Gotowa bibliografia na temat „Population genetic connectivity”

The Mugger Crocodile (Crocodylus palustris) is a threatened reptile inhabiting the Indian Sub-continent and Western Asia. Despite its “Vulnerable” conservation status, data about population genetic structure and connectivity are unavailable. This study makes a preliminary assessment of the genetic diversity, population structure and habitat connectivity ofC. palustrisin Iran. Ten tissue samples collected along the Sarbaz-Bahukalat basins were analysed and a set of 12 microsatellites was genotyped. Genetic diversity indices were estimated and population substructuring was assessed through Bayesian clustering analysis. Potential connectivity was verified through Remote Sensing water indexes, further implemented in a circuit analysis. Low genetic diversity was observed (mean observed heterozygosity = 0.35; mean expected heterozygosity = 0.43) and no population structure was found (K = 1). Water index and circuit analysis suggested possible connection among sites. This study highlights the potential vulnerability of crocodile populations and the importance of habitat connectivity for their persistence in the arid regions of Iran.

Roanoke bass (Ambloplites cavifrons) persist in five river basins in the eastern US, where they are threatened by invasive species, habitat loss and degradation, and hydrologic fragmentation. We conducted the first conservation genetic study of A. cavifrons, analyzing variation at 19 nuclear microsatellite DNA loci and the cytochrome b mitochondrial DNA gene to estimate population structure and demography, genetic relationships among populations, and the role of landscape features in regulating genetic diversity and differentiation. Most streams harbored genetically distinguishable populations, with high connectivity among reaches within streams but no contemporary dispersal among streams. In contrast, mitochondrial divergence within and among basins was weak, suggesting historically higher range-wide connectivity. Most populations exhibited small effective population sizes and evidence of past population bottlenecks. Genetic diversity correlated positively with patch size but negatively with watershed urban and agricultural development, suggesting that habitat loss, degradation, and fragmentation have acted in concert to reduce population viability. Mitigating these impacts may require a combination of tactics, including restoring habitat, limiting the spread of invasive competitors, and reestablishing historical connectivity.

Ecological restoration can promote biodiversity conservation in anthropogenically fragmented habitats, but effectiveness of these management efforts need to be statistically validated to determine ’success.’ One such approach is to gauge the extent of recolonization as a measure of landscape permeability and, in turn, population connectivity. In this context, we estimated dispersal and population connectivity in prairie vole (Microtus ochrogaster; N = 231) and meadow vole (M. pennsylvanicus; N = 83) within five tall-grass prairie restoration sites embedded within the agricultural matrix of midwestern North America. We predicted that vole dispersal would be constrained by the extent of agricultural land surrounding restored habitat patches, spatially isolating vole populations and resulting in significant genetic structure. We first employed genetic assignment tests based on 15 microsatellite DNA loci to validate field-derived species-designations, then tested reclassified samples with multivariate and Bayesian clustering to assay for spatial and temporal genetic structure. Population connectivity was further evaluated by calculating pairwise FST, then potential demographic effects explored by computing migration rates, effective population size (Ne), and average relatedness (r). Genetic species assignments reclassified 25% of initial field identifications (N = 11 M. ochrogaster; N = 67 M. pennsylvanicus). In M. ochrogaster population connectivity was high across the study area, reflected in little to no spatial or temporal genetic structure. In M. pennsylvanicus genetic structure was detected, but relatedness estimates identified it as kin-clustering instead, underscoring social behavior among populations rather than spatial isolation as the cause. Estimates of Ne and r were stable across years, reflecting high dispersal and demographic resilience. Combined, these metrics suggest the agricultural matrix is highly permeable for voles and does not impede dispersal. High connectivity observed confirms that the restored landscape is productive and permeable for specific management targets such as voles and also demonstrates population genetic assays as a tool to statistically evaluate effectiveness of conservation initiatives.

Contemporary oceanic conditions and local dispersal of propagules influence the genetic diversity and connectivity among seagrass populations. The degree of connectivity between populations of Zostera muelleri in south-eastern Australia is unknown. In this study we examined genetic connectivity among 25 sites containing Z. muelleri using nine polymorphic microsatellite DNA loci. We hypothesised minimal sharing of genetic material between distant populations and a degree of connectivity between local populations. Genotypic diversity was high, with 64% of populations having unique multilocus genotypes (MLGs), indicating the importance of sexual reproduction. Two sites shared MLGs, which may be due to the dispersal and recruitment of vegetative propagules. Genetic differentiation was observed between most sites. With the exception of two outlying sites, two genetic population clusters were identified across the studied populations. Regionally, the populations have high clonal diversity, are strongly differentiated and generally exist in isolation from one another. However, non-significant within-estuary differentiation was observed for three estuaries, indicating a degree of connectivity. The results of this research improve our understanding of the connectivity of Z. muelleri populations in the region, an important process for managing this ecosystem engineer.