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An Impact Source Determination method, used to identify point and nonpoint sources of impacts to stream water quality on the basis of benthic macroinvertebrates, was examined for concordance with impairment sources inferred from chemical and physical site characteristics, watershed characteristics, and biomonitoring results collected from 26 sites in the Hudson River Basin during 1993–94. Most classifications agreed with the resulting interpretations; site locations on Canonical Correspondence Analysis triplots corresponded with interpretation of environmental gradients as (1) overall pollution including organic enrichment and contaminants from point and nonpoint sources, (2) nonpoint nutrients from both agricultural and urban sources, and (3) sediment and suspended organic carbon from agricultural runoff. High-level taxonomic resolution was important in identifying the environmental gradients, and may be necessary for impairment source identification.
We estimate between 1,150 to 1,300 Harlequin Ducks wintered in Maine in the late 1990s. This represents over 50% of the total known wintering population in eastern North America. About 75% of these wintering birds in Maine were located in the Isle au Haut area from Vinalhaven to Swans Island. Smaller concentrations of birds were also present in eastern Hancock County (Sally Islands area) and York County (Cape Neddick area). At four groups of islands in the Isle au Haut area, numbers show a pattern of decline from 1989 to 1993 followed by increases since then. In contrast, the maximum number of birds reported each winter in York County has increased from about five birds in 1955 to about 75 birds in 1999 (rs = 0.73, n = 42, P < 0.001). The proportion of males to females observed during mid-winter counts increased from a low of 0.8:1.0 in 1992 to a high of 1.2:1.0 in 1996 (rs = 0.54, n = 35, P = 0.001) and averaged 1.0:1.0 (n = 35, SD = 3.5) from 1989–99. Given the small numbers and limited distribution of Harlequin Ducks in Maine, they should remain under full protection in the foreseeable future.
Total mercury (Hg) content was determined in an epiphytic moss (Dicranum montanum Hedw.); a corticolous macrolichen (Punctelia subrudecta (Nyl.) Krog) growing on tree bark; tree foliage from black cherry (Prunus serotina Ehrh.), red maple (Acer rubrum L.) and northern red oak (Quercus rubra L.); red oak leaf litter (freshly fallen leaves); the organic soil horizon; and mineral soil within an oak forest in southwestern Pennsylvania during 1999. Mean Hg concentrations of tree leaves and red oak litter were low (averaging 0.05 to 0.10 µg/g). The mineral soil contained slightly higher Hg contents (0.12 µg/g). Total Hg concentrations in the lichen species, organic soil horizon, and the epiphytic moss averaged 0.18, 0.43 and 0.50 µg/g, respectively. Based on these results, we selected the epiphytic moss and organic soil horizon for use in future studies as biomonitors to evaluate spatial and temporal variations of Hg within the mixed-hardwood forests of Pennsylvania.
I documented successful breeding by a pair of Sandhill Cranes (Grus canadensis) in a wetland in Kennebec County, Maine in 2000 and 2001. In 2000 I observed two adults with a chick on 5 and 14 July and 5 August. In 2001 I found the pair incubating a nest with two eggs on 18 May and observed them with one chick on 3 and 22 July. The wetland is a large sedge- and sphagnum-dominated lakeside fen and cattail (Typha latifolia) marsh that supports one of the most diverse wetland bird communities in the state. The nest was surrounded by cattails and was constructed of year-old cattail leaves and stems. These first records of breeding Sandhill Cranes in Maine and New England are likely the result of recent increases and eastward expansion of a crane population centered in the midwestern United States and Ontario. Historical literature suggests that this species was formerly a common migrant north to New England and may have nested here as well.
In order to better illuminate the genotoxic effects of a “complex mixture” of anthropogenic chemical toxins, we have employed the comet assay to measure the level of genotoxicity induced in a sentinel animal species, Micropterus dolomieu. Our analysis reveals a significant level of genetic damage in Androscoggin River smallmouth bass that increases in a downstream gradient in parallel with toxic equivalent concentrations. Individual concentrations of recognized, anthropogenic chemical toxins in Androscoggin River fish tissues are measured on an annual basis as part of a State monitoring program. Subsequent fish consumption and river use advisories are issued based, in part, on these assessments.
Nitrogen and phosphorus were measured in large and small fully senesced leaves of Acer rubrum and Quercus alba to determine whether leaf size influences nutrient resorption proficiency. Large Acer leaves were ≥ 3.3 times higher in mass and surface area than small Acer leaves collected from the same individual trees, yet concentrations of nitrogen and phosphorus in large and small senesced leaves (i.e., resorption proficiency of these two nutrients) were identical. Large Quercus leaves were ≥ 2.8 times higher in mass and surface area than small Quercus leaves collected from the same individual trees, yet concentrations of nitrogen and phosphorus were nearly identical in large and small senesced leaves. Although there are theoretical reasons to expect leaf size to influence resorption, leaf size did not play a role in controlling nitrogen or phosphorus resorption proficiency in these two deciduous forest species.
A partial albino Storeria occipitomaculata occipitomaculata (Storer 1839) was field-collected in Vermont on 25 July 1998. The specimen (AMNH-R 144501) could be the only known partial albino specimen of the species and is one of only a few such snakes known from localities in the northeastern United States. The existence of color variations in wild snake populations is discussed.
Propagules of four species of the algal genus Vaucheria—V. aversa, V. frigida, V. prona, and V. undulata—are shown to survive enteric passage through the exotic earthworm, Metaphire levis. One species previously known from the northeastern Connecticut collection site, V. geminata, did not appear in the worm castings cultures, and another, V. aversa, was previously unknown there. In that earthworm castings are a mechanism for the movement of soils, we postulate that they can also be the source of dispersal of Vaucheria propagules which, when wafted into the atmosphere as dust from castings, could disperse to nearby or distant locations.
Butterfly communities were inventoried at two national parks, Allegheny Portage Railroad National Historic Site (ALPO) and Johnstown Flood National Memorial (JOFL), Pennsylvania, in 1998. Information on presence, abundance, and distribution of butterflies is important to National Park Service personnel, who are mandated to manage the biodiversity of natural resources. As large tracts of public lands, such as national parks, become more insular with increased habitat fragmentation, they will become increasingly valuable for the long-term maintenance of faunal diversity and the functional integrity of ecosystems in the eastern United States. Surveys were conducted monthly from late spring to early fall along two transects in ALPO and one in JOFL. Twenty-eight butterfly species were noted in the study. At ALPO, most species and individuals were found along open (non-wooded) sectors of the transects, including Phyciodes tharos (Drury) (Pearl Crescent), Boloria bellona (F.) (Meadow Fritillary), and Thymelicus lineola (Ochs.) (European Skipper). At JOFL, the most abundant butterfly was T. lineola. We observed 27 of 110 flowering plant species being used as nectar sources by butterflies on 200 occasions in both parks combined. At both parks, an effort should be made to develop mowed lawns into unmowed grasslands to increase their use by butterfly species by providing habitat for wildflowers (nectar sources).
A recent find of the groundwater-inhabiting copepod crustacean Diacyclops harryi extended the known range of this species far northwestward, to include northern Ohio and the drainage basin of the Laurentian Great Lakes. The species was previously collected in drainages of the Atlantic Slope from New York to North Carolina. Ostracodes tentatively identified as ?Nannocandona n. sp., and amphipods belonging to the subterranean species Bactrurus mucronatus were also found at the Ohio locality.