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Myotis septentrionalis (Northern Long-eared Bat) and Myotis lucifugus (Little Brown Bat) are 2 species of North American bat that currently are experiencing extreme population declines because of white-nose syndrome (WNS). The state of Georgia lies at the southeastern tip of both of these species' reported ranges, though current records are sparse. Previously, Little Brown Bats had been recorded in only 5 Georgia counties and Northern Long-eared Bats in 9 counties. New records provided herein expand the known range to 20 and 23 counties, respectively. This information greatly increases our knowledge of the ranges of these 2 at-risk species and can help biologists and managers better understand overall population changes as WNS continues to spread.
Anthropogenic disturbance to natural habitats has been identified as a major threat to freshwater biodiversity. Human activities can destroy critical habitat of aquatic species by altering hydrodynamic stream characteristics. Movement and removal of shelter rocks within and along streams has been postulated to be detrimental to survival of aquatic salamanders; however, empirical data are lacking. Cryptobranchus alleganiensis alleganiensis (Eastern Hellbender) is a fully aquatic salamander species that shelters under cobble and boulder as both a juvenile and as an adult. Herein, we document mortality of both adult and larval Eastern Hellbender salamanders associated with anthropogenic habitat disturbance (i.e., moving and stacking of rocks to build small dams). To our knowledge, these observations are the first of their kind in the scientific literature. Given the high number of visitors to and increasing recreational use of rivers on public lands in the southeastern US, managers should consider implementing outreach education programs and monitoring popular recreation areas to deter in-stream habitat alteration.
Accurate estimates of species' distributions are needed to ensure that conservation-planning efforts are directed at appropriate areas. Since the early 1980s, temperate-breeding populations of Branta canadensis (Canada Goose) have increased, yet reliable estimates of the species' distribution are lacking in many regions. Our objective was to identify the landcover features that best predicted Canada Goose distribution. In April 2015, we surveyed 300 one-km2 plots across North Carolina and observed 449 Canada Geese. We quantified percent coverage of 7 continuous landcover variables at 5 different spatial extents for each of the 300 plots. We fit logistic regression models using presence and absence at the 300 plots as the dependent variable and percent-cover covariates as independent variables. The best model for predicting Canada Goose presence included percent pasture within the 9 km2 surrounding the survey plot and percent open water within the 1-km2 survey plot. The probability of Canada Goose presence increased with increasing percent open water and percent pasture, albeit at different spatial extents, which provided important cover and food resources, respectively. Our approach using remote-sensing data to accurately predict Canada Goose presence across a large spatial extent can be employed to determine distributions for other easily surveyed, widely distributed species.
Myotis septentrionalis (Northern Long-eared Bat) is a federally threatened insectivorous bat facing devastating population declines due to white-nose syndrome (WNS). Our study provides pre-WNS (2009) capture rates and roosting-behavior data for Northern Long-eared Bats in the southern Appalachians. We conducted mist-net surveys at 37 sites and radio-tracked female Northern Long-eared Bats to their day roosts in eastern Tennessee and western North Carolina. We compared tree and plot characteristics for roosts and corresponding random trees using Wilcoxon rank-sum tests. Our 43 survey nights yielded 302 bats of 11 species; Northern Long-eared Bats were the most commonly captured species (n = 97). We located 14 unique roosts for 7 radio-tracked bats; Pinus strobus (White Pine) snags (n = 8) were the most common roost sites. We observed a colony of 72 bats using a White Pine snag as a maternity roost. Roost trees were significantly larger in diameter and had more solar exposure above the roost and within the plot than random trees. Our data show the high abundance of Northern Long-eared Bats pre-WNS, highlight the use of White Pine roosts in an area impacted by a Dendroctonus frontalis (Southern Pine Beetle) outbreak, and support previous determinations of roost-selection flexibility by Northern Long-eared Bats across their range.
We assessed habitat characteristics and measured daily survival rate of 72 nests of Charadrius wilsonia (Wilson's Plover) during 2012 and 2013 on South Island and Sand Island on the central coast of South Carolina. At both study areas, nest sites were located at slightly higher elevations (i.e., small platforms of sand) relative to randomly selected nearby unused sites, and nests at each study area also appeared to be situated to enhance crypsis and/or vigilance. Daily survival rate (DSR) of nests ranged from 0.969 to 0.988 among study sites and years, and the probability of nest survival ranged from 0.405 to 0.764. Flooding and predation were the most common causes of nest failure at both sites. At South Island, DSR was most strongly related to maximum tide height, which suggests that flooding and overwash may be common causes of nest loss for Wilson's Plovers at these study sites. The difference in model results between the 2 nearby study sites may be partially due to more-frequent flooding at Sand Island because of some underlying yet unmeasured physiographic feature. Remaining data gaps for the species include regional assessments of nest and chick survival and habitat requirements during chick rearing.
Organisms in lotic habitats often experience dietary shifts over their lifetime. The diet of adult Cryptobranchus alleganiensis (Hellbender) is well studied throughout the species' range, but knowledge regarding the natural history of larval Hellbenders, including dietary information, remains scarce. We obtained non-lethal diet samples from 23 larval Hellbenders. Larval Hellbenders consumed primarily invertebrate prey including mayfly (Ephemeroptera) and caddisfly (Trichoptera) nymphs. Since these items do not comprise a large proportion of the adult diet, Hellbenders may undergo an ontogenetic dietary shift. Therefore, future management and conservation decisions regarding the Hellbender should consider the abundance and density of aquatic insect populations.
Cambarus cryptodytes (Dougherty Plain Cave Crayfish) is an obligate inhabitant of groundwater habitats (i.e., a stygobiont) with troglomorphic adaptations in the Floridan aquifer system of southwestern Georgia and adjacent Florida panhandle, particularly in the Dougherty Plain and Marianna Lowlands. Documented occurrences of Dougherty Plain Cave Crayfish are spatially distributed as 2 primary clusters separated by a region where few caves and springs have been documented; however, the paucity of humanly accessible karst features in this intermediate region has inhibited investigation of the species' distribution. To work around this constraint, we employed bottle traps to sample for Dougherty Plain Cave Crayfish and other groundwater fauna in 18 groundwater-monitoring wells that access the Floridan aquifer system in 10 counties in southwestern Georgia. We captured 32 Dougherty Plain Cave Crayfish in 9 wells in 8 counties between September 2014 and August 2015. We detected crayfish at depths ranging from 17.9 m to 40.6 m, and established new county records for Early, Miller, Mitchell, and Seminole counties in Georgia, increasing the number of occurrences in Georgia from 8 to 17 sites. In addition, a new US Geological Survey (USGS) Hydrologic Unit Code 8 (HUC8) watershed record was established for the Spring Creek watershed. These new records fill in the distribution gap between the 2 previously known clusters in Georgia and Jackson County, FL. Furthermore, this study demonstrates that deployment of bottle traps in groundwater-monitoring wells can be an effective approach to presence—absence surveys of stygobionts, especially in areas where surface access to groundwater is limited.
Unlike avifauna, which have been inventoried and monitored for decades at Tishomingo National Wildlife Refuge, OK, herpetofauna have had few targeted inventories on the refuge. Therefore, in 2010 we established 6 permanent drift fence arrays to expand the current knowledge on the terrestrial herpetofauna present within the refuge. The arrays were in operation for a total of 105 nights over 5 years (2010–2014), capturing 1122 vertebrates including 12 anuran, 1 salamander, 13 snake, 5 lizard, and 2 turtle species. The surveys resulted in the discovery of 5 new amphibian species as well as a new mammal species on the refuge. By placing arrays across 3 different habitat types, we were able to compare and determine that there were differences in species diversity and relative abundance across those habitats. The results have shown the richness of herpetofauna in the area has been underestimated. The study also indicates that a preserve established for the conservation of one particular species group (waterfowl and neotropical migratory birds) can have appreciable diversity of another vertebrate group.
Given natural variation in weather conditions and increased risk of drought associated with climate change, understanding how birds respond to fluctuations in precipitation is a necessary step toward development of more-effective, long-term management strategies for species of conservation concern. We compared behaviors and reproductive output of the federally endangered Vireo atricapilla (Black-capped Vireo, hereafter Vireo) during an extreme drought event and a year with moderate rainfall. During the drought, Vireos had lower pairing and territory success, delayed nest initiation, fewer re-nesting attempts, and lower nest-success. Brood parasitism by Molothrus ater (Brown-headed Cowbirds), which is one of the main threats to Vireo population persistence, was also greater during the drought year. Nest placement varied between years, with Vireos using the evergreen Juniperus asheii (Ashe Juniper) as a nest substrate more often when conditions were dry and the deciduous Diospyros texana (Texas Persimmon) under moderate conditions. Removal of Ashe Juniper and Brown-headed Cowbirds from Vireo habitat are common management practices used to support Vireo conservation efforts. Our results suggest that regional weather patterns should be considered when making decisions regarding Ashe Juniper removal. In addition, increased Brown-headed Cowbird removal may be warranted in dry areas during drought years.
Matthew R. Acre, Celeste Alejandrez, Jessica East, Wade A. Massure, Seiji Miyazono, Jessica E. Pease, Elizabeth L. Roesler, Heather M. Williams, Timothy B. Grabowski
Evaluating the precision of age estimates generated by different readers and different calcified structures is an important part of generating reliable estimations of growth, recruitment, and mortality for fish populations. Understanding the potential loss of precision associated with using structures harvested without sacrificing individuals, such as scales or fin rays, is particularly important when working with imperiled species, such as Cycleptus elongatus (Blue Sucker). We collected otoliths (lapilli), scales, and the first fin rays of the dorsal, anal, pelvic, and pectoral fins of 9 Blue Suckers. We generated age estimates from each structure by both experienced (n = 5) and novice (n = 4) readers. We found that, independent of the structure used to generate the age estimates, the mean coefficient of variation (CV) of experienced readers was approximately 29% lower than that of novice readers. Further, the mean CV of age estimates generated from pectoral-fin rays, pelvic-fin rays, and scales were statistically indistinguishable and less than those of dorsal-fin rays, anal-fin rays, and otoliths. Anal-, dorsal-, and pelvic-fin rays and scales underestimated age compared to otoliths, but age estimates from pectoral-fin rays were comparable to those from otoliths. Skill level, structure, and fish total-length influenced reader precision between subsequent reads of the same aging structure from a particular fish. Using structures that can be harvested non-lethally to estimate the age of Blue Sucker can provide reliable and reproducible results, similar to those that would be expected from using otoliths. Therefore, we recommend the use of pectoral-fin rays as a non-lethal method to obtain age estimates for Blue Suckers.
Sagittal otoliths are the preferred aging structure for Micropterus spp. (black basses) in North America because of the accurate and precise results produced. Typically, fisheries managers are hesitant to use lethal aging techniques (e.g., otoliths) to age rare species, trophy-size fish, or when sampling in small impoundments where populations are small. Therefore, we sought to evaluate the precision and accuracy of 2 non-lethal aging structures (i.e., anal fin spines, dorsal fin spines) in comparison to that of sagittal otoliths from known-age Micropterus salmoides (Largemouth Bass; n = 87) collected from the Ocmulgee Public Fishing Area, GA. Sagittal otoliths exhibited the highest concordance with true ages of all structures evaluated (coefficient of variation = 1.2; percent agreement = 91.9). Similarly, the low coefficient of variation (0.0) and high between-reader agreement (100%) indicate that age estimates obtained from sagittal otoliths were the most precise. Relatively high agreement between readers for anal fin spines (84%) and dorsal fin spines (81%) suggested the structures were relatively precise. However, age estimates from anal fin spines and dorsal fin spines exhibited low concordance with true ages. Although use of sagittal otoliths is a lethal technique, this method will likely remain the standard for aging Largemouth Bass and other similar black bass species.
Acorns represent a critical pulsed food source for American Black Bears (Ursus americanus) in the southern Appalachians, and represent their primary hibernation reserves. We used 20 years of acorn-mast data collected in northwestern South Carolina and examined time-lagged correlations to American Black Bear population growth rates (lambda), human—bear interactions, and bear visitation to bait stations. Our goal was to assess the relative significance of annual indices monitored for state bear management. Our results indicated that lambda was linked to acorn crop quality, although the correlation varied with oak species: positive with white oaks and negative with red oaks. Human—bear interactions were negatively correlated to mast in the same year. There was no significant relation between bait-station visitation and mast or lambda. Overall our study reflects gaps in current monitoring practices, and we provide ideas towards refining them.
Freshwater-turtle ecologists rely on effective baits to capture target species. We conducted a bait-preference study for Sternotherus odoratus (Eastern Musk Turtle) in 2 phases during the 2014, 2015, and 2016 field seasons at Comal Springs, New Braunfels, TX. During Phase 1, we compared the effectiveness of buffalo chicken to other malodourous or previously used successful baits for capturing Eastern Musk Turtles. During Phase 2, we compared catch rates when using buffalo chicken, raw chicken, or fried chicken as bait. We also tested for differences in the effectiveness of buffalo chicken as a bait choice between sexes and among seasons. During Phase 1, we captured 231 of 276 Eastern Musk Turtles (84%) in traps baited with buffalo chicken. During Phase 2, we captured 46 of 72 Eastern Musk Turtles (63.9%) in traps baited with buffalo chicken. We captured significantly more turtles when we used Buffalo chicken in comparison to all other baits. Our results indicate that buffalo chicken is an effective novel bait that could be used to increase capture rates of Eastern Musk Turtles. Additional studies are needed in other portions of the Eastern Musk Turtle's range to determine if the attraction to buffalo chicken as a trap bait is a local or widespread phenomenon.
The Altamaha River region of southeastern Georgia is widely recognized for its biodiversity and conservation value for imperiled species. Even so, intensive amphibian and reptile surveys have never been conducted in this area. From 2008 to 2016, we conducted herpetofaunal surveys at 13 conservation lands located along the Altamaha River and along the lower reaches of a main tributary, the Ocmulgee River. We used a variety of field methods including visual encounter surveys, turtle trapping, frog-call surveys, drift fences, and surveys for snakes at Gopherus polyphemus (Gopher Tortoise) burrows. From these data, combined with a review of the published literature and a search of relevant museum collections, we determined that conservation and other nearby lands along the Altamaha River support a diverse herpetofauna of 100 species, including 41 amphibian species (18 salamander and 23 frog and toad species) and 59 reptile species (1 crocodilian, 11 lizard, 33 snake, and 14 turtle species). Seventeen species (12 reptile and 5 amphibian species) that are either federally listed, state-listed, or tracked as special concern by the Georgia Department of Natural Resources have been documented here, and sandhills along the Altamaha River support significant populations of Gopher Tortoises, Drymarchon couperi (Eastern Indigo Snake), and Crotalus adamanteus (Eastern Diamond-backed Rattlesnake). Biogeographically, the Altamaha River is a notable influence on the distributions of many amphibians and reptiles. High species richness, including many declining species, underscores the Altamaha River's importance to conservation, and future efforts should focus on long-term monitoring of imperiled species and effective management of conservation lands.
The only remaining wild Canis rufus (Red Wolf) are part of an experimental population inhabiting the Albemarle peninsula of northeastern North Carolina. This population was established in the late 1980s as part of the US Fish and Wildlife Service's Red Wolf Recovery Program. Recently, controversy has arisen over whether to maintain, expand, or end the recovery program. This controversy is complex, but one source of concern about the program is the perception among some local stakeholders that, compared to the smaller, sympatric C. latrans (Coyote), Red Wolves put greater pressure on game species, such as Odocoileus virginianus (White-tailed Deer). However, previous research comparing fecal remains indicated a broad dietary overlap between sympatric populations of the 2 species. In this study, we investigated the question of dietary overlap between Red Wolves and Coyotes using stable isotope analysis. Our results are consistent with those based on fecal analyses in showing that sympatric populations of Red Wolves and Coyotes have similar diets. This finding has important conservation and management implications for Red Wolves because it suggests that: (1) this species does not prey upon game species, such as White-tailed Deer, to any greater degree than sympatric Coyotes; and (2) whereas the loss of the only wild population of Red Wolves would result in a reduction of phylogenetic diversity in northeastern North Carolina, it may not result in a loss of functional diversity if Coyotes or Coyote—Red Wolf hybrids are able to play a similar ecological role to that of Red Wolves.
The purpose of this study was to use acoustic telemetry to elucidate the small-scale habitat-utilization patterns of Sphyrna tiburo (Bonnethead Shark, hereafter, Bonnethead) in relation to diel and tidal cycles in a shallow tidal creek system along the coast of Georgia. We found that Bonnetheads utilized the main channel of a tidal creek at night, dawn, and during ebb and low tides. In addition, we found the first evidence of Bonnetheads utilizing smaller 3rd-order creeks. Bonnetheads used these tributaries at night and dawn, during flood and high tides when the water level facilitated access. The movement patterns of these Bonnetheads could be representative of those in other areas with semidiurnal tides.
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