NEWS NOTES ON SUSTAINABLE WATER RESOURCES  Water and Ecosystems at the USGS  https://www.usgs.gov/mission-areas/ecosystems?qt-mission_...

NEWS NOTES ON SUSTAINABLE WATER RESOURCES  Water and Ecosystems at the USGS  https://www.usgs.gov/mission-areas/ecosystems?qt-mission_areas_l2_landing_page_ta=0#qt-mission_areas_l2_landing_page_ta  In most cases a healthy ecosystem implies a close relationship with water resources. The above link leads to the USGS Ecosystems Mission Area, with many examples of biological dependence on water. The USGS Ecosystems Mission Area, the biological research arm of the Department of the Interior (DOI), provides science to help America achieve sustainable management and conservation of its biological resources. This work is done within the broader mission of the USGS to serve the Nation with science that advances understanding of our natural resources and inform land and water stewardship.   This site includes many news items, which can be expected to change periodically. This includes publications as well as ongoing projects. For example, the Grand Canyon Monitoring and Research Center currently has 11 active science projects as a part of its Triennial Work Plan (FY2018-2020) for work conducted as the science provider to the Glen Canyon Dam Adaptive Management Program.  One such project attempts to determine what environmental conditions reduce predation vulnerability for juvenile Colorado River native fishes. Here is a summary of this work.  “The incompatibility of native Colorado River fishes and nonnative warm-water sport fishes is well documented with predation by nonnative species causing rapid declines and even extirpation of native species in most locations. In a few rare instances native fishes are able to survive and recruit despite the presence of nonnative warm water predators, indicating that specific environmental conditions may help reduce predation vulnerability.   “We experimented with turbidity, artificial blue water colorant, woody debris, rocks, and aquatic vegetation in a laboratory setting to determine if any of these types of cover could reduce predation vulnerability and confer survival advantages for four species. Juvenile native fishes were exposed to predation by adult largemouth bass, smallmouth bass, green sunfish, flathead catfish, and black bullhead catfish, in overnight trials.   “Turbidity above 500 NTU reduced predation vulnerability by up to 50%, for the sight-feeding predators, but increased predation vulnerability to non-sight feeding predators such as flathead catfish and bullhead catfish. Turbidity was the only treatment which appeared to significantly alter predation mortality of native prey.   “These results may help to explain recent patterns of wild juvenile razorback sucker recruitment at the inflow of the San Juan River into Lake Powell and the inflow of the Colorado River into Lake Mead. These are both areas of high turbidity where flathead catfish are not currently present but other nonnative sport fish are relatively abundant.”