Browsing by Subject "Conservation assessment"
Now showing 1 - 2 of 2
- Results Per Page
- Sort Options
Item Conservation Status of the Plains Spotted Skunk, Spilogale putorius interrupta, in Texas, with an Assessment of Genetic Variability in the Species(2017-09-30) Dowler, Robert C.; Perkins, J. Clint; Shaffer, Alexandra A.; Wolaver, Brad D.; Labay, Benjamin J.; Pierre, Jon Paul; Ferguson, Adam W.; McDonough, Molly M.; Ammerman, Loren K.In this report, we present results of research on the conservation status of the plains spotted skunk (Spilogale putorius interrupta) in Texas and an assessment of the genetic variability in populations throughout the range of the species. The conservation status portion of the study included (1) mapping the species’ potential habitat in Texas using maximum entropy modeling (Maxent) with historic museum specimen records, (2) field-based surveying of locations in 10 counties to determine occurrence of the plains spotted skunk, (3) seeking additional occurrence records in Texas through crowd sourcing and citizen scientist approaches (4) using all current (2001 – 2017) occurrences to produce a model of probable geographic distribution in Texas and (5) assessing anthropogenic changes in land use, which may threaten the species’ habitats, by mapping current and forecasted oil and gas development and urbanization within the species’ modeled range. The species distribution model, combined with the land-change assessment, was used to select sites in 10 representative counties for field-based surveys in the hopes of revealing patterns of current distribution. Field surveys were carried out using live traps, enclosed track plates, and camera traps. These methods documented detections of plains spotted skunks (n = 12) in 4 of the 10 sites sampled. All methods of detection were successful, but cameras and live traps out-performed track plates. Crowd-sourced approaches and citizen scientist camera trapping revealed an additional 82 occurrences in the state, 79 of which were since 2009. These recent records were used to produce a species distribution model that provides relative probability of occurrence for the plains spotted skunk in the state. Our land-change mapping revealed potential anthropogenic threats to habitats at 2 of the sites (Katy Prairie and Fort Hood), which also had robust populations of plains spotted skunks based on 25 and 51detections, respectively). For our genetic assessment, samples of tissue from three sources (i.e., field surveys, state agencies throughout the distribution of the eastern spotted skunk, and museum tissue collections) allowed a detailed assessment of the genetic variability in the species (S. putorius) using both microsatellite markers and cytochrome b gene sequence. Our analysis of 119 specimens was able to establish that genetic patterns were consistent with currently accepted taxonomy of the 3 recognized subspecies of S. putorius (S. p. putorius, S. p. ambarvalis, and S. p. interrupta). We also determined that there was no evidence for hybridization with the congener, S. gracilis (western spotted skunk), a species co-occurring with the eastern spotted skunk in parts of Texas. The differentiation between S. p. putorius and S. p. ambarvalis was less pronounced (FST = 0.178; cytochrome b sequence divergence = 1.2%) than between these subspecies and the plains spotted skunk (average FST = 0.278; cytochrome b sequence divergence = 2.9%). Overall, genetic variability (observed heterozygosity = 0.474) in the plains spotted skunk was lower than that seen in common carnivores (striped skunks, raccoons), but slightly higher than some endangered carnivores (black-footed ferret). The heterozygosity levels more closely resemble the levels found within the island spotted skunk (S. gracilis amphiala) from the Channel Islands of California and other vertebrates that have a “threatened” conservation status. Key findings of the study include: 1) the current geographic distribution of the plains spotted skunk in Texas is reduced relative to historic records; 2) the species distribution model based on recorded occurrences since 2001 suggests areas of the state that are in need of further survey efforts; 3) genetic variability of plains spotted skunks is lower than more common carnivores, but higher than some recognized endangered species; 4) the subspecies, S. p. interrupta is a distinct genetic subunit of the eastern spotted skunk; and 5) continued energy development and especially future urbanization in some parts of Texas may affect populations of the plains spotted skunk.Item Final Report: Conservation assessment and mapping products for GPLCC priority fish taxa(2014-12-08) Hendrickson, Dean A.; Labay, Ben J.Strategic conservation planning for broad, multi-species landscapes benefits from a data-driven approach that emphasizes persistence of all priority species populations and utilized landscapes, while simultaneously accounting for human uses. This study presents such an assessment for priority fishes of the Great Plains of the United States. Species distribution models for 28 priority fishes were created and incorporated into a prioritization framework using the open source software Zonation, accounting for species-specific connectivity needs and current fish habitat condition. Multiple additional assessments were then produced that i.) identify distinct species management units based on distance and compositional similarity of stream segments containing priority species, ii.) compare results of ranking species' conservation values at the local (state) and global scale, and iii.) provide 'bang-for-buck' perspectives, emphasizing richness of priority species, at state and major basin scales. Together, these analyses are intended to aid managers in effective allocation of conservation action with regards to imperiled fishes of the Great Plains. Implementation of a broad-scale multi-species approach such as this complements traditional reactive management and restoration by encouraging cooperation and coordination among stakeholders and partners, increasing efficiency of future monitoring and management efforts.