therefore can accommodate more species. Another set of hypotheses focuses on historical causes such as the greater stability of tropics over geological timescales allowing greater speciation rates and lower extinction rates. However, it is hard to tease apart these hypotheses because geological stability and productivity are both greater in the tropics compared to temperate regions. Studying diversity gradients along elevational gradients offers one way to test these hypotheses because productivity usually declines as one moves up the mountain, but geological stability and biogeographic history is not expected to vary as much. For my dissertation in the Committee on Evolutionary Biology at University of Chicago, I am studying the diversity pattern of songbirds along one such elevational gradient in the eastern Himalayas.
In the eastern Himalayas, songbird diversity peaks at mid-elevations at around 2000m. This contradicts with the expectation from the productivity-diversity hypothesis and understanding the causes of this diversity gradient may shed some light on the processes shaping diversity patterns in general. Previous work in the Price lab has shown that ants are abundant at low elevations but essentially absent at the mid-elevations around 2000m. Ant abundance is similarly very low at montane cloud forests elsewhere in the world including in the Andes and south-east Asia. Incidentally, bird and small mammal diversity is usually highest in these cloud forests. Ants are a very important part of the ecosystem, especially in tropical regions, and can be highly voracious predators that potentially compete with birds and small mammals for food. In my research, I am examining the role of interactions between birds and ants in shaping the observed diversity gradient of birds.
I am co-advised by Dr. Trevor Price and Dr. Corrie Moreau and my research involves about three months of fieldwork every year conducting field experiments, collecting ants and catching birds to understand their diet through their feces.
My research has been supported by National Geographic Young explorers grant, two grants from the Henry Hinds fund for students at University of Chicago, Rufford Small grant and the Graduate Collaboration grant from the Art, Science and Culture Initiative. I have also received the Field Museum Women in Science graduate fellowship and the Schlumberger Foundation’s Faculty for the future fellowship.
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