Assessing changes of anthropogenic footprint on water-limited ecosystems

Assessing and understanding changes in human appropriation of terrestrial ecosystems is of crucial importance for ensuring sustainable and balanced development of Societies and ecosystems on Earth. Biodiversity loss and loss in ecosystem services have been reported as a result of unsustainable land use and climate change. Yet major uncertainties remain regarding our capability to accurately assess on-going land changes, as well as to comprehensively attribute these changes to natural and/or anthropogenic drivers. Indeed ecosystem response to external pressures is often complex (e.g. non-linear) and non-unique (i.e. same response, different drivers).

Here we used 35 years of climate and vegetation data to quantify the anthropogenic footprint on water-limited ecosystems at global scale. We applied the assessment method developed by Horion et al. (2016) that showed that basic information on the nature of the drivers can be inferred from combined analysis of climate and vegetation trends. One of the main outcomes of our study is a global categorisation of levels of anthropogenic footprint, ranging from over-productive to under-productive ecosystems. In addition, trajectories of change in anthropogenic footprint were assessed over ecosystems that encountered an abrupt change in their functioning during the period of observation. This is the first global assessment of its kind.

Despite a dominant naturogenic response of ecosystems to climate, our study highlighted substantial anthropogenic footprint over most biodiversity hotspots located in water-limited environment. Our study also indicated interesting hotspots of decreased anthropogenic footprint in South America and more complex changes (both increase and decrease) for the Sahel. These results will be further developed and discussed at AGU, notably in the lights of already existing consolidated assessments of human appropriation of terrestrial ecosystems.

References: Horion, S., Prishchepov, A. V., Verbesselt, J., de Beurs, K., Tagesson, T., & Fensholt, R. (2016). Revealing turning points in ecosystem functioning over the Northern Eurasian agricultural frontier. Global Change Biology, 22(8), 2801-2817. doi:10.1111/gcb.13267

Acknowledgment: This research is funded by the Belgian Federal Science Policy Office (Grant SR/00/339)