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Populations of Neotoma floridana (Eastern Woodrat) are decreasing in parts of their geographic range in the southeastern United States, and the species is stateendangered in Illinois. Once found throughout the Shawnee Hills region of southern Illinois, woodrats were restricted to four known populations in Jackson and Union counties by the late 1980s. We used reintroductions to establish viable populations of Eastern Woodrats at previously occupied sites in Illinois. From April 2003 through March 2009, we released 422 Eastern Woodrats live trapped in Arkansas and Missouri into 5 historically occupied sites in southeastern Illinois. Recapture rate 1 month after release was 12.5%. The continued presence of woodrats at release sites, reproduction, and wide dispersal beyond reintroduction sites all suggest preliminary success of the reintroduction of this r-selected species.
We quantified changes in vegetation and small-mammal communities over a 3-year period in paired creek, forest, and field sites in the central Appalachian Mountains. Prescribed burns were applied to field sites in 2008. Data were collected at all sites during summers of 2008 (pre-burn for fields), 2009 (ca. 2–4 months post-burn for fields), and 2010 (ca. 14–16 months post-burn for fields). In 19,640 trap-nights across 3 years, we captured 605 individuals of 14 small-mammal species. Sørenson index showed substantial differences in mammal communities between 2008 pre-burn and 2009/2010 post-burn fields (<10% similarity for all pre- to post-burn comparisons). Creek and forest habitats showed markedly greater year-to-year similarities (46–82%). Unlike mammals, vegetation and habitat structure showed little change over time. Minimal changes in preand post-burn fields suggest that field vegetation at these sites recovered rapidly after the low-intensity surface fires. In contrast, fire appears to have had a profound effect on small-mammal communities in fields, as documented by dramatic temporal changes in species composition and abundance and little evidence of recovery after 16 months postburn. As many managed fields in this region are burned on 3-year rotations, this potential impact of prescribed fire on small-mammal communities is important. Additional studies are needed to determine whether small-mammal populations are strongly affected by conditions during prescribed burns (i.e., direct effects on species mortality and emigration), or if the changes we observed reflect natural cyclical patterns (annual or multi-annual periodicities) in these populations.
Knowledge of growth in body dimension and mass is important to understanding fundamental elements of wildlife biology and ecology. We evaluated five classical growth models (Gompertz, Logistic, Monomolecular, Richards, and von Bertalanffy) in describing body length and mass growth curves as a function of age to determine which best fit wild Puma concolor coryi (Florida Panther). When used for inferences on body length and mass growth curves of both genders, the von Bertalanffy function proved to be the best-fitting theoretical equation to our data set because it used the fewest parameters derived directly from metabolic laws, had lowest residual standard deviation of data points about fitted model, with lower Akaike Information Criterion value, and largest Akaike weight. The von Bertalanffy model estimated that male asymptotic body length was 9.4% longer and mass was 33.2% heavier than for females. Both genders grew in body mass for a longer duration than length. Male-biased sexual size dimorphism develops in part because males grew faster and for a more prolonged period. Our results should prove useful in future studies of Panther energetics, reproduction, and in developing conservation and management policies for this species.
Vireo atricapilla (Black-capped Vireo) is an endangered migratory songbird with a breeding range that exists predominantly within Texas. Despite the species' listing under the Endangered Species Act in 1987, Black-capped Vireos were largely undocumented in much of the range. We sampled over 10,700 points in Texas, resulting in 2458 Black-capped Vireo detections. We examined the relationship between Black-capped Vireo occurrence and vegetation and broad-scale landscape variables, and we assessed if detections were clustered. Black-capped Vireo detections occurred often on a common soil type but were found where slopes were higher in the western part of the range. We found evidence of clustering in six of our eight study areas but no evidence of habitat metrics driving that clustering. These data improve the current knowledge of Blackcapped Vireo distribution and offer opportunities for improved guidance for conservation and management efforts.
A cooperative multi-state monitoring effort was initiated for Passerina ciris (Painted Bunting) in 2008 because of a suspected decline in its eastern population. The Florida component of this range-wide study was conducted during 3 consecutive breeding seasons to obtain a better understanding of abundance and habitat use (vegetation associations) than could be obtained from existing indices, to examine factors affecting detectability, and to determine whether short-term trends could be assessed. Sample units (three hundred two 0.01–27-km2 blocks) were allocated for Florida from which 22 were randomly selected, within which 101 point-count survey stations were established. Point-count surveys (n = 906) were conducted annually from 2008 to 2010, and vegetation characteristics were quantified for each location. Abundances were estimated from the counts by an N-mixture model for open populations. Estimated mean breeding density of male Painted Buntings in Florida decreased from 12.4 males/km2 in 2008 to 9.8 males/km2 in 2010; these densities are at the low end of the range previously reported for the eastern population. In combination with an estimate of available habitat (1558 km2), the mean estimate of the total number of males (maximum potential abundance) decreased from 19,319 in 2008 to 15,268 in 2010. Painted Bunting abundance in Florida was greater toward the northern end of its range. Abundance was positively associated with the amount of maritime forest and hammock at count points and negatively associated with the amount of planted pine. Conservation of remaining maritime forest and hammock will be fundamental in maintaining breeding populations of the Painted Bunting in Florida.
Following the reported rediscovery of Campephilus principalis (Ivory-billed Woodpecker) in Arkansas, we initiated searches in South Carolina in February 2006, with additional searches in the winter and spring of 2006–2007 and 2007–2008, concentrating in the Congaree, Santee, and Pee Dee river basins. We accrued a cumulative total of 8893 survey hours. We found suggestive evidence in the form of visual and acoustic encounters, but failed to document conclusive evidence. Based on our search results, we believe it is unlikely that a population of Ivory-billed Woodpeckers persists in Congaree National Park and found limited evidence for their presence on other public lands in South Carolina. However, we cannot rule out the possibility that a small, nomadic population persists in the state.
During the 1970s–80s, Scolopax minor (American Woodcock) on wintering grounds in North Carolina generally used bottomland forests diurnally and fed on earthworms in conventionally tilled soybean fields at night. Researchers surmised the ridges and furrows in conventionally tilled fields provided Woodcock protection from predators and winter weather. Since the 1980s, farmers widely adopted no-till practices for soybean agriculture, and this change in field structure may have altered Woodcock crop field use. We returned to the same area as previous research and conducted a study of Woodcock crop field and forest use in a landscape where crop fields are the dominant open-habitat type. During December 2009–March 2010, we captured and radio-tracked 29 Woodcock. Every 24 hours, we located each radio-marked Woodcock during diurnal and nocturnal periods, and verified the habitat type on foot as either crop field or bottomland forest. We recorded 94% of nocturnal locations in forest, 6% of nocturnal locations in crop fields, and 100% of diurnal locations in forest. Percent of an individual Woodcock's nocturnal locations in crop fields ranged from zero to 44%, with a mean of 6% (± 2% SE). The adoption of no-till technology and associated reduction in ridge and furrow micro-habitat available in crop fields may contribute to the low frequency of Woodcock nocturnal field use. Because Woodcock primarily were relocated in bottomland forests diurnally and nocturnally, forest stands should be conserved when managing agricultural landscapes.
The opening of the Morganza Spillway in Louisiana on 18 May 2011 to relieve historic flooding along the lower Mississippi river subsequently inundated thousands of acres of bottomland forest in the Atchafalaya basin. Since 2001, we have conducted Meleagris gallopavo silvestris (Eastern Wild Turkey) population ecology research on the Sherburne Wildlife Management Area, located approximately 30 km south of the Morganza spillway. In expectation of the Morganza spillway opening, between 11 and 14 May, we captured and fitted 5 (1 M, 4 F) adult Eastern Wild Turkeys with µGPS transmitters to monitor turkey response to basin flooding. By 19 May 2011, our study area was inundated with >3 m of flood waters, and remained completely inundated until 11 June 2011. Via radio-telemetry, we confirmed one female was depredated immediately before flood waters inundated our study site, and one female survived and reached dry ground created by receding water on 16 June. A second female lived 21 days and made circuitous movements within the tree canopy before dying, and the lone male died after 31 days. Movements of the second female through the canopy during flooding suggested a deliberate search for topographically higher areas within her range. Our findings suggest that rapid, widespread flooding conditions created by opening of the Morganza spillway likely negatively affected Wild Turkey populations across the Atchafalaya basin through direct reductions in survival. Further research is needed to assess how flood mitigation efforts affect Wild Turkey populations in floodplains along the Mississippi River and other alluvial floodplains.
Federally threatened Scutellaria montana (Large-flowered Skullcap) is a perennial herbaceous species endemic to southeastern Tennessee and northwestern Georgia. A large population of S. montana is located at the 648-ha Tennessee Army National Guard Volunteer Training Site (VTS) in Catoosa County, GA. Due to necessary operational activities that include vegetation clearing along site boundaries to maintain security and prescribed burning and overstory clearing to reduce fuel loads as a wildfire-prevention measure, S. montana individuals and groups at the VTS may be disturbed unavoidably at times. Our objectives were to provide recommendations for land managers at the VTS and elsewhere regarding the response of S. montana to transplantation when plant rescue is necessary and to guide site selection for transplantation by elucidating the effects of pre-transplantation burning and canopy thinning on transplant survival and subsequent success. We relocated 100 S. montana individuals in spring 2010 from a site scheduled for clearing to plots that were burned (B), thinned (T), treated with a combination of burning and thinning (B T), or not treated (C; control). Survival, growth, reproductive potential, development, and physiological measurements were used throughout the 2010 and 2011 growing seasons to evaluate the success of transplantation overall and in various relocation plots. At one year post-transplantation, 91% of the original transplants had survived relocation, and among all transplants, mean stem height and the numbers of stems, leaves, and flowers per individual significantly increased. Additionally, the percentage of total transplants that were juveniles was much lower one year post-transplantation than immediately following transplantation (5.7% vs. 27%), while the proportion that were reproductive adults was greater one year post-transplantation (37.5% vs. 22%). However, reduced survival was found in the canopy-thinned plots (84% in both plot T and plot B T) compared to plot B (100%) and plot C (96%) one year post-transplantation. The main effects of both burning and thinning included significant increases in stem damage and in the proportion of transplants that were vegetative adults, with an associated decrease in the proportion of reproductive adults. Combined, these findings may have resulted from increased trampling and feeding activity of vertebrate herbivores in burned and thinned plots. Overall, we considered our transplantation efforts to be successful due to high survivability and continued growth and development of individuals one year post-transplantation. However, to maximize the success of S. montana relocation, we suggest that transplants be relocated into unburned, unthinned forests and that vertebrate herbivory be subsequently controlled though the use of exclosures.
Ecological restoration is becoming an increasingly important tool in humanity's attempt to manage, conserve, and repair the world's ecosystems. In the current study, the objective was to compare the effects of two restoration methods on arthropod biodiversity and community composition in two former pine plantations; these treatments included both intensive restoration effort (= cleared) and moderate restoration effort (= thinned). For the cleared treatment, vegetation was clear-cut to the soil surface, and all vegetation was removed from the plots, while the thinned treatment consisted of reducing the Pinus elliotii (Slash Pine) density to that of a native ecosystem and removing of all exotic plants from the plots as well. Arthropods were sampled by employing pitfall traps, sticky traps, and sweep netting and identified to family and morphospecies; species richness, diversity, and community similarity were compared between treatments and sites. Experimental treatments quickly reached or exceeded arthropod diversity and richness of an unmanipulated control treatment; however, the two sites produced non-overlapping ordination plots, suggesting that the diversity of the two sites are either compositionally different (alpha diversity) or community assemblage is incomplete and overall regional (beta) diversity has not reached an equilibrium across sites. Additional long-term data should reveal if these plots are proceeding along different successional trajectories in terms of community species composition, or whether treatments, while having similar richness, support different communities because the three types of plots used in this study (control, thinned, and cleared) represent various successional stages which affect arthropod species identity, but not overall richness.
Cryptobranchus alleganiensis alleganiensis (Eastern Hellbender) is a large, imperiled aquatic salamander found in rocky upland streams from New York to Alabama. Although widespread, many Hellbender populations are now highly fragmented by impoundments and degraded habitats. Hellbenders likely require specific stream habitats with relatively low anthropogenic impacts in order to maintain population viability. The Elk River is a small (5th order), high-gradient tributary of the Watauga River drainage that originates in Avery County, NC and flows northwest to Watauga Reservoir in northeastern Tennessee. Although the Elk River's headwaters are heavily impacted by development in the resort towns of Banner Elk and Sugar Mountain; its lower reaches flow through portions of the Pisgah and Cherokee National Forests and over several large waterfalls before reaching the reservoir. Hellbender presence was undocumented in the Elk River prior to 2010. We learned that Hellbenders were likely present in the lower Elk River from anecdotal reports of sightings in Tennessee. In 2010 and 2011, we surveyed for Hellbenders at 10 sites in the Elk River drainage. We observed multiple size classes, including larvae and juveniles, present in the lower Elk River. Development in headwater regions of the Elk River in North Carolina may have caused habitat degradation in the upper Elk River causing the extirpation of Hellbenders in the upper reaches.
Cambarus (Depressicambarus) harti (Piedmont Blue Burrower) is a state-endangered primary burrowing crayfish found in highly organic soils associated with seepage areas only in Meriwether County, GA. As is the case with many native burrowing crayfishes, virtually nothing is known about the biology and ecology of this species. To help fill this gap, the current study provides information on population demographics, environmental correlates of activity, burrowing behavior, and habitat fidelity of C. harti. Field surveys from the type locality revealed that crayfish could be found throughout the year, with a near 3:1 ratio of female to male adults captured, an ovigerous female found in June, and the highest number of small juveniles found in August. Adults were not found together in burrows; however, juveniles were often found sharing the burrows of females. Burrowing activity was generally higher in the summer than winter, and also increased with receding groundwater levels. Based on observations and experiments with artificial burrowing chambers (ABCs), the burrows of C. harti followed a predictable form and were often capped with at least one chimney of seemingly deliberate construction. Total burrow area and mean chimney pellet diameter increased with crayfish size. It appeared that C. harti will burrow in other soils, but displays a strong affinity to its type-locality soils, particularly below groundwater level. Observations from a communal ABC revealed that adults use burrows to brood young and will share burrows with other adults for a period of time, possibly during burrow construction and/or times of disturbance, but eventually tend to segregate to solitary occupancy. Taken together, these data offer insight into the biology and ecology of this highly endemic and elusive animal that will be useful for management and conservation efforts and provide much-needed scientific information about burrowing crayfishes in general.
Pleurobema strodeanum (Fuzzy Pigtoe), is listed as threatened under the Endangered Species Act. The purpose of this study was to estimate growth rate, morphometric ratios, and ages for this species. One hundred and sixty-one P. strodeanum were originally tagged and measured in 2004 at Eightmile Creek, Walton County, FL. In 2011, 28 of those 161 were recovered and re-measured. Growth-rate percentages were determined based on length, width, height, and volume. Age was estimated using the von Bertalanffy growth equation. Results indicate that over a period of seven years, P. strodeanum grew 0.48 mm/year (SD = 0.14) in length. The age estimations in this study ranged from 48.7 to 74.5 years. The growth constant (K) was 0.018 per year, and the asymptotic length L∞) was 71.97 mm. Natural history data such as these will be useful in understanding the basic biology of P. strodeanum and may assist in successful mussel management.
The results of statistical analyses conducted on monthly trawl and seine data collected from a multiyear fisheries-independent monitoring program, between July 2006 and March 2009 on the lower Apalachicola River, FL were used to determine which regions of the river, and what time of year should be further studied to determine if and how freshwater flow alterations affect the nekton. Differences in nekton community structure were clear between each of the 3 predefined habitat regions for shoreline seine catches. Deepwater trawled habitats showed a distinct difference between the upper river channel and both distributary regions, and less pronounced differences between the two distributary regions. The strongest pattern in seasonality of nekton communities coincides with seasonal fluctuations in recruitment of juveniles into the estuary and the periods of greatest salinity differences in the marshgrass-dominated lower distributary region for shoreline and deepwater habitats. Seasonal variations in community structure were evident and mostly likely dominated by recruitment, whereas the response of organisms to fluctuations in salinity may be dictated by their relative position within the lower reaches of the Apalachicola River system. Our results suggest that future studies of the effects of changes in flow on nekton assemblages in the lower Apalachicola River would best be performed during the dry season in the upper and lower portions of the distributary region.
Predation from aquatic and terrestrial predators are important factors structuring the size and depth distribution of aquatic prey. We conducted mesocosm and tethering experiments on Little Mulberry Creek in northwest Arkansas during low flows to examine the effects of predators on fish and crayfish survival in intermittent streams. Using shallow artificial pools (10 cm deep) and predator exclusions, we tested the hypothesis that large-bodied fish are at greater risk from terrestrial predators in shallow habitats compared to small-bodied individuals. Twenty-four circular pools (12 open top, 12 closed top) were stocked with two size classes of Campostoma anomalum (Central Stoneroller) and deployed systematically in a single stream pool. In addition, we used a crayfish tethering experiment to test the hypothesis that the survival of small and large crayfish is greater in shallow and deep habitats, respectively. We tethered two size classes of Orconectes meeki meeki (Meek's Crayfish) along shallow and deep transects in two adjacent stream pools and measured survival for 15 days. During both experiments, we monitored the presence or absence of predators by visual observation and from scat surveys. We demonstrated a negative effect of terrestrial predators on Central Stoneroller survival in the artificial pools, and larger individuals were more susceptible to predation. In contrast, small crayfish experienced low survival at all depths and large crayfish were preyed upon much less intensively during the tethering study, particularly in the pool with larger substrate. More studies are needed to understand how stream drying and environmental heterogeneity influence the complex interactions between predator and prey populations in intermittent streams.
Male Gambusia holbrooki (Eastern Mosquitofish) express a heritable pigmentation polymorphism: ≈99% of males are silver, and only ≈1% have a melanic, black-spotted pattern. Sex-linkage, an autosomal modifier, and temperature control the expression of this heritable melanism. In many teleosts, melanin also accumulates around the site of parasitic invasion. We have identified black-spot disease in wild mosquitofish from their native habitat. Here, we demonstrate convergence upon the black-pigmented phenotype through two means: 1) heritable melanism, and 2) melanic spotting on the silver genotype that results from infection with immature encysted trematodes. Females are silver and express greater avoidance of melanic males during mating attempts. The resemblance of the black-spotted pattern of the melanic genotype to that of silver genotype infected with trematodes may affect the fitness of melanic males if females perceive them as diseased. Alternatively, females may shun parasitized silver fish because they resemble the melanic genotype, which is larger and has a larger mating organ.
We sampled stocked Salvelinus namaycush (Lake Trout) in Watauga Lake and South Holston Lake, TN using experimental gill nets in 2009–2010 to describe their growth, longevity, and condition. Annuli in sagittal otoliths formed once a year in early spring in both reservoirs. South Holston Lake (n = 99 Lake Trout) has been stocked since 2006, and the oldest fish was age 4. Watauga Lake has been stocked since the mid-1980s, and we collected 158 Lake Trout up to age 20. Annual mortality for age-3 and older fish in Watauga Lake was 24%. When compared to Lake Trout in northern lakes, Tennessee Lake Trout exhibited average to above-average growth and longevity. Condition of Lake Trout in both reservoirs varied seasonally and tended to be lowest in fall, but rebounded in winter and spring. Lake Trout in both reservoirs appeared to be spatially segregated from pelagic prey fishes during summer stratification, but growth rates and body condition were high enough to suggest that neither system was being overstocked.
Understanding food-web ecology is valuable to conservation by linking interactions of multiple species together and illustrating the functionality of trophic exchange. Alosa alabamae (Alabama Shad), an anadromous species, reproduces in northern Gulf of Mexico drainages from February through May, and for this study, the Pascagoula and Apalachicola rivers were chosen to sample juvenile Alabama Shad. The age-0 fish mature within these rivers and have the potential to impact the food web of the systems in which maturation occurs. The focus was to determine if diet changes as Alabama Shad mature, and to identify diet differences between drainages. Diets of Alabama Shad <50 mm standard length (SL) consisted primarily of a dark, almost black material labeled as unidentifiable organics, while larger Alabama Shad, >50 mm SL, fed almost exclusively on insects. Many groups of aquatic and terrestrial insects were found in the stomachs of this species. Alabama Shad diets also differed among drainages, with the Apalachicola River being dominated by terrestrial insects, and the Pascagoula River having both terrestrial and aquatic insects. Diet and trophic placement of Alabama Shad may allow managers to understand the importance of this fish within its natal rivers.
Sternula antillarum (Least Tern) are small, migratory seabirds that are listed as threatened or endangered in every state in which they occur. While their natural nesting habitat is open beach, Least Terns have adapted to nest on flat tar and gravel roofs, sometimes many kilometers inland. We used the “fish drop” technique to collect fish that birds dropped around a roof colony in Pinellas County, FL to assess use of fresh and saltwater fish species as prey. We collected 37 fish from 12 different species. The most common (n = 11) was Dorosoma petenense (Threadfin Shad), a species found primarily in marine/brackish waters, but often stocked in man-made freshwater ponds to supplement piscivorous fish prey. Eighteen of the remaining 26 fish, encompassing 7 of the remaining 11 species, are marine/brackish species, 5 individuals are freshwater species, and 3 are freshwater/brackish species. Roof-nesting Least Terns appeared to forage in stormwater ponds and a lake found near the colony, but they also traveled a minimum of 4.8 km to forage in marine/brackish waters. Roof nesters may face greater challenges than beach nesters, because they are potentially exposed to more pollutants in stormwater ponds and expend more energy and time to travel farther to forage at saltwater sites.
We describe the first detection of a Babesia sp. in a Lynx rufus (Bobcat). The Bobcat was from Georgia and was coinfected with Cytauxzoon felis and a Sarcocystis sp. The Babesia species was closely related to Babesia sp. “Coco”, a parasite previously only detected in Canis familiaris (Domestic Dog). The only other Babesia sp. in North America that infects felids is a novel Babesia species in Puma concolor coryi (Florida Puma). The low prevalence of this Babesia (<1%) in Bobcats suggests that they are not the normal host or reservoir and this may have been an incidental infection.