Amber L. Pitt

Water quality of small seasonal wetlands in the Piedmont ecoregion, South Carolina, USA: Effects of land use and hydrological connectivity.

Small, shallow, seasonal wetlands with short hydroperiod (2-4 months) play an important role in the entrapment of organic matter and nutrients and, due to their wide distribution, in determining the water quality of watersheds. In order to explain the temporal, spatial and compositional variation of water quality of seasonal wetlands, we collected water quality data from forty seasonal wetlands in the lower Blue Ridge and upper Piedmont ecoregions of South Carolina, USA during the wet season of February to April 2011. Results indicated that the surficial hydrological connectivity and surrounding land-use were two key factors controlling variation in dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) in these seasonal wetlands. In the sites without obvious land use changes (average developed area <0.1%), the DOC (p < 0.001, t-test) and TDN (p < 0.05, t-test) of isolated wetlands were significantly higher than that of connected wetlands. However, this phenomenon can be reversed as a result of land use changes. The connected wetlands in more urbanized areas (average developed area = 12.3%) showed higher concentrations of dissolved organic matter (DOM) (DOC: 11.76 ± 6.09 mg L(-1), TDN: 0.74 ± 0.22 mg L(-1), mean ± standard error) compared to those in isolated wetlands (DOC: 7.20 ± 0.62 mg L(-1), TDN: 0.20 ± 0.08 mg L(-1)). The optical parameters derived from UV and fluorescence also confirmed significant portions of protein-like fractions likely originating from land use changes such as wastewater treatment and livestock pastures. The average of C/N molar ratios of all the wetlands decreased from 77.82 ± 6.72 (mean ± standard error) in February to 15.14 ± 1.58 in April, indicating that the decomposition of organic matter increased with the temperature. Results of this study demonstrate that the water quality of small, seasonal wetlands has a direct and close association with the surrounding environment.

Evaluation of Microorganisms Cultured from Injured and Repressed Tissue Regeneration Sites in Endangered Giant Aquatic Ozark Hellbender Salamanders

Investigation into the causes underlying the rapid, global amphibian decline provides critical insight into the effects of changing ecosystems. Hypothesized and confirmed links between amphibian declines, disease, and environmental changes are increasingly represented in published literature. However, there are few long-term amphibian studies that include data on population size, abnormality/injury rates, disease, and habitat variables to adequately assess changes through time. We cultured and identified microorganisms isolated from abnormal/injured and repressed tissue regeneration sites of the endangered Ozark Hellbender, Cryptobranchus alleganiensis bishopi, to discover potential causative agents responsible for their significant decline in health and population. This organism and our study site were chosen because the population and habitat of C. a. bishopi have been intensively studied from 1969–2009, and the abnormality/injury rate and apparent lack of regeneration were established. Although many bacterial and fungal isolates recovered were common environmental organisms, several opportunistic pathogens were identified in association with only the injured tissues of C.a. bishopi. Bacterial isolates included Aeromonas hydrophila, a known amphibian pathogen, Granulicetella adiacens, Gordonai terrae, Stenotrophomonas maltophilia, Aerococcus viridans, Streptococcus pneumoniae and a variety of Pseudomonads, including Pseudomonas aeruginosa, P. stutzeri, and P. alcaligenes. Fungal isolates included species in the genera Penicillium, Acremonium, Cladosporium, Curvularia, Fusarium, Streptomycetes, and the Class Hyphomycetes. Many of the opportunistic pathogens identified are known to form biofilms. Lack of isolation of the same organism from all wounds suggests that the etiological agent responsible for the damage to C. a. bishopi may not be a single organism. To our knowledge, this is the first study to profile the external microbial consortia cultured from a Cryptobranchid salamander. The incidence of abnormalities/injury and retarded regeneration in C. a. bishopi may have many contributing factors including disease and habitat degradation. Results from this study may provide insight into other amphibian population declines.

Potential recovery of a declined turtle population diminished by a community shift towards more generalist species

Models suggest that a declined turtle population may rebound if the cause of decline is remedied and adult mortality is reduced, but recovery time will likely be slow. In 2005-2007, we reexamined a river turtle community which included a population of Northern Map Turtles (Graptemys geographica) that had been reduced by approximately 50% between 1969 and 1980 likely as a result of harvesting, and had failed to rebound by 2004 despite no evidence of continued harvesting. Comparisons of population estimates for G. geographica showed no significant differences between 2005 and 2006 (z = 1.79, P = 0.073) or between 2006 and 2007 (z = 1.07, P = 0.284). However, the population estimate for 2007 was not significantly different from the population estimate for 1969 (z = 0.48, P = 0.629) but was significantly higher than the population estimate for 1980 (z = 2.96, P = 0.003), suggesting the population had returned to its pre- decline (1969) size. While the recovery of the G. geographica population demonstrates that a previously harvested river turtle population may rebound if no further harvesting occurs, the recovery period will be extensive, thus confirming model predictions. Furthermore, the turtle community composition was shifting towards a higher relative abundance of generalist species and a lower relative abundance of specialist species - a pattern that can be expected with habitat degradation, another threat which may present new challenges to G. geographica, a dietary specialist.

Reassessment of the Turtle Community in the North Fork of White River, Ozark County, Missouri

In an effort to identify long-term changes in a river turtle community and its habitat, we reexamined the turtle community in a 4.6 km section of the North Fork of White River (NFWR), Ozark County, Missouri, that was previously studied between 1969 and 1980. We compared data collected in 2004 to data from 1969 and 1980 to determine if alterations in the habitat, community composition, or Northern Map Turtle (Graptemys geographica) population size and structure had occurred. Previous studies showed that the population of G. geographica declined between 1969 and 1980. Our results indicate that the population of G. geographica failed to rebound by 2004. The population of Red-eared Sliders (Trachemys scripta elegans) that established in the research section between 1971 and 1980 expanded their distribution between 1980 and 2004. Threats to the population of G. geographica included lack of basking sites, increased human recreational use of the stream, and water quality degradation.

Small Parks as Local Social–Ecological Systems Contributing to Conservation of Small Isolated and Ephemeral Wetlands

ABSTRACT: Publicly owned lands designated as parks can be important tools for biodiversity conservation. In the U.S., state parks are afforded direct protection from localized development pressures, which may help to protect small, ecologically significant ecosystems such as isolated and ephemeral wetlands and headwater streams. We used the South Carolina State Park system as a case study to examine the structural and functional differences between small wetlands located inside vs. outside of parks in the Piedmont and Blue Ridge ecoregions in order to evaluate the efficacy of a small-scale conservation framework for protecting small, under-protected freshwater ecosystems. We evaluated data relating to water quality, wetland structure, and biodiversity parameters collected between January 2010 and June 2011. Our results indicated marked differences between park and non-park wetlands, with park wetlands having shallower depths, higher abundances of sensitive benthic macroinvertebrate taxa, and lower average tolerance values consistent with more sensitive macroinvertebrate species and higher water quality. These findings demonstrate that state parks can serve to protect freshwater ecosystems and biodiversity. State parks, thus, represent a preexisting network of protected areas to aid in the protection of localized habitats, such as small isolated and ephemeral wetlands, that may not otherwise receive the conservation protection warranted by their ecological function.

Effects of Japanese Knotweed on avian diversity and function in riparian habitats

AbstractThe impacts of the invasive plant Japanese Knotweed (Fallopia japonica) on native plant and invertebrate communities in its introduced range have been relatively well studied, and studies have revealed predominantly negative impacts. However, little research has focused on the impact of knotweed on higher trophic levels. This study investigated how riparian bird communities respond to different levels of knotweed invasion. Birds were counted in 21 fixed-width transects located along ten streams in Pennsylvania, a prime avian breeding area, winter roosting site, and migratory staging area located along the Atlantic Migratory Flyway. Species richness and overall abundances did not significantly differ between levels of knotweed coverage. However, three species exhibited significant positive correlations with knotweed cover, and one species exhibited a significant negative correlation. Species and foraging guild composition differed between survey locations with and without knotweed. Species frequently found around human habitation and in degraded habitats were associated with knotweed, while more sensitive species were associated with native vegetation. Locations with knotweed were also associated with fewer foraging guilds and lacked an association with shoreline gleaners, water ambushers, and ground foragers, indicating a potential loss of ecological function. Given the widespread distribution of Japanese Knotweed, management actions to reduce or eliminate knotweed from riparian corridors are necessary in order to preserve avian diversity and function.ZusammenfassungDie Folgen von Japanischem Knöterich für die ornithologische Vielfalt und die Funktion von Flussuferhabitaten Die Auswirkungen von Japanischem Knöterich (Fallopia japonica) auf die heimischen Pflanzen- und Wirbellosengemeinschaften in Gebieten, in denen diese invasive Pflanzenart eingeschleppt wurde, sind relativ gut untersucht, und Studien belegen überwiegend negative Effekte. Allerdings haben sich bislang nur wenige Forscher mit Auswirkungen von Knöterich auf höhere Trophiestufen beschäftigt. In dieser Studie untersuchten wir, wie Vogelgemeinschaften der Flussufer auf unterschiedlich starkes Vordringen von Knöterich reagieren. Es wurden Vogelzählungen in 21 Transekten fester Breite entlang von zehn Flüssen in Pennsylvania durchgeführt, einem wichtigen Brut- und Überwinterungsgebiet sowie Versammlungsplatz für Zugvögel entlang des Atlantischen Zugkorridors. Artenvielfalt und Gesamthäufigkeiten unterschieden sich nicht signifikant zwischen verschiedenen Graden der Knöterichbedeckung. Allerdings wiesen drei Arten signifikant positive Beziehungen zur Knöterichbedeckung auf, eine Art zeigte eine signifikant negative Korrelation. Das Artenspektrum und die Zusammensetzung der Nahrungsgilden unterschieden sich zwischen Probeflächen mit und ohne Knöterich. Arten, die oft in der Nähe menschlicher Siedlungen und in degradierten Lebensräumen vorkamen, standen mit Knöterich in Verbindung, wohingegen sensible Arten mit heimischer Vegetation assoziiert waren. Stellen mit Knöterich standen außerdem mit weniger Nahrungsgilden in Beziehung und es fehlte der Zusammenhang mit Vogelarten, die ihre Beute an der Uferlinie sammeln, ihr im Wasser auflauern oder Nahrung am Boden suchen, was auf einen möglichen Verlust an ökologischer Funktion hindeutet. In Anbetracht der weiten Verbreitung des Japanischen Knöterichs bedarf es Managementmaßnahmen zur Reduzierung oder Ausrottung des Knöterichs an Flussuferkorridoren, um die ornithologische Artenvielfalt zu schützen und ihre Funktion zu erhalten.