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Species management and conservation strategies require accurate information about species distributions and behaviors. Neovison vison evergladensis (Everglades Mink) is listed in Florida as threatened, yet its current population status and distribution are unknown. We report the first incontrovertible evidence of the occurrence of Everglades Mink in Everglades National Park (ENP) in 15 years. Specifically, we found Everglades Mink hair in the stomach contents of a 254-cm (total length) adult male Alligator mississippiensis (American Alligator) captured in 2011 in the southwestern corner of ENP. Our finding confirms that Everglades Mink still inhabit the park, but we present a hypothesis suggesting that very few may be left there; potential causes of the decline include alterations to ENP hydrology and a recent increase in the number of large predators in ENP.
Many animal species are important dispersers of seeds; however, relatively little attention has been paid to the seed-dispersal capabilities of reptiles, and almost nothing is known about the seed-dispersal capabilities of crocodilians. This lack of information is surprising given that seeds have been found in the stomach contents of a majority of crocodilian species. Here we present the first experimental investigation of the seed-dispersal potential of a crocodilian. Using a comparative germination experiment, we tested the viability of Annona glabra (Pond-apple Tree) seeds recovered from the stomach of an Alligator mississippiensis (American Alligator [Alligator]) captured in the Florida Coastal Everglades. We found that seeds from the Alligator's stomach were nonviable under ideal germination conditions and that fresh, non-digested Pond-apple seeds exposed to the same germination conditions were highly viable. The seeds recovered from the Alligator’s stomach were nonviable because they were likely destroyed by stomach acids. Thus, Alligators are likely not dispersers of Pond-apple seeds and may instead act as seed predators. Further research is needed to test the potential of crocodilians as dispersers of other types of seeds from different plant families.
The recent expansion of Canis latrans (Coyote) into the eastern United States has generated interest among wildlife managers because of the potential impacts on Odocoileus virginianus (White-tailed Deer) populations. Coyotes have been reported as predators of adult and neonate White-tailed Deer in some parts of their range, but recent studies in the Southeast have documented only Coyote predation on neonates. We report 4 confirmed Coyote predation events on adult female White-tailed Deer that were radiocollared, implanted with vaginal implant transmitters, monitored every 4–8 hours, and apparently healthy. Field necropsies confirmed killing-bite wounds to the upper throat and base of the mandible, and feeding behavior on the carcasses was consistent with what has been observed for Coyotes. Further, we used swabs from bite wounds to confirm the presence of predator DNA, and the 3 carcasses that were swabbed tested positive for the presence of Coyote DNA. To our knowledge, our results represent the first scientifically documented Coyote predations on adult female White-tailed Deer in the Southeast.
Birds that require early-successional habitat are declining in North America due to habitat loss. Their increasing reliance on anthropogenic landscapes, such as the extensive Pinus spp. (pine) plantations of the southeastern US, makes it important to assess how management alternatives within these forests influence habitat quality. We examined how 2 site preparation variables, tree row spacing (4.3 m vs. 6.1 m) and arrangement of post-harvest woody debris (piled vs. scattered), influenced species richness, abundance, and breeding activity of disturbance-dependent (early-successional) birds. We studied bird communities and vegetation structure during the first 5 years of growth on replicated plots in 4 intensively managed Pinus taeda (Loblolly Pine) plantations in Louisiana. We used model selection to determine which site-preparation and vegetation characteristics most influenced avian communities. All measures of bird communities responded positively as vegetation structure and cover increased over time. However, neither row spacing nor debris placement affected vegetation variables important to birds for at least for the first 5 years following stand establishment; bird communities responded to successional changes and variation among plots, but not to site preparation. Land managers seeking to provide early-successional habitat in recently established plantations for disturbance-dependent birds can do so by increasing structural complexity and groundcover through selective herbicide applications, mechanical treatments, or other means.
Relatively little work has been done on the population genetics and phylogenetic patterns in Notophthalmus viridescens (Eastern Newt). The most recent study by Gabor and Nice (2004) divided the sampled populations into northern and southern groups rather than along taxonomic lines, and patterns of genetic variation indicated the southern populations were isolated and undergoing genetic drift. To re-evaluate these patterns, we collected sequence data on the mitochondrial ND2 and the flanking tRNAMet genes in fifteen South Carolina populations in the piedmont, sandhills, and lower coastal plain where three of the four subspecies were located (we found no Eastern Newts in the upper coastal plain). Haplotypes did not group by taxonomic designation in phylogenetic analyses, suggesting introgressive hybridization has occurred. Statistical parsimony analysis resolved the haplotype groups into two geographic groups, and partitioning of genetic variation between these groups was significant. We suggest these groups represent populations established during the last glacial maximum, a pattern that has been observed in other pond-breeding salamanders.
Studies of Sciurus niger (Fox Squirrel) in the Southeast have focused on habitat relationships with limited emphasis on other life-history characteristics. We estimated survival rates for 51 radio-collared Scinrns n. niger (Southeastern Fox Squirrel) on Fort Bragg, NC, during March 2011-June 2012 using the Kaplan-Meier staggered-entry design. Also, we calculated composite and seasonal 99% kernel-density home-range estimates for male and female Fox Squirrels. During our study, 22 radio-collared Fox Squirrels died: 8 were depredated, 2 were hunter harvested, and 12 died of unknown causes. Survival rates differed among the seasons when the sexes were combined; survival was greatest in the winter and lowest in the fall. Male annual survival (0.35) was lower than female annual survival (0.66) at the a = 0.10 level. Male home ranges were larger than female home ranges, potentially exposing them to greater predation risk. High mortality of male Fox Squirrels may warrant reevaluation of harvest regulations for declining, hunted Fox Squirrel populations. Additionally, large space requirements for Fox Squirrels may be indicative of low availability of forage on the landscape, a condition that should prompt land managers to adjust management actions to improve habitat conditions for Fox Squirrels.
Small mammals are key consumers in the marsh food web and could serve as indicators of a marsh's potential to support higher-level predators. We studied how small-mammal occupancy varied among plant communities in coastal Louisiana freshwater marshes. We sampled small mammals at 36 sites on 4 different occasions during the late spring in freshwater marshes of the Mandalay National Wildlife Refuge, LA. Mammalian diversity was low; we captured only Oryzomys palustris (Marsh Rice Rats). Occupancy modeling revealed a positive association between Marsh Rice Rat site occupancy and Sagittarialancifolia (Bulltongue Arrowhead) biomass. Our data suggest that subtle changes in plant-species composition within a marsh may affect the distribution of the most common small mammal in the ecosystem.
Seeds of Capsicum spp. (wild chilies ) are coated with capsaicin, which deters mammalian seed predators. During gut passage through frugivorous birds, its presence on seeds likely is greatly reduced, presumably increasing the seeds' susceptibility to postdispersal seed predation by mammals. We tested whether gut passage influences the rate at which dispersed seeds are removed from dispersal sites by different types of seed consumers. We predicted that seeds passed through birds (passed seeds) would be removed at higher rates than seeds taken directly from fruits (non-passed seeds). Removal rates of passed seeds were either lower or no different than removal rates of non-passed seeds, contrary to our prediction. In a second set of trials, we placed caged and exposed (control) seeds in pairs on the ground to determine whether vertebrates or invertebrates were primarily responsible for post-dispersal seed removal. We found an inconsistent effect of caging on frequency of seed removal, indicating that both invertebrates and vertebrates harvest chili seeds at our site. These results suggest that capsaicin's role in mediating interactions with vertebrate seed dispersers and predators is largely restricted to the wild chilles' fruiting stage.
The herbaceous ground-layer community is a key target of restoration efforts in Pinns palustris (Longleaf Pine) ecosystems (LLPE). Identification of life-history traits that correlate with endemism could shed light on advantages or limitations of restoration strategies. We investigated whether dispersal and longevity (life cycle) correlate with species endemism in the LLPE. We characterized plant species as obligate associates of the LLPE (LLO), strong associates (LLP), or neither (N). We predicted that increased dependency on the LLPE (N < LLP < LLO) would correlate with decreased dispersal and greater longevity (longer life cycle). We failed to detect a significant relationship between LLPE affinity and dispersal ability. However, there was a significant positive relationship between LLPE affinity and longevity. We suggest that if dispersal is not limiting, LLO species restoration may depend on both soil properties and the precise use of fire to enhance their establishment and persistence.
The Mollicy Farms Unit of Upper Ouachita National Wildlife Refuge, LA, consists of former agricultural land replanted with traditional bottomland hardwood species. Much of it is surrounded by a containment levee built to hold back the annual floodwaters of the Ouachita River. In 2009, two extreme floods, with water levels over 4 m above the flood stage, breached the levee, leaving the area inside the levee inundated for an extended period of time. We investigated the mortality of trees and saplings following these floods. During the initial reforestation efforts, which began in 1998, trees were planted both inside and outside the levee, allowing us to compare tree and sapling mortality based on location, inside or outside the levee. The average mortality of all trees was 40.59%, and the average mortality of all saplings was 48.23%. Both tree and sapling mortality resulted from a significant interaction between elevation and location inside or outside the levee. Overall, results indicated increased mortality at lower elevations for the area inside the levee. Outside the levee, mortality was unaffected by elevation because floodwaters were able to recede naturally. Levee removal would restore a more traditional flooding regime, likely reducing tree and sapling mortality during future floods.
Native Esox masquinongy (Muskellunge) in the Cumberland River drainage, TN, were nearly extirpated in the 1970s due to decades of over-fishing and habitat degradation from coal mining, logging, and other land-use practices. In an effort to preserve the species in that drainage, a stocking program began in 1976 in the upper Caney Fork River system in middle Tennessee where Muskellunge were not native. A trophy Muskellunge fishery eventually developed, but it was unknown whether Muskellunge were reproducing in the upper Caney Fork River system or whether the fishery was wholly dependent on the stocking program. To establish evidence of natural reproduction, we used seines, backpack electrofishing, and boat electrofishing gear in 2012 to find age-0 Muskellunge in the upper Caney Fork River system. Natural reproduction of Muskellunge was documented in the mainstem Caney Fork River above Great Falls Dam and in 3 of its 4 major tributaries. Seventeen age-0 Muskellunge were collected and one other was observed, but not handled. Age-0 Muskellunge grew rapidly (1.80–2.34 mm/day), and the largest fish collected during the study reached a total length of 399 mm by 9 October 2012. A cessation of stocking for several years coupled with routine monitoring could reveal whether natural recruitment is sufficient to sustain the fishery.
Paralichthys lethostigma (Southern Flounder) inhabits the continental shelf and estuarine waters of the Gulf of Mexico and the east coast of the North Atlantic, from peninsular Florida to Albemarle Sound in North Carolina. Between 30 May and 20 August 2012, we collected 15 juvenile (71–192 mm) Southern Flounder in fyke nets in the Mattaponi River, a tributary of the York River, in southeastern Virginia. This is the first known documentation of juvenile Southern Flounder in any tributary of Chesapeake Bay. We confirmed our identification of the specimens as Southern Flounder morphologically and genetically by counting gill rakers and sequencing cytochrome oxidase subunit I, respectively.
Cleaning symbioses provide net benefits by improving each partner's fitness. Ectosymbiotic Cambarincola spp. (branchiobdellidans) can increase growth and survival of Cambarus chasmodactylus (New River Crayfish), but the nature of the symbiosis might change with female reproductive state because brooding offspring (eggs, young) and worms inhabit the same surfaces. Here, we present the results of field surveys that examined whether the number and location of branchiobdellidans on New River Crayfish varies as a function of female crayfish reproductive state. Reproducing female New River Crayfish had fewer total worms, an absence of cocoons, and a relatively greater proportion of worms on lateral body surfaces than non-reproducing crayfish. The altered distribution and reduced abundance of worms suggest that the symbiosis changes with female reproductive status, but additional experiments will be needed to identify the mechanism responsible.
Etheostoma luteovinctum (Redband Darter) is a benthic headwater fish of the Caney Fork and Stones rivers (Cumberland River drainage) and the Duck and Elk rivers (Tennessee River drainage) of central Tennessee. The Redband Darter was regarded as a species of special concern due to its small native range, but was recently designated as stable. The current status of the species was assessed by sampling 65 historical localities and collecting other nearby habitat-appropriate sites to document presence or absence. Redband Darter was not found at 63% of the 65 sampled historical localities, indicating the stable status of the species is not valid. Additionally, comments on observations of a unique burying behavior are provided.
The Alabama River drainage is a biologically diverse system containing over 180 native fishes and at least 33 endemics. Many studies have surveyed single species of conservation concern, such as the federally endangered Scaphirhynchus suttkusi (Alabama Sturgeon), Alosa alabamae (Alabama Shad), and Crystallaria asprella (Crystal Darter), but few have documented entire fish assemblages. Maintaining fish-assemblage data is an important process in monitoring species and assemblage composition through time so that large-scale ecological change can be detected. In this study, we surveyed fish assemblages of sand/gravel bar habitat in the lower Alabama River and compared these data to those collected from historical surveys. Diel and seasonal surveys were conducted along 19 sandbars from Dixie Landing (river mile 22) to Claiborne Lock and Dam (river mile 72). We recorded a total of 48 species in 41 collections during summer, fall, and spring 2010–2011. Based on the Jaccard index, these samples had low similarity to historical samples collected by R.D. Suttkus and the Geological Survey of Alabama, suggesting temporal fish assemblage shifts. In 2010, we detected extremely high numbers of Brevoortia patronus (Gulf Menhaden) during summer and fall, which is a new distributional record. Diel comparisons using the Morisita index indicate low similarity reflecting large numbers of catfish species detected mostly in night collections. These data also indicate seasonal faunal changes among sandbar fish assemblages. Ongoing habitat alteration on the Alabama River is a potential factor leading to assemblage homogenization and potential loss of biodiversity. Future monitoring in the Alabama River should consider diel and seasonal sampling to accurately document fish species and assemblages, including potential shifts that may be occurring over space and time.
Post-emergence dispersal behavior of hatchling turtles has been investigated in several species, and a variety of species-specific orientation patterns have been reported. In the current study, we examined the orientation and dispersal behavior of hatchling, post-hatchling, and yearling Malaclemys terrapin pileata (Mississippi Diamond-backed Terrapin) by utilizing an orientation arena on two natural nesting beaches. Each age group displayed strong orientation and dispersal towards high-marsh vegetation instead of open water. The results suggest an innate behavior in young Diamond-backed Terrapins in which they orient from open beach areas toward vegetated marsh areas. The results also stress the importance of having healthy marsh habitat adjacent to nesting areas to provide critical habitat for these vulnerable life-history stages of Diamond-backed Terrapins.
Our study examined variation in and correlation of reproductive traits for a population of Caretta caretta (Loggerhead Sea Turtle) nesting in Georgia and compared the results with those of other studies. We assessed variability in reproductive traits (i.e., maternal length, clutch size, egg diameter, egg mass, hatchling length, and hatchling mass) on the population level and individual level. At the population level, we investigated interannual and intraseasonal variation of these traits for 810 Loggerhead Sea Turtle nests in Georgia, on Wassaw National Wildlife Refuge (NWR) and Blackbeard Island NWR during 2000–2003 and 2001–2003, respectively. As the nesting season progressed, we observed a decrease in clutch size, mean egg diameter, mean egg mass per clutch, mean hatchling length per clutch, and mean hatchling mass per clutch. Further, we measured all previously mentioned traits on a subset of the female turtles encountered on the beach (n = 24) and used these data to examine the variability of the traits on the individual level. Generalized linear modeling using this more refined individual-level data set indicated that 55% of the variability in clutch size was explained by a combination of maternal length (47%) and hatchling length (8%). This model suggested that clutch size was positively related with maternal length (t = 4.79) and negatively related with hatchling length (t = -1.90). Greater maternal length resulted in larger clutch size, but not larger egg size; thus, egg size was relatively constant irrespective of maternal length. These results support optimal egg-size theory, indicating a trade-off between clutch size and hatchling size to produce the optimum maternal investment per offspring.
In waterfowl banding studies, the preseason banding period is commonly accepted as July through September; however, in an effort to increase Aix sponsa (Wood Duck) banding in the Atlantic Flyway, several state agency biologists have considered banding Wood Ducks in June. We analyzed existing Wood Duck banding data to determine if direct band-recovery rates of Wood Ducks banded in June differed from those banded during July—September. We calculated direct recovery rates by state, month, and year for 1998–2007 at selected states in the Atlantic Flyway. Arcsine-transformed direct band-recovery rates differed by month of banding (P = 0.0099; F = 3.973; df = 3, 111) and were lower in June than in July or August. We suggest that state or federal agencies conducting Wood Duck banding should spend their time and effort during the traditional banding period 1 July—30 September.
Introduced applesnails (Ampullariidae: Pomacea) have been responsible for crop and habitat damage in freshwater systems around the world. Two Pomacea species known to damage aquatic vegetation, P. maculata (Island Apple Snail) and P. canaliculata (Channeled Apple Snail), have been introduced into Florida. This investigation was conducted to evaluate efficacy of a hand-removal program for the management of nonindigenous Pomacea in a small (1.62 ha), relatively isolated urban pond. We removed snails and egg masses from the pond by hand at pre-determined time intervals during May 2008—June 2011. We made a total of 107 collections; 21,343 snails and 20,244 egg masses were removed during the study period with >90% of both removed during the first year (20,961 and 18,934, respectively). Snail densities were reduced in the wadeable near-shore habitat from 1–3/m2 to <0.001/m2. The total cost of the project (salary, supplies, travel) was $10,475. At the time of the final collection in year 3, we observed no snails and removed only two egg masses. Four followup assessments September 2011—May 2012 indicated that the hand-removal program was successful and snails had been nearly eradicated from the site. Occasional connections with a population occupying an adjacent drainage ditch could result in a future re-colonization of the pond. Compared with chemical methods, control was achieved with lower monetary cost and less ecological risk. Further evaluations of this method will be necessary to apply it or use it in larger connected ecosystems.
We trapped freshwater turtles using hoop nets and 3 different bait types along a short section of Oyster Creek, Fort Bend County, TX. Using a model-selection approach, we tested the effectiveness of different baits on capture success, taking into consideration the length of time the bait was in the water, time of day, and the number of hours for the set (trap hours). We had significantly more success when we used dry dog food and dry cat food than traditional canned sardine bait. Bait age and time of day when traps were checked had no influence on capture success. Contrary to our expectations, the number of captures decreased throughout the study. Our results suggest that turtle researchers should consider using alternative bait types to maximize trap effort. However, there was a significant interaction between canned sardines and bait age for Trachemys scripta elegans (Red-eared Slider) captures, suggesting that canned sardines should be replaced often. In addition, more research is needed to test capture success when baits are older than one day.
Zooarchaeological deposits present a unique insight into the trajectory of faunal communities through time. Freshwater mussels (Bivalvia: Unionidae) are one of the world's most imperiled faunal groups, and, at the same time, constitute a significant component of the archaeological record in North America. Current conservation efforts can be informed by studies of prehistoric mussel assemblages that catalog communities as they existed prior to any extensive modern impacts, ultimately representing an ecological baseline against which current populations can be evaluated. Over 47,000 freshwater mussel valves were recovered from the late prehistoric (ca. A.D. 700–1200) Kinlock site (22SU526), in Sunflower County, MS. Analyses revealed that the Sunflower River once supported a mussel community with greater taxonomic richness and more evenness among all the major species than today. Additionally, the presence in the archaeological record of numerous species which are currently considered rare, endangered, or extinct in the Sunflower River is indicative of a habitat disturbed by increased human environmental impact in historic times.