Dryland Dynamics and Driving Forces

Drylands are the largest biomes on Earth, yet also one of the most vulner-able to climate change and human activities. Dryland ecosystems in the world are characterized by unique and distinctive features and are known to be particularly sensitive to natural and anthropogenic disturbances. Understanding the dynamics of dryland ecosystems and their direct and indirect drivers in socio-economic and natural terms will not only provide facts and knowledge about the dynamics and drivers of future trajectories, but also provide scientific guidance for the development of appropriate measures to improve the resilience of dryland ecosystems in response to human-driven climate change. We first provide an overview of the pecu-liar nature of dryland land cover, which features spare and patterned vegetation, soil biocrust, and man-made solar energy surface. We specifically highlight new opportunities for remote sensing observations and discuss their potential to provide new insights into dryland ecosystem functions and services. We next discuss the importance of and trends in water availability with emphasis on the different plant water utilization strategies found across global drylands, non-rainfall water absorp-tion, water availability estimation, and hydrological impact of land cover changes. Together these factors determine the development and degradation of drylands across global gradients of water availability. We then outline the role of climate change, population increase, and human activities in driving dryland changes. We end with a forward-looking perspective on future dryland research.