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Climate change has been documented for over 120 years with increasing scientific rigor, and its impacts are already observable in marine and freshwater fisheries. But after decades of communication to underscore the validity of these changes, and the urgency for action, a large component of the public and many elected officials deny the scientific consensus and reject the need for action. Therefore, we outline a more effective strategy to convey the climate message to stakeholders and inspire them to act.

ABSTRACTChronic-wasting disease (CWD) is a prion-derived fatal neurodegenerative disease that has affected wild cervid populations on a global scale. Susceptibility has been linked unambiguously to several amino acid variants within the prion protein gene (PRNP). Quantifying their distribution across landscapes can provide critical information for agencies attempting to adaptively manage CWD. Here we attempt to further define management implications of PRNPpolymorphism by quantifying the contemporary geographic distribution (i.e., phylogeography) of PRNPvariants in hunter-harvested white-tailed deer (WTD; Odocoileus virginianus, N = 1433) distributed across Arkansas (USA), including a focal spot for CWD since detection of the disease in February 2016. Of these, PRNPvariants associated with the well-characterized 96S non-synonymous substitution showed a significant increase in relative frequency among older CWD-positive cohorts. We interpreted this pattern as reflective of a longer life expectancy for 96S genotypes in a CWD-endemic region, suggesting either decreased probabilities of infection or reduced disease progression. Other variants showing statistical signatures of potential increased susceptibility, however, seemingly reflect an artefact of population structure. We also showed marked heterogeneity across the landscape in the prevalence of ‘reduced susceptibility’ genotypes. This may indicate, in turn, that differences in disease susceptibility among WTD in Arkansas are an innate, population-level characteristic that is detectable through phylogeographic analysis.

Many species have evolved or currently coexist in sympatry due to differential adaptation in a heterogeneous environment. However, anthropogenic habitat modifications can either disrupt reproductive barriers or obscure environmental conditions which underlie fitness gradients. In this study, we evaluated the potential for an anthropogenically-mediated shift in reproductive boundaries that separate two historically sympatric fish species (Gila cyphaand G. robusta) endemic to the Colorado River Basin using ddRAD sequencing of 368 individuals. We first examined the integrity of reproductive isolation while in sympatry and allopatry, then characterized hybrid ancestries using genealogical assignment tests. We tested for localized erosion of reproductive isolation by comparing site-wise genomic clines against global patterns and identified a breakdown in the drainage-wide pattern of selection against interspecific heterozygotes. This, in turn, allowed for the formation of a hybrid swarm in one tributary, and asymmetric introgression where species co-occur. We also detected a weak but significant relationship between genetic purity and degree of consumptive water removal, suggesting a role for anthropogenic habitat modifications in undermining species boundaries or expanding historically limited introgression. In addition, results from basin-wide genomic clines suggested that hybrids and parental forms are adaptively nonequivalent. If so, then a failure to manage for hybridization will exacerbate the long-term extinction risk in parental populations. These results reinforce the role of anthropogenic habitat modification in promoting interspecific introgression in sympatric species by relaxing divergent selection. This, in turn, underscores a broader role for hybridization in decreasing global biodiversity within rapidly deteriorating environments.

AbstractHabitat modification and introduced species are impacting native fishes in western North America, a situation now exacerbated by drought and anthropogenic water acquisition. One species of concern, the Bluehead Sucker Catostomus discobolusin the Bonneville basin of Utah, Idaho, and Wyoming, has experienced sharp population declines potentially augmented by hybridization with native Utah Sucker C. ardens. To evaluate this situation, we sequenced three diagnostic nuclear DNA loci and two mitochondrial genes across 81 Bluehead Suckers, 74 of which were collected in a basinwide genetic assessment and 7 from a targeted morphological evaluation. Combined, we detected 14 hybrids from the single site in the Bear River and the three sites in the Weber River that hosts the three largest remaining populations in the basin. All individuals sampled as putative hybrids were confirmed as F1hybrids, ascertaining efficacy of field-based morphological identifications. Hybridization may be especially problematic for the numerically reduced Bluehead Sucker because it can further depress recruitment. However, no evidence of post-F1backcrosses was found, suggesting in turn that hybrids are not reproducing, although the reasons for this are currently not understood. These results underscore the need to quantify the proportion of Bluehead Sucker recruitment lost to hybridization.Received January 6, 2016; accepted August 31, 2016 Published online November 28, 2016

The Fourth International Symposium on “Alien Species in the Holarctic” was convened September 22–28, 2013, by the Russian Academy of Sciences at the I.D. Papanin Institute for the Biology of Inland Waters (IBIW) on the Volga River in Borok (∼355 km north of Moscow). The Organizing Committee spanned five countries (France, People's Republic of China, Poland, Russian Federation, and the United States), with participants (n=150) across the breadth and depth of the Russian Federation, from countries in proximity to it (i.e., Armenia, Lithuania, Kazakhstan, Kyrgyzstan, Ukraine, Siberia, and The Republic of China), and more globally from the United States to Tasmania and Norway to South Africa. This report provides a synopsis of invasive species issues that were discussed at the symposium and, as such, provides an international window for the evaluation of fisheries-related topics in this part of the globe.

The article focuses on the survey conducted by the Illinois Conservation and Molecular Ecology Lab on the impact of the environmental changes on the prairie-chicken population. Topics discussed include the collection of feathers to be used as a source of genetic material, the use of the laboratory technique called polymerase chain reaction to determine the genetic profile of the birds in the area, and the important factors that can be assessed from the results of the survey.

Bobcats (Lynx rufus) are valuable indicators of connectivity in the highly fragmented landscape of coastal southern California, yet their population sizes and densities are largely unknown. Using noninvasive scat sampling in a capture–recapture framework, we estimated population sizes for 2 similar areas of natural habitat with differing levels of isolation by human development in Santa Monica Mountains National Recreation Area, California. We used scat transects with geographic information system land-use layers and home-range sizes of bobcats to estimate effective sampling area and population densities. Estimates of population size in the study area connected to a much larger habitat area (26–31 individuals) were similar to estimates for the area that was completely surrounded by development (25–28 individuals). Bobcat densities for the 2 study areas also were similar (ranging from 0.25 to 0.42 bobcat/km2) and likely represent recent population declines because of notoedric mange likely interacting with toxicants. These methods proved effective despite particularly low densities of bobcats and may be especially useful when study areas are geographically isolated, reducing the uncertainty in size of the sampling area.

Several geographically distinct mitochondrial DNA (mtDNA) lineages of the big brown bat (Eptesicus fuscus) have been documented in North America. Individuals from 2 of these lineages, an eastern and a western form, co-occur within maternity colonies in Colorado. The discovery of 2 divergent mtDNA lineages in sympatry prompted a set of questions regarding possible biological differences between haplotypes. We captured big brown bats at maternity roosts in Colorado and recorded data on body size, pelage color, litter size, roosting and overwintering behaviors, and local distributions. Wing biopsies were collected for genetic analysis. The ND2 region of the mtDNA molecule was used to determine lineage of the bats. In addition, nuclear DNA (nDNA) intron 1 of the ß-globin gene was used to determine if mtDNA lineages are hybridizing. Eastern and western mtDNA lineages differed by 10.3% sequence divergence and examination of genetic data suggests recent population expansion for both lineages. Differences in distribution occur along the Colorado Front Range, with an increasing proportion of western haplotypes farther south. Results from nDNA analyses demonstrated hybridization between the 2 lineages. Additionally, no outstanding distinctiveness was found between the mtDNA lineages in natural history characters examined. We speculate that historical climate changes separated this species into isolated eastern and western populations, and that secondary contact with subsequent interbreeding was facilitated by European settlement.