Global change drivers, such as land use intensification, frequently cause a loss of biodiversity and this can impact the functioning of ecosystems. However, as well as changing diversity, land use intensification alters species composition and total abundance, at multiple trophic levels, and both of these changes can also affect ecosystem functioning and service provision. Alongside its various indirect effects, land use is also likely to directly affect function. Although all of these processes are likely to be important, we have very little information about which direct or indirect effects matter for different ecosystem functions. We disentangle the various effects of land use on ecosystem function using a large biodiversity and functioning dataset from German grasslands differing in land-use intensity. We included measures of 20 ecosystem functions, or service proxies, and data on around 2000 species of microbes, arthropods, pathogens and plants.
Results/Conclusions
There was substantial variation in the importance of these different effects across functions. Some functions, related to soil carbon and belowground production, were mostly directly affected by land use, while functions such as pollination, pest control and decomposition were largely affected by compositional changes. Diversity change had the largest effects on cultural service proxies and on nutrient use and decomposition. In general, changes in abundance tended to be less important than the other effects. Changes in both above and belowground groups were important but were often contrasting as the two responded differently to land use intensification. These results show that global change affects functioning through a variety of different mechanisms and understanding this variation will better allow us to predict and manage its effects on ecosystems.