Prioritizing present and future conservation efforts for native fishes in the Lower Colorado River Basin

Authors: Angela L. Strecker, Julian D. Olden

Year: 2010 (xlii)

Abstract

With increasingly severe losses of biodiversity and habitat fragmentation, the need for effective conservation strategies is immediate. This is of particular importance given the limited funding available for conservation; solutions need to be cost-effective. The best allocation of resources should protect the maximal number of native and endemic species, but trade-offs exist that confound conservation efforts in aquatic systems. These trade-offs may include maintaining hydrological connectivity, avoidance of non-native species, human population growth, future climate change, single-species versus community approaches, and costs involved with acquiring land for protection and/or restoration. Here, we examine the efficacy of landscape-scale tools for prioritizing conservation areas for threatened desert fishes in the Lower Colorado River Basin, with consideration of the trade-offs identified above. We also provide an overview of different landscape-scale tools available for scientists. The first step in the conservation prioritization process is to generate a basin-wide model of species distributions; this is a necessary step, as distributions of species of concern are often lacking at broad spatial scales. This was done using a combination of hydrological, topographical, land use, and climate variables. Maps of species probability of occurrence were then used as input for conservation planning efforts. We then developed a conservation priority rank of all catchments in the Lower Colorado River Basin that contrasted native species diversity with distribution models of non-native species and contemporary threats to fish species. These rankings were then compared to scenarios of human population growth and climate change over the 21st century. Our research highlights the necessity for the understanding and inclusion of the trade-offs facing conservation efforts in the basin, and the strengths and pitfalls of landscape approaches to conservation. Innovative approaches to conservation must be considered to prevent further losses of diversity of this unique fauna.