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Using museum collection records and variables computed by digital terrain modeling in a geographic information system, we examined the relationship of elevation, aspect, and “cove” patch size to the presence or absence of 7 common woodland salamanders in mature cove hardwood and northern hardwood forests in the southern Appalachians of Georgia, North Carolina, and South Carolina. Overall, elevation, aspect and patch size were poor discriminators among salamander species presence or absence at collection sites. Increased elevation was an important variable explaining the presence of Ocoee salamanders (Desmognathus ocoee) and Jordan's salamanders (Plethodon jordani). In contrast, decreased elevation was an important variable explaining the presence of slimy salamanders (Plethodon glutinosus). Our study contrasts with recent research indicating that suitable habitat patch size is an important determinant of woodland salamander species richness and abundance at recently disturbed sites. In these mature stands, we believe that cove patch size as determined by modeling either was well above effect-level thresholds for influencing individual species presence or our modeling failed to reflect true collection site conditions.
In the Ohio River basin, the northern madtom, Noturus stigmosus Taylor, is morphologically similar to and sympatric with the mountain madtom, Noturus eleutherus Jordan. Although recognized as distinct sympatric (and syntopic) species, N. stigmosus and N. eleutherus are difficult to distinguish in streams where they are associated, based on previously defined characters. Sheared principal component analysis (PCA) of morphometric data revealed characters that more effectively differentiate the two species. Noturus stigmosus differs from N. eleutherus in having longer pectoral fins and spines, a longer dorsal fin and spine, a shorter and higher adipose fin, and a longer first dorsal saddle. As juveniles (20–30 mm standard length), N. eleutherus more closely resembles N. stigmosus on the basis of morphometry and pigmentation, but differs from the former in lacking a distinct dark adipose blotch. Meristic comparisons indicate that the two species differ most consistently at sizes > 30 mm SL in the numbers of caudal fin rays (usually > 48 in N. stigmosus vs. < 47 in N. eleutherus) and preoperculomandibular (POM) pores (modally 11 in N. stigmosus vs. 10 in N. eleutherus).
Changes in arthropod populations (numbers of individuals identified to the family level in most cases) were studied during the decomposition of coarse woody debris (CWD) in the Atchafalaya River Basin of Louisiana. The arthropod study was linked with a CWD decomposition study installed after disturbance by Hurricane Andrew. Arthropod numbers were compared between two canopy disturbance classes and between two spatial orientations of CWD (i.e., suspended above- and in contact with the soil). Results during 30 months in the field suggested little influence of canopy disturbance or spatial orientation of CWD on arthropod numbers. Counts were most frequently dominated by Collembola and Acarina and peaked after 18–24 months within larger debris.
Perch-site selection is thought to be an important component of foraging success for sit-and-wait avian predators, such as flycatchers. Perch selection has further consequences for territorial advertisement and display. We quantified perch characteristics of Acadian Flycatchers in three bottomland hardwood forests in Arkansas, Louisiana, and South Carolina. We compared measurements made at flycatcher perches with those made at randomly selected trees and branches. In two of our study areas, flycatchers perched on dead limbs more often than expected by chance, and foliage volume was less around flycatcher perches than at randomly selected branches. Both of these results suggest a preference for foraging and displaying sites that provide a relatively unobstructed view. Discriminant function analysis revealed substantial overlap in perch-site characteristics among study areas, indicating that species-wide preferences were at least as important as local conditions in perch-site selection by Acadian Flycatchers.
A pedestrian survey of snakes was conducted for 1022 days (79% of the available days) along 6 km of rural roads through xeric upland habitats in Hernando County, Florida. Two hundred twenty-eight snakes of 18 species were recorded, 93% of which were dead. The relative abundance of many snake species, such as the rough green snake (Opheodrys aestivus) and southern hognose snake (Heterodon simus), differed between the road survey and three drift fence surveys in xeric upland habitats that trapped 22 species. The pedestrian road survey was successful at detecting small snake species and neonates. Mean annual mortality of all snake species was 12.8/km/yr, despite low traffic volume on the roads surveyed, and 70% of carcasses remained on roads for <1 day. Peak periods of snake activity were June–July and September–November. Snakes were not found along roads in proportion to the coverage of four natural and three ruderal habitat types; snakes were found proportionally less frequently adjacent to lawns and improved pastures. Some snake species, such as the southern hognose snake, can apparently persist in areas of fragmented and altered upland habitats, but this study suggests that loss and degradation of natural habitats may have long-term impacts on populations of large snake species. Roads may be a significant source of mortality for some snake populations, especially for dispersing neonates, which comprised 80% of road-killed snakes in September–December.
I studied the life history of Striped Newts (Notophthalmus perstriatus) at a breeding pond in north-central Florida. Newts were captured in pitfall traps at a drift-fence as they migrated into and out of the pond basin. During the 2-year study, I recorded 10,290 captures (8,127 individuals) of newts at the drift-fence. Newts were active during each month of the study, but there were four peak activity periods, each of which included immigration and emigration events. Immigration events were almost exclusively comprised of adults, whereas emigration events were comprised of adults and recently transformed larvae. I documented 5,296 recently transformed, immature larvae (efts) and 435 recently transformed mature larvae (paedomorphs) during four distinct periods of emigration. Efts matured in the uplands before returning to the pond to breed. In the uplands, male efts (n = 16) grew 0.0183 mm/day on average, whereas average female (n = 24) growth was 0.0167 mm/day. Immigrating adults of both sexes were significantly smaller than emigrating adults. Emigrating efts were smallest, followed by emigrating paedomorphs, immigrating adults, then emigrating adults. The overall adult sex ratio was 1:1.25 (m:f). Sex ratio of emigrating paedomorphs was highly skewed towards females, with one male for every 4.43 females. Newts tended to move during wetter periods, and captures were significantly correlated with rainfall, but rainfall was a poor predictor of the magnitude of newt movements.
Freshwater mussels were surveyed in the mainstream Duck River downstream of Centerville, Tennessee, during June and October 2000. A total of 32 species (1 Margaritiferidae and 31 Unionidae) representing 23 genera was found. Comparisons with species reported in the literature revealed that three species, spectaclecase, Margaritinopsis monodonta (Say, 1829); Wabash pigtoe, Fusconaia flava (Rafinesque, 1820); and clubshell, Pleurobema clava (Lamarck, 1819), were new records for the Duck River drainage. One of these, Pleurobema clava, is a federally listed endangered species. Our survey also documented downstream range extensions within the Duck River for six species, Tennessee pigtoe, Fusconaia barnesiana (Lea, 1838); wavyrayed lampmussel, Lampsilis fasciola Rafinesque, 1820; slabside pearlymussel, Lexingtonia dolabelloides (Lea, 1840); Ohio pigtoe, Pleurobema cordatum (Rafinesque, 1820); rabbitsfoot, Quadrula cylindrica (Say, 1817); and painted creekshell, Villosa taeniata (Conrad, 1834). The range extensions included one federally endangered candidate species, Lexingtonia dolabelloides, and the remaining five species are reported by the Tennessee Valley Authority, Natural Heritage Project, as listed or candidates for conservation status by one or more states within their range. The results from this limited survey indicate the presence of unusual mussel diversity and calls attention to the need for increased conservation activities on the Duck River.
The high elevation beech gaps of the Great Smoky Mountains have become the killing front of beech bark disease. This insect/fungal pathogen was introduced into Nova Scotia in the late 1800's, and has since spread southward to the Southern Appalachians. In affected stands, mortality of beech stems frequently approaches 90 to 100 percent. We used inter-simple sequence repeats (ISSR) markers to assess the relationship between host genotype and degree of pathogen infection in beech trees in Great Smoky Mountains National Park. We used statistical analyses to test the relationship between stem diameter and degree of pathogen infection. We found no correlation between host genotype and degree of infection. We did find a significant positive relationship between stem size and degree of infection. Among three stem size classes, smallest stems (<1.5 cm) were least likely to be infected, while largest stems (>3.0 cm) were most likely to be infected. Implications for future studies are discussed.
Yellow-poplar (Liriodendron tulipifera) flowers have been reported to be an important component of the spring diets of white-tailed deer (Odocoileus virginianus) in the southern Appalachians. We quantified the nutritional contribution of yellow-poplar flowers by comparing flower nutrient content to published nutrient requirements for deer. Yellow-poplar flowers exceeded the calcium, phosphorus, crude protein, and digestible energy requirements (P < 0.001) for productive processes. However, sodium requirements for antler growth and digestible energy requirements for peak lactation for twin fawns were not met by yellow-poplar flowers. Similar to oak (Quercus spp.) mast in the fall months, yellow-poplar flowers are an important seasonal source of energy for deer.