Museum Genomics Provide Evidence for Persistent Genetic Differentiation in a Threatened Seabird Species in the Western Atlantic.

Connectivity among wildlife populations facilitates exchange of genetic material between groups. Changes to historical connectivity patterns resulting from anthropogenic activities can therefore have negative consequences for genetic diversity, particularly for small or isolated populations. DNA obtained from museum specimens can enable direct comparison of temporal changes in connectivity among populations, which can aid in conservation planning and contribute to the understanding of population declines.

Waste not, want not: Microsatellites remain an economical and informative technology for conservation genetics.

Comparisons of microsatellites and single-nucleotide polymorphisms (SNPs) have found that SNPs outperform microsatellites in population genetic analyses, questioning the continued utility of microsatellites in population and landscape genetics. Yet, highly polymorphic markers may be of value in species that have reduced genetic variation. This study repeated previous analyses that used microsatellites with SNPs developed from ddRAD sequencing in the black-capped vireo source-sink system.

Breeding Brown Pelicans Improve Foraging Performance as Energetic Needs Rise.

Optimal foraging theory states that animals should maximize resource acquisition rates with respect to energy expenditure, which may involve alteration of strategies in response to changes in resource availability and energetic need. However, field-based studies of changes in foraging behavior at fine spatial and temporal scales are rare, particularly among species that feed on highly mobile prey across broad landscapes. To derive information on changes in foraging behavior of breeding brown pelicans (Pelecanus occidentalis) over time, we used GPS telemetry and distribution models of their dominant prey species to relate bird movements to changes in foraging habitat quality in the northern Gulf of Mexico.

Asymmetrical gene flow of the recently delisted passerine black-capped vireo () indicates source-sink dynamics in central Texas.

Habitat fragmentation can produce metapopulations or source-sink systems in which dispersal in crucial for population maintenance. Our objective was to investigate connectivity among black-capped vireo () populations in tandem with a demographic study (Biological Conservation, 2016, 203, 108-118) to elucidate if central Texas populations act as a source-sink system. We genotyped 343 individuals at 12 microsatellite loci to elucidate the movement ecology of the black-capped vireo in central Texas surrounding Fort Hood; the largest and most stable breeding population of black-capped vireos inhabit Fort Hood.

Impacts of human recreation on carnivores in protected areas.

Mammalian carnivores can be particularly sensitive to human disturbance, even within protected areas (PAs). Our objective was to understand how human disturbance affects carnivore communities in southern Arizona, USA by studying habitat occupancy based on data collected using non-invasive methods in three PAs with different levels of human disturbance. Carnivore occupancy varied based on human disturbance variables (i.

Genetic structure of brown pelicans (Pelecanus occidentalis) in the northern Gulf of Mexico in the context of human management and disturbance.

Environmental disturbances, both natural and anthropogenic, have the capacity to substantially impact animal behavior and abundance, which can in turn influence patterns of genetic diversity and gene flow. However, little empirical information is available on the nature and degree of such changes due to the relative rarity of longitudinal genetic sampling of wild populations at appropriate intervals. Addressing this knowledge gap is therefore of interest to evolutionary biologists, policy makers, and managers.

Closing the gaps for animal seed dispersal: Separating the effects of habitat loss on dispersal distances and seed aggregation.

Habitat loss can alter animal movements and disrupt animal seed dispersal mutualisms; however, its effects on spatial patterns of seed dispersal are not well understood. To explore the effects of habitat loss on seed dispersal distances and seed dispersion (aggregation), we created a spatially explicit, individual-based model of an animal dispersing seeds (SEADS-Spatially Explicit Animal Dispersal of Seeds) in a theoretical landscape of 0%-90% habitat loss based on three animal traits: movement distance, gut retention time, and time between movements. Our model design had three objectives: to determine the effects of (1) animal traits and (2) habitat loss on seed dispersal distances and dispersion and (3) determine how animal traits could mitigate the negative effects of habitat loss on these variables.

Using Genealogical Mapping and Genetic Neighborhood Sizes to Quantify Dispersal Distances in the Neotropical Passerine, the Black-Capped Vireo.

Dispersal is a key demographic process, ultimately responsible for genetic connectivity among populations. Despite its importance, quantifying dispersal within and between populations has proven difficult for many taxa. Even in passerines, which are among the most intensely studied, individual movement and its relation to gene flow remains poorly understood.

Development of novel microsatellite markers for the secret cave cricket, Ceuthophilus secretus.

The secret cave cricket, Ceuthophilus secretes Scudder (Orthroptera: Rhaphidophoridae), is an obligate trogloxene endemic to central Texas, USA, and is a primary source of energy and nutrients for sensitive cave ecosystems. In this study, nine polymorphic microsatellite markers were developed from genomic DNA of C. secretes.

Birds in space and time: genetic changes accompanying anthropogenic habitat fragmentation in the endangered black-capped vireo (Vireo atricapilla).

Anthropogenic alterations in the natural environment can be a potent evolutionary force. For species that have specific habitat requirements, habitat loss can result in substantial genetic effects, potentially impeding future adaptability and evolution. The endangered black-capped vireo (Vireo atricapilla) suffered a substantial contraction of breeding habitat and population size during much of the 20th century.

How far is too close? restricted, sex-biased dispersal in black-capped vireos.

Understanding the interplay of dispersal and how it translates into gene flow is key to understanding population processes, and especially so for endangered species occupying fragmented habitats. In migratory songbirds, there is evidence that long-distance movement capabilities do not translate well into observed dispersal. Our objectives were to (i) define the fine-scale spatial genetic structure in endangered black-capped vireos to characterize dispersal patterns and (ii) to correlate dispersal dynamics to overall population genetic structure using a simulation approach.

Heritability of heat tolerance in a small livebearing fish, Heterandria formosa.

Climate change is expected to result in an increased occurrence of heat stress. The long-term population-level impact of this stress would be lessened in populations able to genetically adapt to higher temperatures. Adaptation requires the presence of genetically-based variation.

Population structure in an endangered songbird: maintenance of genetic differentiation despite high vagility and significant population recovery.

Black-capped vireos (Vireo atricapilla), an endangered, migratory species dependent upon early successional habitat, have experienced significant recovery since its protection. In light of its vagility and known increase in population size and range, limited genetic differentiation would be expected in the species. Using 15 microsatellite loci and an extensive sampling regime, we detected significant overall genetic differentiation (F(ST) = 0.

Habitat fragmentation and genetic diversity of an endangered, migratory songbird, the golden-cheeked warbler (Dendroica chrysoparia).

Landscape genetic approaches offer the promise of increasing our understanding of the influence of habitat features on genetic structure. We assessed the genetic diversity of the endangered golden-cheeked warbler (Dendroica chrysoparia) across their breeding range in central Texas and evaluated the role of habitat loss and fragmentation in shaping the population structure of the species. We determined genotypes across nine microsatellite loci of 109 individuals from seven sites representing the major breeding concentrations of the species.

Adaptation as a potential response to sea-level rise: a genetic basis for salinity tolerance in populations of a coastal marsh fish.

Relative sea-level rise is resulting in the intrusion of saline waters into marshes historically dominated by fresh water. Saltwater intrusions can potentially affect resident marsh species, especially when storm-related tidal surges cause rapid changes in salinity. We examined the role of historical salinity exposure on the survival of Gambusia affinis from two locations in coastal Louisiana.

Role of inbreeding depression and purging in captive breeding and restoration programmes.

Inbreeding depression is a major force affecting the evolution and viability of small populations in captive breeding and restoration programmes. Populations that experience small sizes may be less susceptible to future inbreeding depression because they have been purged of deleterious recessive alleles. We review issues related to purging, as they apply to the management of small populations, and discuss an experiment we conducted examining purging in populations of mosquitofish (Gambusia affinis).

Laboratory culturing and selection for increased resistance to cadmium reduce genetic variation in the least killifish, Heterandria formosa.

Populations exposed to environmental contaminants can undergo intense selection pressures, which in turn can lead to a loss of genetic variation. We assessed this loss of genetic variation in the least killifish Heterandria formosa for laboratory populations that had undergone eight generations of selection for an increased resistance to cadmium. Using microsatellite markers, we compared genetic variation between three selection and three control laboratory populations and between these laboratory populations and the source population.

Breeding distributions of north American bird species moving north as a result of climate change.

Geographic changes in species distributions toward traditionally cooler climes is one hypothesized indicator of recent global climate change. We examined distribution data on 56 bird species. If global warming is affecting species distributions across the temperate northern hemisphere, these data should show the same northward range expansions of birds that have been reported for Great Britain.

Multiple paternity in a salamander with socially monogamous behaviour.

In the majority of birds and mammals, social monogamy is not congruent with genetic monogamy. No research to date has compared social and genetic monogamy in amphibians. We analysed paternity in clutches of red-backed salamanders (Plethodon cinereus), a species in which social monogamy has been demonstrated in the laboratory, and 28% of individuals in the forest are found in male-female pairs in the noncourtship season.

ENHANCING THE RETRDEVABILITY OF POPULATION GENETIC SURVEY DATA? AN ASSESSMENT OF ANIMAL MITOCHONDRIAL DNA STUDIES.

Surveys of genetic variation in natural populations represent a valuable and often irreplaceable resource. It may be desirable to reanalyze data as new methods are developed for comparisons with other populations or for comparisons with the same populations at different times. We evaluated existing mechanisms of data preservation in a survey of 627 published surveys of mitochondrial DNA variation in animal and found that over half of the datasets (56%) contained insufficient information for reanalysis.

Aggression and nest spacing in single and mixed species groups of seabirds.

When heterospecific seabirds are part of a nesting colony, there may be less opportunity for conspecifics to come in direct contact with each other, resulting in lower intraspecific aggressiveness. To determine if individuals spend less time in aggressive behavior when nesting in conspecific rather than heterospecific groups, we compared the behavior of black skimmers (Rhynchops niger) nesting with gull-billed terns (Sterna nilotica) in three mixed species subcolonies to those of black skimmers in three single species subcolonies. In contrast to our predictions, black skimmers spent significantly less time in aggressive behaviors when nesting in single species subcolonies than when nesting with heterospecifics.

EFFECTS OF POPULATION BOTTLENECKS ON GENETIC DIVERSITY AS MEASURED BY ALLOZYME ELECTROPHORESIS.

Low levels of allozyme heterozygosity in populations are often attributed to previous population bottlenecks; however, few experiments have examined the relationship between heterozygosity and bottlenecks under natural conditions. The composition and number of founders of 55 experimental populations of the eastern mosquitofish (Gambusia holbrooki), maintained under simulated field conditions, were manipulated to examine the effects of bottlenecks on three components of allozyme diversity. Correlations between observed and expected values of allozyme heterozygosity, proportions of polymorphic loci, and numbers of alleles per locus were 0.