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In anticipation of the loss of Tsuga canadensis (Eastern Hemlock) dominated forests due to infestation by Adelges tsugae (Hemlock Woolly Adelgid), this study assessed the relative abundance of the ecologically important terrestrial salamander, Plethodon cinereus Green (Eastern Red-backed Salamander), in five Eastern Hemlock-dominated stands and four mixed deciduous stands at Harvard Forest in Petersham, MA. Pooling data from four seasons (fall 2003-fall 2004; excluding winter), the relative abundance of P. cinereus as measured by the monitoring of artificial cover objects (ACOs) was significantly higher in Eastern Hemlock-dominated stands than in mixed deciduous stands (n = 444 P. cinereus observations). The relative abundance of P. cinereus was not significantly different in the two forest types as measured by natural cover object (NCO) searches over two seasons (fall 2003 and spring 2004), although sample sizes were small (n = 45 P. cinereus observations). This evidence that Eastern Hemlock-dominated forests provide equal or greater quality habitat for P. cinereus as mixed deciduous forests at Harvard Forest contrasts with studies from other areas of Eastern Hemlock's range, which have found the abundance of P. cinereus to be lower in this forest type. The conversion of Eastern Hemlock-dominated forest to mixed deciduous forest will have either have a negative impact or no impact on the relative abundance of P. cinereus at Harvard Forest.
We examined the distribution of Plethodon cinereus (Red-backed Salamander) with respect to cover-object type in the Green Mountains of Vermont by exploring their distribution under cover objects relative to the total availability of cover objects on the forest floor. We conducted cover-object searches in sixteen 50-m transects in forest stands >50 years old to explore the distribution of large (>3.47 cm snout-vent length) and small (<3.47 cm snout-vent length) salamanders with respect to object material, size, and texture. There were more salamanders than would be expected by chance under rocks and fewer under woody objects (branches and logs). Salamander counts were higher than would be expected under large cover objects and lower under small ones. Our results also indicate that salamanders were more common than would be expected under fibrous woody objects and less common under solid ones. Finally, we found that large salamanders were more common than would be expected under rocks, while small salamanders were more common under woody objects. These results could have important implications for improving the recovery of salamanders following forest management applications.
Larger nektonic fishes, many of which are economically important, comprise a large portion of the biomass in estuaries and may influence energy flow through their migrations and feeding, yet we know relatively little of this faunal component. To elucidate the patterns of species composition, distribution, and abundance in Delaware Bay, we sampled (n = 2298 sets) nektonic fishes (n = 3693 individuals, mean length = 261.4 mm, range = 53–600 mm) with multi-mesh gill nets in near-shore bay and marsh creek habitats during the summer and fall (June-November 2001) when fishes are more abundant in temperate estuaries. For the most abundant species, the older and larger individuals (age 1 ) often dominated the catches. Patterns of assemblage structure were influenced by spatial gradients in salinity and dissolved oxygen and temporal changes in temperature. Many of the large nektonic fishes that dominate in Delaware Bay are also found in other temperate estuaries from the Gulf of Maine to Chesapeake Bay, in part, because these species are highly migratory.
Preserved specimens of the crayfish Cambarus bartonii, Orconectes limosus, and Orconectes virilis from 27 locations in New Brunswick, and O. limosus from Freshwater Lake, Cape Breton Highlands National Park, Cape Breton Island, NS, Canada, were examined for branchiobdellidans. Three species of branchiobdellidans—Bdellodrilus illuminatus, Cambarincola fallax, and Xironogiton instabilis—were identified on C. bartonii. Only branchiobdellidan cocoons were recorded on O. limosus, and only X. instabilis was recovered from O. virilis in New Brunswick. The introduction of O. limosus and O. virilis into New Brunswick does not appear to have simultaneously introduced non-native branchiobdellidans. No branchiobdellidans were found on introduced O. limosus from Freshwater Lake, NS. This work provides the first records of branchiobdellidans occurring in the Maritime Provinces of Canada, and establishes the eastern limit for these ectosymbionts in North America. In addition, one specimen of C. bartonii was found to have a total of 39 B. illuminatus in the branchial chambers, the largest infestation of this species yet recorded.
Accumulations of nuisance drift macroalgae along the open coast Atlantic beaches of the Cape Cod National Seashore have been observed on an anecdotal basis for over 50 years. This entire stretch of coastline is sandy, with no solid substrata for algal attachment. During the summer of 2006, we collected data on drift macroalgal accumulations repeatedly throughout this National Seashore. Peak biomass (consisting of several filamentous red species and green algae, primarily Ulva lactuca) was found in early August, mainly at the northernmost site. Our data, together with ocean current patterns and anecdotal evidence, suggest that macroalgae may originate in rocky shorelines of northern New England and are transported south by Gulf of Maine currents. Algae are most likely caught along the Cape Cod National Seashore shoreline by sand bars, particularly in the northern part of the shoreline.
Bryophytes are often noted for their growth on specific rock types and their value as indicator species. However, some evidence suggests that restriction of a species to specific rock types may be less rigid and could vary under different environmental conditions. We assessed richness and distribution patterns of bryophytes at 22 rock outcrop locations in upstate New York (NY) and coastal Maine (ACAD). At each location, detailed surveys were done in five replicate 5-m by 2-m plots on vertical rock faces. We report on the 194 bryophyte species found in these surveys and present detailed analyses for the 137 species that occurred at two or more of the 22 locations. In general, liverworts were less likely to be dominant within a plot than mosses. Within-site dominance and frequency of liverworts were less well correlated to larger-scale frequency (number of locations and regions of occurrence). In NY, although there was no significant difference in bryophyte richness by rock type, rare species were more often found on calcium-containing rock types. Rock type, soil influence, number of liverwort species, and region were significant correlates with bryophyte species composition patterns. The importance of rock type in explaining species composition patterns was still significant though weaker when ACAD locations were included in the analysis. This difference resulted from a higher prevalence of leafy liverwort species on calcium-containing rock types in ACAD. Our results present further evidence that apparent restrictions to specific rock types may shift depending on environmental conditions such as increased humidity and narrower temperature extremes that occur along the north Atlantic coast.
A survey was conducted in New Brunswick (NB) over 5 years (1996–2000), to assess the status of Quercus macrocarpa (Bur Oak). Bur Oak in NB is separated from the fringe of its contiguous native range by approximately 750 km. Historically, the species occurred throughout the lower Saint John River Valley and in the floodplains of the Grand Lake Complex. The range in NB has been reduced and fragmented, and now consists of a few small populations, along with scattered individuals, occupying a combined area of less than 5 km2. The most isolated of the small populations in NB is at least 40 km from the nearest seed or pollen source. Elements of a conservation strategy are presented, which include preservation of existing stands by government and non-government organizations, landowner education, and restoration planting in appropriate habitats.
Tsuga canadensis (Eastern Hemlock) is a common forest species that is declining throughout its range in the eastern United States because of the invasion of an exotic forest pest, Adelges tsugae (Hemlock Woolly Adelgid). This pest kills infected trees, and over time, infected stands are replaced by deciduous forests. The conversion of forests from hemlock to deciduous species is predicted to impact the hydrology, chemistry, and biology of associated headwater streams. In this study, we examined the macroinvertebrate communities of two adjacent headwater streams with differing hemlock influence in central Massachusetts. Abundance, taxa richness, diversity, and unique taxa were generally greater in the deciduous stream. Differences in the distribution of functional feeding groups were observed: the hemlock stream had a greater percentage of collector-gatherers while the deciduous stream had a greater percentage of shredders and predators. These findings suggest that macroinvertebrate communities in streams draining hemlock and deciduous watersheds may differ in structure and function, and that anticipated hemlock mortality may impact the region's stream ecology.
Stenamma diecki is a small ant with a widespread distribution. Systematic plot excavations in two locations have allowed us to collect data on a large number of S. diecki nests in order to examine seasonal and spatial differences in nest demography and allocation decisions within this species. Populations of this species from New York and Vermont nest in cavities far more commonly than has been reported, and thus we could compare our results with data on this species and with patterns of demography and reproduction for two other well-studied cavity-dwelling ants. We found nests were monogynous at all locations, but showed considerable variation in mean queen number and mean worker number. Most nests did not produce any males or reproductive females in a season, and this pattern was also site specific. Sexual and reproductive allocation was similar for all sites tested. Finally, demographic patterns within a site over 3 seasons are consistent with those predicted by seasonal polydomy.
We report several cases in which Gordionus lineatus (Horsehair Worm) (Nematomorpha) parasitizes the diplopod Cambala annulata (Myriapoda, Diplopoda) in Ohio. Diplopods as host for nematomorphs in North America have previously only briefly been mentioned. This report is the first host record for a Nearctic Gordionus species. Gordionus lineatus is also a new record for Ohio. Though the sample size is small, the prevalence may be high (50%). Myriapods appear to survive the parasitization. As Cambala annulata is likely to be herbivorous, pathways of infection with nematomorphs are discussed.
The distribution and status of the bats of Prince Edward Island (PEI) is largely unknown. We addressed this information gap by compiling records from museums and published documents, and surveying for bats with traps and ultrasonic detectors during the summers of 2004 and 2005. Myotis lucifugus (Little Brown Bat) and M. septentrionalis (Northern Long-eared Bat) were the most abundant and widespread species of bats on the island. These species form maternity colonies, but the potential for there to be large natural hibernacula on the island is considered low. Lasiurus cinereus (Hoary Bat) is the only other species of bat that has been recorded on PEI, but its occurrence is rare. Diversity and abundance of bats on PEI may be limited by its northern insular geography, patchy distribution of forested areas, and lack of hibernacula. These limitations make protecting such resources on PEI and in neighboring provinces important for conserving the region's bat fauna.
Surveys of dragonfly exuviae have been used to assess rare species' habitats, lake water quality status, and wetland restoration programs. Knowledge of the persistence of exuviae on various substrates is necessary to accurately interpret exuvial surveys. In 2006, we recorded exuvial persistence at defined areas in a variety of small freshwater wetlands in Rhode Island. Exuviae were field-identified, labeled with small daubs of nail polish, and observed every three weeks from June through September. Overall, exuvial persistence displayed exponential decline, disappearing rapidly during the first few weeks, and more slowly thereafter. The initial rate of decline was similar for most species, but differed in some taxa. There was no significant difference in exuvial retention on emergent vegetation vs. rock substrate.
Few data are available that describe the roosting and foraging ecology of the Hoary Bat (Lasiurus cinereus), and no such data are available for the northeastern United States. We captured a juvenile Hoary Bat in south-central New Hampshire during July of 2007 and monitored its roosting behavior for ten days and its foraging behavior for one night. The bat roosted with two other bats, which we presumed were its mother and sibling. These bats roosted exclusively in Tsuga canadensis (Eastern Hemlock Tree) and tended to roost near tree tops in the forest canopy. The radiotagged bat used at least six roost trees and changed roost location eight times during the ten-day observation period. Although roost-tree fidelity was low, all roost trees were located within a maximum circular area of 0.5 ha. The bat foraged over an estimated 156-ha area of mostly forest habitat (68%), with additional open habitats (15%) and wetlands (17%). These data are the first observations of roosting and foraging behaviors by the Hoary Bat in the northeastern region of its geographic range.
We used remote cameras to detect Lynx canadensis (Canada Lynx) in northern Maine during July-October 2005. A total of 1680 animal images was collected in 2512 camera-days of effort. Forty-five lynx detections were recorded, at a detection rate of 2 animals/100 camera-days of effort. Our analysis provides baseline detection rates for lynx in northern Maine and recommendations regarding survey design for other biologists. We suggest remote cameras are useful to survey lynx occurrence in an occupancy-estimation and -modeling framework, and in areas where snow-tracking surveys are not practical.