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Benthic macroinvertebrates were washed from nearly 1000 federally endangered freshwater mussels that had been collected from Pennsylvania during a reintroduction project to 2 eastern Illinois streams. Most benthic macroinvertebrates collected were larvae of the Neophylax fuscus, but other caddisflies and segmented worms were also observed. No unoccupied caddisfly cases were observed on live mussels, leaving open the question as to the seasonal fate of these microhabitats after caddisflies pupate and emerge in the Autumn of each year. Unionid mussel shells might modify local-scale species diversity by influencing physical and hydrau lic properties of microhabitats.
Shorebirds (Order Charadriiformes) exhibit a wide variety of breeding systems, and have been the subject of extensive studies on the evolution of these systems. Nevertheless, there are many monogamous species within this clade. Previous studies of Charadrius vociferus (Killdeer) have shown that they are monogamous, with only a single documented variation (serial polyandry). We report observations at a nest that contained 7 eggs (typical nests have 4 eggs). The nest was being attended by 3 adults, and it successfully fledged young. This is the first documented Killdeer nest with possible simultaneous polygamy.
Housing development along lakeshores typically results in the loss of native shoreline vegetation, which can negatively impact habitat structure and associated wildlife populations. We evaluated vegetation restoration efforts on 2 lakeshores in Vilas County, WI, and contrasted them with undeveloped reference lakeshores. The primary goal of the restoration activities was to restore native understory vegetation and habitat structure. Initial measurements made at reference lakeshores showed greater visual obstruction density, greater sapling and shrub densities, greater abundance of downed woody material, and higher canopy coverage relative to initial measurements made at developed lakeshore sites. Three years post-restoration we observed significant increases in visual obstruction density and increased shrub and sapling density at restoration sites. While restoration of complex understory habitats is a slow and uncertain process, a nonmetric multi-dimensional scaling ordination of wildlife habitat attributes suggested that restoration sites are on a developmental trajectory that should increase their similarity to reference sites with time. Further monitoring and adaptive management will likely be needed to ensure restoration goals are met.
The European and Asian earthworms introduced to eastern North American forests have great potential to facilitate plant invasions, in part through selective seed predation and dispersal. The invasive plant Alliaria petiolata (Garlic Mustard) contains secondary metabolites that may deter earthworms from eating its seeds. In 2 growth-chamber experiments, I determined whether the invasive earthworms Lumbricus terrestris (Nightcrawler) and Eisenia fetida (Red Wiggler) could aid the spread of Garlic Mustard by ingesting its seeds at lower rates than the similar-sized seeds of the native forest herb Geranium maculatum (Wild Geranium). Earthworms had similar rates of seed ingestion regardless of earthworm or plant species and digested the majority of seeds they ate (67–73%). There was no interaction between earthworm and plant species. Given a choice between Garlic Mustard and Wild Geranium, seed selectivity cannot explain positive associations between earthworm abundance and Garlic Mustard invasion.
We surveyed bees inhabiting inland dune and ridge woodlands at 30 sites in Worcester County, MD, in 2008 and 2009 . We collected and identified 4878 bees representing 5 families, 31 genera, and 121 species. Here, we report data on annual and seasonal variation. Expanding survey efforts to include multiple years and seasons served to increase the overall number of species encountered, primarily through documenting the presence of rare or infrequently collected species. Eighty-eight species (73%) were represented by fewer than 10 individuals; of these 30 were represented by a single individual (25% of the total). The 5 most dominant species represented nearly half (48%) of the total number of specimens. We report a list of bee species collected from inland dune and ridge woodlands and discuss the presence of apparently habitat-restricted species.
We report 100 lichen and allied fungi species for the first time from Québec, Canada. Six of these species are new to North America: Arthonia subastroidea, Biatora mendax, Cornutispora pyramidalis, Gyalecta hypoleuca, Taeniolella pertusariicola, and Varicellaria lactea. Six additional species are new to Canada: Cecidonia xenophana, Lecidea commaculans, L. herteliana, Polycoccum sporastatiae, Scoliciosporum intrusum, and Stereocaulon leucophaeopsis. All collections are from parc national de la Gaspésie on the Gaspé Peninsula in eastern Québec. Our collections were made between 2012 and 2017, primarily during Crum and Tuckerman Workshops. We provide diagnostic descriptions of all species that are new continental or national records. Our results demonstrate the park's rich and unexplored biodiversity and conservation importance, and contribute to a better understanding of the lichen and allied fungus biota of Canada and North America.
Climate change is influencing the ocean environment in myriad ways and many of its effects can directly or indirectly impact coastal ecosystems. In this study, I analyzed data for a number of variables describing atmospheric and ocean conditions (AOC) from a National Oceanographic and Atmospheric Administration (NOAA) data buoy located near the Cape Cod, MA, peninsula. The data suggest that a number of significant trends have occurred during the period of data collection spanning 1982–2015. Changes include up to a 2 °C and 3 °C warming of air and water temperatures in summer, reduced barometric pressure in the summer/fall, declining wind speeds in the spring, shorter average wave-periods in the winter and spring, a clockwise change in wind direction in the summer, and increased wave heights in the summer and fall. The AOC variables also exhibited a number of relationships with each other, which helped explain some mechanisms of change. With the exception of barometric pressure and fall wave-height, none of the variables exhibited significant correlations with the North Atlantic Oscillation (NAO) indices, which themselves have exhibited a declining trend over the last several decades. The analyses indicate that greenhouse gas emissions may be the primary driver of these changes. Herein, I further discuss the results in the context of potential consequences for coastal ecosystems of the Cape Cod region.
Alosa aestivalis and A. pseudoharengus are herring congeners that are important forage species for piscivorous fish and birds. We measured population structure metrics for these species using microsatellite markers. The Southern Gulf of Maine study area allowed the assessment of these species at an inter- and intra-watershed level. We found no detectable population structure within or among watershed for either species which agrees with other recent research. Our results support regional-scale (e.g., Gulf of Maine) plans for management for A. aestivalis and A. pseudoharengus. We found that 5.4% of our samples were hybrids. Our study adds to a growing body of evidence that hybridization and introgression should be management concerns for these species, and precautions should be taken to preserve species barriers. An error rate of morphological identification was calculated by comparing morphological identifications against genetic classifications. We found an overall identification error rate of 16%, which differed significantly from zero (P = 0.008). Managers should also take note of the uncertainty in morphological identifications and adjust stock models and policies accordingly.
Vagrant individuals from cryptic species complexes pose a persistent challenge for accurate species identification, hindering our understanding of vagrancy in these taxa. Here, we used non-invasive sampling of fecal matter to sequence the ND2 mitochondrial gene of 2 vagrant western flycatchers observed in northeastern North America. The DNAsequence data we recovered from these vagrants fell within a clade of known Empidonax difficillis (Pacific-slope Flycatcher) haplotypes. Our work provides robust records of 2 vagrant Pacific-slope Flycatchers in the northeastern US. These findings illustrate the power of non-invasive sampling for species identification of vagrants from cryptic species complexes.
Although Odocoileus virginianus (White-tailed Deer, hereafter, Deer) are abundant on private lands throughout much of the western Virginia mountain region, populations are comparatively low on publicly owned lands in this area. Concerns voiced by sportsmen regarding declining numbers of Deer on public lands in western Virginia prompted research to estimate the population density in selected areas within this region. From January 2012 through April 2013, we used ground-based transect sampling with forward-looking infrared (FLIR) techniques in a distance-sampling framework to estimate seasonal Deer density in mountainous western Virginia. We included habitat variables and abiotic factors thought to influence detection and ranked models using AICc model selection in the program DISTANCE. We observed 430 groups of Deer (mean group size = 2.9) during 5 sampling sessions conducted along 562.5 km traveled in Bath County, versus 102 groups (mean group size = 2.6) along 643.6 km in Rockingham County. Wind speed negatively affected detection, and minimum temperature positively influenced detection. Detection rates were higher in open areas and forest edges, and higher closer to a full moon. Overall, we found Deer densities to be lower in the mountainous areas we sampled compared to the few studies using similar sampling techniques in other nearby areas of the state. Additionally, we found that while density did not vary seasonally, Deer densities were higher in Bath County (4.75–16.06 Deer/km2) than in Rockingham County (0.17–3.55 Deer/km2), likely due to the presence of more edge and open habitat in Bath County. We suggest that distance estimation is a viable technique to survey Deer, but caution that our sample sizes were small for some surveys and suggest that future research should seek to account for low detection rates on national forest lands by increasing effort.
Lianas are structural parasites that depress growth, fertility, and survival rates of their hosts, but the magnitude to which they alter these rates differ among host species. We tested the hypothesis that Platanus occidentalis (Sycamore) would have fewer adventitiousroot climbing lianas than other tree species. We reasoned that because Sycamore possesses exfoliating bark, it would periodically shed newly-established lianas from the trunk. We investigated the distribution of lianas on the trunks of trees ≥10 cm DBH in floodplains in southwestern Ohio. Contrary to our predictions, Sycamore trees had significantly more lianas than expected at 3 of 5 sites, and significantly fewer than expected at 1 site. In contrast, Acer negundo (Boxelder) had less than half the lianas expected. We find no support for our hypothesis that bark exfoliation protects Sycamore trees from climbing lianas, and suggest possible mechanisms that might protect Box Elder from adventiti ous-root climbing lianas.
Quercus velutina (Black Oak) is a dominant deciduous tree in Cape Cod, Martha's Vineyard, and Nantucket, MA. In recent years, Black Oak trees in these regions have experienced severe canopy loss due to the infestation of a stem-gall wasp, Zapatella davisae. In addition to infestations first documented in the Cape Cod region in 2012, Zapatella davisae has been present in Long Island, NY, since the 1990s. We investigated the life cycle of Z. davisae, specifically emergence patterns and timing of development. We evaluated differences in the severity of the infestations in Long Island and Cape Cod. We also identified towns in Cape Cod that contained Z. davisae infestations to better estimate the geographic extent of the infestation in the region. We found that Zapatella davisae completes 1 generation per year and emerges throughout the month of May. The severity of the infestation was the greatest in Cape Cod, an indication that something is controlling the population in Long Island. We concluded that Z. davisae is widespread and present in all towns in Cape Cod, Nantucket, and Martha's Vineyard. Our research will lay the foundation for future biological control efforts and will help arborists and landowners make management decisions regarding Z. davisae in the Cape Cod region and Long Island.
Genetic analysis (i.e., DNA sequence data from the mitochondrial cytochrome b and cytochrome oxidase subunit I genes) confirms the presence of Lethenteron appendix (American Brook Lamprey) in Shorey's Brook, a small stream located in the towns of Eliot and South Berwick, ME. This study documents the easternmost record of this species in New England, and the first known occurrence of the American Brook Lamprey in Maine.
The monitoring of changes in benthic macroinvertebrate communities over time facilitates the evaluation of any changes that occur in the function and structure of aquatic ecosystems. We hypothesized that it would be possible to determine, through running simulations, which trophic group of fishes' gut content can and should be used to best determine benthic macroinvertebrate community composition. Researchers could use this knowledge to estimate historic benthic macroinvertebrate communities of aquatic systems from fishes catalogued in museums. These historical data could then be compared to current data to see how macroinvertebrate communities have changed over time. In this study, we identified the fishes whose gut content most accurately reflected the benthic macroinvertebrate community of Marshalls Creek in East Stroudsburg, PA. We collected fish species and benthic macroinvertebrate samples at various sites and at different times of year to reflect seasonal variation. Enneacanthus gloriosus (Bluespotted Sunfish), Lepomis auritus (Redbreast Sunfish), and Catostomus commersonii (White Sucker) were the species that best represented the benthic macroinvertebrate community from their gut content. We determined that these species predicted 81% of all taxa that occur in summer. To estimate sampling distribution, we ran 100 simulations in R 3.0.2 on each combination of 3 fish species to determine the average quantity of taxa consumed (to the family level) along with sampling variation. Data obtained from the dissection of museum specimens could then be compared to data obtained from more recently collected specimens and a comparison made to determine changes in the macroinvertebrate community over time.