Quantitative Biosciences Thesis Proposal 

Sidharth Srinivasan

School of Biological Sciences

Advisor: Dr. Benjamin Freeman (School of Biological Sciences)

Open to the Community

The impact of seasonality on the ecology, evolution and response to climate change in mountain avifauna
March 17, 2026, at 9:00am

Location = Ford ES&T, L1205

Committee Members:

Dr. Jenny McGuire (School of Biological Sciences/School of Earth & Atmospheric Sciences)

Dr. James Stroud (School of Biological Sciences)

Dr. Umesh Srinivasan (Indian Institute of Science, Bangalore, India)

Abstract:

Seasonality - the periodic fluctuation of temperatures, precipitation, and resource availability - is a fundamental force driving where species live. Nowhere are these effects more dramatically compressed than on mountains, where steep elevational gradients recreate latitudinal climate zones within a short distance. However, important gaps remain in our understanding of how seasonal variation structures mountain bird ecology and evolution, and how birds will respond to a rapidly changing climate. My thesis addresses these questions across four interconnected chapters spanning different scales - from macroecological patterns to individual movement ecology, with a focus on the Himalaya - Earth's tallest and most climatically diverse mountain range. I begin at the global scale (1) a meta-analysis revisiting Janzen's (1967) key hypothesis that tropical mountain passes act as stronger physiological barriers to dispersal than temperate ones and (2) examining a key life history trait shaped by seasonality - breeding phenology - in tropical birds using a large citizen science dataset. I then move to the regional scale and focus on the Himalaya, quantifying how bird communities have shifted over the past decade across two seasons because of climate warming. In the final chapter, I test mechanisms driving individual movement at the local scale - the climatic drivers of elevational migration in populations of a focal Himalayan species. Together, my thesis will provide a multi-scale framework for understanding how seasonality shapes mountain avifauna, and for predicting how birds will respond in an increasingly changing world.