Isolated populations are challenging to manage and conserve, as they are particularly vulnerable to genetic drift, allelic fixation, and inbreeding and may express markedly reduced phenotypic variability. We sought to improve our understanding of how spatial isolation, occupancy range, and restricted gene flow influence contemporary phenotypic variation within and among native populations of Brook Trout Salvelinus fontinalis by examining the neutral genetic and phenotypic characteristics of 35 isolated headwater populations from Great Smoky Mountains National Park. Across a suite of 13 neutral microsatellite loci, we observed high levels of allelic fixation and considerable genetic differentiation among populations, subwatersheds, and watersheds that were consistent with patterns of isolation. We found significant positive correlations between allelic diversity and estimates of effective population size. In contrast, we observed considerably less phenotypic structure among streams, subwatersheds, and watersheds. Much of the *Corresponding author: tcw5095@psu.edu 1 Retired. 2 Deceased.

Broad-scale patterns of genetic diversity for Brook Trout Salvelinus fontinalis remain poorly understood across their endemic range in the eastern United States. We characterized variation at 12 microsatellite loci in 22,020 Brook Trout among 836 populations from Georgia, USA, to Quebec, Canada, to the western Great Lakes region. Withinpopulation diversity was typically lower in the southern Appalachian Mountains relative to the mid-Atlantic and northeastern regions. Effective population sizes in the southern Appalachians were often very small, with many estimates less than 30 individuals. The population genetics of Brook Trout in the southern Appalachians are far more complex than a conventionally held simple "northern" versus "southern" dichotomy would suggest. Contemporary population genetic variation was consistent with geographic expansion of Brook Trout from Mississippian, mid-Atlantic, and Acadian glacial refugia as well as differentiation among drainages within these broader clades. Genetic variation was pronounced among drainages (57.4% of overall variation occurred among 10-digit hydrologic unit code [HUC10] units or larger units) but was considerable even at fine spatial scales (13% of variation occurred among collections within HUC12 drainage units). Remarkably, 87.2% of individuals were correctly assigned to their collection of origin. While comparisons with fish from existing major hatcheries showed impacts of stocking in some populations, genetic introgression did not overwhelm the signal of broad-scale patterns of population genetic structure. Although our results reveal deep genetic structure in Brook Trout over broad spatial extents, fine-scale population structuring is prevalent across the southern Appalachians. Our findings highlight the distinctiveness and vulnerability of many Brook Trout populations in the southern Appalachians and have important implications for wild Brook Trout management. To facilitate application of our findings by conservation practitioners, we provide an interactive online visualization tool to allow our results to be explored at management-relevant scales.

Increasing human population growth, exurban development, and associated habitat fragmentation is accelerating the isolation of many natural areas and wildlife populations across the planet. In Tanzania, rapid and ongoing habitat conversion to agriculture has severed many of the country's former wildlife corridors between protected areas. To identify historically linked protected areas, we investigated the genetic structure and gene flow of African savanna elephants in Tanzania using microsatellite and mitochondrial DNA markers in 688 individuals sampled in 2015 and 2017. Our results indicate distinct population genetic structure within and between ecosystems across Tanzania, and reveal important priority areas for connectivity conservation. In northern Tanzania, elephants sampled from the Tarangire‐Manyara ecosystem appear marginally, yet significantly isolated from elephants sampled from the greater Serengeti ecosystem (mean F ST = 0.03), where two distinct subpopulations were identified.Unexpectedly, elephants in the Lake Manyara region appear to be more closely related to those across the East African Rift wall in the Ngorongoro Conservation Area than they are to the neighboring Tarangire subpopulations. We concluded that the Rift wall has had a negligible influence on genetic differentiation up to this point, but differentiation may accelerate in the future because of ongoing loss of corridors in the area. Interestingly, relatively high genetic similarity was found between elephants in Tarangire and Ruaha although they are separated by >400 km. In southern Tanzania, there was little evidence of female‐mediated gene flow between Ruaha and Selous, probably due to the presence of the Udzungwa Mountains between them. Despite observing evidence of significant isolation, the populations of elephants we examined generally exhibited robust levels of allelic richness (mean A R = 9.96), heterozygosity (mean µH E = 0.73), and effective population sizes (mean N e = 148). Our results may inform efforts to restore wildlife corridors between protected areas in Tanzania in order to facilitate gene flow for long‐term survival of elephants and other species.

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Faidherbia albida (DEL.) A. Chev is widely grown in the northern region of Cameroon because of its many benefits to local communities. However, droughts and deforestation have led to decreases in the abundance of this species, increasing the need to identify improved genotypes for conservation, management, and breeding. The genetic diversity of F. albida in nine populations from the Sudano-Sahelian region of northern Cameroon was characterized using microsatellite (SSRs) markers. A total of 28 alleles were recorded across 8 loci and 255 samples. The effective mean number of alleles per locus was 2.3. Observed heterozygosity ranged from 0.24 to 0.30, while expected heterozygosities ranged from 0.22 to 0.26. For most loci, F IS was negative. Higher variation was observed within than among the northern Cameroon populations, and principal component and admixture analyses did not reveal any population substructure. Phenotypic diversity in 3-month-old seedlings was also characterized and significant within population variation was found for most morphological traits. Although some populations differed significantly for one or more traits, in general the populations were phenotypically similar. These results suggest little barrier to gene flow between populations of F. albida in northern Cameroon, and that no single provenance is likely to be superior for selection and breeding purposes.