Drought Experiment 2021

Dr. Dana Warren, Dr. Catalina Segura, and graduate student Allison Swartz are exploring how drought conditions affect streams and the animals that live in streams. Under low-flow conditions, trout and salamanders aggregate in pools or cooler water, increasing competition for macroinvertebrate prey, and causing reduced growth and survival. Groundwater inputs may reduce the severity of drought effects on stream flow and temperature.  In 2021 the researchers tested their ideas and techniques by conduct a pilot drying and warming experiment in a stream at the Andrews Forest. They created separate sections of stream with (a) low flow and (b) elevated temperatures (using passive heating of water traveling through black coils of tubing before returning the water to the stream). They measured groundwater contributions using longitudinally distributed temperature sensors and synoptic measurements of O18. In the study and control stream sections, they measured prey availability, fish and salamander individual growth, abundance, survival, and use of deep pools. The researchers will use the information from their pilot study to inform how they set up a larger experiment, to test drought conditions and groundwater input.