Browsing by Author "McBaine, Kathryn E."

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    Detectability, movement, and population structure of the endangered Candy Darter in Virginia
    McBaine, Kathryn E. (Virginia Tech, 2021-07-15)
    Minnows and darters are the most imperiled freshwater fish species in North America as a result of habitat degradation and restricted ranges, which often results in isolated populations. The Candy Darter Etheostoma osburni was recently listed as Endangered and may represent a suite of other imperiled fishes in terms of their ecology, life-history traits, and conservation needs. I examined the effects of microhabitat features, sampling effort, species abundance and morphology on riffle-dwelling species. My results confirm many of the well-known influences on detection, while adding to the knowledge of species-specific attributes that can influence detection of common riffle species. Using physical marking and molecular methods, I describe movement patterns and provide insight into the spatial distribution of related pairs and reproductive contribution of the endangered Candy Darter. Minimum detected movements of adults were greater for molecular methods than for visual markings. Indirect movements inferred from the spatial extent between related pairs indicated that parents and offspring move along their entire 18.8-km distribution in Stony Creek, while individual parents and offspring in Laurel Creek move throughout half of their 4.25-km distribution. Additionally, I provide evidence that the lifetime reproductive contribution of Candy Darter is greater than previously described. Using microsatellite DNA markers, I describe population genetic structure and estimate effective population sizes of the four extant populations of Candy Darter in Virginia and provide insight into which populations may be successful as sources for reintroduction or translocation efforts. The four extant populations in Virginia are demographically isolated, but results also suggest historical connectivity. Effective population estimates for all populations were less than the recommended 500 to maintain evolutionary potential, but three populations numbered > 130, indicating they may be viable options for source populations for translocations. My results suggest that all populations may benefit from translocations to overcome genetic drift and inbreeding and to safeguard the historical genetic variation of the species.
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    Direct and molecular observation of movement and reproduction by Candy Darter, Etheostoma osburni, an endangered benthic stream fish in Virginia, USA
    McBaine, Kathryn E.; Hallerman, Eric M.; Angermeier, Paul L. (2022-01-27)
    Direct and indirect measures of individual movement provide valuable knowledge regarding a species’ resiliency to environmental change. Information on patterns of movement can inform species management and conservation but is lacking for many imperiled fishes. The Candy Darter, Etheostoma osburni, is an endangered stream fish with a dramatically reduced distribution in Virginia in the eastern United States, now known from only four isolated populations. We used visual implant elastomer tags and microsatellite DNA markers to directly describe movement patterns in two populations. Parentage analysis based on parent‐offspring pairs was used to infer movement patterns of young‐of‐year and age‐1 individuals, as well as the reproductive contribution of certain adults. Direct measurements of movement distances were generally similar between methods, but microsatellite markers revealed greater distances moved, commensurate with greater spatial frames sampled. Parent‐offspring pairs were found throughout the species’ 18.8‐km distribution in Stony Creek, while most parent‐offspring pairs were in 2 km of the 4.25‐km distribution in Laurel Creek. Sibship reconstruction allowed us to characterize the mating system and number of spawning years for adults. Our results provide the first measures of movement patterns of Candy Darter as well as the spatial distribution of parent‐offspring pairs, which may be useful for selecting collection sites in source populations to be used for translocation or reintroductions. Our results highlight the importance of documenting species movement patterns and spatial distributions of related individuals as steps toward understanding population dynamics and informing translocation strategies. We also demonstrate that the reproductive longevity of this species is greater than previously described, which may be the case for other small stream fishes.
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    Genetic Structure across Isolated Virginia Populations of the Endangered Candy Darter (Etheostoma osburni)
    McBaine, Kathryn E.; Angermeier, Paul L.; Hallerman, Eric M. (MDPI, 2023-10-01)
    Candy darter Etheostoma osburni, a federally endangered non-game fish, has been extirpated from most of its historic range in Virginia and now occurs in four isolated populations in the New River drainage. Understanding of population genetic structure will provide insights into the recent natural history of the species and can inform conservation management. Our objectives were to: characterize population genetic structure, estimate and compare effective population sizes (Ne), and use this information to infer recent population history. Variation at mitochondrial cytochrome b sequences among 150 individuals showed 10 haplotypes separated by 1–14 mutational steps, some shared and some unique to particular populations. Variation at 12 microsatellite loci among 171 individuals showed lower variation in Dismal Creek than in other populations. All populations showed evidence of having experienced a genetic bottleneck and were highly differentiated from one another based on both types of DNA markers. Population genetic structure was related to stream position in regard to the New River, suggesting that populations were once connected. Ne estimates for all populations were less than the 500 recommended to maintain evolutionary potential, but most estimates were greater than the 100 needed for use as source populations. Our findings indicate that habitat management to allow expansion of populations, and translocations to exchange genetic material among populations, may be effective tactics to promote conservation of candy darter in Virginia.
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    Natural history, threats, and current research related to Candy Darter (Etheostoma osburni) in Virginia
    McBaine, Kathryn E.; Angermeier, Paul L. (New River Symposium, 2017-05-16)
    The candy darter (Etheostoma osburni) is a small riffle-dwelling, non-game fish species endemic to the New River drainage in Virginia and West Virginia. It is narrowly restricted to medium-size streams with cold-cool temperatures, high-velocity riffles, and silt-free substrates. It primarily eats aquatic insects. Candy darter’s distribution has been sharply reduced over the last century, now occurring in only four streams in Virginia. Stony Creek, in Giles County, is thought to support the largest and most stable population in Virginia. It is listed as a species of Special Concern in Virginia and is being reviewed for federal listing under the Endangered Species Act. Main threats include fine sediment, warming waters, and introduction of non-native species. Potential management actions to facilitate conservation include improving riparian buffer and excluding cattle from streams. Key knowledge gaps germane to conservation include spatiotemporal distributions, population dynamics, and genetic differentiation of populations. Our research is addressing the following questions: 1) How does detectability of candy darter vary across habitat configurations and seasons? 2) How does the juxtaposition of suitable habitat patches influence movement of candy darter? Answers to these questions could inform management regarding protection and/or enhancement of critical habitats and of connectivity among populations.