Spatial Conservation Assessment for Native Fishes in the Lahontan and Central Nevada Basins, USA

Abstract

Freshwater biodiversity is declining faster than terrestrial and marine biodiversity. The protection and restoration of aquatic habitats are based, in part, on stemming this decline. We conducted a spatial conservation assessment of native fishes in the Lahontan and central Nevada basins using core-area zonation. The complementarity-based assessment yielded a landscape value (rank) of all subwatersheds (12-digit hydrologic unit code; ~12,000 ha) whereby high-ranking subwatersheds, as a set, maximized the representation of all native species, subspecies, and the within-species ecological diversity of salmonids, while accounting for aquatic connectivity and risk of aquatic habitat degradation. The high-ranking subwatersheds encapsulated small patches of habitat inhabited by endemic desert fishes, as in the Ash Meadows National Wildlife Refuge. They also highlighted clusters of high-value subwatersheds, such as in the Truckee River watershed that has extant populations of, and historical habitat for, Lahontan cutthroat trout in its headwaters, with species such as the mountain whitefish with migratory life histories, and endemic cui-ui, Chasmistes cujus, at Pyramid Lake—a terminal lake. Both the Truckee River headwaters and Pyramid Lake have been recipients of ongoing native fish conservation efforts. The landscape rankings will be used by the Desert Fish Habitat Partnership to inform regional conservation investments, and the rankings are available for broader use by resource agencies working on native fish conservation at landscape scales.