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Successful long-term monitoring programs of amphibians require the ability to distinguish natural population fluctuations from human-caused declines. Because recruitment in populations of pond-breeding amphibians depends on optimal environmental conditions of rainfall and hydroperiod, extended periods of drought may have adverse effects. We examined the breeding biology of Ambystoma cingulatum at a breeding site in northwestern Florida for four consecutive seasons (1999–2002) during and immediately following a drought. The number of immigrating adults declined steadily during this period, and larvae and metamorphs were not observed. Potential explanations for the observed decline in number of adults include disruption of migration as a result of insufficient rainfall during the breeding season and cumulative rainfall deficit, lack of juvenile recruitment, and adult attrition. We believe reduction in number of adults is best explained as attrition of adults without recruitment of juveniles.
Recovery of the federally threatened Ambystoma cingulatum (Flatwoods Salamander) will require monitoring of known populations, as well as continued searches for additional populations. In an effort to develop recommendations for maximizing efficiency of future surveys of larval Flatwoods Salamanders, we combined data from surveys conducted between 1990 and 2004 in Florida and Georgia. Analysis of these data revealed variation in the number of larvae captured, survey effort, capture rates, and larval body size among years and months. An average of 16 min or 45 one-m long dipnet sweeps was required to catch each larva. For wetlands surveyed twice in a season, results (i.e., larval presence or assumed absence) were consistent in 74% of consecutive surveys. We make recommendations for conducting future surveys and the implementation of a coordinated research and monitoring program for Flatwoods Salamanders.
This study was conducted to determine the relationship between water chemistry and presence of stygobitic (cave-obligate) crayfishes (Cambaridae) in Tennessee, Alabama, and Georgia. We analyzed nine chemical factors in water samples from twenty caves, twelve of which contained stygobitic crayfish and eight in which none were found. A multiple analysis of variance using principal components scores suggested that absence of crayfish was associated with lower dissolved oxygen, higher ammonia, and higher water temperature. Caves with externally originating streams supported no stygobitic crayfishes, and the chemical factors of the water in these caves were more variable.
A new non-destructive method of sampling burrowing crayfish, the burrowing crayfish net, was compared to the Norrocky burrowing crayfish trap. The new sampling method captured significantly more crayfish than did the trap. Captured crayfish sizes were similar and sex ratios were not biased in the two methods. Sixteen species of crayfish have been captured with the burrowing crayfish net.
Effective conservation of mussels in streams of the lower Flint River basin, southwest Georgia, requires more rigorous understanding of mussel-habitat associations and factors shaping assemblage composition in stream reaches. We surveyed mussels and habitat conditions at 46 locations, and used regression, correlation and multivariate direct gradient analysis (Canonical Correspondence Analyses) to identify species-habitat relationships and characteristic species-assemblage types in Flint basin streams. Riparian wetland and catchment forest cover, average mid-channel depth, and drainage network position accounted for 49% of the variability in mussel species richness, 36% of the variability in unionid abundance, and 32% of the variability observed in Shannon-Wiener diversity across survey sites. Species were grouped into four assemblage types based on their habitat associations: large-river-riffle associates, slackwater associates, habitat generalists, and stream-run associates. Results are broadly concordant with anecdotal reports of mussel-habitat relationships and provide insight into the habitat conservation needs of mussels.
Simpsonaias ambigua (salamander mussel) is a small-shelled member of a monotypic unionid genus and the only freshwater mussel reported to be an obligate parasite of amphibians. Recent surveys of the Duck River drainage found no historical or recent records of the salamander mussel, but documented records for 73 other species, including 53 extant taxa. In 2003, a fresh-dead shell of S. ambigua was collected from the Duck River in Humphreys County, TN. Additional specimens were found in June 2005. These specimens represent the only known occurrence of S. ambigua in the Duck or Tennessee River drainages and may represent the only remaining Tennessee population.
A survey of the terrestrial mollusks of the Sipsey Wilderness Area, Bankhead National Forest, in northwestern Alabama was conducted from August 2003 to May 2004. A total of 15 sites were sampled across a number of different habitat and vegetation types found within the area. A total of 50 species were found, representing 14 families and 30 genera, including 58 new county and 2 new state records. This represents a significant increase in the known diversity of the area based on a preliminary survey conducted in the 1960s, which yielded only six species. The current survey highlights the need for more detailed survey work across Alabama and the southeastern United States.
Streams were sampled throughout the Upper Black Warrior River basin to (1) determine the current distribution of Necturus alabamensis (Black Warrior Waterdog) and (2) identify its habitat requirements. Individuals were observed at 14 of 112 localities within 60 streams. Discriminant function analysis of stream characteristics revealed that waterdog populations were associated with the presence of ephemeropteran larvae on a local scale and with water depths of 1–4 m, large leaf packs, and low percentage of fine sediments on a regional scale. Where present, N. alabamensis occurs at relatively low population densities, and populations monitored in our survey exhibited a 1:1 sex ratio with no apparent age-class structure or sexual size dimorphism. We conclude that this species is rare on the basis of its restricted geographic range, low abundance, and unpredictable occurrence in suitable habitat; as such, N. alabamensis should be considered for federal protection.
Cyprinella gibbsi (Tallapoosa shiner) is sympatric with Etheostoma tallapoosae (Tallapoosa darter) and both species are endemic to the Tallapoosa River system of Georgia and Alabama. The darter population has been shown to be divided into genetically divergent populations. In this study, mitochondrial ND4L sequences were analyzed for 10 populations of the Tallapoosa shiner from throughout its distribution. Phylogenetic analysis and analysis of molecular variance show that the shiner population is also divided into genetically divergent populations. These can be designated as management units for future monitoring of the species. The distributions of the genetically divergent populations of the shiner and the darter are similar, and indicate that the two species share a common biogeographic history.
Fall Line sandhills vegetation occurs on dry, sandy ridgetops and supports a suite of rare or uncommon plant species (TES). We surveyed nine sandhills sites and 32 “matrix” mixed pine-hardwood stands at Fort Benning to characterize canopy and groundlayer vegetation patterns and determine the extent of sandhills vegetation, including characteristic dominant species and TES, over the upland landscape. The relative abundance of Pinus palustris (longleaf pine), P. taeda (loblolly pine), and P. echinata (shortleaf pine) and sandhills oaks contributed to canopy composition differences among sites. The sandhills communities support a unique set of groundlayer species, including state-listed Chrysoma pauciflosculosa. Although there is some species overlap, especially in overstory composition, characteristic sandhills vegetation is not widely distributed in mixed pine-hardwood stands at Fort Benning and conservation might best be achieved by maintaining existing sites.
The fungus Fusarium semitectum infects the flowering heads of Rudbeckia auriculata at two sites in Alabama. This is the first report of a fungal agent infecting this globally rare species. The fungus produces orange-tinged or pinkish-white spores on the flower heads and renders infected flowers sterile. Fungal spores superficially resembled pollen and are picked up by the main pollinator, the composite specialist bee Andrena aliciae, which serves as a dispersal agent for the fungal pathogen. Fungal spores were found attached in higher ratios in those areas of the bee's body that come into most direct contact with the flowering heads during feeding. The rate of spread of the fungus on potted plants indicated significant negative correlations between number of infections and the distance from the fungal source. Fusarium colonies were isolated from the entire length of flowering stems, and apparently invade vegetative portions of the plants. As R. auriculata is a perennial plant that reproduces almost exclusively by the production of short stolons, the fungus poses no serious threat to its immediate existence.
In Spring of 1995 and 1997, 170 ha of a savanna-glade complex in the Ozark Mountains of Arkansas were burned. These prescribed burns included 5 of 18 permanent plots established across the site in 1993. We surveyed the ground flora, seedling, sapling, and overstory vegetation of these plots before and after burning. The burns greatly impacted the sapling layer, where density decreased from 2540/ha preburn to 610/ha after the second burn. Ground flora richness was unchanged following burning, but evenness and diversity increased. Species richness, evenness, and diversity also increased on the unburned plots. We observed large increases in the cover of several glade and savanna species after burning. We observed similar trends, but of lesser magnitude, on unburned plots.
Sphyrapicus varius (Yellow-bellied Sapsuckers) are winter residents of mature Pinus palustris (longleaf pine) forests in the southeastern US. Sapsuckers pierce the bark of mature pines to create wells on living trees and consume the sugar-rich exudate and insects attracted to this food source. To determine sapsucker preferences for individual trees, for locations along boles, and for edge vs. interior habitat, we surveyed an old-growth Pinus palustris stand in lower Alabama with recent sapsucker activity. Individual tree characteristics and stand conditions were evaluated to assess their influence on the number and location of sap wells. Of 596 pines sampled, 74 (12.4%) contained wells. Sapsuckers selected trees with greater diameter at breast height (mean dbh of welled trees = 40.4 cm; non-welled trees = 24.6 cm; P < 0.01). Among pines with wells, sapsuckers fed differentially on different aspects and stem heights. Sap wells were concentrated on the north aspect of the bole (P < 0.05), where wells were 40% more likely to occur than any other aspect. No stand characteristics (plot distance to stand edge, plot basal area, plot tree density, 5-year radial increment growth) significantly influenced sapsucker tree-selection patterns.
I surveyed bird communities during the 1999 and 2000 breeding seasons in oak-pine sawtimber (ST) stands, pine poletimber (PT) stands, high-density pine seedling (SS) stands, and recently clearcut areas throughout Holly Springs National Forest (HSNF), in north-central Mississippi. Species richness was 25% greater in forested stands compared to clearcut areas, yet total bird density was 50% greater in clearcut areas. Bird communities ranged from open-habitat assemblages in clearcut areas to forest-obligate assemblages in ST stands. Little overlap of avian community composition was observed between ST stands and clearcut areas. PT and SS stands supported avian communities where most species were observed at intermediate abundance values compared to ST or clearcut areas. Highly fragmented, closed-canopy stands embedded within the silvicultural landscape of HSNF do not support large populations of species traditionally associated with detrimental edge effects on forest-obligate songbirds. Intensively managed PT and SS stands appear to provide suboptimal habitat for forest and grassland species. Land managers in HSNF could maximize regional avian diversity by maintaining a mosaic of large closed-canopy, oak-pine stands, and fire-maintained open areas embedded among other silvicultural stand types.
Obtaining reliable survival estimates is important in the management of wildlife populations, particularly for the construction of computer simulation models. Many methods for estimating survival (e.g., radiotelemetry) are cost-prohibitive or time consuming. Life tables can provide survival estimates using data routinely collected by some management agencies. We calculated annual survival for Odocoileus virginianus clavium (Key deer) using age-specific mortality data. We compared our life-table estimates to those calculated from radiotelemetry data. Key deer survival estimates derived from life tables were similar to rates calculated from radiocollared deer. The only exception was for yearling/adult females on north Big Pine Key, where the life-table estimate was only slightly outside of the 95% confidence interval for the radiotelemetry estimate. Our results suggest that life tables based on age-specific mortality data can be a useful tool in estimating survival for Key deer. Comparing survival estimates from both methods allowed us to evaluate potential biases due to violation of assumptions associated with life-table calculations. While wildlife managers should be aware of the potential biases, age-specific mortality data may provide an adequate and cost-effective alternative for estimating survival.
Peromyscus leucopus (white-footed mice) and Ochrotomys nuttalli (golden mice) were live-trapped in eight experimental plots of lowland and upland deciduous forest during 2001 and 2004. An outbreak of Cuterebra fontinella (botfly) parasitism occurred on both species of small mammals during the 2001 and 2004 trapping seasons, with peaks in mid-July each year. A second peak of parasitism was observed in late October 2004, which differed greatly from 2001 where only one peak occurred. We suggest that a greater three-dimensional home-range size and pattern of behavioral activity exhibited by P. leucopus led to a greater incidence of parasitism (41.7%) compared to the more arboreal O. nuttalli (6.3%–12.5%). The second outbreak of parasitism appeared to have been the result of a late-summer deluge of tropical weather caused by an exceptionally active hurricane season affecting the southeastern United States.
Chironomid pupal exuviae were sampled monthly using drift nets and hand sieves over an annual cycle from Hendrick Mill Branch (HMB; Blount County, AL) and Payne Creek (PC; Hale County, AL). Taxon richness, community composition, and emergence phenologies were similar despite marked differences in physical/chemical characteristics of the study streams. The highest emergence rates were observed in spring (PC) or both spring and fall (HMB). However, there was no significant relationship between emergence/emergent biomass and date. Estimates of daily emergence and emergent biomass were much higher in HMB than in PC. These patterns may have resulted from a more consistent flow regime, higher substrate stability, lower variation in temperature/chemical characteristics, greater channel surface area, and a more significant hyporheic zone in HMB than in PC.
Here we evaluate monthly and daily activity patterns of Neoseps Reynoldsi (Sand Skink), through examination of museum specimens and population studies at Archb old Biological Station (ABS), Highlands County, FL, and in Ocala National Forest (ONF), Marion County, FL. Sand Skinks are active throughout the year, with highest captures in February through May, and August through October. Museum specimen data suggest a peak in December, but this reflects collector bias. Number of captures is significantly negatively related to precipitation and positively related to temperature for Sand Skinks at ABS, but this relationship is due to capture of hatchlings from July through October. At ONF, no relationship between temperature and precipitation and number of captures exists. The number of Sand Skink tracks per day at ABS is not related to temperature, but is significantly negatively related to precipitation.