bluuebunny/crossref_metadata_2025 huggingface dataset:
Microbial groundwater quality and its health implications for a border-strip irrigated dairy farm catchment, South Island, New Zealand
Authors: Close Murray , Dann Rod , Ball Andrew , Pirie Ruth , Savill Marion , Smith Zella
Published: November 2007

Intensification of dairying on irrigated pastures has led to concern over the microbial quality of shallow groundwater used for drinking purposes. The effects of intensive dairying and border-strip irrigation on the leaching of E. coli and Campylobacter to shallow groundwater were assessed over a three-year period in the Waikakahi catchment, Canterbury, New Zealand. Well selection excluded other sources of contamination so that the effect of dairying with border-strip irrigation could be assessed. Groundwater samples (135) were collected, mostly during the irrigation season, with E. coli being detected in 75% of samples. Campylobacter was identified in 16 samples (12%). A risk assessment of drinking water with these levels of Campylobacter was undertaken. A probability distribution was fitted to the observed Campylobacter data and the @RISK modeling software was used, assuming a dose response relationship for Campylobacter and consumption of 1 L/day of water. The probability of infection on any given day in the study area was estimated at 0.50% to 0.76%, giving an estimated probability of infection during the irrigation season of 60% to 75%. An epidemiological assessment of the Canterbury region comparing areas encompassing dairy within major irrigation schemes (∼55% border-strip irrigation) to two control groups was undertaken. Control group 1 (CG1) encompasses areas of dairying without major irrigation schemes, and a second larger control group (CG2) comprises the rest of the Canterbury region. Comparisons of the subject group to control groups indicated that there was a statistically significant increase in age-standardised rates of campylobacteriosis (CG1 Relative Risk (RR)=1.51 (95% CI = 1.31-1.75); CG2 RR = 1.51 (1.33–1.72)); cryptosporidiosis (CG1 RR = 2.08 (1.55–2.79); CG2 RR = 5.33 (4.12–6.90)); and salmonellosis (CG2 RR = 2.05 (1.55–2.71)).
Wetland Selection by Mallard Broods in Canada's Prairie‐Parklands
Authors: RAVEN GARNET H. , ARMSTRONG LLWELLYN M. , HOWERTER DAVID W. , ARNOLD TODD W.
Published: November 2007

ABSTRACT  Although brood survival has a pronounced effect on population growth in mallards (Anas platyrhynchos), knowledge of brood ecology is more limited than for other vital rates. During 1993–1997 we collected wetland selection data from 210 radiomarked mallard broods on 15 study areas located throughout the Canadian Prairie‐Parklands. We used information‐theoretic approaches to select the best‐approximating model of habitat selection in relation to wetland characteristics. Wetland permanence, cover type, width of flooded emergent vegetation, and interactions between these variables and date, moisture level, and dominant species of emergent vegetation were all important predictors of wetland selection. Mallard broods selected deeper wetlands, especially later in the brood‐rearing season. Mallard broods also selected wetlands with large central expanses of open water and wide peripheral zones of flooded emergent cover. These habitat characteristics can most easily be met in landscapes that already contain an abundance and diversity of natural wetland habitats. Where such wetlands are unavailable, restoration or management of deeper wetlands may be necessary to meet the habitat requirements of mallard ducklings.
Effects of Logging Pattern and Intensity on Squirrel Demography
Authors: HERBERS JIM , KLENNER WALT
Published: November 2007

ABSTRACT  We examined the effect of harvesting intensity and pattern on red squirrels (Tamiasciurus hudsonicus), northern flying squirrels (Glaucomys sabrinus), and yellow‐pine chipmunks (Tamias amoenus) in mature inland Douglas‐fir (Pseudotsuga menziesii glauca) forests in south‐central British Columbia, Canada. We sampled squirrels 1 year before harvesting through 4 years after harvesting and estimated population parameters using open‐population models. Relative to unharvested stands, each of the 3 species showed a strong response to tree removal. From 2 years to 4 years after logging, red squirrel density was 40% (SE = 7.1) lower in stands with 50% basal‐area tree removal. From 1 year and up to 4 years after logging, northern flying squirrel density averaged 60% (SE = 5.2) lower in harvested treatments regardless of intensity or pattern of logging. In contrast, density of yellow‐pine chipmunks increased markedly with increased logging intensity. Beginning 3 years after logging, yellow‐pine chipmunk density was 734% (SE = 269) greater in stands with 50% basal‐area tree removal. In the short term, harvesting intensity was a more important determinant of squirrel density than harvesting pattern. Retaining >10 m2 per ha of live residual stand structure in mature inland Douglas‐fir forests maintained habitat for forest‐dependent species such as red squirrels and northern flying squirrels, albeit at lower densities.
Landscape Use by Hairy Woodpeckers in Managed Forests of Northwestern Washington
Authors: RIPPER DANA , BEDNARZ JAMES C. , VARLAND DANIEL E.
Published: November 2007

ABSTRACT  The hairy woodpecker (Picoides villosus) is a keystone species in forest ecosystems of Washington, USA, providing nesting and roosting cavities for many species of wildlife. Therefore, management practices that promote healthy populations of this bird will help to conserve cavity‐nesting communities as a whole. The objective of this study was to determine patterns in forest type and landscape use by hairy woodpeckers, and thus, provide landscape‐level recommendations to forest managers. We documented the ranging patterns and habitat use of 23 hairy woodpeckers on the Olympic Peninsula using radiotelemetry and a Geographic Information System analysis. Use patterns of stand age, type, and size, as well as distance‐from‐edge analyses revealed that the hairy woodpecker is a relative generalist in its use of the managed forest landscape. However, certain features, such as older stands with large trees, were used more heavily by nesting pairs. Hairy woodpeckers used 61–80‐year forest stands significantly (P < 0.05) more than expected relative to their availability within the birds' home ranges. We also documented significant underuse of 6–10‐year and 11–20‐year stands, whereas the birds used 41–60‐year stands, >80‐year stands, and clear‐cuts (< 5 yr) equivalent to their availability. We suggest that hairy woodpeckers select older stands with larger, dying trees for foraging, but also use clear‐cuts proportionally due to the residual snags, decaying trees, and remnant dead wood available. Higher use (P < 0.001) by hairy woodpeckers of small forest patches (0–5 ha) and intermediate‐sized stands (5–30 ha) than large patches (>30 ha) may be a result of the older, higher‐quality habitat available in small stands in the managed forest landscape. We recommend that land managers interested in maintaining healthy managed forest ecosystems with a full complement of cavity‐using species in forests of western Washington and northwestern Oregon maintain a landscape mosaic with approximately 45% of the landscape in stands >40 years, and >30% of the landscape in stands >60 years.
Genetic and Environmental Interaction in White‐Tailed Deer
Authors: LOCKWOOD MITCHELL A. , FRELS DON B. , ARMSTRONG WILLIAM E. , FUCHS EUGENE , HARMEL DONNIE E.
Published: November 2007

ABSTRACT  We applied an 8‐year selection process in an attempt to determine if yearling antler quality in subsequent cohorts could be improved by selecting for yearling male white‐tailed deer (Odocoileus virginianus) exhibiting relatively superior antler potential under suboptimal nutritional conditions. In 41 single‐sire (breeding M) breeding herds, 217 yearling males were produced on an 8% protein diet of limited quantity. All antler measurements increased significantly (P < 0.001) during the study: number of points (+3.2), inside spread (+96.5 mm), main beam length (+129.1 mm), basal circumference (+21.6 mm), and total antler weight (+231.3 g). Furthermore, mean gross Boone and Crockett (GBC) score increased (P < 0.001) linearly throughout the study, with the GBC of the 1999 cohort exceeding that of the 1993 cohort by 36.4 in (923.0 mm). These data provide insight to the effectiveness of a selection process (i.e., culling) in an overall deer‐management program.
Waterfowl Use of Dense Nesting Cover in the Canadian Parklands
Authors: ARNOLD TODD W. , CRAIG‐MOORE LEA M. , ARMSTRONG LLWELLYN M. , HOWERTER DAVID W. , DEVRIES JAMES H. , JOYNT BRIAN L. , EMERY ROBERT B. , ANDERSON MICHAEL G.
Published: November 2007

ABSTRACT  Dense nesting cover (DNC) has been a conspicuous component of habitat management for upland‐nesting ducks for >30 years, but its benefits for nesting ducks have been contentious. During 1994–1999 we monitored 3,058 dabbling duck (Anas spp.) nests in 84 DNC fields located throughout the Canadian Parklands to examine sources of among‐field variation in nest density and nesting success. Nest density averaged 1.51 (SE=0.15) nests/ha and overall nesting success was 20.4%, but there was pronounced annual variation in both estimates. Nesting success increased with increasing field size (range = 6–111 ha), but nest density remained constant. Nest density increased with percent wetland habitat within DNC fields and declined with percent perennial cover in the surrounding 2.4 × 2.4‐km landscape, but these variables were not important for predicting nesting success. Nest abundance and nesting success roughly doubled in fields seeded with alfalfa (Medicago sativa) or sweet clovers (Melilotus spp.), but there was no benefit from using native as opposed to tame grasses. We recommend that waterfowl managers in the Canadian Parklands establish DNC with alfalfa in large fields in landscapes with abundant wetlands but minimal competing cover.
Comparing King, Gentoo, and Royal Penguin Responses to Pedestrian Visitation
Authors: HOLMES NICK D.
Published: November 2007

ABSTRACT  For wildlife managers, determining inter‐species differences in the behavioral responses of seabirds to visitation can allow greater efficacy of visitor guidelines. Two key management outcomes for such information include 1) tailoring visitor guidelines to protect the most sensitive species and 2) improving self‐regulation during visits by identifying behaviors likely to indicate a change in the natural activity of visited species. On subantarctic Macquarie Island, Australia, I collected the behavioral responses of guarding king (Aptenodytes patagonicus), gentoo (Pygoscelis papua), and royal (Eudyptes schlegeli) penguins before, during, and after exposure to a standardized pedestrian visit, to compare species' behavioral responses to visitation. Gentoo penguins appeared more sensitive than royal or king penguins, exhibiting altered behavior for 5 minutes after the stimulus was removed; this pattern was not evident in kings or royals. Response behaviors useful for visitors to assess their impact on penguins include vigilance (repeated rapid head turning) in all 3 species, agonism in king and royal penguins (reaching and striking at conspecifics), and low threat‐display (bill pointing) in gentoo penguins. This study is valuable for wildlife managers as it provides practical information in the application of on‐ground visitor guidelines.
Effectiveness of Avian Predator Perch Deterrents on Electric Transmission Lines
Authors: LAMMERS WENDY M. , COLLOPY MICHAEL W.
Published: November 2007

ABSTRACT  A new high‐voltage transmission line in north‐central Nevada, USA, was considered a potential threat to greater sage‐grouse (Centrocercus urophasianus) because avian predators are attracted to and hunt from elevated perches. As a mitigation measure, perch deterrents were installed on the transmission line towers at the time of construction; in addition, 2 existing high‐voltage transmission lines were retrofitted with deterrents. Previous published studies have investigated the efficacy of perch deterrents in preventing or reducing electrocution of avian predators and fecal contamination of insulators, but none have evaluated deterrents as a means of eradicating perching on towers. We conducted point transect surveys and perching‐duration observations of corvids and raptors and determined that although perch deterrents did not prevent perching, the perching duration of raptors on the deterrents was reduced compared to other perching substrates. Perching of raptors indicated that some hunting most likely took place from the towers; therefore, the deterrents did not completely obviate the threat that avian predators posed to greater sage‐grouse. Although the deterrents reduced the probability of avian predators perching on the towers, avian predators overcame the deterrents to take advantage of the height of the towers where no other perches of similar height existed. The perch deterrents as designed did not have the desired short‐term effect on avian predators, but further monitoring may reveal longer‐term effects and distinguish perching behaviors specific to different species of avian predators.
Habitat‐Suitability Bounds for Nesting Cover of Northern Bobwhites on Semiarid Rangelands
Authors: ARREDONDO JUA A. , HERNÁNDEZ FIDEL , BRYANT FRED C. , BINGHAM RALPH L. , HOWARD RONNIE
Published: November 2007

ABSTRACT  Northern bobwhite (Colinus virginianus) is a species for which extensive knowledge exists regarding its ecology, life history, and habitat. Although the qualitative aspects of bobwhite habitat have been described and known for many decades, researchers have neglected to characterize bobwhite habitat quantitatively (i.e., habitat selection). Thus, biologists have been capable of identifying components that compose bobwhite habitat but have only been able to speculate on how much of each component was necessary. We documented selection‐avoidance behavior of nesting bobwhites in Brooks County, Texas, USA, during May‐August, 2004–2005. We measured 5 vegetation features (i.e., nesting‐substrate ht and width, suitable nest clump density, herbaceous canopy coverage, and radius of complete visual obstruction) at nest sites (n = 105) and at random points (n = 204). We used continuous selection functions to assess habitat use and identify bounds of suitability. Selection domains for nesting‐substrate height and radius of complete visual obstruction were 16.9–31.2 cm and 1.05‐4.35 m, respectively. Across all measurements, bobwhites selected for nest sites with a nesting‐substrate width ≥22.4 cm, suitable nest‐clump density ≥730 nest clumps/ha, and herbaceous canopy coverage ≥36.7%. This knowledge will provide an important foundation for managers to evaluate current nesting conditions on semiarid rangelands and provide a basis for habitat management aimed at creating suitable nesting habitat for bobwhites.
County‐Level Factors Contributing to Deer‐Vehicle Collisions in Arkansas
Authors: FARRELL MICHAEL C. , TAPPE PHILIP A.
Published: November 2007

ABSTRACT  Arkansas harbors a substantial white‐tailed deer (Odocoileus virginianus) population, boasts an expanding human population, and both enjoys and suffers the resulting consequences. A highly visible negative consequence is the occurrence of deer‐vehicle collisions (DVCs). Several studies have investigated site‐specific factors that may contribute to DVCs. However, few studies have explored the role of broader scale factors. In this study, we used an exploratory, multivariate approach to examine the influence of county‐level factors on the density (no./1,000 km) of reported DVCs in Arkansas, USA, during 1998–2001. Factors considered to contribute to DVCs in Arkansas included human and deer population densities, urban growth, various roadway characteristics, daily traffic counts, timber harvests, and landcover composition and spatial characteristics. Using principal components and regression analysis we determined that there were 2 important components contributing to DVC densities in Arkansas. Component 1 represented a predominantly forested matrix with high edge density and contrast. Component 2 described an urban environment, with high road densities, human population densities, and average daily traffic counts. These 2 components were strongly related to DVCs (r2 = 0.55, P < 0.001), with component 2 explaining the most variation (71.4%). The identification and recognition of the contribution of these broad‐scale factors to DVCs provide insight useful in making informed decisions related to DVC mitigation.
Responses of Songbirds to Magpie Reduction in an Urban Habitat
Authors: CHIRON FRANÇOIS , JULLIARD ROMAIN
Published: November 2007

ABSTRACT  Bird communities change in response to urbanization, which poses a challenge for conservationists. We examined the consequences of the recent increase in European cities of black‐billed magpie (Pica pica), which has become the main bird nest predator in many urban parks, yet its impact remains disputed. We tested predator role in the limitation of postfledging and adult numbers of 10 common songbird species. We conducted before‐after, control‐treatment experimental magpie removal in the suburbs near Paris, France, during our 3‐year study. We also compared the productivity and the relative densities between urban and rural habitats for 14 songbirds. We found that magpies had very limited effect on songbird productivity, even for species sensitive to predation by corvids. In addition, impact of the magpie on population levels of passerines would also be minimized because we found no relationship between productivity of prey and their densities. Thus, the recent colonization of urban parks by magpies should not threaten persistence of local songbird populations. Yet, there was evidence that a small number of non‐territorial bird species were attracted to places where magpies were removed. Magpie densities may have modified habitat selection for foraging that might be explained by predator avoidance. But overall, characteristics of urban habitat explain variations of productivity and densities of songbirds better than did magpie predation. In France, conservationists widely use the control of predators, aiming at increasing levels of prey populations. Despite very high densities of magpies in urban parks, we gave evidence that removal of this predator was ineffective to preserve populations of common passerines. This would suggest that the risk induced by the presence of magpies is independent of its density, and conservationists must carefully assess its impact. In the future, we recommend management policies include long‐term monitoring of magpie‐prey interactions during breeding season to detect potential changes in songbird responses to magpie presence.
A Field Evaluation of Distance Measurement Error in Auditory Avian Point Count Surveys
Authors: ALLDREDGE MATHEW W. , SIMONS THEODORE R. , POLLOCK KENNETH H.
Published: November 2007

ABSTRACT Detection distance is an important and common auxiliary variable measured during avian point count surveys. Distance data are used to determine the area sampled and to model the detection process using distance sampling theory. In densely forested habitats, visual detections of birds are rare, and most estimates of detection distance are based on auditory cues. Distance sampling theory assumes detection distances are measured accurately, but empirical validation of this assumption for auditory detections is lacking. We used a song playback system to simulate avian point counts with known distances in a forested habitat to determine the error structure of distance estimates based on auditory detections. We conducted field evaluations with 6 experienced observers both before and after distance estimation training. We conducted additional studies to determine the effect of height and speaker orientation (toward or away from observers) on distance estimation error. Distance estimation errors for all evaluations were substantial, although training reduced errors and bias in distance estimates by approximately 15%. Measurement errors showed a nonlinear relationship to distance. Our results suggest observers were not able to differentiate distances beyond 65 m. The height from which we played songs had no effect on distance estimation errors in this habitat. The orientation of the song source did have a large effect on distance estimation errors; observers generally doubled their distance estimates for songs played away from them compared with distance estimates for songs played directly toward them. These findings, which we based on realistic field conditions, suggest measures of uncertainty in distance estimates to auditory detections are substantially higher than assumed by most researchers. This means aural point count estimates of avian abundance based on distance methods deserve careful scrutiny because they are likely biased.
Multiscale Habitat Selection by Burrowing Owls in Black‐Tailed Prairie Dog Colonies
Authors: LANTZ SARAH J. , CONWAY COURTNEY J. , ANDERSON STANLEY H.
Published: November 2007

ABSTRACT Some populations of western burrowing owls (Athene cunicularia hypugaea) have declined in recent decades. To design and implement effective recovery efforts, we need a better understanding of how distribution and demographic traits are influenced by habitat quality. To this end, we measured spatial patterns of burrowing owl breeding habitat selection within black‐tailed prairie dog (Cynomys ludovicianus) colonies in northeastern Wyoming, USA. We compared burrow‐, site‐, colony‐, and landscape‐scale habitat parameters between burrowing owl nest burrows (n= 105) and unoccupied burrows (n= 85). We sampled 4 types of prairie dog colonies: 1) owl‐occupied, active with prairie dogs (n= 16); 2) owl‐occupied, inactive (n= 13); 3) owl‐unoccupied, active (n= 14); and 4) owl‐unoccupied, inactive (n= 14). We used an information‐theoretic approach to examine a set of candidate models of burrowing owl nest‐site selection. The model with the most support included variables at all 4 spatial scales, and results were consistent among the 4 types of prairie dog colonies. Nest burrows had longer tunnels, more available burrows within 30 m, and less shrub cover within 30 m, more prairie dog activity within 100 m, and were closer to water than unoccupied burrows. The model correctly classified 76% of cases, all model coefficients were stable, and the model had high predictive ability. Based on our results, we recommend actions to ensure persistence of the remaining prairie dog colonies as an important management strategy for burrowing owl conservation in the Great Plains of North America.
Selenium in Aquatic Birds From Central California
Authors: PAVEGLIO FRED L. , KILBRIDE KEVIN M.
Published: November 2007

ABSTRACT  After mostly freshwater replaced agricultural drainage water used for wetland management in 1985, Selenium (Se) concentrations in 3 wintering waterfowl species and black‐necked stilts (Himantopus mexicanus) from the North and South Grasslands of central California, USA, declined in the years from 1986 to 1988 and 1989 to 1994. However, Se concentrations were still above the threshold for potential reproductive impairment and exceeded background levels for some species. Consequently, we measured Se concentrations in aquatic birds in 2005 after long‐term use (20 yr) of predominately freshwater for wetland management in the Grasslands. As in 1986–1994, Se concentrations in 2005 were higher for birds from the South Grasslands, which historically received more undiluted drainage water compared with the North Grasslands. Liver Se concentrations for stilts from the South Grasslands were at levels associated with potential reproductive impairment. All species from the South Grasslands, as well as mallards (Anas platyrhynchos), northern pintails (A. acuta), and American coots (Fulica americana) from the North Grasslands, were above species‐specific background levels. From 1994 to 2005, Se levels in some aquatic birds stabilized above background levels likely indicating long‐term cycling within the Grasslands. We recommend Se‐contaminated drainage water (≥ 2 ppb Se) not be used for management or allowed as an input into arid wetlands throughout the western United States.
Effects of Coyote Population Reduction on Swift Fox Demographics in Southeastern Colorado
Authors: KARKI SEIJA M. , GESE ERIC M. , KLAVETTER MEAD L.
Published: November 2007

ABSTRACT  The distribution and abundance of swift foxes (Vulpes velox) has declined from historic levels. Causes for the decline include habitat loss and fragmentation, incidental poisoning, changing land use practices, trapping, and predation by other carnivores. Coyotes (Canis latrans) overlap the geographical distribution of swift foxes, compete for similar resources, and are a significant source of mortality amongst many swift fox populations. Current swift fox conservation and management plans to bolster declining or recovering fox populations may include coyote population reduction to decrease predation. However, the role of coyote predation in swift fox population dynamics is not well‐understood. To better understand the interactions of swift foxes and coyotes, we compared swift fox population demographics (survival rates, dispersal rates, reproduction, density) between areas with and without coyote population reduction. On the Piñon Canyon Maneuver Site, Colorado, USA, we monitored 141 swift foxes for 65,226 radio‐days from 15 December 1998 to 14 December 2000 with 18,035 total telemetry locations collected. Juvenile swift fox survival rate was increased and survival was temporarily prolonged in the coyote removal area. Adult fox survival patterns were also altered by coyote removal, but only following late‐summer coyote removals and, again, only temporarily. Coyote predation remained the main cause of juvenile and adult fox mortality in both areas. The increase in juvenile fox survival in the coyote removal area resulted in a compensatory increase in the juvenile dispersal rate and an earlier pulse in dispersal movements. Adult fox dispersal rate was more consistent throughout the year in the coyote removal area. Coyote removal did not influence the reproductive parameters of the swift foxes. Even though juvenile survival increased, swift fox density remained similar between the areas due to the compensatory dispersal rate among juvenile foxes. We concluded that the swift fox population in the area was saturated. Although coyote predation appeared additive in the juvenile cohort, it was compensatory with dispersal.
Assessing the Conservation Status of an Iberian Moth Using Pseudo‐Absences
Authors: CHEFAOUI ROSA M. , LOBO JORGE M.
Published: November 2007

ABSTRACT  Knowing the distribution of endangered species is of substantial importance for conservation. We considered a useful approach for modeling species distribution when managing information from atlases and museums but when absence data is not available. By modeling the distribution for Graellsia isabelae, a threatened moth species, we assessed its current conservation status and identified its most relevant distribution explanatory variables using Geographic Information System and Generalized Linear Models. The distribution model was built from 136 occurrence records and 25 digitized explanatory variables at a 10 × 10 km resolution. Model predictions from logistic‐regressed pseudo‐absences, obtained from a presence‐only method (Ecological‐Niche Factor Analysis), explained 96.23% of the total deviance. We found that the best predictor variables were summer precipitation, aridity, and mean elevation. With respect to host plants, the presence of G. isabelae associated mainly with Scots pine (Pinus sylvestris) and Austrian pine (P. nigra). The finding of 8 areas, exclusively in the eastern Iberian territory, and a larger unoccupied habitat in the western Iberian Peninsula indicates that this species is probably not in equilibrium with its environment by historical factors. Sites of Community Importance under protection do not seem sufficient to maintain current populations, necessitating the protection of suitable neighboring habitats. Our methodology is useful to manage the conservation status of species for which reliable absence data is not available. It is possible to determine those variables that most affect the distribution of species as well as the potential suitable areas with the purpose of evaluating protected areas, connectivity among populations, and possible reintroductions.
Diets, Movements, and Consequences of Providing Wildlife Food Plots for White‐Tailed Deer in Central North Dakota
Authors: SMITH JASON R. , SWEITZER RICHARD A. , JENSEN WILLIAM F.
Published: November 2007

ABSTRACT  White‐tailed deer (Odocoileus virginianus) in North Dakota, USA, have greatly increased over the past 100 years due to conversion of prairie to agriculture, planting of tree rows, regulated hunting, and extirpation of large predators. In support of management to maintain harvestable big game while minimizing depredation damage to agriculture, the North Dakota Game and Fish Department manages wildlife management areas (WMAs) where planted trees and food plots provide habitat and public hunting. These WMAs are typically surrounded by agricultural fields, and management that concentrates deer in these areas may expose surrounding agricultural producers to increased depredation. We investigated diets, habitat use, and movements of white‐tailed deer at a large WMA in central North Dakota (Lonetree WMA) to understand how the animals are responding to management designed to enhance wildlife populations. We also evaluated survival of white‐tailed deer for an improved understanding of the recent trend for population growth. Diets of deer varied seasonally, including a relatively high proportion of crops from food plots in winter and mostly herbaceous forbs and browse during spring and summer. Data from radiocollared animals and biweekly spotlight surveys revealed that deer are being drawn from a relatively large area to Lonetree WMA during fall and winter. Hunting was the most important cause of mortality, but annual survival of adult and fawn females exceeded 80%. The original purpose of food plots at Lonetree WMA was to alleviate depredation on adjacent private lands. Depredation has been limited, but the multiyear trend of increased deer numbers is a new concern. A possible consequence of provisioning white‐tailed deer with food plots during winter when some starvation would normally occur could be for the population to exceed a threshold above which regulated hunting will be unable to prevent irruptive growth. Research on how food plots influence winter survival is needed to inform management and prevent possible rapid increase in white‐tailed deer populations across the prairie‐coteau region of central North Dakota.
Testing Global Positioning System Telemetry to Study Wolf Predation on Deer Fawns
Authors: DEMMA DOMINIC J. , BARBER‐MEYER SHANNON M. , MECH L. DAVID
Published: November 2007

ABSTRACT We conducted a pilot study to test the usefulness of Global Positioning System (GPS) collars for investigating wolf (Canis lupus) predation on white‐tailed deer (Odocoileus virginianus) fawns. Using GPS collars with short location‐attempt intervals on 5 wolves and 5 deer during summers 2002–2004 in northeastern Minnesota, USA, demonstrated how this approach could provide new insights into wolf hunting behavior of fawns. For example, a wolf traveled ≥1.5–3.0 km and spent 20–22 hours in the immediate vicinity of known fawn kill sites and ≥0.7 km and 8.3 hours at scavenging sites. Wolf travel paths indicated that wolves intentionally traveled into deer summer ranges, traveled ≥0.7–4.2 km in such ranges, and spent <1–22 hours per visit. Each pair of 3 GPS‐collared wolf pack members were located together for ≤6% of potential locations. From GPS collar data, we estimated that each deer summer range in a pack territory containing 5 wolves ≥1 year old and hunting individually would be visited by a wolf on average every 3–5 days. This approach holds great potential for investigating summer hunting behavior of wolves in areas where direct observation is impractical or impossible.
Landscape Analysis of Bobcat Habitat in the Northern Lower Peninsula of Michigan
Authors: PREUSS TIMOTHY S. , GEHRING THOMAS M.
Published: November 2007

ABSTRACT  Controversy over bobcat (Lynx rufus) management in the northern Lower Peninsula of Michigan (NLP), USA, stimulated a need for information on the distribution of Michigan bobcats. From March 2003 to October 2004, we conducted a radiotelemetry and scentstation survey study of bobcats in the NLP. We developed a spatial model to predict bobcat distribution throughout the NLP based on bobcat area requirements, habitat and landscape variables derived from remotely sensed land‐cover data, and a multivariate distance statistic. Bobcat 50% minimum convex polygon core areas were comprised of more lowland forest (51%), nonforested wetlands (9%), and streams (3%) than the surrounding NLP. The NLP was comprised primarily of upland forest (44%) and field (32%). Habitat in the northeast and central regions of the NLP was most similar to the habitat composition of bobcat core areas. This model will be useful in aiding Michigan wildlife management agencies with assessing the status and distribution of the NLP bobcat population by identifying areas important to bobcats and supporting the development of regional strategies for carnivore conservation.
Noninvasive Estimation of Black Bear Abundance Incorporating Genotyping Errors and Harvested Bear
Authors: DREHER BRIAN P. , WINTERSTEIN SCOTT R. , SCRIBNER KIM T. , LUKACS PAUL M. , ETTER DWAYNE R. , ROSA GUILHERME J. M. , LOPEZ VERONICA A. , LIBANTS SCOT , FILCEK KRISTI B.
Published: November 2007

ABSTRACT  Estimating black bear (Ursus americanus) population size is a difficult but important requirement when justifying harvest quotas and managing populations. Advancements in genetic techniques provide a means to identify individual bears using DNA contained in tissue and hair samples, thereby permitting estimates of population abundance based on established mark‐capture‐recapture methodology. We expand on previous noninvasive population‐estimation work by geographically extending sampling areas (36,848 km2) to include the entire Northern Lower Peninsula (NLP) of Michigan, USA. We selected sampling locations randomly within biologically relevant bear habitat and used barbed wire hair snares to collect hair samples. Unlike previous noninvasive studies, we used tissue samples from harvested bears as an additional sampling occasion to increase recapture probabilities. We developed subsampling protocols to account for both spatial and temporal variance in sample distribution and variation in sample quality using recently published quality control protocols using 5 microsatellite loci. We quantified genotyping errors using samples from harvested bears and estimated abundance using statistical models that accounted for genotyping error. We estimated the population of yearling and adult black bears in the NLP to be 1,882 bears (95% CI = 1,389‐2,551 bears). The derived population estimate with a 15% coefficient of variation was used by wildlife managers to examine the sustainability of harvest over a large geographic area.
Energetic Carrying Capacity of Actively and Passively Managed Wetlands for Migrating Ducks in Ohio
Authors: BRASHER MICHAEL G. , STECKEL JASON D. , GATES ROBERT J.
Published: November 2007

ABSTRACT  Habitat conservation strategies of the North American Waterfowl Management Plan (NAWMP) are guided by current understanding of factors that limit growth of waterfowl populations. The 1998 implementation plan of the Upper Mississippi River and Great Lakes Region Joint Venture (UMR and GLRJV) assumed that availability of foraging resources during autumn in wetlands actively managed for waterfowl was the primary limiting factor for duck populations during the nonbreeding season. We used multistage sampling during autumn and spring 2001–2004 to estimate energetic carrying capacity (ECC) of actively and passively managed wetlands in Ohio, USA, and examine this assumption. Energetic carrying capacity during autumn was similar between actively and passively managed wetlands each year. Averaged across years, energetic carrying capacity was 3,446 and 2,047 duck energy‐days (DED)/ha for actively and passively managed wetlands, respectively. These estimates exceeded the UMR and GLRJV assumption that 1,236 DED/ha were provided by managed wetland habitats. Energetic carrying capacity declined each year by >80% between autumn and spring migration. Consequently, ECC of actively and passively managed wetlands was low during spring ( = 66–242 DED/ha). These results suggested that duck foraging resources in actively and passively managed wetland habitats are abundant during autumn, but overwinter declines may create food‐limiting environments during spring.
Minimizing Leg‐Hold Trapping Trauma for Otters With Mobile Phone Technology
Authors: NÉILL LUGHAIDH Ó , DE JONGH ADDY , DE JONG TJIBBE , OZOLINŠ JANIS , ROCHFORD JOHN
Published: November 2007

ABSTRACT We present and evaluate a protocol for the capture of otters (Lutra lutra) using padded leg‐hold traps coupled with Global System for Mobile communication (GSM) trap alarms. The trapping method was highly efficient, capturing 46 otters at 6.9 trap‐nights each. Functioning alarms allowed us to remove 36 otters from their traps within 22 (SD = 14) minutes of capture. We caught 10 otters in trap sets with malfunctioning trap alarms and retrieved them the following morning, after ≤24 hours. Functioning alarms reduced the injuries suffered from an average cumulative score of 77.7 to just 5.5 on the International Organization for Standardization 10990‐5 trauma scale (Z=‐5.074,P≤ 0.001). As a result, we strongly encourage the use of GSM trap alarms under the principle of refinement in animal experiments.
Factors Predicting Den Use by Maternal Giant Pandas
Authors: ZHANG ZEJUN , SWAISGOOD RONALD R. , WU HUA , LI MING , YONG YANGE , HU JINCHU , WEI FUWEN
Published: November 2007

ABSTRACT  We studied the denning ecology of giant pandas (Ailuropoda melanoleuca) in the Foping Nature Reserve, China. We identified 17 used and 21 unused cavities of appropriate size to accommodate denning and measured several variables potentially affecting the suitability of these cavities for panda denning. Principal component analysis, combined with traditional univariate tests, indicated that maternal females preferred deeper cavities with a high interior‐to‐entrance ratio for height and width, suggesting a preference for narrow entrances and roomy chambers. Microhabitat features, including slope and distance to water, were also useful in predicting den use by maternal females. We believe that the availability of suitable dens may limit population size, especially in areas where tree dens have been eliminated by logging of old growth forests. Conservation managers in giant panda reserves can use our data to determine the number of suitable panda dens that are in an area, estimate whether there are enough for the adult female population to use as birthing dens, and—if needed—construct suitable artificial dens to increase the rate of reproduction.
Pond‐Breeding Amphibian Species Richness and Habitat Selection in a Beaver‐Modified Landscape
Authors: CUNNINGHAM JESSE M. , CALHOUN ARAM J. K. , GLANZ WILLIAM E.
Published: November 2007

ABSTRACT  Beaver (Castor canadensis) activity creates wetland habitats with varying hydroperiods important in maintaining habitat diversity for pond‐breeding amphibians with significantly different breeding habitat requirements. We documented pond‐breeding amphibian assemblages in 71 freshwater wetlands in Acadia National Park, Maine, USA. Using 15 variables describing local pond conditions and wetland landscape characteristics, we developed a priori models to predict sites with high amphibian species richness and used model selection with Akaike's Information Criterion to judge the strength of evidence supporting each model. We developed single‐species models to predict wood frog (Rana sylvatica), bullfrog (R. catesbeiana), and pickerel frog (R. palustris) breeding site selection. Sites with high species richness were best predicted by 1) connectivity of wetlands in the landscape through stream corridors and 2) wetland modification by beaver. Wood frog breeding habitat was best predicted by temporary hydroperiod, lack of fish, and absence of current beaver activity. Wood frog breeding was present in abandoned beaver wetlands nearly as often as in nonbeaver wetlands. Bullfrog breeding was limited to active beaver wetlands with fish and permanent water. Pickerel frog breeding sites were best predicted by connectivity through stream corridors within the landscape. As beavers have recolonized areas of their former range in North America, they have increased the number and diversity of available breeding sites in the landscape for pond‐breeding amphibians. The resulting mosaic of active and abandoned beaver wetlands both supports rich amphibian assemblages and provides suitable breeding habitat for species with differing habitat requirements. Land managers should consider the potential benefits of minimal management of beavers in promoting and conserving amphibian and wetland diversity at a landscape scale.
Management‐Induced Reproductive Failure and Breeding Dispersal in Double‐Crested Cormorants on Lake Champlain
Authors: DUERR ADAM E. , DONOVAN THERESE M. , CAPEN DAVID E.
Published: November 2007

ABSTRACT  We studied breeding dispersal of double‐crested cormorants (Phalacrocorax auritus) associated with management practices that suppressed their reproduction on Lake Champlain in the northeastern United States. We implemented an experiment on one colony by spraying corn oil on cormorant eggs in portions of the colony and leaving other portions untreated. Gulls (Larus spp.) consumed cormorant eggs during the oiling process, but we reduced and then eliminated predation levels after the first year of the study. We used mark‐recapture techniques within the experimental framework to measure rates of breeding dispersal for cormorants from the experimental colony and an unmanaged colony in Lake Champlain. Egg oiling increased the movement rate to the unmanaged colony by 3% during the year with no egg predation by gulls. When gulls depredated cormorant eggs at high rates during egg oiling, movement to the unmanaged colony increased by 20%. When cormorants are managed to reduce population sizes, methods that limit dispersal away from the managed colony may be most effective. Such methods would mitigate effects to nontarget populations and allow for a greater portion of the metapopulation to be managed.
Greater Sage‐Grouse Population Response to Energy Development and Habitat Loss
Authors: WALKER BRETT L. , NAUGLE DAVID E. , DOHERTY KEVIN E.
Published: November 2007

ABSTRACT  Modification of landscapes due to energy development may alter both habitat use and vital rates of sensitive wildlife species. Greater sage‐grouse (Centrocercus urophasianus) in the Powder River Basin (PRB) of Wyoming and Montana, USA, have experienced rapid, widespread changes to their habitat due to recent coal‐bed natural gas (CBNG) development. We analyzed lek‐count, habitat, and infrastructure data to assess how CBNG development and other landscape features influenced trends in the numbers of male sage‐grouse observed and persistence of leks in the PRB. From 2001 to 2005, the number of males observed on leks in CBNG fields declined more rapidly than leks outside of CBNG. Of leks active in 1997 or later, only 38% of 26 leks in CBNG fields remained active by 2004–2005, compared to 84% of 250 leks outside CBNG fields. By 2005, leks in CBNG fields had 46% fewer males per active lek than leks outside of CBNG. Persistence of 110 leks was positively influenced by the proportion of sagebrush habitat within 6.4 km of the lek. After controlling for habitat, we found support for negative effects of CBNG development within 0.8 km and 3.2 km of the lek and for a time lag between CBNG development and lek disappearance. Current lease stipulations that prohibit development within 0.4 km of sage‐grouse leks on federal lands are inadequate to ensure lek persistence and may result in impacts to breeding populations over larger areas. Seasonal restrictions on drilling and construction do not address impacts caused by loss of sagebrush and incursion of infrastructure that can affect populations over long periods of time. Regulatory agencies may need to increase spatial restrictions on development, industry may need to rapidly implement more effective mitigation measures, or both, to reduce impacts of CBNG development on sage‐grouse populations in the PRB.
Conservation Reserve Program Benefits on Henslow's Sparrows Within the United States
Authors: HERKERT JAMES R.
Published: November 2007

ABSTRACT  Henslow's sparrow (Ammodramus henslowii) is one of North America's fastest declining songbirds. Population declines combined with a small global population have led to heightened conservation concern. I used data from the North American Breeding Bird Survey to assess the impact that the Conservation Reserve Program (CRP) has had on Henslow's sparrows throughout their United States breeding range. My analysis suggests local Henslow's sparrow population trends are correlated with CRP enrollment, with populations increasing more in areas with relatively high local CRP enrollment, and that CRP appears to be playing a significant role in reversing long‐term population declines.
Breeding Birds in Riparian and Upland Dry Forests of the Cascade Range
Authors: LEHMKUHL JOHN F. , BURGER E. DORSEY , DREW EMILY K. , LINDSEY JOHN P. , HAGGARD MARYELLEN , WOODRUFF KENT Z.
Published: November 2007

ABSTRACT We quantified breeding bird abundance, diversity, and indicator species in riparian and upland dry forests along 6 third‐ to fourth‐order streams on the east slope of the Cascade Range, Washington, USA. Upland dry forest on southerly aspects was dominated by open ponderosa pine (Pinus ponderosa) and dry Douglas‐fir (Pseudotsuga menziesii) plant associations. Upland mesic forest on northerly aspects was dominated by closed‐canopy Douglas‐fir or dry grand fir (Abies grandis) plant associations. Riparian overstory vegetation was dominated by black cottonwood (Populus trichocarpa) plant associations with a prominent hardwood tree and shrub component. We quantified bird assemblages, diversity, and abundance from parallel point transects on riparian and adjacent dry and mesic upslope forests. We detected 80 bird species from >12,000 point‐transect observations during 1998–1999. Eighteen species accounted for 75% of all detections. Species richness and evenness were similar in all 3 forest types, with approximately 35 species and high evenness (0.85) in each forest type. Bird species assemblages differed among dry, mesic, and riparian forest types, with the greatest differences between riparian and both dry and mesic upland forests. Riparian forest had the greatest number (9) of strong characteristic, or indictor, species among the 3 forest types. Upland mesic forest was characterized by 7 indicator species. Upland dry forest had 4 indicator species. Our results indicate that current standards and guidelines for riparian buffers zones would allow for avian refuge and corridor functions along these streams. Forest managers could use our indicator species to predict and monitor shifts in upland forest species composition from thinning and prescribed burning practices that are used to reduce fuels in uplands and to reduce continuity of fire effects between riparian and upland zones.