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Northern (Glaucomys sabrinus) and southern (G. volans) flying squirrels occur in Maine, but there is uncertainty about range overlap in southcentral Maine where the southern flying squirrel reaches its geographic range limit. We surveyed flying squirrels on Mount Desert Island (MDI), located along the central Maine coast, to update the current status and distribution of these species. We captured only northern flying squirrels, and populations (≥ 2 individuals) were located in two conifer stands and one mixed conifer-hardwood stand. All three stands were located in relatively older forests, outside a large area burned in a 1947 fire. Tree diameters were similar between trap stations with and without captures, understory density was low overall, and there was a trend of higher seedling density at capture locations. Low understory density may allow squirrels more effective gliding movements between trees, which may enhance predator avoidance. Although the southern flying squirrel was reported from MDl numerous times during the 20thcentury, no voucher specimens exist, and species identification and localities have been poorly documented. Future surveys on MDl should consider collection of voucher specimens to validate subsequent survey efforts and effectively document changes in local biodiversity.
Vernal ponds are important aquatic habitat for many species of amphibians and invertebrates. While many aspects of such ponds have been investigated, small mammal populations in the adjacent upland [catchment] habitat are largely unstudied. We selected three ponds in central Massachusetts to determine whether the presence of vernal ponds in forested habitat influences shrew species composition and abundance. Pitfall-trap arrays were installed in pond catchment basins and in adjacent upland forest habitat. A total of 2124 small mammals of nine species were captured during 3880 trap nights. Of these, 341 were shrews of three species. We found no significant differences in abundance between pond-side and upland habitat for any shrew species. In addition, no differences were found in structural and vegetation characteristics between habitats. While there may be some indication that vernal ponds provide some residual effects during dry periods, vernal ponds in the northeastern United States are small and highly variable in hydroperiod, apparently providing an unreliable resource for shrews.
There is considerable evidence that the Blackpoll Warbler (Dendroica striata) undertakes a non-stop, transoceanic, fall migration from New England and Atlantic Canada to South America. However, this unique migration strategy is not yet clearly understood. Based on flight range estimates, Blackpoll Warblers must require large amounts of fat for this flight. I captured Blackpoll Warblers during fall migration on Bon Portage Island, a small island off southern Nova Scotia, to determine if Blackpoll Warblers either arrive with, or remain on the island and deposit, the large fat reserves necessary for their migration. Most Blackpoll Warblers did not arrive at Bon Portage with sufficient fat reserves to complete transoceanic migration from Nova Scotia to South America. Furthermore, although young Blackpoll Warblers did show moderate rates of diurnal fat deposition while on Bon Portage, most did not remain long enough to accumulate the necessary fat reserves for transoceanic migration. I conclude then, that Bon Portage Island is not one of the final sites for Blackpoll fat deposition, and I discuss several possible explanations for these results.
A wild population of Loesel's twayblade, Liparis loeselii (L.) Richard (Orchidaceae), in Franklin County, Massachusetts, was studied from 1993 to 1999. Mortality in one subpopulation was 97% over a five year interval, but population size declined only 52% in the same period, suggesting that recruitment, rather than longevity of individuals, is an important factor in maintenance of the population. Mean leaf length, height, and number of flowers increased over the duration of the study, perhaps due to competition. Individuals with flowers and fruit in one year were more likely to produce flowers and fruit in the following year than those without flowers or fruit. Herbivore activity appeared to strongly influence survivorship. The decline of this species in many parts of its North American range may be a result of both habitat destruction and reforestation since the decline of agriculture in the 19th century.
During 1993 and 1994 an extensive qualitative survey was conducted on the unionid community in Patterson Creek, an Atlantic slope stream in Grant and Mineral counties, West Virginia. The primary purpose of this survey was to determine the status of two federal species of concern. Unionids were found at 17 of the 23 sites surveyed and represented eight species. The number of taxa per site ranged from 0 to 6. The taxon listed as Lampsilis spp. may represent either the native L. cariosa, the introduced L. cardium, or both with possible intergrades. Lampsilis spp. were observed alive at 11 sites, and empty shells were found at an additional six sites. Alasmidonta varicosa (federal species of concern) was found alive at 12 of the 23 sites and shell material at an additional two sites. Specimens of A. varicosa ranged from 25.1 mm to 80.2 mm in length, and appeared to represent a healthy reproducing population. Only one valve of Lasmigona subviridis (federal species of concern) was observed in Patterson Creek during this survey. Other species found during this survey included Alasmidonta undulata, Elliptio complanata, E. fisheriana, and Strophitus undulatus. Although many impacts were evident throughout the watershed (i.e., cattle access to the stream, streambank degradation, lack of riparian canopy, storm-water runoff, poultry farming, and increased urbanization) this stream has a relatively diverse unionid fauna. Knowing what still remains in Patterson Creek today, we can only speculate, due to the lack of historical data, that this stream must have once been home to a diverse and abundant unionid fauna.
We present distributional maps and discuss native status for fish species characteristic of coldwater lakes, sampled from 203 randomly selected lakes in the northeastern USA (New England, New York, New Jersey). Eleven coldwater fish species from four families (Salmonidae, Osmeridae, Gadidae, Cottidae) were collected during the summers of 1991 to 1996 by the Environmental Monitoring and Assessment Program (EMAP). The most widespread species were brook trout and rainbow smelt, collected at 23% and 18% of the sampled lakes, respectively. Stocked (put-and-take) rainbow trout occurred at 10% of the lakes, while the remaining fish species (brown trout, landlocked Atlantic salmon, lake trout, Arctic char, lake whitefish, cisco, burbot, slimy sculpin) were collected at less than 6% of the lakes. We also provide comparative data on physical (surface area, depth, elevation), chemical (pH and total phosphorus), and watershed characteristics of the lakes where these species were collected.
Two species of sculpins (Cottidae), the grubby, Myoxocephalus aenaeus, and the shorthorn sculpin, M. scorpius, were studied in rocky tidepools along the coast of Maine. Fishes were captured and measured during 116 sampling trips between 1979 and 1996. Both of these species of sculpins are from the northwestern Atlantic Ocean and are present in tidepools nearly every month of the year and are the only fish species found in Maine tidepools during winter. Both sculpin species are important components of tidepool ecosystems and dominate the rocky tidepool fish communities from late autumn to early spring, a time when other fish species decline in abundance or are absent. There was no apparent relationship between sculpin abundance and salinity, but the two species of Myoxocephalus were encountered in water temperatures of 1.5 to 18.9°C, with 55.0% of the shorthorn sculpins and 57.3% of the grubbies encountered in tidepools where water temperatures ranged from 12 to 15°C. Between 1988 and 1996, 102 individuals from both species were marked. Of these, 21.3% were recaptured, some repeatedly in the same tidepools and even at specific locations within tidepools over successive tidal cycles—an indication of homing behavior.
An existing index of biotic integrity (IBI) for Vermont streams performed poorly in assessing coldwater streams with fewer than five species. A coldwater IBI (CWIBI) for these small streams was subsequently devised that effectively measures the integrity of fish assemblages containing two to four species. Fourteen candidate metrics were tested on eighteen least-disturbed stream sites and eleven degraded sites. Impacts to streams that were assessed included mostly physical habitat degradation with some experiencing acid mine drainage. Metrics were evaluated for sensitivity to impact and redundancy. Six were selected for final inclusion into the CWIBI. In composite, the metrics clearly reflected the widely observed shift from brook trout and slimy sculpin-dominated assemblages in least-degraded streams, to minnow-sucker based assemblages with increasing degradation.
A lake bioassessment integrity index (LBII) derived from 12 macroinvertebrate metrics was used to evaluate the biological integrity of 19 lakes in five New England States (Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont). Of the 19 lakes classified according to temperature and size (warm, small; warm, large; cold, small; cold, large), 15 lakes had anthropogenic disturbances (including residential, agricultural, silvercultural, and fish stocking), and one minimally disturbed reference lake was selected from each category. The bioassessment index successfully ranked the biological integrity for 17 of the 19 lakes. Index scores of anthropogenically disturbed lakes were significantly higher (P <0.05) than index scores of reference lakes with little disturbance in each temperature and size category, indicating that the index may be useful in separating impacted from non-impacted lakes in the New England States.