Watershed Responses to Disturbance

Watersheds and streams, such as this one at the H.J. Andrews Experimental Forest, are impacted by disturbances such as fire and reduced snowpack.  Photo by Ben Nash.

As climate change intensifies, natural disturbances are dramatically reshaping ecosystems. This is especially prevalent across the western United States, particularly in vulnerable mountain regions with complex landscapes and tightly linked land-water systems. In this study, we examine how disturbances—whether sudden events like wildfires and bark beetle outbreaks, or ongoing pressures like reduced snowpack and gradual vegetation changes—affect the chemistry and flow of streams in temperate montane watersheds. Through a combination of conceptual frameworks and analyzing long-term "hydrochemograph" data from Western watersheds, we reveal how these disturbances upset the balance of these already resource-limited systems. For example, clearcutting in an H.J. Andrews watershed demonstrates how sudden vegetation loss leads to high nitrate fluxes. Our study emphasizes the importance of long-term ecological monitoring to anticipate and mitigate the cascading impacts of climate change on water resources. As disturbances grow more frequent and severe, their impact on downstream communities—many of which rely on these watersheds for drinking water, agriculture, and recreation—will become increasingly severe and far-reaching. By advancing our knowledge of how these systems respond to various ecological stressors, we can support better resource management and policy planning to help communities adapt to changing water availability and quality. In a time of rapid environmental change, this research calls for heightened awareness of watershed health and urges continued investment in long-term data collection.

Rock, L.A., Shoup, B., Ajowele, J.A. et al. Watershed Responses to Climate Change-Driven Disturbances in Temperate Montane Ecosystems of the Western United States. Ecosystems 27, 1123–1142 (2024). https://doi.org/10.1007/s10021-024-00942-9