Celebrating and conserving the diversity of desert fishes

Authors: Chris Hoagstrom, Derek Houston, Norman Mercado-Silva

Year: 2016 (xlviii)

Abstract

The desert environment is a hotbed of endemism in fishes. Ongoing research continues to discover and describe more and more endemic diversity. Based on an up-to-date literature review, there are over 300 putative endemic taxa (species, subspecies, and distinct evolutionary lineages) occurring throughout arid/semiarid North America. These endemics are distributed among 28 separate geographical areas, each of which has a history of isolation from other areas due to limited aquatic connectivity that restricts inter-area dispersal. Overall, there is very little faunal overlap between opposing subgroups of 13 northern and 15 southern areas of endemism. This is evidence that each subgroup constitutes a distinct desert region for fish endemism, with greater levels of aquatic connectivity among areas within regions than between them. However, nested within this subdivision, all areas of endemism have unique assemblages of endemics. In addition, estimated times of origin for endemic taxa are broad and range from the Middle Miocene to the Quaternary. Thus, endemic biodiversity has arisen largely independently throughout these desert areas and has built up over millions of years. That is, each area of endemism has been a generator of endemic taxa and thereafter has served as a living museum or natural repository for ancient taxa that have accumulated over time. Hence, to preserve the sum of desert-fish biodiversity, conservation efforts will be needed in all areas of endemism. Further, conservation actions must prioritize protection of the natural habitats and ecological processes that have produced and maintained each unique taxon.