ABSTRACT. A list is provided of all crayfishes (family Cambaridae) in the southern United States, which includes common names, global conservation status, an alternative review of the conservation status based on the IUCN red list criteria, and state distribution. This list includes 357 native crayfishes, of which 12 (3.4%) are critically endangered, 37 (10.4%) are endangered, 126 (35.3%) are vulnerable, 181 (50.7%) are lower risk, and 1 (0.3%) is not evaluated. The leading factors causing imperilment are restricted ranges caused by anthropogenic impacts from changes in land use, contaminants, invasion by non-indigenous species, and habitat fragmentation. In order to conserve and manage diversity of native crayfish, consistency is needed in determining conservation status and more complete distribution and life history information are needed for about 60% of species.

Keywords: imperiled species, global vulnerability, International Union for Conservation of Nature, biodiversity, threatened species

INTRODUCTION

North American aquatic biodiversity has been disproportionately affected by anthropogenic influences. A major focus is to fill gaps in research on crayfish ecology and present new information on imperilment of aquatic species. This need has benefited from the focus produced by the Natural Heritage Global (G) compilation of conservation status ranks (Master 1991). As a result of the Global status ranks, other groups have increased their emphasis on assessing other freshwater faunal diversity. The American Fisheries Society (AFS) Endangered Species Committee evaluated the conservation status of North America's freshwater fish fauna (Deacon et al. 1979; Williams et al. 1989; Warren et al. 2000), freshwater mussels (Williams et al. 1993), and North American freshwater crayfishes (Taylor et al. 1996, 2007). Taylor et al. (2007) assessed the conservation status and threats to native crayfishes in the United States and Canada using the best information available, provided updated state/ provincial distributions, updated the list of references on the biology, conservation, and distribution of crayfishes in the United States and Canada, and assigned standardized common names. All of the AFS conservation assessments used the best professional judgment of taxonomic group experts to determine imperilment.

Crayfishes are closely related to marine lobsters (Crandall et al. 2000) and are members of the order Decapoda, which includes crabs, lobsters, and shrimps. Crayfishes are included in three families, and native inhabitants occur in freshwater ecosystems on every continent except Africa and Antarctica. Two families, Astacidae and Cambaridae, are native to North America and include about 408 species and subspecies, representing about 77% of the global species diversity in North America (Taylor 2002). The majority of the North American fauna (99%) is assigned to the family Cambaridae with over two-thirds of its species endemic to the southeastern United States.

Crayfishes occur in every seasonally wet and terrestrial habitat including a variety of aquatic habitats. They possess unique life-history traits adapted for these habitats, including alteration of reproductive form and burrowing abilities that allow colonization (Hobbs 1981; Welch & Eversole 2006). Our purpose for this research is to report on the conservation status of the North American crayfish fauna distributed in the southeastern United States using the...