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To assess pathological changes associated with natural infections of the trematode Odhneriotrema incommodum in wild-caught American alligators Alligator mississippiensis and assess potential first intermediate hosts.Tongues from two wild-caught alligators were obtained from a commercial alligator processor in Port Gibson, Mississippi, USA. Tongues were subjected to gross parasitological examination and routine histological assessment. Eggs were expressed from adult trematodes collected from these tongues into distilled water, where they hatched into infectious miracidia. The snails Planorbella trivolvis, Physa gyrina, and Biomphalaria havanensis were exposed to these miracidia and observed for cercarial emergence for 200 days post-exposure.Histological assessment of alligator tongues revealed marked hemorrhage, necrosis, presence of bacteria, and inflammation at sites of Odhneriotrema incommodum attachment, differing from previous histological reports from controlled experimental studies. Cercarial emergence was not observed in snails exposed to infectious miracidia.Wild-caught alligators infected with Odhneriotrema incommodum exhibit more severe pathology than was previously noted from experimentally infected alligators. This adverse pathology may be associated with microbes present in eutrophic natural habitats that are absent from controlled environments used in experimental exposures. Impacts of this parasite in wild alligator populations are likely underestimated and damage associated with parasite attachment could increase host susceptibility to secondary infections. Given the importance of alligators as game animals and sustained demand for alligator products, further study into the role of O. incommodum on alligator health is warranted. Results of snail exposures to miracidia suggest these snail species are not suitable first intermediate hosts for this trematode and the true first intermediate host of O. incommodum remains unknown.

This data article provides the methods and procedures followed to collect and analyse soil, vegetation and bird data on three different treatment islands in Guntersville Reservoir, Alabama. Samples were collected from randomly selected plot points from islands that were placed into three different treatment types: Colony (currently occupied by Double-crested Cormorants) (Phalacrocorax auritus; n = 5), Historic (historically occupied by cormorants and currently abandoned; n = 3) and Reference (never occupied by cormorants; n = 4). We compared vegetation and tree metrics such as structure and diversity, as well as soil chemistry and bird diversity and communities among islands within Guntersville Reservoir. These data document for the first time that we are aware of the long-term effects of soil chemistry changes, vegetation changes, and impacts to avian diversity, in temperate forest ecosystems, by cormorant colonies. All data is associated with the recent article by Veum et al. [1] and provided here as raw data. Keywords: Waterbird, Southeastern forest, Diversity, Avian, Vegetation, Soil

Low-grade weirs placed within agricultural drainage ditches in the Lower Mississippi Alluvial Valley can be used as a management practice to enhance nitrogen removal. The addition of organic carbon amendments within ditches that contain weirs could further increase nitrogen removal. Through repeated trials, changes in NO 3 - -N concentration between inflow and outflow were variable in the ditch without weirs, while only decreases in concentration were observed in ditches with weirs. Significant differences in NO 3 - -N concentrations were observed between treatments, with greater removal of NO 3 - -N observed in dissolved organic carbon treatments compared to control and particulate organic carbon treatments. At medium- and high-flow rates, respectively, dissolved organic carbon treatments resulted in greater NO 3 - -N concentration decreases of 31.6% and 27.1% compared to 19% and 11.6% in particulate organic carbon treatments and 18.6% and 17.2% in control treatments. Significant effects of weirs and sampling date on nirS, nirK, nosZ, and 16S rRNA gene abundances were observed. Observed increases in NO 3 - -N removal with organic carbon amendments, provides support for continued investigation on improving the efficacy of organic carbon amendments as a best management practice for NO 3 - -N removal in agricultural drainage ditches. PRACTITIONER POINTS: Dissolved organic carbon amendments increased nitrate-nitrogen removal. Only decreases in nitrate-nitrogen concentration were observed in ditches with weirs. Increasing flow rate did not affect nitrate-nitrogen removal. Abundance of denitrification-performing microbes likely did not affect N removal. Lack of anaerobic soil conditions and short residence time reduced nitrate-N removal.

Novel molecular data from both mitochondrial ( cytochrome c oxidase subunit 1) and ribosomal regions ( 18S, ITS1-5.8S, ITS2, and 28S) are provided for Sebekia mississippiensis Overstreet, Self,Vliet, 1985 , a pentastome infecting the American alligator, Alligator mississippiensis Daudin, 1801, and the spotted gar, Lepisosteus oculatus Winchell, 1864. Adult and nymphal pentastomes are described from the lungs and liver of the type host, A. mississippiensis, collected from Mississippi, while additional nymphs are described from the esophageal lining of L. oculatus specimens collected from Louisiana. This sequencing data will facilitate more accurate identification of various life cycle stages of S. mississippiensis, enabling future work to resolve many ambiguities in the literature regarding this species. Additionally, histopathological data are provided from both the definitive and intermediate hosts.

An effective vaccine for respiratory syncytial virus (RSV) is an unrealized public health goal. A single dose of the prefusion-stabilized fusion (F) glycoprotein subunit vaccine (DS-Cav1) substantially increases serum-neutralizing activity in healthy adults. We sought to determine whether DS-Cav1 vaccination induces a repertoire mirroring the pre-existing diversity from natural infection or whether antibody lineages targeting specific epitopes predominate. We evaluated RSV F-specific B cell responses before and after vaccination in six participants using complementary B cell sequencing methodologies and identified 555 clonal lineages. DS-Cav1-induced lineages recognized the prefusion conformation of F (pre-F) and were genetically diverse. Expressed antibodies recognized all six antigenic sites on the pre-F trimer. We identified 34 public clonotypes, and structural analysis of two antibodies from a predominant clonotype revealed a common mode of recognition. Thus, vaccination with DS-Cav1 generates a diverse polyclonal response targeting the antigenic sites on pre-F, supporting the development and advanced testing of pre-F-based vaccines against RSV.

Brown-headed cowbirds (Molothrus ater) are obligate brood parasites that lay eggs in host species’ nests. Studies on effects of host nest characteristics (e.g., nest placement, concealment, nest size) on parasitism rates by brown-headed cowbirds have yielded ambiguous results. To elucidate potential relationships between nest characteristics and brood parasitism rates, we collected data from indigo bunting (Passerina cyanea; n = 68), prairie warbler (Setophaga discolor; n = 30), and yellow-breasted chat (Icteria virens; n = 127) nests from early successional, managed loblolly pine (Pinus taeda) stands in Kemper County, Mississippi, USA, during 2012–2013. We recorded concealment, percent canopy cover, nest height (m), and nest morphometrics for each nest to test how these parameters related to frequency of brown-headed cowbird nest parasitism for each species. We predicted that larger, heavier nests would have an increased likelihood of parasitism. We recorded nest parasitism of 3%, 18%, and 24% for yellow-breasted chat, indigo bunting, and prairie warbler nests, respectively. Model coefficients for nest size did not differ from zero and nest size metrics did not differ between parasitized and unparasitized nests, thus contradicting our hypotheses and findings of previous studies relating nest size to parasitism. Our results suggest that the relationship between host nests and risk of brown-headed cowbird parasitism likely varies according to species of interest, geographic location, and features of available habitat. © 2016 The Wildlife Society.

Intercropping switchgrass (Panicum virgatum), within managed loblolly pine (Pinus taeda) stands, has been proposed as an alternative source from which to create biofuels while also supporting wildlife biodiversity. However, little evidence is available on which to gauge if this practice affects nutrient availability and/or wildlife diets within pine stands. This study compares total carbon (C), total nitrogen (N), and C:N ratios in loblolly pine and blackberry (Rubus spp.) located in intercropped loblolly stands, including those managed with herbicides for hardwood control. This study also used stable isotopes (12C and 13C) to compare diet of an early successional bird species (yellow-breasted chat [Icteria virens]) in intercropped loblolly stands and loblolly stands managed with herbicides for hardwood control. Results indicate intercropping does not influence total C or N in loblolly or blackberry samples, although total N is elevated among blackberry samples in hardwood control loblolly stands. Results also illustrate that intercropping increases the ratio of 13C: 12C (δ13C) in yellow-breasted chat associated with areas where intercropping has been undertaken. Our study demonstrates that biofuel cultivation can affect nutrient flow within managed forest ecosystems. The influence of this nutrient flow should be considered when implementing biofuel production goals.

In November 2017, oocysts of the coccidian Eimeria macyi Wheat, 1975 were isolated from the faeces of a single eastern red bat Lasiurus borealis Muller in Lowndes County, Mississippi, USA. Sporulated oocysts, morphologically consistent with previous accounts of E. macyi in other chiropterans, were spherical to sub-spherical in shape with a highly mamillated outer wall that appears bi-layered. Oocysts allowed to sporulate in 2.5% potassium dichromate at ambient temperature (c.23°C) for 7 days were 17–25 × 15–20 (20.7 × 17.9) µm. Micropyle and oocyst residuum were absent with one to two polar granules scattered among sporocysts. The four ovoid sporocysts were 7–12 × 6–8 (9.9 × 7.1) µm. Stieda bodies were prominent and sub-Stieda bodies were present. Two sporozoites were reflexed within each sporocyst. Nuclear 18S rRNA gene, plastid 23S rRNA gene and mitochondrial cytochrome c oxidase subunit 1 (cox1) gene were sequenced from sporulated oocysts and compared to other molecular data of Eimeria spp. from rodent and chiropteran hosts. No sequence data in the NCBI database matched E. macyi. Phylogenetic analyses of the sequence data of the 18S rRNA and 23S rRNA genes placed E. macyi within a clade containing Eimeria spp. from rodents and basal to a clade populated by sequences derived from Eimeria spp. of rodents and bats. This account represents a new host record of E. macyi in an eastern red bat and a new geographic locality. Additionally, the cox1 sequence data of Eimeria macyi represents the first mitochondrial sequence of an Eimeria sp. in bats.

Double-crested Cormorants are expanding their breeding range to historic wintering and migratory regions, such as Guntersville Reservoir in Alabama. This study lends insight into how cormorants breeding in a temperate ecosystem impact plants, trees, soil and bird communities as well as home range and movement of cormorants during the breeding season and whether they reside on this reservoir year-round. Results suggest that breeding cormorants have a negative impact on this ecosystem and do not move far from colony sites. Stable isotopes from cormorants and prey fish suggest that cormorants are migrating from this system after breeding, potentially to a marine source. This study corroborates past studies of negative impacts of cormorant colonies, and provides novel results of how southeastern cormorants use and move on Guntersville Reservoir. This thesis can provide biologists information on how best to control populations and mitigate impacts on this and other similar southeastern systems.

To improve habitat quality for wildlife, habitat managers prescribe various disturbances. Habitat management techniques alter the vegetation structure, composition, and quality, changing food and cover resources and availability. To investigate how habitat management and vegetation heterogeneity affect space use by wildlife species, I deployed 81 camera-traps and collected fine scale vegetation data across a variety of treatments (i.e., canopy reduction, prescribed fire, and herbicide application) in a managed loblolly pine forest. I created a new method for accounting for imperfect detection and error in camera count data. My method provided better inference about the effects of variables on animal use. Species responded differently to different functional groups of plants, but predicted use from generalized additive models showed higher use in the most intensively managed pine stands, indicating that management promotes animal use by improving habitat quality. Animals used every treatment, indicating the need for heterogeneity in resources when managing wildlife.

Managed loblolly pine ( Pinus taeda ) stands are common in the southeastern United States and provide young forest conditions for early successional breeding birds. Common pine management practices (e.g. hardwood control) and novel practices (e.g. switchgrass [ Panicum virgatum ] intercropping), may influence breeding bird use. I evaluated breeding bird abundance, diversity, and resource use within loblolly stands treated to control hardwood species, intercropped with switchgrass, and with no additional management. Hardwood control and switchgrass intercropping both decreased hardwoods and shrubs, and increased forbs. Switchgrass intercropping increased some early successional bird abundances. However, diversity was not different among treatments. Switchgrass intercropping increased 13C:12C in birds and vegetation; both hardwood control and switchgrass intercropping increased 15N:14N in birds and vegetation. Birds moved freely among stands of different ages and management practices. My results suggest these practices improve conditions for some early successional birds and may help maintain ecological value of loblolly stands for birds.

Based on specimens collected from harvested American alligator Alligator mississippiensis Daudin, 1801 in Mississippi, USA, novel molecular data for both nuclear ribosomal genes (18S, ITS1-5.8S, ITS2, and 28S) and mitochondrial genes (cytochrome c oxidase subunit 1 and nicotinamide adenine dinucleotide dehydrogenase subunit 1) are provided for Odhneriotrema incommodum (Leidy, 1856), a trematode of the family Clinostomidae Luhe, 1901 infecting A. mississippiensis and the Florida spotted gar Lepisosteus platyrhincus DeKay, 1842. This represents the first sequencing data available for the genus Odhneriotrema and the subfamily Nephrocephalinae Travassos, 1928. Additionally, the results of phylogenetic analyses, additional morphometric data, a photomicrograph, and a line drawing supporting the present identification of O. incommodum are provided. These data will aid in elucidating the life cycle of O. incommodum through molecular identification of larval stages as well as understanding the evolutionary history of Clinostomidae and its subfamilies. Implications for the currently accepted organization of the Clinostomidae are discussed.

Use of high-elevation balds by Nearctic-Neotropical passerines remains a poorly understood component of migration ecology. We used radio-telemetry to assess the habitat use of 20 Oreothlypis peregrina (Tennessee Warbler) at a high-elevation bald during September 2011. Our goals were to estimate the duration of stopover, examine variation in stopover length by age class, and determine patterns of habitat use during fall migration. For radio-tracked birds, the average length of time spent at the bald was 4.6 days (range: 1-12 days). The ma- jority of tracked locations corresponded with heath habitat that surrounded the bald opening (79% of locations), relative to the more distal and less complex, hardwood forest. Collective- ly, these results provide information on the important, yet ephemeral role that high-elevation balds play in supporting the autumnal migration of eastern North American passerines.

Effects of Double-crested Cormorants (Phalacrocorax auritus) on vegetation, soil chemistry and tree health have been documented from their breeding colonies in the northern breeding grounds of Canada and the United States (U.S.) but not for areas within the southeastern United States where breeding activity is relatively novel. We compared vegetation and tree metrics such as structure diversity, and soil chemistry among colony islands, uninhabited islands, and abandoned colony islands within Guntersville Reservoir, a temperate forest ecosystem. Avian diversity and community structure were also quantified on these islands. Concentrations of potassium (K), phosphorus (P) and nitrate (NO3−) in soil were negatively related to cormorant use, while tree diversity was lower on historic (tree mean = 4.35 ± 2.46 species) and colony (tree mean = 3.91 ± 3.12 species) islands relative to reference islands (tree mean = 9.11 ± 3.88 species). Canopy cover was less (min

Since first confirmation of nesting in 1987, there has been a steady southward expansion of breeding Tachycineta bicolor (Tree Swallow) in Alabama. Using 220 breeding season occurrence records, we performed a breakpoint analysis to quantify the breeding expansion rate of Tree Swallows in the state. Between 1988 and 2013, our models indicated Tree Swallows expanded ∼130 km south at a mean rate of 5.2 km/year. Possible drivers of this southward expansion include increased artificial nest box availability, aerial insect declines in more northern historic ranges, changing climate, and altered land-management practices. Our findings indicate Tree Swallows are following a similar southward breeding expansion pattern to that exhibited by Hirundo rustica (Barn Swallow) and Petrochelidon pyrrhonota (Cliff Swallow) in recent decades.

Enticed by the migratory irruption of 2007, we established three banding stations in northeastern Alabama, USA, to determine the prevalence of Northern Saw-whet Owls (Aegolius acadicus) in the state and subsequently examine the broader extent of migration patterns and demographics at latitudes ≤35°N. We captured 202 Northern Saw-whet Owls between 2007 and 2016, with annual totals ranging from 3 in 2014 to 64 in 2012. The proportion of hatch-year owls captured was 38.1% overall, which was considerably lower than levels reported at more northern stations. Morphometric estimates and a sex-specific discriminant function analysis table indicated 63.9% of all Northern Saw-whet Owls captured were female and 11.9% were males, with the remaining 24.2% of undetermined sex. Peak migration occurred during mid-November. We locally recaptured 44 individuals and determined that recaptures were bimodally distributed, with most owls recaptured 1 wk after initial banding and a second peak 10–13 wk afterward. We estimated 50% of owls emigrated from stations within 3 wk of initial banding. We encountered seven owls initially banded at northern stations; one of these had flown 1518 km from Whitefish Point Bird Observatory, Michigan to Hollins, Alabama. Of these encounters, three were intra-seasonal and represented owls that had migrated at an average rate of 36.2 km/night. Four owls banded in Alabama were encountered during subsequent seasons in the northern United States. Although limited, these data suggest owls follow the Appalachian Mountains and western Great Lakes migration routes into Alabama. Our findings indicate Northern Saw-whet Owls regularly overwinter in northeastern Alabama, although abundances probably vary annually with migration dispersion cycles. We recommend additional Northern Saw-whet Owl banding stations be established across the southeastern United States to further study this secretive species within the southern periphery of its winter range.

Novel molecular data from both mitochondrial (cytochrome c oxidase subunit 1) and ribosomal regions (18S, ITS1-5.8S, ITS2, and 28S) are provided for Sebekia mississippiensis Overstreet, Se...

The Lake Ontario–upper St. Lawrence River (LOUSL) population of American Eels Anguilla rostrata (hereafter, “eels”) was once one of the most important groups of the species but is now in a state of serious decline. Given that thiamine deficiency has been observed in almost all of the top predators in Lake Ontario, we assessed the potential that adiet-induced thiamine deficiency associated with consumption ofAlewives Alosa pseudoharengus could be involved. Muscle thiamine was measured in eels from throughout the LOUSL corridor and was compared with putative threshold effect levels established from the literature. Mirex concentrations were used to separate Lake Ontario-resident eels from non-Lake Ontario-resident eels.Stable isotope analyses of eel muscle samples and potential prey, including Alewives, were combined with mixing model softwareto infer the diets consumed by Lake Ontario eels. Although residence in Lake Ontario was associated with a significant declinein muscle thiamine concentration, estimated Alewife consumptionby eels was unexpectedly low. Instead, mixing model results indicated that crayfish and Round Goby Neogobius melanostomus werethe major prey. Both taxa are known to contain thiaminase and have the potential to cause thiamine deficiency, but there are no reports of thiamine deficiency associated with Round Goby consumption, thus implicating crayfish. There was no recovery in thiamine levels prior to the initiation of oceanic migration. Asa result, thiamine levels of Lake Ontario-resident eels prior to migration were only slightly above putative threshold effect levels for pathological and behavioral effects in Japanese EelsAnguilla japonica, but this would require confirmation with American Eels. Since thiamine levels are expected to decline further during migration, additional effects on eel behavior, reproduction, and survival seem probable. Because of panmixia, such effects—when combined with the relatively high reproductive potential of Lake Ontario-resident eels—may have consequences for the entire species. © 2013 Taylor & Francis Group, LLC.

A growing trend towards increased urbanization emphasizes the role of suburban parks in wildlife conservation. Spatial planning aimed at maintaining biological diversity and functionality must consider how changes at landscape and more local scales will influence the biotic structure of urban areas. From May 2006 to July 2010, bird surveys were conducted in three metropolitan parks in Cleveland, Ohio, USA. Surveys were conducted with the goal of examining the effect of vegetation structure and adjacent land cover on the distribution and species richness of breeding birds within this park system. A total of 65 species were recorded throughout the study area. Avian species richness was linked to several habitat metrics, measured at both the local and landscape scale. Generally, species richness was highest at locations characterized by moderate forest cover. The proportion of canopy cover at survey sites related negatively to species richness and the density of understory vegetation showed a positive relationship with species diversity. Despite the influence of these three metrics, sensitivity analysis indicates that the density of understory vegetation is the most significant correlate to avian diversity within this suburban park system. Management actions aimed at providing habitat for the greatest diversity of breeding songbirds within the study area should allow for moderate canopy cover while retaining or improving the structural complexity of understory vegetatation.

Since the introduction of white perch (Morone americana) into Lake Erie over 50 years ago, the population size of native yellow perch (Perca flavescens) has decreased up to 79 % and significant changes to the ecosystem have occurred. We examined long-term population estimates and used stable isotopes of carbon (δ 13C) and nitrogen (δ 15N) paired with stomach content analysis to quantify the trophic ecology and niche overlap of adult yellow perch and white perch in the western basin of Lake Erie. We found that changes in yellow perch abundance since 1979 appeared to be better correlated with changes in fishery exploitation rates than with food competition effects from white perch. At the time of this study, yellow perch were found to have higher δ 13C values, indicating greater utilization of benthic food resources than white perch, and white perch occupied higher trophic positions based on δ 15N. The diets of both species varied spatially and seasonally based on stable isotopes and stomach contents, likely driven by changes in prey abundance. Comparison of niche widths using stable isotope population metrics and Schoener diet similarity index suggested a low to moderate degree of niche overlap between species. Isotopic niches of white perch were generally larger than those of yellow perch demonstrating broader resource utilization by this non-indigenous species. We submit that isotopic niche overlap comparisons are more appropriate for studies seeking to understand interactions among populations over course temporal scales, while diet overlap indices, such as the Schoener index provide a means to study fine-scale interactions such as ontogenetic and seasonal diet shifts.

Agricultural fertilizer applications have resulted in loading of nutrients to agricultural drainage ditches in the Lower Mississippi Alluvial Valley. The purpose of this study was to determine effects of dissolved organic carbon (DOC) and particulate organic carbon (POC) amendments on nitrate-nitrogen (NO3 −-N) removal from overlying water, pore water, and sediment of an agricultural drainage ditch. Two experiments were conducted. In experiment 1, control (i.e., no amendment), DOC, and POC treatments were applied in laboratory microcosms for time intervals of 3, 7, 14, and 28 days. In experiment 2, control, DOC, and POC treatments were applied in microcosms at C/N ratios of 5:1, 10:1, 15:1, and 20:1. There were statistically significant effects of organic carbon amendments in experiment 1 (F 2,71 = 27.1, P

Recent development of multi-dimensional stable isotope models for estimating both foraging patterns and niches have presented the analytical tools to further assess the food webs of freshwater populations. One approach to refine predictions from these analyses is to include a third isotope to the more common two-isotope carbon and nitrogen mixing models to increase the power to resolve different prey sources. We compared predictions made with two-isotope carbon and nitrogen mixing models and three-isotope models that also included sulphur (δ34S) for the diets of Lake Ontario lake trout (Salvelinus namaycush). We determined the isotopic compositions of lake trout and potential prey fishes sampled from Lake Ontario and then used quantitative estimates of resource use generated by two- and three-isotope Bayesian mixing models (SIAR) to infer feeding patterns of lake trout. Both two- and three-isotope models indicated that alewife (Alosa pseudoharengus) and round goby (Neogobius melanostomus) were the primary prey items, but the three-isotope models were more consistent with recent measures of prey fish abundances and lake trout diets. The lake trout sampled directly from the hatcheries had isotopic compositions derived from the hatchery food which were distinctively different from those derived from the natural prey sources. Those hatchery signals were retained for months after release, raising the possibility to distinguish hatchery-reared yearlings and similarly sized naturally reproduced lake trout based on isotopic compositions. Addition of a third-isotope resulted in mixing model results that confirmed round goby have become an important component of lake trout diet and may be overtaking alewife as a prey resource.

Summary 1. Declining abundances of forage fish and the introduction and establishment of non-indigenous species have the potential to substantially alter resource and habitat exploitation by top predators in large lakes. 2. We measured stable isotopes of carbon (δ13C) and nitrogen (δ15N) in field-collected and archived samples of Lake Ontario lake trout (Salvelinus namaycush) and five species of prey fish and compared current trophic relationships of this top predator with historical samples. 3. Relationships between δ15N and lake trout age were temporally consistent throughout Lake Ontario and confirmed the role of lake trout as a top predator in this food web. However, δ13C values for age classes of lake trout collected in 2008 ranged from 1.0 to 3.9‰ higher than those reported for the population sampled in 1992. 4. Isotope mixing models predicted that these changes in resource assimilation were owing to the replacement of rainbow smelt (Osmerus mordax) by round goby (Neogobius melanostomus) in lake trout diet and increased reliance on carbon resources derived from nearshore production. This contrasts with the historical situation in Lake Ontario where δ13C values of the lake trout population were dominated by a reliance on offshore carbon production. 5. These results indicate a reduced capacity of the Lake Ontario offshore food web to support the energetic requirements of lake trout and that this top predator has become increasingly reliant on prey resources that are derived from nearshore carbon pathways.

We examined stopover site fidelity by Tennessee Warblers (Oreothlypis peregrina) at two Tennessee banding stations (Whigg Meadow and Big Bald) operated during fall migration, ∼1,000 km from the nearest breeding areas. We captured and banded 4,324 Tennessee Warblers at Whigg Meadow from 1999 to 2008 with 14 individuals (0.3%) recaptured in subsequent years. We banded 5,514 Tennessee Warblers at Big Bald from 2003 to 2008 where, despite relatively close geographical proximity to Whigg Meadow (

Global climate change is expected to significantly affect coastal ecosystems worldwide. For tidal marsh birds of the Gulf of Mexico, the extent of these impacts on future population dynamics is unknown. Here, we present information on our current understanding of marsh bird responses to climate change, identify gaps in that understanding, and propose ways of improving our ability to predict impacts on avian populations. Our understanding of how Gulf Coast avian populations will respond to environmental drivers such as sea-level rise, precipitation patterns, and hurricanes is limited, and detailed local and regional studies linking avian biology to wetland processes are needed. Impacts of wetland change on marsh bird species will be optimally assessed and forecasted within an adaptive framework, making use of process-driven studies that include models designed to elucidate patterns in avian biology and wetland dynamics. Further, because management and conservation efforts are implemented at local or site-specific scales, we recommend that process-driven studies incorporate hierarchical structures, nesting local efforts within a regional context. Implementing this research program will prove fundamental in furthering our understanding of avian population dynamics within the changing Gulf of Mexico environment.

Fire is frequently applied as a management tool on both public and private lands. However, in some ecosystems there is little information about bird species’ responses to these fire programs. In 2004 we measured habitat characteristics and conducted point counts in 12 burned sites and four unburned sites in the Chattahoochee National Forest of northern Georgia. Burns were categorized by severity (low, medium, or high) and time since fire (1–2 or 3–6 years). The basal area of snags, shrub stem density and percent canopy cover were similar among all treatments except high severity. Otherwise, fire severity had limited impacts on measured habitat characteristics. Following fires the densities of early-succession species such as eastern towhee ( Pipilo erythropthalmus ) and indigo bunting ( Passerina cyanea ) were greatest in areas of higher fire severity. A ground-nesting species (ovenbird [ Seiurus aurocapilla ]) was less abundant in burned sites and the density of a shrub nesting species, the hooded warbler ( Setophaga citrine ) was greatest in areas that received low severity fires. Scarlet tanager ( Piranga olivacea ), tufted titmouse ( Baeolophus bicolor ), red-eyed vireo ( Vireo olivaceus ), black-throated green warbler ( Setophaga virens ), and black-and-white warbler ( Mniotilta varia ) had similar densities among all burn severities and showed no relationships with time since fire. Low and medium severity fires provided few benefits for most bird species. When conditions allow for their application, severe fires may be considered as a useful and historically appropriate management tool for some high-priority bird species in the southern Appalachian Mountains.

Stable isotopes of carbon (δ13C) and nitrogen (δ15N) often have unique values among lake habitats (e.g. benthic, littoral, pelagic), providing a widely used tool for measuring the structure and energy flow in aquatic food webs. However, there has been little recognition of the spatial and temporal variabilities of these isotopes within habitats of aquatic ecosystems. To address this, δ13C and δ15N were measured in seston, zebra mussels (Dreissena polymorpha) and young-of-year (YOY) yellow (Perca flavescens), and white perch (Morone americana) collected from four sites across the offshore habitat of the western basin of Lake Erie during June–September 2009. Values of δ13C and δ15N showed significant spatial and temporal variations, with month accounting for >50% of the variation, for both stable isotopes and all the species except seston. Such variation in isotope values has the potential to significantly influence or confound interpretation of stable isotopes in measures, such as trophic position (TP) which use lower trophic level organisms as their baseline. For example, TP was found to vary up to 0.7 for yellow and white perch (TP = δ15Nfish − δ15Nzebra mussel/diet-tissue fractionation factor) depending on the zebra mussel data used (e.g., from a different location or a different collection month). As the use of stable isotopes continues to move from qualitative to more quantitative measures of trophic structure, food web research must recognize the importance of stable isotopes' variability in lower trophic level organisms, especially in large lake systems.

Animals can influence the structure of an ecosystem by changing the levels of nutrient input. This is of particular importance for the islands of western Lake Erie, which are relatively nutrient poor, but have experienced increases in nutrient input from growing double-crested cormorant ( Phalacrocorax auritus ) populations. The objectives of this study were to evaluate changes in soil characteristics (nutrients [nitrate (NO 3 ), total P], pH, and δ 13 C [as a tracer of cormorant-associated nutrients]) across a gradient of cormorant nest density on two islands (Middle and East Sister) in western Lake Erie. For both islands, soil pH decreased and P concentrations increased with nest density. On Middle Island, soil nitrate concentrations increased with cormorant nest density, and varied with breeding phenology, with highest concentrations during the early and mid nesting season (272 ± 19 μg g − 1 ) and lowest concentrations late in the season (165 ± 11 μg g − 1 ). Following a 3-year absence of nesting activity at sites on Middle Island, soil nitrate concentrations were similar to those at low density sites. In contrast, nitrate concentrations measured on East Sister Island did not correlate with temporal or spatial patterns of cormorant nesting and remained elevated 10 years post-cormorant use. While the results of this study confirm that chronic input of allochthonous materials alters soil properties of these islands, the unique conditions of each island must be considered when predicting ecological effects and setting long-term management objectives.

It has been suggested that adult Paddlefish Polyodon spathula have no natural predators with the exception of humans and few heterospecific freshwater fishes which tend to target only early life stages (i.e., larvae, age-0 juveniles). However, we photographically documented another natural predator, the American alligator. The predation event took place in a small waterbody (0.8 ha) over a 45-minute period during which the alligator frequently transported the Paddlefish onto land, and retracted back into the water. This is the second event of its kind documented in this small river system. From a capture-recapture study, we have identified over 100 fish in the pool, 50 of which were surgically implanted with an acoustic transmitter for continuous monitoring of emigration. However, two have unexplainably disappeared, presumably from predation. Given the two known alligator mortality events, and two potential additional events suggested by transmitter disappearance, we presume adult Paddlefish predation may be more common than previously thought. Although adult Paddlefish were thought to have no natural predators, this newly documented predator-prey linkage provides support that alligator predation on Paddlefish may occur more frequently in southeastern waterbodies than previously believed, particularly when Paddlefish are in high abundance or in relatively small systems such as ours.

We investigated how variation in fire severity (control or no fire; low, medium, and high severity fires) and interval (1–2 years vs. 3–6 years after fires) affected habitat and avian abundance, species diversity, richness, and evenness in the southern Appalachian Mountains. Fire severity and interval had significant implications for both habitat and avian communities. Species richness within 2 years of fires was on average 26% higher in areas receiving medium and high severity treatments than in unburned control units. Species diversity and species richness were markedly greater 3–6 years after fires within high severity treatments (12 and 44%, respectively), compared to unburned controls. Relative abundance and species evenness did not vary with fire severity or time since fire. The short-term effects of low severity fires, or high severity fires with short rotation periods (≤2 years) may have limited positive effects on avian communities. Facilitation of disturbance regimes including mid to hi...

Monitoring programs aimed at understanding the population trends of secretive marshbirds can be altered to benefit from the creative interplay between predictions, designs and models, and provide the template for doing so. Effective application of information to decision making typically requires integration of several types of information in a common framework, including “found” data and retrospective studies, innovative sampling designs and the use of hierarchical data structures. Hierarchical and state-space modeling provide a unified modeling structure for such designs and data. These ideas are illustrated with the problem of investigating and mitigating the effects of climate change on secretive marshbirds in coastal North America. How both ecological theory and available data can be used to provide predictions about the impacts of regional and local climate changes on these avian communities are illustrated.

Guppies (Poecilia reticulata) are models for understanding the interplay between natural and sexual selection. In particular, predation has been implicated as a major force affecting female sexual preferences, male mating tactics and the level of sperm competition. When predation is high, females typically reduce their preferences for showy males and engage more in antipredator behaviours, whereas males exploit these changes by switching from sexual displays to forced matings. These patterns are thought to account for the relatively high levels of multiple paternity in high-predation populations compared to low-predation populations. Here, we assess the possible evolutionary consequences of these patterns by asking whether variation in sperm traits reflect differences in predation intensity among four pairs of Trinidadian populations: four that experience relatively low levels of predation from a gape-limited predator and four that experience relatively high levels of predation from a variety of piscivores. We found that males in high-predation populations had faster swimming sperm with longer midpieces compared to males in low-predation populations. However, we found no differences among males in high- and low-predation populations with respect to sperm number, sperm head length, flagellum length and total sperm length.

To document nest survival and habitat differences in the nesting habitats of Clapper Rails (Rallus longirostis) in tidal marshes of the northern Gulf of Mexico, we monitored 76 active nests within the Pascagoula River Marsh Coastal Preserve (a freshwater-dominated estuary) and the Grand Bay National Estuarine Research Reserve (a marine-influenced estuary) in coastal Mississippi from 2005 to 2007. During 2006, we measured the height of each Clapper Rail nest, sampled vegetation at active Clapper Rail nests and at random locations, and measured the distance to the nearest tidally influenced body of water and the average height and density of vegetation. Early in the breeding season, the average nest height was lower at the Pascagoula (36 cm) than at Grand Bay (60 cm), but, as the season progressed, nest height increased at the Pascagoula only. Within both estuaries, Clapper Rail nest sites were more structurally complex than at random locations and were associated with a greater diversity of veget...

Much of North America’s tidal marsh habitat has been significantly altered by both natural and man-made processes. Thus, there is a need to understand the trophic ecology of organisms endemic to these ecosystems. We applied carbon (δ 13C) and nitrogen (δ 15N) stable isotope analysis, along with isotope mixing models, to egg yolk, liver, and muscle tissues of clapper rails (Rallus longirostris) and their likely prey items. This analysis enabled us to explore variation in trophic niche and diet composition in this important marsh bird in two northern Gulf of Mexico tidal marshes that are river and ocean-dominated. For the river-associated estuary, δ 13C and δ 15N of egg yolks, liver, and pectoral muscle tissue samples provided evidence that clapper rails maintained a similar diet during both the winter and the breeding season. A trophic link between C3 primary productivity and the clapper rail’s diet was also indicated as the δ 13C of clapper rail egg yolks related negatively with the aerial cover of C3 macrophytes. Clapper rails from the ocean-dominated estuary had a narrower trophic niche and appeared to be utilizing marine resources, particularly, based on modeling of liver stable isotope values. Variation in stable isotope values between egg yolk and liver/muscle in both systems suggests that endogenous resources are important for egg production in clapper rails. These results demonstrate that diet composition, prey source, and niche width of clapper rails can vary significantly across different estuaries and appear to be influenced by hydrological conditions.

Human-induced and natural processes continue to act upon the estuaries of the northern Gulf of Mexico. Predictive models have been applied to project the interactions between habitat modification and population estimates for some estuarine species. However, these assessments may be furthered by focusing on a suite of species, such as a subset of the marsh birds that inhabit these ecosystems. During 2004 and 2005, we conducted point count surveys within the estuarine systems of Alabama and Mississippi, USA to assess whether small-scale wetland characteristics and a broader scale metric of habitat modification influenced the distributions of several marsh bird species: clapper rail (Rallus longirostris), common yellowthroat (Geothlypis trichas), least bittern (Ixobrychus exilis), marsh wren (Cistothorus palustris), and seaside sparrow (Ammodramus maritimus). On the basis of current habitat, we project change in species occupancy through several scenarios. Projections suggest that habitat alteration through loss of emergent marsh and increased cover of the halophyteJuncus roemerianus may be most influential to the distribution of these marsh bird species. Thus, continued alteration of existing conditions coupled with sea-level rise will likely have a significant impact on the distribution of this group of marsh bird species as well as the integrity of their habitat.

Relationships between egg volume and an array of life-history traits have been identified for many bird species. Despite the importance of egg volume and the need for precise and accurate measurements, egg volume is usually estimated using a mathematical model that incorporates length and width measurements along with a shape variable. We developed an instrument that provides precise estimates of egg volume and can be easily used in the field. Using Clapper Rail (Rallus longirostris) eggs, we compared egg volumes measured using our instrument with estimates based on linear measurements. We found our instrument to be both precise and accurate. Compared with a method based on linear measurements of eggs, use of our instrument reduced variation in egg volume estimates by 1.6 cm3, approximately 8% of the volume of a Clapper Rail's egg. Further advantages of our technique include ease of use, increased accuracy of field-based volume estimates, and increased resolution of variation in egg volume estimates. In addition, our technique does not require postdata collection processing time and did not influence hatching success. Also, for Clapper Rails and similar species, our technique can be combined with other techniques (e.g., egg flotation) so that both egg volume and embryonic stage can be estimated at the same time. © 2009 Association of Field Ornithologists.

We estimated apparent annual survival probability of adult Purple Martins (Progne subis) using a 14-year data set from a population in northwestern Pennsylvania. We modeled age, sex, and year effects on adult survival using known-age birds (585 males and 392 females) first banded or resighted as one-year-olds in two core breeding colonies. We resighted banded birds at (1) the two core breeding colonies, (2) other breeding colonies within 50 km of the core colonies, and (3) a large premigratory roost that attracts adult Purple Martins from colonies ≤200 km away. Apparent annual survival probability for one-year-olds increased by 0.08 when we included encounters outside the core colonies. Survival probability for older males and females was largely unaffected, a result of their high breeding-site fidelity. The model with age-specific survival (1 year old, 2–4 years old, ≥5 years old) and an age*sex interaction had the strongest support when all encounters were included. Apparent annual survival of...

To assess geographic distributions of elements in the Arctic we compared essential and non-essential elements in the livers of polar bears (Ursus maritimus) collected from five regions within Canada in 2002, in Alaska between 1994 and 1999 and from the northwest and east coasts of Greenland between 1988 and 2000. As, Hg, Pb and Se varied with age, and Co and Zn with gender, which limited spatial comparisons across all populations to Cd, which was highest in Greenland bears. Collectively, geographic relationships appeared similar to past studies with little change in concentration over time in Canada and Greenland for most elements; Hg and Se were higher in some Canadian populations in 2002 as compared to 1982 and 1984. Concentrations of most elements in the polar bears did not exceed toxicity thresholds, although Cd and Hg exceeded levels correlated with the formation of hepatic lesions in laboratory animals. © 2007 Elsevier Ltd. All rights reserved.

Studies on the effects of forest fragmentation on the reproductive ecology of forest songbirds have focused almost exclusively on the egg and nestling stages. Little is known about survival or habitat use of fledglings in their first weeks out of the nest. We radiotracked adult Hooded Warblers (Wilsonia citrina) attending fledglings from large (>150-ha) and small (

Estimates of nest survival rate are often based on the assumption that the rate is constant during the nest cycle. Because violating this assumption can generate biased estimates, determining the age of a nest is important. For precocial marsh birds, including Clapper Rails (Rallus longirostris), current estimates of nest survival do not take this source of bias into account because a standardized, nondestructive method for aging eggs in not available. We developed a nondestructive flotation technique using known-age nests that can be used to estimate the projected hatch date of Clapper Rail eggs within 3 d of the actual hatch date. This precision is limited in part due to variance in the length of incubation between nests and the common occurrence of asynchronous hatching. However, for investigators assessing the fate of Clapper Rail nests, our technique provides an effective and nondestructive method for projecting the hatch date of Clapper Rail eggs, and will facilitate unbiased estimates of nest survival rates. SINOPSIS Los estimados de la tasa de sobreviviencia comunmente estan basados en la presuncion de que esta es constante a traves del ciclo de anidamiento. Si violamos dicho postulado se puede generar sesgo en los estimados. A tales efectos es necesario entonces determinar la edad del nido. Para aves precoces de marjales, incluyendo a individuos de Rallus longirostris, los estimados actuales de sobrevivencia de nidos no toman en consideracion lo mencionado porque no hay un metodo estandarizado, no destructivo, para determinar la edad de los huevos. Desarrollamos un metodo no destructivo que consiste de hacer flotar los huevos, utilizando huevos de edad conocida, para estimar o proyectar el dia en que nacen los pichones dentro de tres dias de la fecha de eclosionamiento. La precision esta limitada en parte por la variabilidad en el largo del periodo de incubacion entre nidos y al hecho de que ocurre eclosionamiento asincronico. Sin embargo, para investigadores que tratan de determinar lo que finalmente ocurre con los nidos del ave, nuestra tecnica provee una forma efectiva, y no destructiva, para proyectar la fecha de eclosion, y reduce el sesgo para determinar la supervivencia de huevos.

Modifications to riverine systems that alter freshwater inflow to downstream estuarine habitats have resulted in altered patterns of nekton distribution and abundance. To examine how nekton assemblages respond to variable hydrologic patterns, we used trawl and seine survey data to compare the seasonal trends (dry vs. wet season) expected of a natural system to those of a river with regulated flow discharges that often magnify high flow events. Nekton assemblages differed between seasons in a representative natural system, similar to other estuaries of the region. For example, assemblage differences were characterized by significantly higher abundance and richness in trawl surveys, and significantly higher richness in seine surveys in the wet relative to the dry season. These seasonal trends were dampened in the altered system. Species important in defining seasonal dissimilarities in both systems were characterized as estuarine resident species, including Anchoa mitchilli, Menidia spp., Cynoscion arenarius, and Trinectes maculatus, yet were observed largely to have opposing seasonal trends in abundance between the two rivers. Our comparison provides evidence that flow modifications result in a loss of natural seasonal variability in estuarine nekton assemblages, but additional investigations of flow-altered systems are needed to confirm these findings.

Canadian and U.S. federal wildlife agencies completed four decadal surveys, spanning the years 1977 to 2009, to census colonial waterbirds breeding on the Great Lakes and adjoining bodies of water. In this paper, we reports abundance, distribution, and general population trends of three species: Black-crowned Night-Heron (Nycticorax nycticorax), Great Egret (Ardea alba), and Great Blue Heron (Ardea herodias). Estimates of nest numbers ranged from approximately 4000-6100 for the Black-crowned Night-Heron, 250-1900 for the Great Egret, and 3800-6400 for the Great Blue Heron. Average annual rates of change in nest numbers between the first (1977) and fourth (2008) census were â'1% for the Black-crowned Night-Heron, +23% for the Great Egret, and â'0.27% for the Great Blue Heron. Across the 30-year census, Black-crowned Night-Heron estimates decreased in U.S. (â'57%) but increased (+18%) in Canadian waters, Great Egret nests increased 1381% in Canadian waters with a smaller, but still substantial increase in the number of nests at U.S. colonies (+613%), and Great Blue Heron numbers increased 148% in Canadian waters and 713% in U.S. waters. Although a single factor cannot be clearly linked to changes observed in each species' distribution, hydrological variation, habitat succession, nest competition with Double-crested Cormorants (Phalacrocorax auritus), and land use changes likely all contributed. Management activities should support both breeding and foraging conditions including restoration of early successional habitats and anticipate continued northward expansions in the distributions of these waterbirds.

SUMMARY 1. We measured stable isotopes of carbon (d 13 C) and nitrogen (d 15 N) and fatty acid profiles inLake Ontario alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax), slimy sculpin (Cottuscognatus) and round goby (Neogobius melanostomus) collected from 1982 to 2008 to investigate howtemporal variability in these ecological tracers can relate to ecosystem-level changes associated withthe establishment of highly invasive dreissenid mussels.2. Prey fish d 15 N values remained relatively constant, with only slimy sculpin exhibiting a temporalincrease in d 15 N. In contrast, d 13 C values for alewife, rainbow smelt and, especially, slimy sculpinbecame less negative over time and were consistent with the benthification of the Lake Ontario foodweb associated with dreissenids.3. Principal components analysis revealed higher contributions of 14:0 and 16:1n-7 fatty acids andincreasingly negative d 13 C values in older samples in agreement with the greater historical impor-tance of pelagic production for alewife, rainbow smelt and slimy sculpin.4. Temporal declines in fatty acid unsaturation indices and Σn-3/Σn-6 ratios, and also increased24:0/14:0 ratios for alewife, rainbow smelt and slimy sculpin, indicated the increasing importance ofnearshore production pathways for more recently collected fish and resulted in values more similarto those for round goby.5. These results indicate a temporal convergence of the food niche, whereas food partitioning hashistorically supported the coexistence of prey fish species in Lake Ontario. This convergence is con-sistent with changes in food-web processes associated with the invasion of dreissenid mussels.Keywords: Dreissena spp., fatty acids, nearshore, offshore, stable isotopes

Ornithogenic nutrients derived from waterbirds such as the double-crested cormorant ( Phalacrocorax auritu s, Lesson) have been linked to habitat change within nesting colonies. For the islands of Lake Erie, where increasing cormorant populations and subsequent habitat change have spurred management activity, estimates of the quantity and chemical characteristics of avian-derived contributions are lacking. To evaluate the quantity and chemical characteristics of ornithogenic litterfall beneath a double-crested cormorant colony on a western Lake Erie island we investigated the mass of material and nutrient composition (PO 4 3 − , NO 3 − and NH 4 + ) reaching the forest floor under three nest densities (Low: 1–96 nests ha − 1 ; Medium: 97–255 nests ha − 1 and High: > 255 nests ha − 1 ). As expected, litterfall (total mass) input differed among nest densities with the most substantial input (225.05 g/m 2 week − 1 ) measured under High nest density conditions. Nutrient concentrations also showed increases with nest density to a point, where mean PO 4 3 − and NH 4 + concentrations showed no differences between Medium and High nest density sites. As well, NO 3 − concentrations were highest under Medium density, with no differences in this nutrient observed between Low and High density. Collectively, litterfall nutrient composition was similar to those linked to habitat changes in other waterbird colonies. Similarities in the concentrations of several nutrients between Medium and High nest density categories suggest that management actions aimed at reducing allochthonous nutrient contributions should try to sustain nest density at or below 96 nests ha − 1 .

Freshwater inflow from riverine sources is essential for estuarine productivity. How- ever, human alterations to freshwater flow have resulted in modifications to the seasonal complex- ities of estuarine communities. To quantify changes in energy transfer at the trophic guild and consumer levels that result from anthropogenic-altered flow, we evaluated seasonal trends over a 1 yr period in stable isotopes of carbon (δ 13 C), nitrogen (δ 15 N) and sulfur (δ 34 S) in nekton species sampled from 2 subtropical tidal rivers, one that is relatively natural and one that experiences reg- ulated flow discharges that result in autumnal high-flow events. Primary and secondary con- sumers in the flow-altered estuary exhibited a significant depletion in 13 C and enrichment in 15 N (~2‰ in both isotopes respectively) with the onset of the wet season, while the stable isotope val- ues of high trophic level species (i.e. ≥ tertiary consumers) remained relatively consistent, trends were not apparent in the natural estuary. These isotopic trends were evident in both benthic and pelagic consumers, suggesting a food web-wide influence of altered flow on nutrient dynamics. Although the relative trophic structure, based on δ 15 N, was consistent across seasons and among estuaries, the δ 34 S values were less seasonally variable in the flow-altered estuary and were indicative of more terrestrial/freshwater-influenced values compared to the natural estuary, suggesting a lengthened influence of high flow. Although limited in temporal scope, our results indicate a noteworthy difference in seasonal isotope dynamics of lower trophic level consumers in a flow-altered estuarine food web. The importance of this effect on ecosystem function warrants further attention.

Characterizing dietary resources and species interactions in estuaries is challenging, particularly when considering the dynamic nature of these ecosystems, the ranges in body sizes of species, and the potential for trophic roles to vary with ontogeny. We examined the influence of season and location on relationships between body size and δ 15N, δ 13C, and δ 34S values across a range of fishes from two subtropical estuaries. The results suggest that isotopic values of estuarine fishes are independent of body size. However, seasonal variation propagated throughout the assemblage as the majority of fishes integrated different δ 15N, δ 13C, or δ 34S values. The absence of δ 15N-, δ 13C-, and δ 34S-body size relationships suggests that either (1) dietary preference of these fishes do not shift within the range of body sizes sampled, (2) these fishes shift to an alternate diet that is not isotopically distinct, or (3) that spatial and temporal variation in isotopic signatures of prey negate any size-based relationships. Seasonal variability in the isotopic values of these fishes suggests either movement to an alternative habitat or a shift in organic matter source associated with the transition of dry to wet seasons. Moreover, variance distributions of the best-fit models indicate that seasonal dietary preferences of conspecifics do not vary over moderate spatial scales. Seasonal variability among fishes in these estuaries suggests plasticity in feeding strategies that may afford greater adaptive flexibility to these species in response to changes in food availability resulting from variable environmental conditions. © 2011 Coastal and Estuarine Research Federation.