Ecosystem resilience is defined as the ability of the system to remain
unchanged or regain its prior state after subjected to perturbations. In
this study, we have considered two kinds of perturbations namely; climate
factors and above-ground trophic interactions. As plants form a bridge
between above-ground and below-ground trophic interactions, plants are
considered as an assay to evaluate the status of an ecosystem. In the
current scenario of global warming, the temperature and precipitation
patterns have shown increasing variation, with a shift in mean global
temperature and precipitation patterns. Researchers have documented
increase in temperature and changes in precipitation patterns in
Trans-Himalayan region. Thus Trans-Himalaya is a model ecosystem to
examine vegetation-climate relationships. We hypothesize changes in
phenology considering plant-soil interactions, with the background of
on-going climatic changes in the Trans-Himalayan landscape. In this study,
phenology is used to understand the vegetation state. Phenological changes
can be detected by examining time series data on vegetation. Hence remote
sensing data is used to understand large scale vegetation changes due to
climatic conditions in Trans-Himalayan landscape. Our preliminary analysis
shows that the majority of the area of Trans-Himalayas has not changed
from 2002-2015. We address this resilience of the Trans-Himalayan
vegetation to climatic variations through resource co-limitation
hypothesis.
Above-ground trophic interactions like herbivory and carnivory can have
direct (consumption) and indirect (non-consumption) effects on vegetation.
These above-ground trophic interactions determine the chemical composition
and quantity of detritus. The nutrient in the detritus is recycled back to
plants by soil microbes, and this ecosystem process depends on the abiotic
conditions like soil temperature and moisture. Hence it is important to
understand the interaction between climate factors and above-ground
interactions in determining vegetation structure and composition. The
interactions between above-ground organisms and plants are highly complex.
Trophic cascade provides a framework to understand these complex
interactions. We apply the concept of trophic cascade by conducting
herbivore, carnivore exclusion experiments in grassland ecosystem. These
field experimental plots are set-up across a gradient of rainfall to
capture the interactions between above ground interactions and water
availability. Here I present preliminary results of grass biomass
subjected to different scenarios of above ground trophic interactions.