Invited Seminar at CES on 12 April 2021 at 11:00 am titled "On the edge of (co-)existence: diversity in human-modified forests" by Dr. Meghna Krishnadas from CCMB

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On the edge of (co-)existence: diversity in human-modified forests
Dr. Meghna Krishnadas, CCMB
Date & Time: 
12 Apr 2021 - 11:00am
Event Type: 
Invited Seminar
Microsoft Teams

We live in a human-dominated Earth. Human activities have broken up many once contiguous terrestrial habitats into smaller fragments—where ecological communities lose diversity. Patterns of diversity loss in forest fragments have been widely documented. Yet, we know surprisingly little about how the mechanisms that maintain diversity fare in fragments. Long-standing theory and growing empirical evidence indicate that in plant communities, pests and pathogens—natural enemies—help maintain diversity via negative feedbacks on host plant populations. The diversifying effects of enemies are especially strong during the early life-stages of seedling establishment and survival, but its imprint can last many generations. Could weaker enemy effects explain reduced plant diversity in forest fragments? In a human-modified forest, I found that enemies such as insects and fungi were less able to maintain diversity of tree seedlings near forest edges compared to interiors. Weaker effects of enemies also changed the functional characteristics of recruiting seedlings. Simulations using this field data show that changes to seedling dynamics can compromise the long-term ability of fragments to maintain diversity. Contrary to common expectation, canopy openness, a correlate of light availability, did not correlate with spatial variation in diversity of species or traits. With nearly 20% of the world’s forests being within 100 m of an edge, loss of cryptic biotic interactions may pose a widespread threat to plant diversity. In my future work, I will delve deeper into the mechanisms that link enemy-mediated feedbacks to species performance and diversity in forest edge vs. interior. Furthermore, I will expand on my ongoing work that examines how a changing climate (drought) will interact with edge effects to shape performance of tree species, and hence their fitness, in human-modified forests. Mechanistic insights that combine ecological theory with observation and experiment can help predict the trajectories of human-modified ecosystems in a fast-changing world.

Speaker Bio: 
I am fascinated by the complexity of the natural world around us. As a community ecologist, my research stems from a curiosity to understand the mechanisms that maintain diversity in ecosystems. In any ecological community of similar species, what processes allow species to coexist? What prevents one or few species from out-competing others? Also, living in a human-dominated planet, I want to understand how the mechanisms that maintain diversity change when subject to human influence. In a different life past, I was a medical doctor, but I left the hospital halls to walk the forest trails. My transition to ecology began with the realization that biodiversity was being lost at alarming rates. I went from activist to scientist because I felt that knowledge was essential to action, but I was also increasingly driven by sheer intellectual curiosity of nature’s workings. I have a Master’s degree in Wildlife Biology and Conservation from the National Centre for Biological Sciences (NCBS) and a PhD from Yale University’s School of the Environment. I was a Campus Fellow at NCBS and then Project Scientist at the CSIR Centre for Cellular and Molecular Biology (CCMB) where I am currently a Senior Scientist. I enjoy writing and communicating science and believe that it is important for scientists to engage with the wider society. Off work, I like to run, practice yoga and try out new fitness regimens. Good books, great conversations, and gastronomy rank high in my life agenda and someday I would like to farm (at least some of) my own food.