The ripple effect of surface water on dryland ecosystems.

Animals in dryland systems often aggregate around water, concentrating trophic pressure, transporting resources, and modifying habitat. These effects have been described as piospheres of degraded soils and vegetation; however, we argue that this framing is incomplete. We propose that animal aggregations around surface water generate a ripple effect: cross-scale, reciprocal impacts on both terrestrial and aquatic ecosystems that vary with water availability. As surface water becomes increasingly scarce under global change, management and conservation approaches should prioritize the restoration of spatiotemporal variability in surface waters. An integrated approach that bridges linked terrestrial and aquatic ecosystems and combines community and ecosystem ecology is necessary to identify emergent ecosystem properties, predict landscape-scale impacts of altered surface water availability, and inform adaptive management.