Summary
Ephemeral streams across the continental United States have become less reliable sources of surface water over the past 40 years, likely as a result of climate change, researchers reported last month in Environmental Research Letters. That is bad news for the many plants and animals that time their reproduction to the availability of water, especially in deserts, and also has implications for water quality. The drying trend is clearest in arid regions, but it is apparent even in relatively wet areas. In some cases, human activities such as operating dams, irrigation, and groundwater pumping could also be contributing to dewatering. Broader monitoring of intermittent streams is needed, scientists say. Others say the results highlight the need for stronger legal protections for intermittent streams that form the headwaters of many rivers.