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Moose have recently re-colonized the temperate forests of southern New England, raising questions about this herbivore's effect on forest dynamics in the region. We quantified Moose foraging selectivity and intensity on tree species in relation to habitat features in central Massachusetts. Acer rubrum (Red Maple) and Tsnga canadensis (Eastern Hemlock) were disproportionately browsed; Pinus strobus (White Pine) was avoided. Foraging intensity correlated positively with elevation, distance to development, and watershed type and negatively with time since forest harvest, explaining 26% of the variation. Moose may interact with forest harvesting to contribute to a decline in Red Maple and Eastern Hemlock and an increase in White Pine in intensively browsed patches. Nonetheless, foraging impacts may diminish over time, as increasing temperatures and sprawling development increasingly restrict suitable Moose habitat.
Understanding predator-prey dynamics requires an understanding of how prey assess predation risk. This study tested the effect of microhabitat, moon stages, and mammalian predator urines (Vulpes vulpes [Red Fox], Mustela vison [Mink], and Procyon lotor [Raccoon]) on the degree of predation risk perceived by Peromyscus leucopus (White-footed Mouse). Giving-up densities from artificial food patches were used to quantify perceived predation risk. White-footed Mice exhibited a strong preference for cover microhabitat and for the new moon stage. However, the mice did not significantly alter their foraging behavior in response to the predator urines compared to a water control. Additionally, mice foraged less on colder nights. The results suggest that mammalian predator urines may not provide reliable information on actual predation risk for the White-footed Mice and that the mice extensively use indirect cues to assess predation risk.
The US Geological Survey conducted an urban land-use study in the New England Coastal Basins (NECB) area during 2001 to determine how urbanization relates to changes in the ecological condition of streams. Thirty sites were selected that differed in their level of watershed development (low to high). An urban intensity value was calculated for each site from 24 landscape variables. Together, these 30 values reppresented a gradient of urban intensity. Among various biological, chemical, and physical factors surveyed at each site, benthic invertebrate assemblages were sampled from stream riffles and also from multiple habitats along the length of the sampling reach. We use some of the NECB data to derive a four-variable urbanintensity index (NECB-UII), where each variable represents a distinct component of urbanization: increasing human presence, expanding infrastructure, landscape development, and riparian vegetation loss. Using the NECB-UII as a characterization of urbanization, we describe how landscape fragmentation occurs with urbanization and how changes in the invertebrate assemblages, represented by metrics of ecological condition, are related to urbanization. Metrics with a strong linear response included EPT taxa richness, percentage richness of non-insect taxa, and pollution-tolerance values. Additionally, we describe how these relations can help in estimating the expected condition of a stream for its level of urbanization, thereby establishing a baseline for evaluating possible affects from specific point-source stressors.
The plant community types on three tracts within the Burden Hill Forest, a distinctive outlier of the New Jersey Pine Barrens, are described and classified. While these tracts consist largely of a general pine barrens type, they display a number of significant differences from the main body of the Pine Barrens. These differences include additional forest plant community types previously undescribed for New Jersey, higher heterogeneity of community types and woody plant diversity, and the presence of several unusual or rare species including Castanea pumila (Allegheny Chinquapin).
Short peat cores from three sphagnum bogs in central Maine were analyzed palynologically to determine whether recent reforestation approximates forest composition immediately prior to European colonization and deforestation. Radiocarbon dating and palynology show that the cores extend to 600–2000 years b.p., beginning well before 18th-century colonial forest disturbance. Cores from Round Pond bog (Franklin County) and Kanokolus Bog (Waldo County) show that Tsuga canadensis (Eastern Hemlock) was much more abundant on the local landscape at the time of European settlement than it is today; a core from Hamilton Pond bog (Kennebec County) records an abrupt local Eastern Hemlock decline, and accompanying Acer spp. (maple) rise, that preceded European contact by several centuries. All three bogs show increased heath (Ericales) abundance with deforestation, presumably a result of augmented nutrient flux into the bog basins due to increased erosion on surrounding slopes.
Modern forest composition around all three sites is quite different from the forests immediately preceding European colonization and clearing. Pollen types indicative of agricultural activities (Ambrosia, other Asteraceae, Poaceae, Brassicaceae) that mark European deforestation and the onset of farming, have faded or disappeared as many farms have been allowed to revert to forest in the past half-century. Pine (mostly Pinus strobus [White Pine]) is more abundant in the modern pollen record than in subhistoric time, as are Abies spp. (fir) and Picea spp. (spruce); dominant hardwood taxa have responded differently to reforestation of the areas surrounding the study sites, in part determined by local edaphic conditions.
The objective of this paper is to examine the impacts of global climate change on Rhode Island's coastal ecosystems. Average annual air temperature in Rhode Island has increased by 1.7 °C since 1880, water temperatures of Narragansett Bay have increased by 1.2 °C since 1950, precipitation increased 27% between 1895 and 1999, and sea level rose 0.13 m between 1931 and 2007. We can already see the effects of these climatic changes on the Narragansett Bay ecosystem, including ecological changes in the Bay's food web from phytoplankton and Zooplankton to fish, e.g., changes in phenology of seasonal phytoplankton blooms and dominant fish species (e.g., Pseudopleuronectes americanus [Winter Flounder]). These climatic changes have increased freshwater inputs and the concomitant pollutant loads into the Bay. Rising sea level has contributed to ongoing erosion of the coast and has put waterfront homes at increased risk. It is imperative to continue monitoring these effects.
Palaemon macrodactylus (Oriental Shrimp), native to estuarine waters of Southeast Asia, has been reported outside of its native range. The spreading of this species to new regions has been well documented, and its disjunct distribution strongly speaks for its transport being attributed to ballast water. In this paper, we report the first record of P. macrodactylus from the eastern coast of the United States and in the estuarine system of New York City (NYC). While this animal has been reported to have crossed the Pacific, and has been found in the eastern Atlantic along the coasts of Spain, France, Germany, and the British Isles, and in the southwestern Atlantic off the coast of Argentina, it has not been previously sighted in the northwest Atlantic. Our preliminary life-history data indicate that the size range for the 98 adult individuals in the 2001 collection was from 2.05 to 5.05 cm, and exhibited a one-to-one sex ratio. The finding of gravid females among these shrimp collected from 2001–2002 and again in 2008 indicates that the oriental shrimp populations in the coastal waters of NYC have become established, and show reproductive activity from May through October. Further studies are required to evaluate whether P. macrodactylus poses a threat to native aquatic organisms in this region.
Salt marshes are frequently exposed to storm overwashes resulting in large deposits of sand and wrack at the margin of the high marsh and sand dune communities. On Cape Cod, MA, these disturbance-generated areas are dominated by burrows of the crab Uca pugilator and by nest entrances of the ants Formica subsericea and Tetramorium caespitum. We mimicked the effects of storm deposits through additions of sand and wrack and examined their effects on the distributions of the biotic structures of these organisms. We found that while crabs responded negatively to sand deposition, ants did so positively. We suggest that soil temperature and moisture explain these patterns. Wrack deposits extend higher the zone of moist soil and decrease evaporative stress for marine organisms such as crabs, whereas sandy areas tend to be drier and preferred by terrestrial ants. We conclude that disturbance type influences the distribution of these marine and terrestrial organisms over the ecotone.
This study presents prey records and nesting information for 13 species of spider wasps: Hemipepsis ustulata, Priocnessus nebulosus, and Priocnemis cornica (Tribe Pepsini); Auplopus architectus, A. caerulescens (Tribe Auplopodini); and Tachypompilus ferrugineus, T. unicolor, Anoplius (Pompilinus) marginatus complex, A. (P) splendens, A. (Anoplius) nigerrimus, A. (A.) virginiensis, Arachnospila arctus, and A. scelestus (Tribe Pompilini). Cumulative prey records for Priocnessus nebulosus, Tachypompilus ferrugineus, T. unicolor, and Arachnospila scelestus indicate limited prey selection. Cursorial hunting spiders were more susceptible to predation by the spider wasps than web-spinning spiders. Wasp nesting sites varied among natural and man-made microhabitats.
We monitored return rates of 324 color-banded Ammodramus savannarum (Grasshopper Sparrow), 138 Passerculus sandwichensis (Savannah Sparrow), and 49 Dolichonyx oryzivorus (Bobolink) on mowed and unmowed areas on a reclaimed surface mine during seven breeding seasons. We observed 61 returns among Grasshopper Sparrows, 40 returns among Savannah Sparrows, and 11 returns among Bobolinks. Grasshopper Sparrows and Savannah Sparrows returned to mowed and unmowed areas at about equal rates (21 vs. 18% and 26 vs. 31%, respectively), while Bobolinks returned to unmowed areas at a higher rate than mowed areas (28% vs. 17% respectively). When hatching-year birds were excluded, overall return rates increased slightly for Grasshopper Sparrows and Bobolinks (19 to 20% and 22 to 23%, respectively), but more substantially for Savannah Sparrows (from 29 to 36%). Sixteen of 51 returning Grasshopper Sparrows (31%), 12 of 27 Savannah Sparrows (44%), and 2 of 10 Bobolinks (20%) were observed during multiple years. These observations support previous findings that reclaimed surface mines provide suitable nesting habitat for these species. Early-season mowing did not appear to influence the return rates of Grasshopper Sparrows or Savannah Sparrows, although it may have influenced Bobolink returns.
Ammodramus savannarum (Grasshopper Sparrow) is a grassland passerine considered at risk in several regions of eastern USA and Canada. Detailed information is lacking on structure and breeding-habitat components for Grasshopper Sparrows in eastern Canada. We surveyed Grasshopper Sparrows in suitable habitats in southwestern Québec and described habitat characteristics to increase our knowledge of the species' breeding-habitat associations in eastern Canada. Grass-hopper Sparrows were detected in grass-dominated abandoned fields, pastureland, and hayfields generally located on poor sandy soil supporting low and sparse vegetation. Suitable sites with or without Grasshopper Sparrows did not differ in their structural components nor in their plant composition. Sites used by Grasshopper Sparrows were embedded within a perennial crop-dominated matrix where forest cover was reduced, and were larger than sites where they were absent. Conservation and stewardship activities should aim to secure large tracts of grasslands in southwestern Québec.
Two sympatric owl species, Tyto alba (Barn Owl) and Asio otus (Longeared Owl), are found in Lewisburg, PA. These species are of similar size, have similar hunting styles, and most likely use similar prey items. In studying the diets of these two owl species, we were able to determine their prey selection, the types and relative abundance of prey in the area, and how these sympatric predators may be partitioning their resources. A total of 80 pellets (40 from Barn Owls and 40 from Long-eared Owls) were analyzed to understand their diets. Pellets were collected from two locations in Lewisburg, PA approximately 2 km apart. Cranial and postcranial remains within the owl pellets were used to identify species by comparing them against our reference collections and keys. Typically, the Barn Owl is present in Lewisburg from late spring through fall and the Long-eared Owl from late fall through spring. Barn Owl pellets contained a greater number of larger-sized prey than Long-eared Owl pellets. Both owl species rely heavily upon rodents as their primary food source, which make up over 90% of their diets. Temporal differences and differences in prey selectivity are most likely the major factors allowing these species to share their common resources.
Several species of ducks defecate when flushed from their nests, but it is unclear why. Possibly, this behavior reflects manipulation by parasites to facilitate transmission. We analyzed feces of 32 incubating Somateria mollissima (Common Eider) for evidence of parasite transmission stages. We found a total of only 11 parasite transmission stages (identified as digenean and nematode eggs) in feces of 3 different hens, suggesting that defecation around the nest has a low probability of leading to parasite transmission. Other hypotheses for defecation behavior in this and other duck species (repulsion of egg predators, weight loss to increase hen maneuverability to escape predators) appear insufficient to explain its persistence.
Ponds in the White Mountains of Grafton and Coos Counties, NH provide some of the highest elevation breeding habitat for amphibian populations in the north-eastern United States. Between 2007 and 2009, we conducted field surveys of alpine ponds above 1100 m on the Presidential Range and Franconia Ridge in the White Mountain National Forest. These ponds include the only currently known amphibian breeding sites in tundra-dominated landscapes reported from the eastern United States. Four species of anuran and one species of salamander were detected at elevations ranging from 1180 to 1546 m, with direct evidence of breeding observed at every pond complex. This preliminary study contributes to available baseline data for amphibian populations in alpine and subalpine environments in the northeastern United States. Amphibian populations may be strong indicators of climate change and environmental stressors in alpine ecosystems; these populations appear to warrant long-term monitoring.
We provide positive documentation of multiple litters in a single year born to an individual Glaucomys sabrinus (Northern Flying Squirrel) residing in southern Ontario, Canada. The first litter, consisting of four young, was observed on May 18, 2003. The second litter, consisting of five young, was observed 15 weeks later on September 2, 2003. The individual female, identified by a unique ear-tag, established natal nests in different nearby nest boxes. Our finding suggests the Northern Flying Squirrel possesses greater population growth potential than previously thought.
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