Land-use change driven by humans for economic gains has been a common sight in the past few decades. This has lead the humans to alter the structure and functioning of ecosystem . Such alteration of earth-system has led to modification of nutrient cycles, affecting climate and eventually lead to the declines in biodiversity. Rapid change in land-use have shifted the community composition of a range of taxonomic groups including microbial decomposers. This has resulted in biotic homogenisation, where rare and endemic species have been replaced with already widespread species over time and space. Studies addressing the specific functional and ecological consequences of biotic homogenisation have majorly focussed on aboveground trophic levels and it is thus unknown whether land-use change homogenises microbial functions in ecosystem. We measured several microbial functions, particularly respiration and extracellular enzyme activity, from soils collected from different land-use over different points along the growth season (May to September) in semi-arid Trans-Himalayan agro-pastoral ecosystem. Functions measured are responsible for ecosystem functioning by regulating the flow of material and energy in soil. This place has undergone significant human modification where native herbivores have been progressively replaced by domestic livestock and agricultural lands.
Results/Conclusions
We show, microbes alter nutrient turnover with shift in land-use. We found that microbial functional space reduces with change in land use from wild to livestock to agriculture. Agriculture showed lower functional dispersion. We also showed that our results were not an artefact of spatial autocorrelation due to the proximity of agricultural sampling locations. There was temporal variation in all our measures of functional homogeneity. Overall, our results provide evidence for change in variability of soil microbial functions with change in land use in grazing ecosystem, with agricultural lands most functionally homogenised followed by livestock and wild, respectively. So, vulnerability of the ecosystem to future environmental perturbations ultimately depends on the extent to which microbial functions are altered with human domination. Thus, humanity faces the challenge of managing the trade-off between ever-increasing human needs and maintaining ecosystem for its services.