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We examined the ecology of a Black Swamp Snake (Seminatrix pygaea) population inhabiting an isolated wetland in the upper Coastal Plain of South Carolina. The observed population structure was skewed towards mature individuals, with neonates and juveniles underrepresented, perhaps due to trapping bias. The sex ratio was biased during May and June, with females outnumbering males, but no sex ratio bias was evident at other times of the year. Seminatrix pygaea showed sexual dimorphism in body size, with females being longer and heavier than males and males having relatively longer tails than females, but there was no difference in monthly growth rates. Approximately 76.3% of the mature females captured in May and June 1998 were pregnant. Therefore, most mature females in this population probably exhibit annual reproduction, while some undergo biennial reproduction. The majority of females gave birth in July or August, with a few births occurring in September and October, and perhaps even as early as May or June. Our mark-recapture estimates suggest a population density greater than 60 adult snakes per hectare, which indicates this small aquatic snake, endemic to the Southeast, may play a large role as both predator and prey within isolated wetland ecosystems.
We studied the interactive effect of ultraviolet-B radiation and the heavy metal copper on the tadpole fitness of the Spring Peeper (Pseudacris crucifer). Many studies have identified UV-B effects on amphibian survival while others have examined the effects of heavy metals, such as copper; however, few studies have investigated the possibility of interactive effects between UV-B and heavy metals on amphibian fitness. Tadpoles were reared in laboratory containers and tested to ascertain whether UV-B and Cu had interactive effects on P. crucifer fitness. Exposure to UV-B and Cu individually and interactively significantly affected P. crucifer survival. This suggests that in some areas amphibian survival could be impacted due to abiotic interactions.
The antipredator behaviors of Phaeognathus hubrichti (Red Hills Salamander), a large fossorial plethodontid, and the basal member of the desmognathine salamanders, are unknown. The responses of P. hubrichti to tongue-flicks from hand-held snakes, tapping with a rod and pinching with a forceps were recorded with a videocamera. When contacted by a snake tongue-flick, P. hubrichti exhibited several antipredator behaviors including immobility, gape, walk, run, head flatten, head elevation, flip, bite, and flinch. One other antipredator behavior—writhe—was observed in the field. The antipredator behaviors of P. hubrichti are more similar to those species in its sister taxon, Desmognathus, than to those of other less closely related fossorial salamanders. Gape, a threat display, is nearly identical to that of Desmognathus quadramaculatus. Gape, bite, and writhe are proposed to be ancestral behaviors in this group.
We used two experiments to test the hypothesis that variation in growth rate, temperature, and thyroid hormone exposure will induce variation in metamorphic timing in the Black-bellied Salamander, Desmognathus quadramaculatus (Holbrook). In one experiment, second-year larvae (i.e., those approaching a metamorphic summer) were treated with high or low food and exposed to high or low temperature. Low temperature resulted in delayed metamorphosis, while food regime had no effect on metamorphic timing. In a second experiment, first-year larvae (i.e., those not expected to undergo natural metamorphosis during the experiment) were grown at two temperatures and treated with thyroid hormones or control supplements. Larvae at low temperature grew more slowly. Larvae treated with thyroid hormone failed to show any sign of metamorphosis compared to control larvae.
Arnold Air Force Base (AFB) comprises ca. 15,800 ha in the Barrens region of south-central Tennessee. General herpetofaunal field collecting techniques were used to survey low-lying forests subject to seasonal flooding, dry forested slopes, old fields, intermittent and permanent streams, and a 1611-ha reservoir. Sixty species were found, comprising 46% of the known state- and 75% of the suspected Barrens-herpetofaunal species. Several species listed as needing special protection by state or federal agencies occur at the site, including Rana capito, Hyla gratiosa, Ambystoma talpoideum, Hemidactylium scutatum, Pituophis melanoleucus, and Ophisaurus attenuatus. Significant extensions or clarifications of distributions were noted for R. capito, Ambystoma texanum, Nerodia erythrogaster, Virginia valeriae, Thamnophis sauritus, Pseudemys concinna, and Kinosternon subrubrum.
Understanding movement behavior and habitat use is critical for determining how land-use changes affect wildlife. We conducted an experimental study of terrestrial movement paths by displaced adult Northern Green Frogs on a central Missouri golf course. Fluorescent pigments were used to examine habitat use by frogs released at the convergence of three habitat types. Frogs tended to choose the least resistant habitat available, avoiding forested habitats during movements. Although frogs may be conspicuous at urban and suburban ponds, populations may decline even when provided with adequate breeding habitat if the surrounding terrestrial habitats become increasingly less suitable for migration and terrestrial activity.
Museum specimens and published literature records were examined to determine how many taxa of freshwater mussels of the family Unionidae occurred within the boundaries of the State of Mississippi. Eighty nine taxa (85 described species, two of which have two described subspecies within the state; two undescribed species) were found to be distributed over the 10 river drainages within the state. The greatest number of taxa was found in the Tombigbee River drainage (52), followed by the Yazoo River drainage (46), and the Pearl River and the Big Black River drainages (39). The Coastal Rivers drainage, those streams draining into the Gulf of Mexico between the Pearl River and Pascagoula rivers, had the fewest with only six documented species. Almost half of the freshwater mussel taxa in Mississippi are considered imperiled, and 10 species appear to have been extirpated from the state.
This project's goal was to restore populations of four rare fishes into Abrams Creek, Blount County, TN. These species, all on the US Endangered and Threatened Wildlife List, include two catfishes, the smoky madtom (Noturus bailey) and the yellowfin madtom (N. flavipinnis), the duskytail darter (Etheostoma percnurum) and the spotfin chub (Erimonax monachus). Captive propagation, reintroduction, and non-invasive monitoring techniques were used for this restoration effort, which began in 1986. By 2000, there was evidence of reproduction for all four species. As of 2003, the number of these species stocked in Abrams Creek was 3167 smoky madtoms, 1574 yellowfin madtoms, 3430 duskytail darters, and 11,367 spotfin chubs. Increasing population sizes were indicated for three of the four fishes, and smoky madtom and duskytail darter abundances were nearly comparable to native populations in Citico Creek, Monroe County, TN.
Based on analysis of fecal pellets, June bugs, Scarabaeidae, were the most abundant food of a colony of big brown bats, Eptesicus fuscus, from Morrow, GA, forming 36.9% of the food overall. They were eaten heavily early in spring and less so in late summer and fall. Ground beetles, Carabidae, were the second most abundant food item (12.1% of the diet overall). Beetles, collectively, made up 57.7% of the sample, followed by hymenopterans (10.7%; composed primarily of Formicidae), dipterans (10.5%), homopterans (8.8%), and hemipterans (5.0%). Lepidopterans made up 2.8% of the diet.
Mature larvae identified as Thermonectus basillaris by culture to adults revealed that larval characters attributed to the species and commonly used in taxonomic literature are incorrect. Species level identifications that are based on published descriptions of T. basillaris and T. nigrofasciatus ornaticollis (as T. ornaticollis) are problematic, even when these are the only two representatives of the genus in a local fauna.
A comparison of ectomycorrhizal morphotypes and hypogeous fungi (truffles and false-truffles) in northern hardwood and spruce-fir forests on Roan Mountain (NC/TN) was performed to increase our knowledge of the fungal communities in the Southern Appalachian high elevation forests. These forests are home to an endangered subspecies and mycophagist, the Carolina northern flying squirrel (Glaucomys sabrinus coloratus), as well as the popular Christmas tree species and ectomycorrhizal host, Fraser fir (Abies fraseri). Ectomycorrhizal root tips were collected with soil cores and separated into morphotypes for quantification. Fruiting bodies of hypogeous fungi were sampled with a stratified random design, using exclosures to minimize mycophagy. Elaphomyces muricatus was the most commonly found hypogeous fruiting body, and Cenococcum geophilum the most commonly found ectomycorrhiza, in both forest types. Elaphomyces muricatus was most strongly associated with A. fraseri. There were more ectomycorrhizal morphotypes in the spruce-fir forest than in the northern hardwood forest. Functional groups of ectomycorrhizas were classified by exploration type. Historical land use on Roan Mountain is discussed in conjunction with the patterns found in this study, along with future concerns of the fragile Southern Appalachian spruce-fir ecosystem.
Pocket gophers (Geomys pinetis), Gopher Tortoises, armadillos, and fire ants were the primary soil disturbance agents in a longleaf pine ecosystem. Pocket gopher mounds were the most abundant soil disturbance and covered the greatest percentage of the study area. The most prominent feature of the pocket gopher soil disturbance regime was a strong peak in mound formation from November to January each year in the three-year study, with the location of mound clusters shifting from year to year. During the three-year study, the area disturbed in 0.25-ha plots ranged from 0.7–1.0% yr−1. Pocket gopher mound formation rates were negatively correlated with air temperature and influenced by soil type in some cases, but mostly unaffected by prescribed fires.
While single-tree selection, uneven-aged management is being used increasingly on southern national forests as an alternative to clearcutting and planting of pine, its effects on wildlife are largely unknown. We compared breeding season bird abundance, species richness, diversity, and composition among uneven-aged stands and six seral stages of even-aged stands in upland pine (predominantly loblolly pine, Pinus taeda Linnaeus) forests of eastern Texas. Even-aged stands 18–80 years old generally had the lowest abundance, richness, and diversity of birds; uneven-aged stands and even-aged stands 1–9 years old generally had comparable values for all three of these measures. Numbers of migrants were highest in seedling, sapling, and pre-commercially thinned even-aged stands. Although many migrants were encountered in uneven-aged stands, their frequencies of occurrence there (even in the most recently harvested stands) were generally less than in early sere even-aged stands. While overall bird abundance, species richness, and diversity under single-tree selection may be comparable or higher than that found throughout most of a typical national forest even-aged rotation, our data suggest that single-tree selection management will not provide suitable habitat for many migrant species that require early succession conditions.
We investigated the use of pine plantations by Worm-eating Warblers within the coastal plain of North Carolina during the breeding seasons of 1997 and 1998. A total of 60 plantations, representing 10 age categories within the growing cycle, were surveyed for warblers using fixed-radius point counts. Worm-eating Warblers appear to colonize plantations around the time of canopy closure. Singing males were detected within 95.2% of plantations that were 10 years old or older. Mean density within these plantations for both years combined was 0.56 birds/10 ha. With the exception of understory density, habitats used by Worm-eating Warblers within the study site appear to be distinctly different from those reported from other populations throughout the species range. The history of landuse within the region suggests that the use of pine plantations by Worm-eating Warblers is a recent event. Habitat attributes that result from open-canopy pine management appear to mimic those of the historic tall pocosin habitat within the region where this species still breeds in high densities.