Dryland responses to anthropogenic change: a biogeochemical perspective

Sasha C. Reed (Moab, Utah, USA): Dryland ecosystems represent our planet’s largest biome and are home to billions of people, yet, our appreciation of the importance of drylands in global functions and feedbacks is still quite poor. Further, while we know arid and semiarid ecosystems can be affected by a host of anthropogenic changes – such as climate change, increasing atmospheric CO2 concentrations, land use change, and nutrient deposition – a synthetic understanding of the mechanisms and larger-scale consequences of this change remains elusive. In this talk, I will use a biogeochemical lens to examine how dryland plants and soils are affecting and affected by environmental change. By considering the cycles of carbon, nitrogen, and phosphorus both above- and belowground, I will ask questions about how drylands work and how they are responding to a changing world. This will include discussions about the fascinating biological soil crusts that help regulate dryland function. I will cover topics such as temperature effects in warm biomes, the potential for mass mortality events, and unexpected consequences of nitrogen deposition. I hope to leave you with a biogeochemical appreciation for the importance and complicated connections of these spectacular and dry systems.