Interactions of global change drivers in drylands: What theory would predict and what data show

Background/Question/Methods

Drylands represent our planet’s largest terrestrial biome and play dominant roles in maintaining biodiversity, regulating Earth’s climate, and sustaining billions of people. In addition to their importance and large spatial extent, dryland ecosystems seem extremely sensitive to anthropogenic change, such as climate and land use change. Yet, although such disturbances commonly co-occur, our understanding of how climate change and physical disruptions (e.g., from grazing, development) interact to dictate the responses of dryland systems and their functions remains notably poor. In particular, dryland responses to global change may be distinct from those in wetter systems, particularly when it comes to the synergistic and antagonistic effects of multiple co-occurring global change drivers.

Results/Conclusions

Here we explore the paradigms, theories, and emerging data regarding dryland responses to the interacting effects of climate change and land use with the goal of elucidating the responses of dryland plants, soils (including biocrusts), and their associated functions. We will focus on interactions between the effects of aridification (stemming from increased temperatures and drought) and altered physical disturbance regimes (stemming from land uses that physically disrupt plants and soils, such as grazing and energy development). We will blend results and perspectives from observations, cross-site in situ manipulation experiments, modeling, and remote sensing approaches to delve into the consequences of multiple global change drivers, the mechanisms that determine the observed responses, and the role of plant and soil community composition. Both the importance and sensitivity of drylands in directing function are increasingly recognized from the local to the global scale. This talk aims to consider the ‘why’, ‘so what’, and ‘what’s next’ for dryland responses to global change.