We seek to understand the processes that allow species to coexist and thus maintain diversity in ecological communities. We use functional traits—heritable characteristics that mediate species' response to different conditions—to understand patterns and processes that shape biodiversity in different ecosystems. Further, in a world shaped overwhelmingly by humans, we want to predict how global environmental change will shape the future of biodiversity. To understand the organization and potential reorganization of ecological communities at multiple spatial scales, work in the lab focuses on the following broad themes:
 
  1. How abiotic conditions govern community assembly and dynamics

    • Not everything is everywhere. Individuals and species are excluded from some places and do well in other places because they differ in their tolerance of abiotic environments and the resources they need to survive, compete and persist. Plants, for instance, compete for light, water, and nutrients. How efficiently plant acquire and use these resources determines plant performance and in turn their distributions and relative abundances. Work in the lab has detailed the role of key abiotic factors that explain plant species distributions and performance from local to regional scales. For instance, we showed that climatic water deficit is a primary driver of tree species distributions across the Western Ghats. Ongoing work is looking into the role of light, water, and nutrients in shaping patterns of seedling distribution and performance. Such insights spur further work on the mechanisms of community assembly, help predict response to environmental change, and can be applied to habitat restoration.

  1. Biotic interactions of plants

    • While seemingly standing still, plants live complex and dynamic lives as they interact with an astonishing array of organisms: microbes in the soil, insects that eat leaves or pollinate flowers, animals that eat fruits and disperse seeds. Interactions shape plant communities.

    • Soil microbes can help or hinder plants and this plays a role in the ability of plant species to coexist. This has been extensively studied, although very little from Asia, but we don't know whether the role and implications of microbially-mediated plant dynamics depends on abiotic context. We are trying to tease apart the pathways by which soil microbes mediate competition between plants when abiotic conditions vary. We are especially interested in the interactions between plants and fungi.

    • Insects have long danced in evolutionary step with plants. In some regions of the world, like Amazonia, the race for plants to escape insect herbivores has led to an amazing diversity of plant species, differentiated by their chemical defense against insects. Have such processes happened in the Indian subcontinent where the evolutionary context is different from American tropics? We do not know! We have work aimed to establish the ecological effects of insects on plant performance and community dynamics and then link it to evolutionary signals of plant-insect interactions.

    • We are also interested in the impact of dispersal on plant communities, especially to understand how dispersers may drive metacommunity dynamics, i.e., how plant communities connect and interact across space.

  1. How traits shape communities

    • The response of organisms to abiotic and biotic factors relates to their traits—heritable features of their anatomy, morphology, physiology—that relate to functions such as ability to use resources, withstand stresses, or tolerate disease. Our work spans a gamut of plant traits (leaves, roots, flowers, physiology) to test their role in the assembly and structure of plant communities in a range of ecosystems: the humid forests of the Western Ghats, savannas of Eastern Ghats, and alpine grasslands of the Western Himalaya.

  1. Impact of global environmental change on mechanisms that maintain diversity

    • Our planet is rapidly changing and global environmental changes will disrupt ecological communities and ecosystems. Discerning these changes relies on the ideas above as a foundation, which offers fundamental insights into how these systems work. We have applied these concepts to assess how plant species in different ecosystems respond to drought, whether forest fragmentation alters plant interactions with microbes and insects, and how invasive plants alter vegetation dynamics. In the future, we plan to monitor the impact of climate change across elevational gradients.