US: Are Russian olive trees fueling an invasive species in the San Juan River?

The San Juan River, a major tributary of the Colorado River located in the "Four Corners" region of the southwestern United States, is home to two native fish species—the Colorado pikeminnow and the Razorback sucker. Both of these species are federally endangered and are being threatened by an invasive species, the channel catfish. To save the endangered fish, biologists, researchers and wildlife managers have been attempting to better understand how these native and non-native species interact with each other. Christopher Cheek, assistant professor in South Dakota State University's Department of Natural Resource Management, is one of those researchers. Introduced in the late 1800s, channel catfish are a direct threat to native fish through both predation and competition. While the impacts of non-native fish are difficult to quantify, resource managers have deemed them a direct threat to the native fish ...