Because climate and water are intimately linked in deserts, desert streams are well suited for observing consequences of both natural climate variability and human-caused climate change. Here, researchers are studying how stream ecosystem structure changes as variable frequency and magnitude of both flash floods and drought periods over many years cause losses or gains in the abundance of wetland plants. A shift in stream ecosystem structure to dominance by wetland plants affects ecological functions in important but undocumented ways. Both the causes and consequences of this shift will be assessed by surveying structure, monitoring stream chemistry, comparing wetland with unvegetated stream reaches during recovery following winter-spring flooding, and statistically analyzing hydrology-ecosystem relationships. An interdisciplinary team will reevaluate stream ecosystem models and test new models using long-term data from this and other streams.

This research will promote synthesis of long-term data from aridland streams and advance understanding of these ecosystems in ways that can contribute to the general theory of stability of multiple ecosystem states. A distributed graduate seminar will give students experience with use of long-term databases and foster collaborative interactions. The database for this well-known stream ecosystem will be extended to more than 35 years and made available to the scientific and management community, potentially informing management in a highly variable environment where stressors of climate change and population growth are converging.