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This classification Maine's freshwater organic wetlands (peatlands) uses nutrient source, geomorphic-hydrologic setting, gross topography of the peat mass, microtopographic pattern, and presence of pools for distinguishing peatland types. We apply these primarily hydro-geomorphological criteria to landscape units called peatland complexes. Vegetation, while important at lower levels of classification and for the description of individual peatlands, is not used in this classification because, typically, all but the smallest peatland complexes in Maine have major areas of differing vegetational physiognomies and types. This classification resembles the peatland division of Canada's current wetland classification more than the classification in most common use in the United States because a large percentage of Maine peatlands are northern in character. Our classification contains eight peatland types. Two of these are divided into two subtypes. Only one of the types has unique floristic and vegetational elements: plateau (coastal) bog. Large Maine peatlands typically contain multiple complexes, commonly of more than one type. We use the term multiple-unit peatland for these multiple complexes.
Our classification and survey of the distribution of peatland types in Maine is based on a large representative sample of peatlands. We conducted an air photo survey of ∼1100 peatlands throughout the state, observed a representative subset of 171 of these from aircraft at low altitude, and studied a representative subset of 100 of the 171 on the ground. However, to classify a peatland using our system, only air photo study or aerial observation is needed.
The distribution of peatland types in Maine is controlled by gradients of topography, geological substrate, climate, and hydrology. Peatlands are least abundant in the well-drained western uplands. Unpatterned fens occur throughout Maine; hundreds of the smaller ones (∼<10 ha) occur in ice-block depressions (kettles). Five types, all of which also occur in Canada, reach their eastern North American southern limits in Maine: ribbed (string) fens at 45°∼30′N, eccentric bogs at 45°∼10′N, domed bogs with concentric pattern at 44°∼45′N, plateau bogs at 44°∼15′N, and gently convex bogs at 43°∼20′N. These latitudinal limits exclude individual southern outliers). Distributions of peatland types in adjacent areas of New Hampshire and Canada are consistent with those in Maine. We propose that the geographic position of Maine along a steep south (coastal) to north (inland) climatic gradient and a less-steep west-southwest to east-northeast climatic gradient paralleling the coast are the major factors accounting for the diverse representation of peatland types in so limited an area.
We report the results of all readily available inventories of wintering bats in Vermont. Surveys at 23 hibernacula were compiled from the literature and unpublished data of numerous biologists and cavers. The earliest Vermont records date back to 1934. Only five hibernacula were systematically surveyed for more than 45 years. Despite data limitations, several trends have emerged. Since the 1930s, wintering populations of Myotis sodalis have dramatically declined; wintering populations of M. lucifugus have increased; and wintering populations of all other Vermont species (M. leibii, M. septentrionalis, Eptesicus fuscus, and Pipistrellus subflavus) have remained small.
Intertidal distribution, habitat, and diet of the recently introduced western Pacific shore crab Hemigrapsus sanguineus (De Haan) were studied in southern New England. H. sanguineus was found in rocky intertidal coastal and estuarine environments, in salinities as low as 24 ppt. H. sanguineus was more abundant in lower and middle than in upper intertidal elevations, and abundance increased with rock cover. Gut contents of H. sanguineus included a variety of food items, particularly crustacean remains, algae, and vascular plants, indicating an omnivorous diet. H. sanguineus abundances and sizes at different sites suggested a trend of northward expansion of its range.
Crayfishes from 81 sites in New England yielded six species of branchiobdellidans — Bdellodrilus illuminatus, Cambarincola fallax, C. mesochoreus, C. philadelphicus, Pterodrilus missouriensis, and Xironogiton instabilis. This is the first report of the distribution of branchiobdellidans across the region. The Royal Ontario Museum, Toronto, Ontario, Canada, supplied branchiobdellidans, subsequently identified as C. mesochoreus, that had been removed from the gills of preserved marine crabs, Cancer borealis and Callinectes sp., reportedly collected from the Gulf of Maine, USA. Over 100 specimens of Hyas araneus, Cancer irroratus, C. borealis, and Carcinus maenas were collected at irregular intervals since 1978 from the coasts of northern Massachusetts, and Damariscotta estuary, Maine, USA and St. Andrews, New Brunswick, Canada, in an unsuccessful attempt to find a marine branchiobdellidan.
Orconectes neglectus, a crayfish native to the Mississippi River drainage in Arkansas, Oklahoma, Missouri, and Kansas, is reported from streams in southeastern New York for the first time. This species is the newest component of a crayfish fauna that is increasingly dominated by introduced species. Individuals of this species were collected in 1997–1999. First and second form males and females ranged in size from 7.5–40.9 mm carapace length. Ovigerous females were collected in May 1999. These data demonstrate that this species is established and reproducing in clear, rubble-bottom streams in southeastern New York. O. neglectus is readily identifiable by its distinctive coloration and color pattern; other characteristics of the rostrum, mandible, gonopod and annulus ventralis also are useful in distinguishing it from other species inhabiting northeastern North America. Currently, O. neglectus is known in the northeastern United States only from tributaries of the upper Croton River of the lower Hudson River drainage. We assume that it was introduced into the area accidentally.
Five species of epiphytes were found associated with the basidiocarps of the wood-rotting fungus, T. versicolor. Four algae were identified, Hormidium sp., Stichococcus bacillaris, Chlorococcum sp., and Trebouxia sp., as well as one species of bacteria, Azotobacter chroococcum. Azotobacter is a nitrogen-fixing bacterium often associated with lichens, and may be a significant source of nitrogen for T. versicolor. Trebouxia, a genus of lichenized algae that is rarely found free living, is the most common epiphyte. Ultrastructural investigation of the generative hyphae of the upper surface of the basidiocarp reveals the presence of concentric bodies, which are cellular organelles primarily found in lichens. The common occurrence of Trebouxia and Azotobacter as epiphytes, and the occurrence of concentric bodies, suggest that the basidiocarps of T. versicolor have the potential to be lichenized.
Abundance and habitat relationships of butterfly communities were examined at 15 sites divided into three different types of residential areas (n = 5 sites/type) in central Pennsylvania from May-September 1997. Seventeen species were noted at the 15 sites, with the two most abundant being non-native, cabbage whites (Pieris rapae, 69.2% of total) and orange sulfurs (Colias eurytheme, 10.0%). The most abundant native species was the monarch (Danaus plexippus, 7.5%). More butterfly species (n = 13 species) but a lower than expected number of individual butterflies of all species combined (P < 0.05) occurred in residential areas with established (homes > 30 years old) and native overstory trees than in the two other types of residential areas. Total species richness of butterflies was positively correlated with the number of homes per site (i.e., smaller lot size) (P < 0.05). On the other hand, the total number of butterflies of all species combined and the total number of cabbage whites were negatively correlated with the number of yards containing native overstory trees (P < 0.05). Compared to forested or agricultural landscapes in central Pennsylvania, the diversity and abundance of butterflies were relatively low in residential areas. In residential landscapes, however, a diverse butterfly community was characteristic of older, established neighborhoods characterized by smaller lot size and native overstory tree species. The planting of gardens containing both nectar sources and hostplants for butterflies will likely enhance their diversity and abundance in residential areas.