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We examined the responses of resident flocks of white-throated sparrows to unfamiliar individuals and vocalizations throughout the winter, while also examining circulating levels of the stress hormone corticosterone, to see if they paralleled behavioral changes. Concurrently, we validated identification of sparrow plumage morphs with genotype assays to determine reliability of field identification. Accuracy of field identification of plumage morphs was 68.8%. Baseline corticosterone did not differ among sampling periods, suggesting these birds did not experience prolonged chronic stress throughout the winter. However, white-throated sparrows responded more aggressively to study skins and playback of conspecific calls and songs in November than in January and March. These results suggest that agonistic displays may be more important for defending winter territories and establishing dominance status in early winter.
Switchgrass (Panicum virgatum L.) has been identified as a versatile and broadly useful bioenergy feedstock, with potential for use in coal-fired power plants as well as ethanol production. However, in order for switchgrass use to markedly influence energy production, conversion to this grass species must occur at a large scale. Little is known about the potential ecological consequences of widescale conversion of land to switchgrass. This study was conducted to identify potential effects of switchgrass planting on small mammal populations. An abandoned perennial cool season grass hayfield in central Kentucky was subdivided into two fields; one field was planted with switchgrass and the control field was maintained as an unmanaged hayfield. Small mammal relative abundance was quantified using a tracking method through the third year following switchgrass planting. Small mammal relative abundance was greater in the switchgrass field than in the control field. Vegetative community analysis showed the control field was dominated by tall fescue, suggesting that thickness of stand and/or fescue toxicity may have been a factor in reduced small mammal abundance. These data suggest that conversion of abandoned old fields to switchgrass will not have a negative effect on small mammal populations. Further research should target potential mechanisms for this variation in small mammal relative abundance, as well as other species in the community which may be affected by conversion to switchgrass.
We compared the long-distance movements of the Frecklebelly Darter, Percina stictogaster, a pelagic fish species, to those of five other sympatric benthic or semipelagic darters. In four reaches of the Red River, Kentucky we tagged 942 individuals of six darter species using subcutaneous injections of visible implant fluorescent elastomer (VIE) from May 2012 to May 2013. These reaches, plus an additional four reaches, were surveyed by snorkeling or seining to detect previously tagged fishes. Over seven sampling sessions spanning June 2012 to November 2013 a total of 58 tagged darters were detected, including 20 P. stictogaster. Most darters were detected in the same reach in which they were tagged; inter-reach movements occurred more in pelagic (3 of 20) and semipelagic species (2 of 4) (both Percina) than in benthic species (2 of 34, all Etheostoma). Most (6 of 7) inter-reach movements were upstream. The relatively high dispersal tendencies of Percina darters suggest these darters are particularly vulnerable to in-stream barriers and that maintaining connectivity among populations should be a critical management goal.
Old fields (at least 67 years since abandonment) within Mammoth Cave National Park, USA are dominated by coniferous species (Juniperus virginiana L. and Pinus virginiana) instead of the desired deciduous species (Carya glabra, Quercus alba, Q. muehlenbergii, Q. prinus, and Q. velutina) that dominate much of the rest of the park. Species composition above ground and in the seedbank of old fields and adjacent desired future condition areas, (identified by the United States National Park Service (NPS) as oak and hickory-dominated) were evaluated and compared. Species composition and dominance have shifted from oak species toward conifer-dominated stands due to previous land conversion to agriculture and the exclusion of fire. Management practices that can be implemented by the NPS to alter the condition of the old fields to achieve the desired future condition include thinning treatments and reintroduction of the historic fire regime.
Accurate and up-to-date data on the location and characterization of Kentucky's wetlands are lacking. The goal of this research was to assess the potential of low-cost, multispectral imagery for the delineation and classification of wetlands in three focal river basins: the Kentucky River Basin, Licking River Basin, and the Salt River Basin. Methods included the classification of mid-resolution multispectral Landsat 8 and ASTER remotely sensed imagery. These data were evaluated in conjunction with ancillary watershed, soil, and hydrologic data layers in a GIS. The field-verified results demonstrate the challenges of classifying Kentucky's wetlands using mid-resolution multispectral imagery due to the spectral similarity of wetlands and other land cover classes. The majority of commission errors occurred in inundated or partially inundated areas with abundant vegetation, notably agricultural fields and forests. Future research may improve classification by incorporating LiDAR slope and elevation data.
Nest location is an important factor that influences nestlings’ success. Poor nest location could lead to exposure to predators and to a lack of nearby resources. We examined nest site selection and nest depredation of Carolina chickadees (Poecile carolinensis) from 2011–2015 at a field site with artificial nest boxes. In this cavity-nesting species, both members of a breeding pair inspect multiple cavities before deciding on a location to build a nest. We examined whether Carolina chickadee nest location preference and predation rates were related to factors such as proximity to the forest edge, a water source, neighboring cavities, and buildings, as well as the forest type the nest was located in. We found that Carolina chickadee nests that were closer to the forest edge were depredated more often; however, despite this increased risk of nest loss near the forest edge, the chickadees did not prefer boxes located away from the edge. The other factors that we measured were not related to nest box occupancy or predation risk. Future research should focus on why these birds continue to nest in more dangerous edge locations and on what other factors affect their nest selection decisions.