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There are at least eight species of Impatiens (Jewelweeds) in the northeast, including native and non-native species, species of temperate and subtropical origins, and wild and planted species. The two native jewelweeds, I. capensis and I. pallida, are common in the region, and I. capensis has been introduced in Europe. Impatiens glandulifera is a non-native species that is locally well established and has the potential to become invasive in the region. The introduced I. balfourii and I. parviflora infrequently naturalize in the Northeast. Three Impatiens species of tropical origins, I. balsamina, I. walleriana, and I. hawkeri, may be able to establish in the Northeast with continued horticultural pressure. We review the descriptions and known distributions of these species, the direct experimental comparisons of their biological traits, and the histories of their introductions and horticultural uses. Such information is beneficial for assessing the invasive potential of these species in the northeast and abroad, and may help to set priorities for control efforts and regulation of horticultural uses.
Nymphaea odorata (American white water lily) is an aquatic plant that displays pronounced heterophylly, the appearance of different leaf forms on a single plant. Water lilies produce leaves that either float or are held above the water's surface. In this paper, we describe the natural history of water lily leaf forms and examine some of the factors that stimulate heterophylly. Over the course of a growing season, the predominant leaf form switches from surface leaves in the early season to aerial leaves in the midseason and then back to surface leaves at season's end. While many factors are known to contribute to heterophylly, our results suggest that changes in the light environment may be the controlling factor in this system.
Benthic algal assemblages were surveyed in five Pennsylvania streams in order to examine trends in biomass and taxonomic groups along an acidification gradient. Acidification severity of each stream was estimated from total dissolved aluminum (AlTD), and discharge regression equations were established for each stream using historic data from the EPA Episodic Response Program. Benthic algae were sampled once after an acidic episode in April and again during August base flows. Chlorophyll decreased with increasing episodic severity in April, thus acid episode severity and associated aluminum toxicity may have influenced algal biomass. Cyanophyta biovolume decreased with increasing severity, while Bacillariophyta, Chlorophyta, and Rhodophyta showed no distinct patterns. A diatom, Eunotia exigua, exhibited a parabolic response in April over the AlTD gradient. Episodic acidification severity may influence algal biomass and composition in streams.
Little is known about the distribution and ecology of intertidal oysters in northeastern North America. North of Chesapeake Bay, intertidal oysters have either been previously reported as non-existent or only occurring as single oysters or sparse clusters. In the present study, we report the occurrence of dense populations of inter-tidal oysters at several estuarine sites within New Hampshire and mid-coastal Maine, with these growing under dense canopies of the long-lived Ascophyllum nodosum (fucoid alga). The densities of these northern intertidal oysters rival subtidal populations in the same geography, and their sizes suggest a persistence of 5 or more years.
We analyzed 73 eels, collected in 2004 and 2005 above the head of tide in six Hudson River tributaries, for total PCBs, length, weight, age, and nitrogen stable isotope ratios (δ15N). Mean total PCB concentration (wet weight basis) was 0.23 ppm ± 0.08 (standard error), with a range of 0.008 to 5.4 ppm. A majority of eels (84%) had concentrations below 0.25 ppm, and only seven eels (10%) had concentrations exceeding 0.5 ppm. Those eels with higher PCB concentrations were 12 yr; there was a weak correlation of PCB concentration with δ15N and also with weight. Compared to recent (2003) data from the mainstem of the Hudson River estuary, these results indicate that tributaries are generally much less contaminated with PCBs. We hypothesize that those tributary eels with high PCB concentrations were relatively recent immigrants from the mainstem. Given concern over the possible adverse effects of PCBs on eel reproduction, these tributaries may serve as refugia. Therefore, providing improved access to upland tributaries may be critically important to this species.
To determine how Tsuga canadensis (eastern hemlock) decline caused by Adelges tsugae (hemlock woolly adelgid) affects bird communities in Pennsylvania, we surveyed breeding birds in hemlock and forested non-hemlock habitats in 2003 and 2004 at Fort Indiantown Gap, PA and monitored nesting Empidonax virescens (Acadian Flycatcher), a hemlock specialist in Pennsylvania. Of the nine species more abundant in hemlocks than other forested habitats, only two, the Acadian Flycatcher and Dendroica virens (Black-throated Green Warbler), were positively associated with living hemlocks. Contopus virens (Eastern Wood-pewee), Myiarchus crinitus (Great-crested Flycatcher), and Hylocichla mustelina (Wood Thrush) were negatively associated with the amount of living hemlocks and were apparently benefiting from the increased number of dead trees and canopy gaps associated with the adelgid infestation. Acadian Flycatcher nest sites had more living hemlocks and were less impacted by adelgid than random sites. Nest success did not differ by habitat variables. Initially, hemlock decline will negatively impact hemlock specialists while providing habitat for opportunistic species. Some specialist species might persist by shifting habitats, but long-term studies are needed.
American Woodcock singing-ground surveys (SGS) have been conducted annually on Fort Drum Military Installation since 1992 (excluding 1993 and 2000). These SGS indicate Fort Drum has a stable to slightly increasing breeding woodcock population, with average numbers of males heard per route ranging between 13.00 and 22.58 birds. These numbers are significantly higher, and in stark contrast, to many parts of the American Woodcock's range, where numbers have been in decline for over 30 years. We suggest that current forest management practices and military training create favorable successional regimes that satisfy all necessary life-history requirements and help sustain these densities of breeding woodcock at Fort Drum.
To evaluate trap success among camera types and across species as well as assess habitat selection by target carnivore species, we established 16 infrared-triggered camera stations across a 26.9-km2 study area located on primarily Jefferson National Forest land in Virginia. We monitored camera stations for 72 days (August to October 2005) for a total of 891 trap nights (TN) of effort. Overall trap success for all animals combined was 40.74 captures per 100 TN. Procyon lotor (raccoon) had the highest predator trap success (2.81/100 TN), followed by: Ursus americanus (black bear, 1.91/100 TN); Lynx rufus (bobcat, 1.46/100 TN); Canis latrans (coyote, 1.01/100 TN); and Urocyon cinereoargenteus (gray fox, 0.56/100 TN). Odocoileus virginianus (white-tailed deer) had the highest overall trap success (21.32/100 TN), followed by Sciurus carolinensis (gray squirrel, 6.17/100 TN). Passive camera units, especially DeerCam, had higher trap success than active camera units, and digital camera units (Reconyx) out-performed film cameras. We extracted percent cover of habitat features (% coniferous, % deciduous, % water, % agricultural) from a geographic information system (GIS) using circular buffers around each trap site and compared carnivore-present sites to carnivore-absent sites. We compared carnivore trap success to the distance to the main access road and to trap success of prey species, primarily deer and gray squirrel. We also compared each carnivore's trap success to that of the other carnivore species to determine if carnivore presence or activity levels influenced other carnivores. Black bear, coyote, and raccoon tended to avoid areas with a high percentage of coniferous forest, and only bobcat showed significant avoidance of coniferous forest. Bobcat trap success increased with distance to the main road, and coyote trap success was positively (but weakly) related to gray squirrel trap success. Human foot traffic did not affect carnivore trap success. This study elucidates differences among camera trap systems, and highlights the potential to monitor carnivore species simultaneously and in combination with a GIS to predict occurrence across a landscape.
Using results from a three-year mist-netting survey of bats in Michigan, we examined effects of three aspects of netting protocols on number of bats caught, relative abundance of species, species diversity, and species evenness. Netting for a second consecutive night at the same location led to a 40% reduction in number of bats captured, although relative abundance, diversity, and evenness were not affected. Proportionately fewer bats were caught during the 5th h after sunset compared with the first 4 h in a night; however, diversity and evenness were greater in the 5th h compared with the first 4 h. Diversity, evenness, and number of bats captured in nets set over wooded areas on land did not differ from nets set over water, but relative abundance differed between habitats. Even slight variations in netting protocols can lead to quantitative differences in the description of a local assemblage of bats.
Standardized mist-netting protocols set guidelines regarding the best way to sample a bat species or community. We evaluated the current mist-netting guidelines designed to determine presence or absence of endangered, Myotis sodalis (Indiana bat). This test was conducted in Deer Ridge Conservation Area (Lewis County, northeastern Missouri), an area known to have an abundance of Indiana bats, including several primary maternity colonies. We mist-netted according to recommended guidelines for Indiana bats for two consecutive nights at three different times during the reproductive season. Anabat II detectors were used in conjunction with mist nets to sample bat activity at the same locations. Captures and detections of Indiana bats and other species of bats varied substantially among the sampling periods. In addition, there was a significant decrease in number of Indiana bats captured with mist nets from night one to night two, although activity levels remained the same. Finally, our data show that augmenting mist nets with ultrasonic detectors can enhance the probability of determining the presence or absence of Indiana bats.
We conducted a formal survey of small-mammal ectoparasite diversity in Iowa. We examined 166 small mammals and documented 54 species of parasitic arthropods present on 12 species of mammals. Ectoparasite species richness was greatest for Blarina brevicauda (northern short-tailed shrew), Microtus ochrogaster (prairie vole), Peromyscus maniculatus (deer mouse), and Peromyscus leucopus (white-footed mouse). Immature (larvae and nymphs) Dermacentor variabilis (American dog tick) were collected from P. leucopus, M. ochrogaster, Reithrodontomys megalotis (western harvest mouse), and Zapus hudsonius (meadow jumping mouse). The fleas Epitedia wenmanni and Orchopeas leucopus, potential vectors of sylvatic plague bacilli, were found on Mus musculus (house mouse), white-footed mouse, and deer mouse. We document 21 new ectoparasite host records for North America and 115 new host locality records for ectoparasites in Iowa.
We studied movement distances and home ranges of Blarina brevicauda (northern short-tailed shrew) for 25 years in bluegrass, alfalfa, and tallgrass habitats in east-central Illinois. Whereas habitat and season influenced movement distances, population density and apparent predation risk did not. Specifically, movement distances were larger in tallgrass than in either alfalfa or bluegrass, presumably because of lower food availability in tallgrass as compared to the other two habitats. Movement distances of both sexes were slightly larger during the breeding season than the non-breeding season, perhaps reflecting searching for mates (males) and increased energetic demands of reproduction (females). Home-range areas did not differ between alfalfa (236 m2) and bluegrass (252 m2); we could not obtain reliable estimates from tallgrass. These data add to the limited information available on movements and home-range areas of the northern short-tailed shrew.
We quantified relative extent of pelage staining in Scalopus aquaticus (eastern mole) as an indicator of scent-gland marking, and evaluated whether staining was associated with colored pelage spots and patches often prevalent on the snout and ventral surface of individuals. Moles were collected from southern Illinois (n = 91) and from Cincinnati, OH (n = 152). Adult moles scent-marked more than juveniles, but pelage staining was independent of breeding season for males and females. Pelage spotting occurred in 33.7% of the sample and was not associated with pelage staining from glandular secretions, as has been suggested by some previous investigators. Pelage spots were most prevalent on the ventral surface. Ventral spotting occurred more often in males than females (P < 0.001). Mean area of ventral spots was 2.81 cm2 with no differences in area related to sex or age.
Faunal remains from the Cole Gravel Pit archaeological site in Livingston County, NY, have been identified as Glyptemys (Clemmys) muhlenbergii (Bog Turtle). This is believed to be only the second prehistoric Holocene record of this species. Two Pleistocene records of Bog Turtle have also been previously reported. Based on archaeological remains, the human occupation of the Cole Gravel Pit site dates to approximately 3900 years B.P. and is associated with the Late Archaic Period. Cole Gravel Pit is in the general area of western New York state considered to be within the historic distribution of Bog Turtle, but modern live specimens of this species have not been discovered within Livingston County.