Aquatic invasive species within Ash Meadows National Wildlife Refuge since 2008: Updates, challenges, and goals

Authors: Darrick S. Weissenfluh, Cristi R. Baldino, Sharon D. Mckelvey, Robert J. Andress, Gayton G. Scoppettone, Brian M. Hobbs

Year: 2009 (xli)

Abstract

Ash Meadows National Wwildlife Refuge (Refuge) has a long history of aquatic invasive species (AIS) introductions, most of which occurred before Refuge establishment in 1984. At the beginning of 2008, there were 77 known populations of AIS occurring within Refuge boundaries. Currently, there are 70 known populations, which are comprised of the following 7 AIS: red swamp crayfish, Procambarus clarkii, western mosquitofish, Gambusia affinis, sailfin molly, Poecilia latipinna, largemouth bass, Micropterus salmoides, green sunfish, Lepomis cyanellus, bullfrog, Lithobates catesbeiana, and red-rimmed melania, Melanoides tuberculatus. Additionally, koi, Cyprinus carpio, and common goldfish, Carassius auratus auratus, have been detected in Refuge waters since 2006, though they have not established reproducing populations. Over the past two years, AIS eradications have been a primary focus of restoration activities. In 2008, rotenone was used to eradicate convict cichlids, Amatitlania nigrofasciata, from the Fairbanks System and western mosquitofish from the Fairbanks and Soda Spring systems. Rotenone was also used to eradicate black bullhead, Ameiurus melas, and a population of western mosquitofish from Davis Spring. Additionally, populations of red swamp crayfish and western mosquitofish were eradicated from School Springs by desiccation. An unsuccessful attempt was also made to eradicate largemouth bass and green sunfish from Crystal Reservoir, Horseshoe Reservoir, and Lower Crystal Marsh by desiccation. Though the Refuge has had success eradicating several populations of AIS, many challenges continue to materialize. A few challenges include expanding AIS populations, data gaps in AIS survival abilities specific to the Mojave Desert, uninformed pet owners, and reduced restoration funding. Despite these challenges, AIS eradications are a primary goal of ongoing restoration activities within the Refuge. Despite early setbacks associated with desiccation, the 2009-2010 goals include the eradication of 4 AIS populations: 1 population of western mosquitofish and red swamp crayfish from each of the North and South Indian springs. If this is achieved, only one spring system (South Scruggs) within the Warm Springs Complex will contain AIS; except red rimmed melania which have persisted despite eradication attempts. This is an important task to support recovery of the endangered Warm Springs pupfish, Cyprinodon nevadensis pectoralis.