The Speckled Dace, Rhinichthys osculus (Girard), is a small species of fish (Cypriniformes, Leuciscidae) that has the widest geographic range of any freshwater dispersing fish in western North America. The dynamic geologic history of the region has produced many isolated watersheds with endemic fish species. However, Speckled Dace from these watersheds cannot be differentiated readily by morphometrics and meristics. This has led to the widely accepted hypothesis that the dace’s adaptability and ability to cross geologic barriers has resulted in interbreeding among neighboring populations, maintaining the dace as a single species. We investigate this hypothesis by looking at Speckled Dace populations in California which are the result of at least three separate colonization events of isolated watersheds. We synthesize results from taxonomic, genetic, and zoogeographic studies in combination with the findings of a recent genomics study, to show that there are distinctive evolutionary lineages within the Speckled Dace complex. These lineages are used to designate multiple species and subspecies. We back up these designations by examining how well these lineages fit with the geologic history of the isolated basins they inhabit and with the presence of other endemic fishes. We conclude the following nine taxa can be recognized within the Speckled Dace complex in California.

While the desert ecosystem is highly dependent on the water resources that sustain it, the Fish Slough spring complex is an arid, spring-dependent wetland undergoing a multidecadal decline in spring outflow. This evaluation updates the source water forensics of the Fish Slough Spring complex, a substantial spring complex in the northern Owens Valley of the Basin and Range geomorphic provinces, in order to better understand the nature of the spring flow decline. The source of spring flow at Fish Slough was evaluated through an integration of the established geologic setting with measured groundwater elevations, and water quality and isotope chemistry compiled from both previously published sources and collection of new samples. While previous efforts to source the Fish Slough springs only considered potential source areas within the local geography, this evaluation considered a larger geographic extent for potential source areas to the spring water. The results infer that Fish Slough springs are sourced from multiple source water areas in hydraulic communication: a basin fill aquifer and warm, sodic spring systems with distinctive chemical signatures. Mixing from these sources occurs along two hypothesized flow paths, one from the northeast through the Tri-Valley area and one from the north and northwest through the Volcanic Tablelands. Northeast Spring has the strongest signature for Tri-Valley area waters, whereas the remaining Fish Slough Springs are comprised of a mixture of both flow paths. These conclusions have important implications for water management activities that have the potential to impact the desert ecosystem supported by these springs.

32Scientific progress depends on evidence-based research, and reliance on accurate scholarship is 33 essential when making management decisions for imperiled species. However, erroneous claims 34 are sometimes perpetuated in the scientific and technical literature, which can complicate policy 35 and regulatory judgments. The literature associated with two enigmatic California desert 36 vertebrates, the Panamint alligator lizard Elgaria panamintina and the Inyo Mountains 37 salamander Batrachoseps campi, exemplifies this problem. We produced a comprehensive threat 38 analysis and status assessment for these species, which are both under review for possible listing 39 under the US Endangered Species Act (ESA). Despite uncertainties and limited data, we find that 40 many sources contain factual errors about the status of these two species, particularly the original 41 petition that advocated for ESA listing. Although localized declines may have gone undetected, 42 no evidence exists of population declines, population extirpation, or population-scale habitat 43 conversion for E. panamintina. However, there is evidence of recent flash flood damage to some 44 occupied B. campi habitat, which has possibly led to population declines at those localities. 45Contrary to inaccurate statements by some authors, all known populations of both species occur 46 exclusively on federal lands, and numerous populations have likely benefited from recent federal 47 management targeted at reducing known threats. Of the 12 threats that we identified for one or 48 both species, only three currently appear to be serious: water diversions, climate change, and 49 flash floods. The remaining threats are neither widespread nor severe, despite numerous contrary 50 yet poorly supported statements in the literature. We thus evaluate the contemporary 51 conservation status of both species as relatively secure, although B. campi is more at-risk 52 compared to E. panamintina. This conclusion is independently supported by a recent review. 53Nonetheless, ongoing stewardship of these species in a multi-use context by federal agencies 54 remains vital, and we identify several priority management actions and research needs for both 55 species. We also recommend updated determinations on the IUCN Red List, and the Species of 56Conservation Concern list of the Inyo National Forest. To maximize the quality and effectiveness 57 of conservation planning, we urge government agencies, non-governmental organizations, and 58 individual scientists to maintain high standards of scholarship and decision-making.