Ecohydrology for me is the confluence of hydrology and ecology really, to improve our understanding of the interaction between water cycle and organismal and ecosystem ecology, to a level beyond what could be achieved by these disciplines standing alone. So, one aspect of this confluence is the various overlapping subject matters; for example, studying the role of water in shaping evolution and ecology of organisms and ecosystems, or the feedback of organismal and ecosystem functioning onto the water cycle. Another more exciting aspect of this confluence for me is the inter-flux of ideas, approaches and principles between ecology and hydrology.
What are your undergraduate and graduate degrees in?
My undergraduate degree, BSc, was in Microbiology, followed by an MSc in Biodiversity, both from Garware College, U. of Pune, India. Then a PhD in Ecology from the Indian Institute of Science, Bangalore.
How did you arrive at working in/thinking about ecohydrology?
In the Earth System Science focused PhD program that I was enrolled in, we were encouraged, or even mandated to undertake inter-disciplinary work, but the scope and means were left to us. I planned to study tropical forests and climate change relationships, especially via understanding plant functional ecology and life-history strategies. I had undertaken a lot of fieldwork in the long-term forest plots network in the Western Ghats Biodiversity hotspot, set up by Prof. R Sukumar’s group. Around then, Dr. Laurent Ruiz, an agro-hydrologist, came as resident researcher at the Indo-French Cell Science for Water Sciences on campus. Laurent was studying the hydrology of a Critical Zone Observatory, not far from my field sites in the Mudumalai National Park. He had showed that the dry forest as a whole was dependent on water in the weathered rock, and the time-scales of shallow and deep-water dynamics were dramatically different. I was captivated by the idea that if trees tap into different water-depth dynamics, they would differ in their responses to droughts, while also providing a window into their life-history strategies. Laurent was equally excited about testing these ideas, enthusiastically advised me, and so I could develop a model linking belowground hydrology to above-ground tree performance. When the work got published, I got a Harper prize for the best-paper in Journal of Ecology that year by an early career researcher (Chitra-Tarak et al. 2018). I also infected Dr. Sean McMahon with the excitement of this kind of work, who in turn invited me to do a post-doc with him in the US and provided all the habitat and mentoring I needed.
Although ultimately a rewarding experience, it was quite risky to begin this ecohydrology project at the peak of my PhD candidacy. Fortunately, I learned from my parents to take risks for the right reason--they themselves married inter-caste jumping strata (even after 40 years, only 5% of marriages are inter-caste in India), and shunned the security of mainstream careers to work for grass-root development (Science for Development in case of my PhD father). It also helped that I had imbibed a tenet of 'Finding valuable questions first, figuring out methods later' from Prof. Milind Watve, who got me interested in Ecology and Evolution in college, and who himself worked on a variety interesting questions in myriad fields.
What do you see as an important emerging area of ecohydrology?
I see that plant community and functional ecology will benefit a lot from eco-hydrology in the coming years, and consequently, the science of climate change. This is because building an understanding of how plants make a living in their given environments is at the cornerstone of plant community and functional ecology. It is also a precursor to predicting the fate of plants under future climate (and in turn, the fate of the climate itself). However, as much as water is a fundamental part of the plants’ environment, we do not know the water environments of the global plant community, historical or otherwise. I see that a full integration of hydrology into plant ecology can turn this around.
Do you have a favorite ecohydrology paper? Describe/explain.
One of my favorite papers is Susan Schwinning and Osvaldo Sala’s “Hierarchy of responses to resource pulses in arid and semi-arid ecosystems” (Oecologia, 2004). I like that this review develops a couple of useful organizing principles. It presents this idea that soil moisture pulse events—characterized by the depth and/or duration for which soil moisture is elevated to a level that promotes biological activity—occur over a large range of spatial and temporal scales (from minutes to multi-decadal). And that this hierarchy of pulse events is matched by a corresponding hierarchy of ecological pulse thresholds, wherein a small pulse event triggers a small set of minor ecological events, while a large pulse event triggers a more inclusive set, and larger ecological events. This review explores the potential evolutionary background for the existence of response thresholds, and ends with an outlook on global change as it perturbs the frequency, duration and depth of the pulse events.
What do you do for fun (apart from ecohydrology)?
Anything that brings me away from the screen into the physical realm: being outdoors and in the wild. Tango. COVID confinement, has shifted this though: to cooking and relishing delicious food. And getting to spend time with my partner like never before. I feel that it is a silver lining that the anti-racism protests are happening in the US as we speak. In India, systemic (and police) brutality on the poor, casteless or low-caste communities, Muslims and Adivasi tribes (indigenous peoples) is so normalized that it doesn’t move us (the few dissenters are silenced, eliminated or hounded). Even elite science and education institutes like IISc continue to be dominated by upper-castes who tout meritocracy while remaining caste-blind or caste-supremacists. We are never shown how privilege works--whether caste, gender or what have you. No wonder then that we come out of the education system as naïve bystanders or outright participants in oppression; even marginalized students end up undermining their own worth and in denial of the discrimination. We are choked by a majoritarian narrative more than ever before, but our tipping point seems that much closer, the more intense the injustice gets.