Joseph E. Duchamp

FORAGING HABITAT OF THE INDIANA BAT (MYOTIS SODALIS) AT AN URBAN-RURAL INTERFACE

Abstract We captured 11 Myotis sodalis and radiotracked them to foraging areas near Indianapolis International Airport during summer 2002. A series (3–7) of multiazimuth triangulations was used to obtain an estimate of the location of each bat throughout the night. Compositional analysis was used to compare habitat that bats used to available habitat at 2 spatial scales. At both spatial scales, bats preferentially used woodlands over other available habitats (especially developed habitats). These findings suggest that suburban development may negatively impact M. sodalis by limiting foraging options. Many conservation plans aimed at protecting bats exclusively target roosting sites. Although roost conservation should continue to be central in efforts to protect bats, available foraging habitat also should be considered.

Shifts in bat community structure related to evolved traits and features of human-altered landscapes

Population declines for many bat species are associated with rapid, human-induced ecosystem changes. In this context, the available species pool is determined in part by historical adaptation to the native ecosystem, but the resulting community structure may be determined principally by the ability of evolved traits to function in the novel context of a human-dominated ecosystem. To investigate the role of human disturbance as a determinant of bat communities, we surveyed assemblages and species occurrence rates in 27 agriculturally dominated landscapes exhibiting a gradient of human-induced forest fragmentation in Indiana, USA. We used multiple linear regression to explore the relationship of landscape environmental variables to species diversity. We then examined the relationship between community structure, evolved species traits and fragmentation conditions across a landscape using RLQ analysis. Overall, species diversity was positively related to the amount of forest and negatively correlated with amount of urban development in a landscape. We also observed a significant relationship between evolved species traits and landscape-level variables that is consistent with globally anticipated trends for bat species extinction risk. Our findings suggest that responses of bat species to human modification of ecosystems on the scale of a few kilometers could drive distributional dynamics at larger spatial and longer temporal scales.

Acoustic Identification of Bats in the Eastern United States: A Comparison of Parametric and Nonparametric Methods

ABSTRACT Ultrasonic detectors are widely used to survey bats in ecological studies. To evaluate efficacy of acoustic identification, we compiled a library of search phase calls from across the eastern United States using the Anabat system. The call library included 1,846 call sequences of 12 species recorded from 14 states. We determined accuracy rates using 3 parametric and 4 nonparametric classification functions for acoustic identification. The 2 most flexible classification functions also were the most accurate: neural networks (overall classification accuracy = 0.94) and mixture discriminant analysis incorporating an adaptive regression model (overall classification accuracy = 0.93). Flexible nonparametric methods offer substantial benefits when discriminating among closely related species and may preclude the need to group species with similar calls. We demonstrate that quantitative methods provide an effective technique to acoustically identify bats in the eastern United States with known accuracy rates.

Estimating Probabilities of Detection for Bat Echolocation Calls: An Application of the Double-Observer Method

Abstract Differential detectability is an issue of great practical importance in bat species (Order Chiroptera) surveys. Bat echolocation recorders increasingly are being used in survey efforts, but recorder-based surveys have not measured differences in detection probability quantitatively. A recently developed avian survey technique uses 2 observers at a site to estimate the probability of detection by comparing birds recorded independently by the 2 observers. We applied this method to bat surveys using remotely operated Anabat echolocation recorders. We placed 2 detectors at each sample point, which were randomly selected from forested habitat within 2 watersheds in Indiana and 2 in Missouri. The first detector was oriented toward the most open area of forest and the second was set 5 m away and oriented toward the most open area that allowed sampling of an area distinct from the first detector. We estimated detection probabilities using the Huggins closed-capture model in program MARK. We compared models of detection probability using the corrected quasi-likelihood Akaikes Information Criterion adjusted for overdispersion (QAICc). The best models accounted for detector placement and region but not species. Overall probability of detection for bats using 2 detectors was 0.62 in Indiana and 0.42 in Missouri. Results confirmed that a second detector increased the probability of detecting different species of bats at a site. Future regional comparisons should account for differences in detection probability to avoid biases associated with surveys relying solely on recorded calls.

Density and distribution of a colonizing front of the American black bear Ursus americanus

Abstract Effective management of small expanding populations is aided by the availability of reliable estimates of distribution, as well as by demographic characteristics such as population density, genetic diversity and sex ratio. The range of the black bear Ursus americanus in the southeastern United States is expanding to include areas from which it has been extirpated for more than a century. Lack of baseline demographic data in recently reoccupied areas leaves little information on which to base emerging management needs. We estimated the current extent of expansion at the colonizing front of a black bear population in the central Appalachian Mountains and identified landscape-scale habitat characteristics affecting the expansion. In 2007, we genotyped hair samples collected throughout a 8,205-km2 area at six microsatellite loci to identify individual black bears and estimate genetic diversity. We used capture-recapture and occupancy analyses to estimate density and distribution of black bears in our study area. Our results suggest that black bears were not uniformly distributed, but were localized to high elevations and protected public conservation lands. Limited availability of high elevations to the west, north and northeast of our study area may limit further expansion. Despite a limited distribution and low estimated population density (7.51 bears/100 km2), genetic diversity at genotyped loci was high (mean Ho = 0.81). Until the population grows further, the small number of individuals in the region may be sensitive to management practices that result in mortalities, especially to females. Our research exemplifies the utility of remote genetic sampling to estimate population demographics of wide-ranging mammals throughout a large study area, particularly where private land ownership hinders intensive study.

Exploring the “nutrient hot spot” hypothesis at trees used by bats

Abstract Temperate bat species are well-known predators of nocturnal insects; however, their role in forest nutrient cycling is unclear. We tested the “nutrient hot spot” hypothesis, which suggests that colonial bats should create nutrient peaks in and around their roosts via guano deposits. We measured the mass and nitrogen content of guano deposited outside of roosts occupied by maternal colonies of 2 tree-roosting species, Myotis septentrionalis and M. sodalis. We assessed whether these measures were related to date, species, and bat abundance using least-squares regression. We then compared the expected amount of nitrogen deposited over a maternity season to the expected annual amount of nitrogen mineralized by a forest. Mass of guano deposited increased with bat abundance and corresponded to periods of parturition and lactation. Nitrogen mineralization near a large roost of bats can be 380% of that due to decay of leaf litter. Such nutrient peaks could influence patterns of forest vegetation by impac...

DISTURBANCE OF ROOSTING BATS BY WOODPECKERS AND RACCOONS

Abstract Bats that inhabit dead or dying trees may interact with a wide variety of other animals that utilize this same habitat, including potential predators. Herein, we report two interactions between Indiana myotis (Myotis sodalis) and woodpeckers (Red-bellied Woodpeckers, Melanerpes carolinus; and Northern Flickers, Colaptes auratus). We also report attempts by common raccoons (Procyon lotor) to prey upon both Indiana myotis and evening bats (Nycticeius humeralis). These represent the first reported interactions between either woodpeckers or raccoons and tree-roosting bats of either species. If predators such as raccoons are superabundant in small forest fragments, then increased predation from these animals could be an important source of mortality for bats roosting within these habitats.

Do the Golden-winged Warbler and Blue-winged Warbler exhibit species-specific differences in their breeding habitat use?

We compared habitat features of Golden-winged Warbler (Vermivora chrysoptera) territories in the presence and absence of the Blue-winged Warbler (V. cyanoptera) on reclaimed coal mines in southeastern Kentucky, USA. Our objective was to determine whether there are species specific differences in habitat that can be manipulated to encourage population persistence of the Golden-winged Warbler. When compared with Blue-winged Warblers, Golden-winged Warblers established territories at higher elevations and with greater percentages of grass and canopy cover. Mean territory size (minimum convex polygon) was 1.3 ha (se = 0.1) for Golden-winged Warbler in absence of Blue-winged Warbler, 1.7 ha (se = 0.3) for Golden-winged Warbler coexisting with Blue-winged Warbler, and 2.1 ha (se = 0.3) for Bluewinged Warbler. Territory overlap occurred within and between species (18 of n = 73 territories, 24.7%). All Golden-winged and Blue-winged Warblers established territories that included an edge between reclaimed mine land and mature forest, as opposed to establishing territories in open grassland/shrubland habitat. The mean distance territories extended from a forest edge was 28.0 m (se = 3.8) for Golden-winged Warbler in absence of Blue-winged Warbler, 44.7 m (se = 5.7) for Golden-winged Warbler coexisting with Blue-winged Warbler, and 33.1 m (se = 6.1) for Blue-winged Warbler. Neither territory size nor distances to forest edges differed significantly between Golden-winged Warbler in presence or absence of Bluewinged Warbler. According to Monte Carlo analyses, orchardgrass (Dactylis glomerata), green ash (Fraxinus pennsylvanica) seedlings and saplings, and black locust (Robinia pseudoacacia) saplings were indicative of sites with only Golden-winged Warblers. Sericea lespedeza, goldenrod (Solidago spp.), clematis vine (Clematis spp.), and blackberry (Rubus spp.) were indicative of sites where both species occurred. Our findings complement recent genetic studies and add another factor for examining Goldenwinged Warbler population decline. Further, information from our study will aid land managers in manipulating habitat for the Golden-winged Warbler. RESUME. Nous avons compare les caracteristiques de l’habitat dans des territoires de Paruline a ailes dorees (Vermivora chrysoptera) avec ou sans la presence de la Paruline a ailes bleues (V. cyanoptera) sur des terrains restaures a la suite de l’exploitation du charbon dans le sud-est du Kentucky (E-U). Notre objectif etait de determiner s’il existe des differences d’habitat propres a chacune de ces especes qui permettraient un amenagement visant a favoriser la persistance de la Paruline a ailes dorees. Comparee a la Paruline a ailes bleues, la Paruline a ailes dorees etablit des territoires a des altitudes plus elevees qui sont caracterises par un recouvrement superieur des strates herbacee et arborescente. La superficie moyenne des territoires (polygone minimum convexe) etait de 1,3 ha (erreur type = 0,1) pour la Paruline a ailes Kentucky Department of Fish and Wildlife Resources, Indiana University of Pennsylvania, University of Kentucky Avian Conservation and Ecology 5(2): 2 http://www.ace-eco.org/vol5/iss2/art2/ dorees en l’absence de la Paruline a ailes bleues; 1,7 ha (erreur type = 0,3) pour la Paruline a ailes dorees en sympatrie avec la Paruline a ailes bleues; et 2,1 ha (erreur type = 0,3) pour la Paruline a ailes bleues. Des recoupements de territoires ont ete observes pour une meme espece et entre les deux especes (18 de 73 territoires, soit 24,7 %). Toutes les parulines a ailes dorees et a ailes bleues ont defendu des territoires incluant une interface entre la zone miniere restauree et la foret mature plutot que d’etablir leur territoire en plein dans les prairies ou arbustaies. La distance moyenne des bordures de territoires par rapport a l’interface la plus proche etait de 28,0 m (erreur type = 3,8) pour la Paruline a ailes dorees en l’absence de la Paruline a ailes bleues, 44,7 (erreur type = 5,7) pour la Paruline a ailes dorees en sympatrie avec la Paruline a ailes bleues et 33,1 m (erreur type = 6,1) pour la Paruline a ailes bleues. Ni la dimension des territoires ni la distance a la foret n’etaient significativement differentes entre la Paruline a ailes dorees avec ou sans la presence de la Paruline a ailes bleues. D’apres des simulations de Monte-Carlo, le dactyle pelotonne (Dactylis glomerata), les semis et gaulis de frene rouge (Fraxinus pennsylvanica), ainsi que les gaulis de robinier faux-acacia (Robinia pseudoacacia) etaient des indicateurs de sites occupes uniquement par la Paruline a ailes dorees. Sericea lespedeza, tandis que les verges d’or (Solidago spp.), les clematites (Clematis spp.) et les muriers (Rubus spp.) etaient des indicateurs de sites ou les deux especes de paruline etaient presentes. Nos resultats viennent completer des etudes genetiques recentes et suggerent un facteur supplementaire a etudier afin de determiner les causes de la diminution des effectifs de Paruline a ailes dorees. De plus, nos travaux aideront les gestionnaires de territoires a amenager l’habitat en faveur de la Paruline a ailes dorees.

Survival and cause-specific mortality of elk Cervus canadensis calves in a predator rich environment

Abstract Quantification of basic demographic parameters such as survival rates and cause-specific mortality is important for effective species management. We conducted a 4-year study (during May 2005-June 2009) of elk Cervus canadensis calf survival and cause-specific mortality in Pennsylvania, USA. We captured and radio-collared 93 elk calves ≤ 7 days old and monitored them weekly to detect mortality and cause of death. Of the 93 radio-collared elk calves, 15 (16%) died during our study. Despite high black bear Ursus americanus and coyote Canis latrans densities, none of the mortalities were the result of predation. Causes of death included poaching (N = 3), legal harvest (N = 2), road kill (N = 2), pneumonia (N = 1) and rumen acidosis (N = 1). We were unable to determine the cause of mortality for six of the elk calves; however, predation was eliminated as a possible source of mortality in all unknown cases. Survival probabilities were similar between sexes and among years. Summer survival (birth-31 October) was 0.92 (SE = 0.03, N = 93) and winter survival (1 November - 1 April) was 0.90 (SE = 0.04, N = 79). Annual estimated elk calf survival was 0.82 (SE = 0.04, N = 93). Our findings suggest that Pennsylvania elk calves have a > 80% chance of survival to one-year of age, despite high densities of predators known to influence elk calf survival elsewhere. The high calf survival rates that we observed indicate the availability of high quality habitat leading to excellent physical condition of elk.

Habitat Patch Use by Fishers in the Deciduous Forest-Dominated Landscape of the Central Appalachian Mountains, USA

Abstract Fishers (Pekania pennanti) are often associated with the coniferous and mixed forests of the northern United States and central Canada, and their ecology has been studied extensively in po...