Forthcoming Events
Herbivores and pathogens shape grassland ecosystems and mediate the effects of environmental changes
Dr. Mayank Kohli, DST INSPIRE Faculty Fellow, National Center for Biological Sciences.
Location : Online
Abstract: Global environmental changes and biodiversity loss are impacting the structure and functioning of ecosystems. Yet, to fully understand their effects on ecosystems, it is important to consider the role of species interactions, such as those between plants and their consumers including herbivores and pathogens. In this talk, I will present some of my previous and ongoing research that examines how plant-consumer interactions shape grassland ecosystems and mediate their responses to environmental changes. Subsequently, I will discuss upcoming and future research that builds upon my findings, and discuss some new research avenues.
First, I will discuss the importance of considering understudied plant consumers like arthropod herbivores and fungal pathogens alongside large herbivores in grasslands. My findings demonstrate that considering these interactions is important to more fully understand how changing biodiversity influences ecosystem functioning and stability. In particular, I found that foliar pathogens exert large effects on plant species composition, annual biomass production and its temporal variability, and through these changes affected overall grassland carbon fluxes. Moreover, the effects of foliar pathogens were contingent on the diversity of the plant community, and the presence of other consumers suggesting that the effects of consumers are context dependent.
Next, I will discuss the effects of climatic changes on montane grasslands in the Himalayas, and importantly, how these are mediated by the effects of large grazing herbivores. Findings from two separate climate experiments in contrasting environments show that climatic warming and droughts have large effects on montane grasslands and these effects vary along major environmental gradients such as aridity and elevation. Further, vegetation responses to climatic changes were dependent upon grazing, and in contrast to widespread assumptions, dampened under grazed conditions. These findings raise several interesting ecological questions, and have implications for the management of grasslands to sustain biodiversity and human well-being.
Lastly, I will discuss some upcoming research that expands on these findings, and some new research avenues. First, in a field experiment spread across multiple sites in the Himalayas, I am examining how changes in snowfall and temperature interactively affect montane grasslands directly and indirectly via changes in plant-consumer interactions. Second, I will examine the extent of top-down control by herbivores and pathogens across several grassland sites in India spanning a range of environmental conditions to understand the generality of patterns observed earlier. Finally, I will discuss some new collaborative work to deepen our understanding of open ecosystems in India, the impacts of grazing on these, and evaluating the threats posed by widespread tree-planting in these ecosystems.
Meeting ID: 910 3865 9643
Passcode: 909263
First, I will discuss the importance of considering understudied plant consumers like arthropod herbivores and fungal pathogens alongside large herbivores in grasslands. My findings demonstrate that considering these interactions is important to more fully understand how changing biodiversity influences ecosystem functioning and stability. In particular, I found that foliar pathogens exert large effects on plant species composition, annual biomass production and its temporal variability, and through these changes affected overall grassland carbon fluxes. Moreover, the effects of foliar pathogens were contingent on the diversity of the plant community, and the presence of other consumers suggesting that the effects of consumers are context dependent.
Next, I will discuss the effects of climatic changes on montane grasslands in the Himalayas, and importantly, how these are mediated by the effects of large grazing herbivores. Findings from two separate climate experiments in contrasting environments show that climatic warming and droughts have large effects on montane grasslands and these effects vary along major environmental gradients such as aridity and elevation. Further, vegetation responses to climatic changes were dependent upon grazing, and in contrast to widespread assumptions, dampened under grazed conditions. These findings raise several interesting ecological questions, and have implications for the management of grasslands to sustain biodiversity and human well-being.
Lastly, I will discuss some upcoming research that expands on these findings, and some new research avenues. First, in a field experiment spread across multiple sites in the Himalayas, I am examining how changes in snowfall and temperature interactively affect montane grasslands directly and indirectly via changes in plant-consumer interactions. Second, I will examine the extent of top-down control by herbivores and pathogens across several grassland sites in India spanning a range of environmental conditions to understand the generality of patterns observed earlier. Finally, I will discuss some new collaborative work to deepen our understanding of open ecosystems in India, the impacts of grazing on these, and evaluating the threats posed by widespread tree-planting in these ecosystems.
Meeting ID: 910 3865 9643
Passcode: 909263