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Urban ecosystems provide habitat for a variety of amphibian and reptile species, but in most places, these communities are understudied. Gradients of urbanization have been used to examine how herpetofaunal communities respond to anthropogenic disturbance. We used visual-encounter surveys along human-made canals that track a gradient of urbanization as a system to examine changes in aquatic and semiaquatic herpetofauna. We found substantial changes in herpetofaunal community composition along the urbanization gradient, primarily driven by the association of exotic invasive amphibians with canals adjacent to urban areas relative to canals adjacent to natural areas.
As part of restoration efforts of Holey Land Wildlife Management Area (HWMA) in the northern Everglades, a pump station in the northwest corner began delivering water from the Miami Canal in 1991. In 2005, Hurricane Wilma damaged the pump, rendering it non-functional until September 2014. These events provided a unique opportunity to examine the impacts of an active water schedule on the vegetation structure of HWMA. Results of linear-regression models show a drastic increase in Typha domingensis (Southern Cattail) abundance during the period when the pump was active and a marked decrease of this species after pump failure. This change was attributable to increased nutrient inputs from canal water pumped into the area. Changes in Cladium jamaicense (Sawgrass) cover may have a lag response to fire activity.
Most field-based life-history studies of amphibians only monitor the first occurrence of major life stages, missing important details of the intervening periods. To help fill this gap, we surveyed the larval growth of Lithobates sphenocephalus (Southern Leopard Frog) at a breeding site in Hammond, Tangipahoa Parish, LA. We repeatedly sampled an ephemeral pool for Southern Leopard Frog tadpoles shortly after oviposition through metamorphosis. We first observed eggs on 21 January 2016. From 29 January 2016 through the following 99–117 d, tadpoles grew an average of 0.163 mm/day in body length before completing metamorphosis between 6 and 23 May. These values are similar to previous literature estimates for the Southern Leopard Frog, but provide novel information on the timing and rates of changes in size and ontogenetic stage, and their interrelationship.
Short-term movements of adult Polyodon spathula (Paddlefish) are well-documented, but long-term movements are underreported. In this study, we describe extraordinary distances traveled by 4 Paddlefish that were captured, tagged, and released in Moon Lake, a remote oxbow lake in Coahoma County, MS. After 8–24 months at large, the 4 fish were recaptured in the Missouri, Mississippi, and Ohio rivers, having traversed 1408–2433 km from Moon Lake through multiple waterways downstream to the Mississippi River at Vicksburg, MS, and then upriver to 4 geographically disparate locations. The multiple waterways used by these fish and the extensive distances traveled demonstrate the potential importance of backwater habitats located away from the mainstem river, and also underscore the need for interstate cooperation to protect Paddlefish populations.
Loss of freshwater mollusk populations nationally has prompted the use of these species in establishing USEPA water quality criteria (WQC). The objectives of this study were to determine the sensitivity (EC50) of 5 at-risk mollusk species endemic to the Mobile River Basin to chloride, potassium, nickel, and zinc. Villosa nebulosa (Alabama Rainbow) was the only species evaluated in the study with an EC50 value included under current WQC for chloride and nickel. All species in the current study were more sensitive to potassium than other mollusk species previously tested, although there is currently no established WQC for that contaminant. For zinc, all species but Leptoxis ampla (Round Rocksnail) had EC50 values included under existing criteria. Results suggest current WQC may be insufficient for basins containing localized endemic species in a relatively small geographical space, such as the Mobile River Basin. We urge broader testing of highly regionalized aquatic species to aid in establishing national WQC.
Many crayfish are of conservation concern because of their use of unique habitats and often narrow ranges. In this study, we determined fine-scale habitat use by 3 crayfishes that are endemic to the Ouachita Mountains, in Oklahoma and Arkansas. We sampled Faxonius menae (Mena Crayfish), F. leptogonopodus (Little River Creek Crayfish), and Fallicambarus tenuis (Ouachita Mountain Crayfish) from wet and dry erosional channel units of 29 reaches within the Little River catchment. We compared channel-unit and microhabitat selection for each species. Crayfish of all species and life stages selected erosional channel units more often than depositional units, even though these sites were often dry. Accordingly, crayfish at all life stages typically selected the shallowest available microhabitats. Adult crayfish of all species and juvenile Little River Creek Crayfish selected patches of coarse substrate, and all crayfish tended to use the lowest amount of bedrock available. In general, we showed that these endemic crayfish used erosional channel units of streams, even when the channel units were dry. Conservation efforts that protect erosional channel units and mitigate actions that cause channel downcutting to bedrock would benefit these crayfish, particularly during harsh, summer drying periods.
Terrestrial habitats are frequently managed to improve perceived economic or aesthetic value of the land and to improve habitat quality for wildlife species. In central Texas, removal of native Juniperus asheii (Ashe Juniper) is a common landscape-management practice due to the species' propensity for invasion of rangeland, vigorous growth leading to dominance of habitats, and reputation for high water-use. Ashe Junipers provide habitat for wildlife species of economic (e.g., Odocoileus virginianus [White-tailed deer], Meleagris gallopavo [Wild Turkey]) and conservation concern (e.g., the endangered Setophagachrysoparia [Golden-cheeked Warbler]); however, the relationship between Ashe Junipers and the federally endangered Vireo atricapilla (Black-capped Vireo) is less clear. Blackcapped Vireos breed in early successional shrublands where Ashe Junipers are often able to invade, grow quickly, and shade out the deciduous shrubby vegetation preferred by vireos. Although Ashe Juniper removal in Black-capped Vireo habitat is common practice, relatively little is known about the impacts of brush management on Black-capped Vireo use and reproductive success. Here we present results of a study on the effects of an Ashe Juniper removal treatment, in which juniper trees were removed but surrounding deciduous vegetation was largely left intact, on Black-capped Vireo habitat use and reproductive success. Comparing before and after Ashe Juniper removal, we found that the number of Blackcapped Vireos settling in manipulated habitats remained similar, and we saw no significant changes in the size of the average territory or reproductive success. We conclude that, when the amount of damage to the surrounding deciduous vegetation is limited, selective Ashe Juniper removal is unlikely to negatively affect Black-capped Vireos.
Pituophis ruthveni (Louisiana Pinesnake) is considered one of the rarest snakes in North America. For that reason, P. ruthveni is not well represented in scientific collections, and each existing specimen is very important. Some museum records for the species are considered questionable or unverified, especially those that represent extralimital records or those from habitats not normally utilized by Louisiana Pinesnake. Clarifying these questionable Louisiana Pinesnake records will ultimately provide a better understanding of its historic and current distribution, which is necessary for listing decisions, critical-habitat designation, and overall conservation efforts for the species. To resolve this uncertainty, we performed a multivariate analysis using 13 morphological characters on 50 specimens representing 3 snake groups: (1) P. ruthveni (n = 23), (2) P. catenifer sayi (Bullsnake; n = 23), and (3) questionable or unverified snakes (n = 4). We included Bullsnake because they are sister to Louisiana Pinesnake genetically and also most morphologically similar. We identified all questionable records of Louisiana Pinesnake examined as Bullsnake. Blotch count, ventral-scale number, and scale-row number at mid-body were the most reliable characters for distinguishing between groups. These results have potential conservation implications for the species. The influence of these erroneous records could be substantial in future research and conservation of the species due to the relatively few known specimens of Louisiana Pinesnake. We recommend that the specimens we identified be annotated and considered erroneous records.
The ornamental plant Lagerstroemia indica (Crapemyrtle) was introduced to American gardens before 1796, but little is known about its use as a food resource by avian species. Local wintering populations of Spinus tristis (American Goldfinch), Juncohyemalis (Dark-eyed Junco), and Haemorhous mexicanus (House Finch) feed heavily on Crapemyrtle seeds, and I observed 5 additional bird species occasionally extracting seeds from dehiscent capsules in Fairfax County, VA. Planted and naturalized Crapemyrtle may be an important food resource for finches and sparrows in southeastern US.
Spilogale putorius (Eastern Spotted Skunk) is an increasingly rare species undergoing population declines throughout many portions of its range. We incidentally captured Eastern Spotted Skunks in snake traps during a study examining effects of woodland restoration on herpetofauna in the Ouachita Mountains of Arkansas. We used extensive habitat data collected at each trap site to determine potential characteristics of sites where Eastern Spotted Skunks were more likely to occur during summer. We recorded 18 Eastern Spotted Skunk captures in 10 of our 36 drift-fence traps. Capture rates of Eastern Spotted Skunks were 6 times greater and occupancy rates were 9 times greater in unmanaged, mature forests with a well-developed midstory than in frequently burned woodlands that lacked a midstory. Higher-occupancy rates were associated with greater total cover, greater cover of woody-understory vegetation, and sparse forb cover. Our data support those of previous studies that suggest Eastern Spotted Skunks occur in areas with dense cover, which may include mature forests with well-developed midstories.
Species of Centrarchidae are major components of inland fisheries in much of North America. Thus, information gained from the assessment of interspecies interactions and/or quantifying predator-prey relationships is a useful tool for fisheries managers. Using preserved fish specimens (n = 717) from 20 species of centrarchids, we made measurements of total length (TL), standard length (SL), horizontal gape, and body depth for each individual. We fitted mathematical models that included horizontal gape and body depth as functions of TL and SL, and TL as a function of SL. Linear-regression-model fits were generally good (r2 = 0.764-0.998) for all 20 species, with 61 of 78 possible models having r2 values exceeding 0.90. Horizontal gape–SL (F3,702 = 77.18, P < 0.001) and body depth-SL (F3,702 = 91.79, P < 0.001) ratios differed significantly along a gradient that reflected the species' likelihood of piscivory. Slopes of TL–SL regressions did not vary by species, which enabled development of a generalized TL–SL model for centrarchids. Supplemental analyses supported that morphometric measurements had not been influenced significantly by preservation. Results of this study are useful to fisheries managers involved with understanding species interactions within centrarchid-dominated food webs, which are of high priority in most fisheries-management plans.
In Illinois, Neotoma floridana (Eastern Woodrat) experienced range reductions and population bottlenecking over the past century. During the period 2004–2005, the isolated remnant populations along the Mississippi bluffs in southwestern Illinois were genetically augmented with 47 Eastern Woodrats from Arkansas and Missouri, resulting in 40% admixture within the largest population. In 2009, a strong windstorm created canopy gaps and woody debris throughout this area, potentially improving habitat for Eastern Woodrats. We investigated the status of Eastern Woodrat populations in southwestern Illinois by livetrapping remnant populations and conducting sign surveys from 2011 to 2015. We captured 263 Eastern Woodrats; mean trapping success was 62.5% higher than trapping during the 1990s, and the number of individuals captured per trap-night was 3–6 times higher than trapping events during the previous 18 years (all P <0.001). We also located sign of Eastern Woodrat 8.9 km east of the remnant populations. We recommend further genetic monitoring to evaluate whether population increases are coupled with increased admixture and recommend forest-management actions that create habitat disturbance and resultant piles of woody debris that increase woodrat habitat quality.
Meleagris gallopavo (Wild Turkey) population dynamics are greatly influenced by female survival, and high female-survival rates may offset low reproductive rates and maintain stability in populations characterized by low productivity. Additionally, reproduction may incur a cost to annual survival, given the physiological stress associated with breeding, and predation risks associated with incubation and brood-rearing. We used radio-telemetry and known-fate modeling to quantify annual survival and identify mortality causes of 54 adult female Meleagris gallopavo ssp. silvestris (Eastern Wild Turkey) tracked during 2002–2004 and 2007–2010 in a population characterized by low productivity in a bottomland hardwood forest in Louisiana. We detected 31 mortalities in which predation was the leading cause (87%), primarily attributed to Canis latrans (Coyote) and Lynx rufus (Bobcat). We estimated an annual survival rate of 0.58 (95% CI = 0.47–0.68) with no evidence of seasonal variation. This level of survival appeared to be sufficient to offset low productivity; the population was considered healthy and stable during the study period. Annual survival rates of females that incubated a nest were lower than reproductively inactive females, although confidence intervals overlapped considerably. The mechanisms underlying survival differences between reproductive classes were not entirely clear because survival of nesting females did not greatly decrease during incubation and brood-rearing seasons relative to non-nesters as would be expected under the hypothesis of increased predation risk during reproduction periods. Future studies should aim to better elucidate the links between reproduction and survival in Eastern Wild Turkey populations because this information will have important management ramifications in the southeast, where region-wide declines in productivity have been observed.
Sandy beaches are frequently visited for recreational purposes. Although such recreational activities are economically beneficial, they cause disturbances to these habitats. Every ecosystem has unique properties; thus, ecosystem-specific species are often used as bioindicators of human disturbances. Here, we pioneer the use of an indirect burrow-counting technique on 20 sandy South Carolina beaches that experience different levels of human disturbance. Our results show that Ocypode quadrata (Atlantic Ghost Crab) is a reliable bioindicator of human disturbance on sandy beaches in South Carolina. The burrow density and width declined significantly as human disturbance increased. We also report that females outnumber males in highly disturbed sites. We conclude that the indirect burrow-counting technique employed in this study could minimize the cost and the effort of determining the human disturbances on coastal regions.
In North Carolina, Odocoileus virginianus (White-tailed Deer) are the definitive natural hosts of Fascioloides magna (Giant Liver Fluke). Previous research identified the enzootic range of Giant Liver Fluke in North Carolina to be within the Tar River and Roanoke River Basins in Halifax and neighboring counties. Recent Giant Liver Fluke infections of Ovis aries (Domestic Sheep), Capra hircus (Domestic Goat), Lama glama (Llama), Vicugna pacos (Alpaca), and Bos taurus (Cattle) outside the historic enzootic range prompted us to investigate the current range of Giant Liver Fluke in North Carolina. From September 2014 to January 2015, we examined livers from hunter-harvested White-tailed Deer within 16 North Carolina counties. We detected Giant Liver Fluke in livers from 5 counties, with an overall prevalence of 10.3%. Besides reporting the first Giant Liver Fluke infections of livestock in North Carolina, we documented new geographic localities (Cabarrus, Franklin, Mecklenburg, Union, Wake, and Washington counties) for Giant Liver Fluke. An increased impact on North Carolina livestock is likely with the possible range expansion of Giant Liver Fluke, which may be related to the increase in populations of White-tailed Deer.
Gonatista grisea (Grizzled Mantis) was previously known in the US from Florida, Georgia, and South Carolina. This paper presents a new state record with a brief discussion of the currently known distribution in the southeastern US.
We present an account of flower-feeding by 2 species of mydas flies in Florida. We observed adults of Mydas clavatus and Mydas maculiventris feeding on flowers of both typical and unusually large (tree-form) Licania michauxii (Gopher Apple; Chrysobalanaceae). We also observed M. maculiventris feeding on flowers of Serenoa repens (Saw Palmetto; Arecaceae) in Florida scrub habitat. We discuss these observations following a brief review of feeding ecology in mydids, and include a checklist of the 12 known Florida mydids with a summary of our current knowledge of adult feeding in these species. We also provide additional sites of tree-form Gopher Apple in Martin County, FL, with a discussion of this unique form and the location of a new record-size specimen in Jonathan Dickinson State Park.
The ogre-faced spider Deinopis spinosa is the sole representative of the family Deinopidae in the US. Museum records suggest this species is restricted to the extreme southeastern US (Alabama and Florida) and Jamaica. Through nocturnal surveys and records from naturalist-oriented internet sites, we have discovered that this species is more widely distributed in the Coastal Plain region of the southeastern US. Herein, we document new state records for Georgia, Mississippi, South Carolina, and Texas, significantly expanding the known range of the species. It is unknown whether these records represent a recent range expansion or if the spider has historically been overlooked due to its cryptic nature and habits.