Eradication of invasive Red Swamp Crayfish, Procambarus clarkii, from a Mojave Desert Spring Complex

Authors: Robert Andress, Hal Fairfield, Darrick Weissenfluh, Lee H* Simons, Laurie S. Simons, Annji Bagozzi

Year: 2015 (xlvii)

Abstract

Red swamp crayfish, Procambarus clarkii, is one of the most widely introduced and invasive of all crayfish, and has infested many areas in southern Nevada, including four of the six springs in the Warm Springs Complex, Ash Meadows National Wildlife Refuge. The Warm Springs Complex consists of six low-discharge spring systems with individual flows ranging from 1.13 x 10-4 to 1.98 x 10-4 cubic centimeters per second. Water temperatures range from 28 to 34 degrees Celsius. Four aquatic invertebrates and the endangered Warm Springs pupfish, Cyprinodon nevadensis pectoralis, are endemic to this Complex; the pupfish was in decline as efforts to eradicate crayfish began in 2008. The smallest of the springs infested with crayfish, School Spring, was diverted and desiccated from April through May 2008. Based on this success, three springheads at North and South Indian springs were diverted and springbrooks desiccated over a period of 21 months, including two cycles of hot summer weather. South Scruggs was the largest and most complex spring system to be cleared of crayfish, involving diversion of three springheads, desiccation for 26 months, including two summer cycles, and aggressive removal of organic debris and substrate in springhead areas. These efforts involved intensive trapping of crayfish pre- and post- eradication, salvage and repatriation of native fish and invertebrates from the springs undergoing rehabilitation, fencing to prevent crayfish movements, and extended monitoring of invertebrates and vegetation impacted by the project and especially for any surviving crayfish. To our knowledge, this 7-year effort represents the first successful eradication of this crayfish from an entire spring complex. Temporary desiccation, combined with a sound plan for containment and capture of surviving target pests, may be a successful strategy for control of aquatic invasive species in other ecosystems.