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Much attention has been given to the biology, ecology, and restoration of wiregrass because of the essential role it plays in the longleaf-slash pine ecosystem of the southeastern United States. A previous morphological study separated wiregrass into two species, A. stricta and A. beyrichiana; but that view conflicts with available allozyme data. This discrepancy inspired us to assess anatomical and morphological characters of herbarium specimens and field-collected material and to conduct common-garden experiments. On the basis of these new data, we conclude that A. stricta and A. beyrichiana are not distinct at the species level.
Biotic pollination should be an important consideration when devising management plans for endangered plant species. In this study we documented inter-annual shifts in the suite of floral visitors to Clematis socialis, a federally endangered species. These pollinator shifts were correlated with shifts in climatic variables that we used as a proxy for the potential effects of climatic change. In addition, we characterized floral visitor behavior and conducted single-visit seed set experiments to assess the pollination effectiveness of floral visitors. Five insect species visited flowers of C. socialis: two lepidopteran species (Erynnis juvenalis and Hemaris diffinis) and three bee species (Anthophora ursina, Bombus pennsylvanicus and Xylocopa virginica). Due to their relatively greater frequency of flower visitation and high single-visit seed set (ca. 2.6–3 seeds/visit), two bee species (Anthophora ursina and Bombus pennsylvanicus) are considered to be the major pollinators of C. socialis. However, the relative importance of each pollinator species varied between years. Anthophora ursina was the most important pollinator in 1997, a year when C. socialis bloomed later in the spring. Queens of Bombus pennsylvanicus were the primary pollinator during 1996, a year when C. socialis bloomed relatively early in the spring. We conclude that management plans that focus on the “best pollinator” of a suite of pollinators may not preserve the long-term reproductive integrity of endangered plants with generalized pollination systems. We further conclude that asynchrony between flowering season and pollinator activity patterns may be a risk factor associated with human-caused global climate change.
Historically, the alligator snapping turtle (Macrochelys temminckii Harlan) was heavily collected in Georgia to provide meat to soup canneries. With the exception of previous studies of the Flint River population, the current status of this species in Georgia is poorly known. We trapped most navigable streams within the species' range in Georgia, except the Flint River, to evaluate the population status and distribution of this threatened species. Populations in the Chattahoochee River catchment and Spring Creek (Apalachicola River drainage) are more robust than those found elsewhere in the state. Despite extensive trapping, M. temminckii was not caught in the Suwannee River. The current prohibition against collecting this species in Georgia should enhance its ongoing recovery, although the Suwannee River drainage warrants further investigation and possibly more intensive recovery strategies.
Tulotoma magnifica (Conrad, 1834) is an enlarged operculate gastropod, formerly found throughout the Coosa River system in Alabama, USA whose range has been severely reduced and is now listed as endangered. We found its current range in 4 of 6 tributaries to be greater than in previous surveys. Neither abundance nor size of T. magnifica was consistently related to five habitat factors that we measured (rock surface area, rock height, water depth, current speed, abundance of other snail species), explaining less than 12–18% of the variation. While T. magnifica consistently used larger and taller rocks, there was no consistent difference in water depth, current speed, and abundance of other snail species between rocks with versus without T. magnifica. Isozyme variation of T. magnifica was greatest in the main channel Coosa River population; some Coosa River alleles were not detected elsewhere. Populations were at Hardy-Weinberg equilibrium at all but two of 17 loci examined, indicating random mating, no selection, no migration, and no mutation (except at those two loci). Genetic similarity (S) among populations ranged from 0.88–0.97; the smaller values are at a level that potentially suggests different subspecies, due primarily to a near fixed difference in allele frequency at the GPI locus. The distribution of T. magnifica within areas where it has been found is greater than thought based on recent surveys. In addition, there exists suitable unoccupied habitat at most sites. We suggest that some of these areas represent locations that could be considered for future efforts at recolonization, should that fit within the species recovery plan.
Information on bat diversity, reproduction, and sex ratios in the southeastern United States is limited, particulary in managed pine (Pinus spp.) forests. Such information is needed if regional forest managers are to consider bats within their overall management plans. Therefore, I mist-netted over water to document bat species richness, diversity, reproduction, and sex ratios in landscapes of managed loblolly pine (Pinus taeda) forests of eastern Mississippi from late April to early September, 1998–2000. In 53 survey nights, I captured 284 bats of six species [eastern red bat (Lasiurus borealis), evening bat (Nycticeius humeralis), Seminole bat (L. seminolus), eastern pipistrelle (Pipistrellus subflavus), hoary bat (L. cinereus), and southeastern myotis (Myotis austroriparius)]. Simpson's diversity index was 0.36 for all years combined. Managed pine forest landscapes in this study appeared to provide suitable habitat for bats. Overall, 84% of captured female bats displayed reproductive activity, indicating that habitat quality was likely sufficient for successful reproduction. Sex ratios for red bats and eastern pipistrelles changed from male-dominated as juveniles to female-dominated as adults. Seminole bats displayed sex ratios skewed toward females as juveniles and adults. Evening bat sex ratios were skewed toward females as juveniles, but nearly even between sexes as adults. Future surveys should include simultaneous recording of bat echolocation calls, bridge surveys, and winter surveys to determine how managed pine forest landscapes contribute to conservation of bat communities in the southeastern United States.
The endangered Cumberland pigtoe is a small mussel endemic to the upper Caney Fork River drainage in middle Tennessee, USA. Gravid individuals were collected from late June through August. Conglutinates obtained from these individuals contained few glochidia and were composed primarily of unfertilized eggs. In the laboratory, 18 species of fish were exposed to glochidia, and metamorphosis occurred on telescope shiners and striped shiners 8 to 10 days later. Although conglutinates contained few (< 50) glochidia, ≥ 30% of the telescope shiners collected from the Collins River were infested with glochidia, and juvenile Cumberland pigtoes excysted from naturally-infested telescope shiners returned alive to the laboratory. The consistent predominance of unfertilized eggs in conglutinates of the Cumberland pigtoe and the high incidence of glochidia encysted on telescope shiners collected from the Collins River support the hypothesis that a high proportion of unfertilized eggs in conglutinates may be adaptive rather than an anomaly in certain species.
Fishes and habitat were sampled at nine sites in the Sipsey Fork River drainage in Bankhead National Forest, Alabama. Stream width, depth, current velocity, substrate type, bank height and amount of large woody debris (LWD) were measured at each site to test for association of these habitat variables with upland stream fish assemblages. Regression of habitat variables onto species richness indicated that only bank height was significantly associated with species richness in our study area. The lack of habitat associations with species richness seemingly contradicts findings by several previous investigators working in lowland streams. The availability of large substrate and both deep and shallow habitats at all sites may have reduced the observed association of these variables and LWD with stream fish assemblages. Stream width and current velocity, though not significant, did show strong positive correlations with species richness. The significant association between high banks and species richness may reflect a more intact riparian zone due to inaccessibility of streams in gorges.
Wing-flashing in northern mockingbirds (Mimus polyglottos) has been studied frequently, but its function remains unclear. I studied wing-flashing associated with northern mockingbird foraging during March–April 1998 in Alabama. Rate of prey attack was negatively related to wing-flashing rate, and wing-flashing rate was not significantly related to ambient temperature. Wing flashing was more likely during mid-day than during morning or evening periods, but was independent of cloud cover, lighting conditions (shaded versus open), and substrate type. Use of wing-flashing to simply flush or illuminate prey appeared unlikely. Wing-flashing may improve foraging efficiency by allowing northern mockingbirds to assess prey mobility or defensive ability.
Although ravens were once widespread throughout Appalachia they are now considered threatened or endangered in many states of the region. We document a nesting pair of common ravens in an area of southeastern Kentucky nearly 50 km northwest of traditional nesting sites. Further, we suggest several factors that may have influenced the patterns of raven abundance in the state and offer management recommendations to assist their recovery.
Swampfish (Chologaster cornuta) occur from southeastern Virginia to east-central Georgia and are often considered to be uncommon. We obtained swampfish from January–April 1976 and January 1977–January 1978 in an east-central North Carolina stream (tributary ditch to Black Swamp Creek, Jones Co.). Swampfish reached sexual maturity by the end of its first year and exhibited a spring (early March–middle April) spawning season. Ovaries were developing by late fall, increasing to a mean gonosomatic index of 7–11% before spawning. Females (n = 156, 20–48 mm SL) had an overall mean of 24.7 mature ova (range 6–98) prior to spawning. The positive relationship between fecundity (F) and standard length (SL) was described by the linear regression: F = 2.67(SL) - 25.71 (r = 0.67). Mean mature ova diameter increased from 1.09 mm in January to 1.48 mm in late March and April. Females were nearly always more numerous and larger than males. Of the 14 taxa eaten by swampfish (n = 289, 13–48 mm SL), amphipods were dominant, occurring in 60.3% of the specimens and representing 41.1% of the foods by number. Chironomids were the next most frequent and abundant food, followed by cladocerans. The preference for amphipods was maintained across all seasons and size groups. Two year classes of swampfish were apparent on every sampling date. We estimated a maximum age of 26 months. Length frequency data suggested very slow or no growth during the summer. Weight (W) and length were highly correlated, and the formula (both sexes combined) was: W = 0.23 × 10−4(SL)2.88, (r = 0.95). The appendage that develops on the snout of male swampfish was not noticeable in age 0 fish through about 16 mm SL. By late age 0 (23–25 mm SL) males could be sexed by locating the organ, and it was fully developed by early age 1 (25 mm). The anterior migration of the vent was most rapid between 10 and 17 mm SL, with little change in fish ≥ 19 mm. The low species richness in the diet, the low fecundity, and the generally greater than reported longevity of these fish could be related to life in the ephemeral ditch.
There is a paucity of information available about the distribution of bats in the southeastern United States. Golley (1966) recorded the distribution and gave a brief summary of the natural history of 11 of 14 species of bats that occur in South Carolina and DiSalvo et al. (2002) recently reported on the distribution of 13 species of bats that occur in South Carolina based on bats submitted to the public health personnel for rabies testing. Maps provided by Golley are outdated and those provided by DiSalvo et al. are not inclusive of museum records, capture records reported in the literature, or records from the South Carolina Department of Natural Resources (SCDNR). We synthesized records from museums, bat captures, and bats submitted for rabies testing to provide a more accurate and useful distribution for natural resource managers and those planning to research bats in South Carolina. Distributional information, including maps, collection localities within counties, and literature references, for all 14 species of bats that occur in South Carolina has never been synthesized. To provide better information on the state's bat fauna, we have updated distributions for all species that occur in South Carolina.