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We assessed the potential for reestablishing elk (Cervus elaphus) in Great Smoky Mountains National Park (GSMNP), USA, by estimating vital rates of experimentally released animals from 2001 to 2006. Annual survival rates for calves ranged from 0.333 to 1.0 and averaged 0.592. Annual survival for subadult and adult elk (i.e., ≥1 yr of age) ranged from 0.690 to 0.933, depending on age and sex. We used those and other vital rates to model projected population growth and viability using a stochastic individual-based model. The annual growth rate (λ) of the modeled population over a 25-year period averaged 0.996 and declined from 1.059 the first year to 0.990 at year 25. The modeled population failed to attain a positive 25-year mean growth rate in 46.0% of the projections. Poor calf recruitment was an important determinant of low population growth. Predation by black bears (Ursus americanus) was the dominant calf mortality factor. Most of the variance of growth projections was due to demographic variation resulting from the small population size (n = 61). Management actions such as predator control may help increase calf recruitment, but our projections suggest that the GSMNP elk population may be at risk for some time because of high demographic variation.
Population parameters of American martens (Martes americana) are often monitored to guide management actions. In order to better understand changing marten population demographics, we estimated marten abundance and several population parameters on a portion of northeast Chichagof Island (NCI), Southeast Alaska, USA, using capture–mark–recapture methods in combination with radiotelemetry and compared these data with demographic estimates derived from the trapper catch from the larger NCI area. We found that capture probability remained relatively high across trapping sessions by using a standard live-trapping protocol, and we found no evidence of capture probability being consistently affected by population or environmental factors. Estimated marten numbers varied greatly over the period, ranging from a low of 14.1 martens (0.17/km2) during winter 1997–1998 to a high of 45.6 martens (0.55/km2) during winter 1995–1996. The annual trend was for decreasing numbers from winter 1990–1991 to winter 1992–1993, then increasing numbers through winter 1995–1996. By winter 1996–1997, numbers had dropped substantially and remained low through 1997–1998. All population parameters varied temporally, including annual survival (0.34–1.00), sex ratio (1.0–3.5), mean age (0.5–2.9), body condition (−0.08–1.35), and fecundity (0.44–2.70). Yearly trapper catches on NCI varied greatly from 19 to 354 martens (0.02 martens/km2 to 0.31 martens/km2) because of changing trapper effort and marten abundance. We found mean ages of carcasses a good predictor of population mean age, but sex ratios were highly variable. Marten numbers and fecundity were strongly correlated with rodent abundance, especially long-tailed voles (Microtus longicaudus). By monitoring demographic parameters of the population or trapper-caught carcasses, managers can gain insight into temporal population dynamics. Also, total captures of individuals may provide a useful estimate of marten numbers without the expense of radiocollaring and tracking individuals because population estimates were highly correlated with number of individuals captured during a standard survey. Because of their high vulnerability to trapping, close monitoring of marten populations is important for the conservation and sustained-yield management of the species. A tracking strategy developed with input data on preseason abundance and age structure may be the best management approach, especially for small populations with limited immigration.
Christopher N. Jacques, Jonathan A. Jenks, Christopher S. Deperno, Jaret D. Sievers, Troy W. Grovenburg, Todd J. Brinkman, Christopher C. Swanson, Bruce A. Stillings
Ungulate mortality from capture-related injuries is a recurring concern for researchers and game managers throughout North America and elsewhere. We evaluated effects of 7 variables to determine whether ungulate mortality could be reduced by modifying capture and handling procedures during helicopter net-gunning. During winter 2001–2006, we captured 208 white-tailed deer (Odocoileus virginianus) and 281 pronghorn (Antilocapra americana) by helicopter net-gunning throughout the Northern Great Plains. Of 281 pronghorn, 25 (8.9%) died from capture-related injuries; 12 were from direct injuries during capture, and 13 occurred postrelease. Of 208 deer, 3 (1.4%) died from injuries sustained during helicopter captures, with no mortalities documented postrelease. We used logistic regression to evaluate the probability that ungulates would die of injuries associated with helicopter net-gun captures by analyzing effects of snow depth, transport distance, ambient and rectal temperatures, pursuit and handling times, and whether individuals were transported to processing sites. The probability of capture-related mortality postrelease decreased 58% when transport distance was reduced from 14.5 km to 0 km and by 69% when pursuit time decreased from 9 minutes to <1 minute. Wildlife managers and researchers using helicopter capture services in landscapes of the Midwest should limit pursuit time and eliminate animal transport during pronghorn and white-tailed deer capture operations to minimize mortality rates postrelease.
In west-central Texas, USA, abatement efforts for the gray fox (Urocyon cinereoargenteus) rabies epizootic illustrate the difficulties inherent in large-scale management of wildlife disease. The rabies epizootic has been managed through a cooperative oral rabies vaccination program (ORV) since 1996. Millions of edible baits containing a rabies vaccine have been distributed annually in a 16-km to 24-km zone around the perimeter of the epizootic, which encompasses a geographic area >4 × 105 km2. The ORV program successfully halted expansion of the epizootic into metropolitan areas but has not achieved the ultimate goal of eradication. Rabies activity in gray fox continues to occur periodically outside the ORV zone, preventing ORV zone contraction and dissipation of the epizootic. We employed a landscape-genetic approach to assess gray fox population structure and dispersal in the affected area, with the aim of assisting rabies management efforts. No unique genetic clusters or population boundaries were detected. Instead, foxes were weakly structured over the entire region in an isolation by distance pattern. Local subpopulations appeared to be genetically non-independent over distances >30 km, implying that long-distance movements or dispersal may have been common in the region. We concluded that gray foxes in west-central Texas have a high potential for long-distance rabies virus trafficking. Thus, a 16-km to 24-km ORV zone may be too narrow to contain the fox rabies epizootic. Continued expansion of the ORV zone, although costly, may be critical to the long-term goal of eliminating the Texas fox rabies virus variant from the United States.
By using Global Positioning System technology, we documented the long-distance dispersal of a wolf (Canis lupus) from the northern Apennines in Italy to the western Alps in France. This is the first report of long-distance dispersal of wolves in the human-dominated landscapes of southern Europe, providing conclusive evidence that the expanding wolf population in the Alps originates from the Apennine source population through natural recolonization. By crossing 4 major 4-lane highways, agricultural areas, and several regional and provincial jurisdictions, the dispersal trajectory of wolf M15 revealed a single, narrow linkage connecting the Apennine and the Alpine wolf populations. This connectivity should be ensured to allow a moderate gene flow between the 2 populations and counteract potential bottleneck effects and reduced genetic variability of the Alpine wolf population. The case we report provides an example of how hard data can be effective in mitigating public controversies originating from the natural expansion and recolonization processes of large carnivore populations. In addition, by highlighting the connectivity between these 2 transboundary wolf populations, we suggest that documenting long-distance dispersal is particularly critical to support population-based, transboundary management programs.
KEYWORDS: Breeding Bird Survey, Central Hardwoods, ecoregion, forest inventory and analysis, Habitat suitability index, landbird, National Land Cover Dataset, validation, verification, West Gulf Coastal Plain/Ouachitas
Emerging methods in habitat and wildlife population modeling promise new horizons in conservation but only if these methods provide robust population–habitat linkages. We used Breeding Bird Survey (BBS) data to verify and validate newly developed habitat suitability index (HSI) models for 40 priority landbird species in the Central Hardwoods and West Gulf Coastal Plain/Ouachitas Bird Conservation Regions. We considered a species’ HSI model verified if there was a significant rank correlation between mean predicted HSI score and mean observed BBS abundance across the 88 ecological subsections within these Bird Conservation Regions. When we included all subsections, correlations verified 37 models. Models for 3 species were unverified. Rank correlations for an additional 5 species were not significant when analyses included only subsections with BBS abundance >0. To validate models, we developed generalized linear models with mean observed BBS abundance as the response variable and mean HSI score and Bird Conservation Region as predictor variables. We considered verified models validated if the overall model was an improvement over an intercept-only null model and the coefficient on the HSI variable in the model was >0. Validation provided a more rigorous assessment of model performance than verification, and models for 12 species that we verified failed validation. Species whose models failed validation were either poorly sampled by BBS protocols or associated with woodland and shrubland habitats embedded within predominantly open landscapes. We validated models for 25 species. Habitat specialists and species reaching their highest densities in predominantly forested landscapes were more likely to have validated models. In their current form, validated models are useful for conservation planning of priority landbirds and offer both insight into limiting factors at ecoregional scales and a framework for monitoring priority landbird populations from readily available national data sets.
Red-shouldered hawks (Buteo lineatus) are a species of special conservation concern in much of the Great Lakes region, and apparent population declines are thought to be primarily due to habitat loss and alteration. To evaluate red-shouldered hawk–habitat associations during the nesting season and at the landscape scale, we conducted repeated call-broadcast surveys in central Minnesota, USA, across 3 landscapes that represented a range of landscape conditions as a result of differing management practices. In 2004, we conducted repeated call-broadcast surveys at 131 locations in 2 study areas, and in 2005, we surveyed 238 locations in 3 study areas. We developed models relating habitat characteristics at 2 spatial scales to red-shouldered hawk occupancy and assessed support for these models in an information–theoretic framework. Overall, a small proportion of nonforest (grass, clear-cut area, forest <5 yr old), and a large proportion of mature deciduous forest (>40 yr old), had the strongest association with red-shouldered hawk occupancy (proportion of sites occupied) at both spatial scales. The landscape conditions we examined appeared to contain a habitat transition important to red-shouldered hawks. We found, in predominately forest landscapes, the amount of open habitat was most strongly associated with red-shouldered hawk occupancy, but in landscapes that included slightly less mature forest and more extensive open habitats, the extent of mature deciduous forest was most strongly associated with red-shouldered hawk occupancy. Our results suggested that relatively small (<5 ha) patches of open habitat (clear-cuts) in otherwise forested landscapes did not appear to influence red-shouldered hawk occupancy. Whereas, in an otherwise similar landscape, with smaller amounts of mature deciduous forest and larger (>15 ha) patches of open habitat, red-shouldered hawk occupancy decreased, suggesting a threshold in landscape composition, based on both the amount of mature forest and open area, is important in managing forest landscapes for red-shouldered hawks. Our results show that during the nesting season, red-shouldered hawks in central Minnesota occupy at similar rates landscapes with different habitat compositions resulting from different management strategies and that management strategies that create small openings may not negatively affect red-shouldered hawk occupancy.
The lesser prairie-chicken (Tympanuchus pallidicinctus) is currently considered a candidate for protection under the Endangered Species Act. To identify potential limiting factors for lesser prairie-chicken populations, we developed an age-based matrix model of lesser prairie-chicken population dynamics to compare the relative importance of components of reproduction and survival, and determine if various management alternatives stabilize or increase rates of population change. We based our analyses on an intensive 6-year population study from which demographic rates were estimated for each age class in Kansas. We used deterministic models and elasticity values to identify parameters predicted to have the greatest effect on the rate of population change (λ) at 2 study sites. Last, we used life-stage simulation analysis to simulate various management alternatives. Lambda was <1 for both populations (site 1: λ = 0.54, site 2: λ = 0.74). However, we found differences in sensitivity to nest success and chick survival between populations. The results of the simulated management scenarios complemented the lower-level elasticity analysis and indicated the relative importance of female survival during the breeding season compared with winter. If management practices are only capable of targeting a single demographic rate, changes to either nest success or chick survival had the greatest impact on λ at site 1 and 2, respectively. Management that simultaneously manipulated both nest success and chick survival was predicted to have a greater effect on λ than changes in survival of adult females. In practice, our demographic analyses indicate that effective management should be based on habitat conservation measures to increase components of fecundity.
Loss of nesting habitat is believed to be a factor in the decline of greater sage-grouse (Centrocercus urophasianus) throughout its range. Few data are available for sage-grouse in Mono County, California, USA, in the most southwestern portion of the species' range. We studied habitat selection of nesting sage-grouse in Mono County, California, from 2003 to 2005 by capturing and radiotracking females to identify nesting locations. We sampled vegetation at nest sites and randomly selected sites within 200 m of nests and within each of 5 subareas within Mono County. Nest sites were characterized by 42.4 ± 1.3% (x ¯ ± SE) shrub canopy cover, 10.5 ± 1.0 cm residual grass height, and 2.7 ± 1.0% residual grass cover. Shrub cover was the only variable found to differentiate nest sites from randomly selected sites. Unlike some other studies, we did not find understory vegetation to be important for selecting nest sites. Mean shrub cover was 38.7 ± 1.5% at random sites within 200 m of nests and 33.6 ± 1.6% at random sites at the approximate scale of home ranges, indicating that nesting females selected nesting areas that contained denser shrubs than their home range, and nest sites that contained greater shrub cover than the vicinity immediately surrounding nests. Our results suggest that managers should consider managing for greater shrub cover in Mono County than what is currently called for in other parts of sage-grouse range and that management for sage-grouse habitat may need to be tied more closely to local conditions.
We studied nest survival of greater sage-grouse (Centrocercus urophasianus) in 5 subareas of Mono County, California, USA, from 2003 to 2005 to 1) evaluate the importance of key vegetation variables for nest success, and 2) to compare nest success in this population with other greater sage-grouse populations. We captured and radiotracked females (n = 72) to identify nest sites and monitor nest survival. We measured vegetation at nest sites and within a 10-m radius around each nest to evaluate possible vegetation factors influencing nest survival. We estimated daily nest survival and the effect of explanatory variables on daily nest survival using nest-survival models in Program MARK. We assessed effects on daily nest survival of total, sagebrush (Artemisia spp.), and nonsagebrush live shrub-cover, Robel visual obstruction, the mean of grass residual height and grass residual cover measurements within 10 m of the nest shrub, and area of the shrub, shrub height, and shrub type at the nest site itself. Assuming a 38-day exposure period, we estimated nest survival at 43.4%, with percent cover of shrubs other than sagebrush as the variable most related to nest survival. Nest survival increased with increasing cover of shrubs other than sagebrush. Also, daily nest survival decreased with nest age, and there was considerable variation in nest survival among the 5 subareas. Our results indicate that greater shrub cover and a diversity of shrub species within sagebrush habitats may be more important to sage-grouse nest success in Mono County than has been reported elsewhere.
Flipper banding has long been the primary method to identify individual penguins, despite studies indicating that it may be detrimental to breeding success and survival. Our objectives were to measure the effects that flipper bands may have on diving performance of little penguins to determine whether the bands may be detrimental. We studied short- and long-term direct effects of flipper banding on diving behavior of free-ranging little penguins (Eudyptula minor) by comparing diving behavior before and after banding and by comparing diving performance of unbanded birds to those that had carried flipper bands for several years, respectively. Recently banded birds displayed increases in multiple variables following banding. Long-term banded penguins did not exhibit differences to their unbanded counterparts in most variables examined. Our findings are useful to those considering or reviewing the use of bands in penguin study and management.
Populations of northern bobwhite (Colinus virginianus) have declined significantly over the past 50 years, and the primary factor contributing to this decline has been the loss of habitat. Forest landowners who are concerned with providing bobwhite habitat as well as generating revenue from timber should balance the silvicultural requirements of timber production with the biological needs of the bobwhite. The goal of this study was to determine the economic tradeoffs between bobwhite and timber management and how to minimize loss or maximize profit when managing for bobwhite and timber simultaneously. I performed discounted cash flow analyses, calculated land expectation value, and determined the financially optimal rotation age and optimal timing and intensity of thinnings for loblolly pine (Pinus taeda) plantations under specific management objectives. My results show that the annual per-hectare economic gains of managing for both bobwhite and timber ranged from US$19.27 to $41.37 on site index 50 land, and ranged from $32.63 to $50.02 on site index 90 land. My analysis indicates that bobwhite management provides an investment opportunity to landowners whose low-productivity sites would be unprofitable if timber is the only product. My study provides an example of integrating multiple uses of goods and services in a way that maximizes economic returns and aids land managers in producing better habitat for bobwhite.
As human development continues in coastal areas, shoreline properties adjacent to expansive tidal marsh habitat are increasingly used for access to coastal waterways via long piers (>30 m) over marsh habitat. These tidal wetlands provide breeding and foraging habitat for many marsh birds, which may be affected by the human disturbance associated with long piers. Our objectives were to determine the effect of long piers over vegetated tidal marshes on the relative abundance and species richness of marsh birds. We completed combined passive and callback surveys in tidal marsh habitat at 22 sites with long piers and 24 sites without long piers, May–July 2005–2006 in Worcester County, Maryland, USA. Pier sites had lower relative abundance and species richness of obligate marsh birds than nonpier sites. Pier sites had a greater relative abundance of gulls, terns, herons, and egrets than nonpier sites. Pier sites had fewer species of herons and egrets than at nonpier sites. The presence of long piers had no affect on facultative marsh birds. Long pier density was negatively related to obligate marsh bird relative abundance and species richness, and facultative marsh bird species richness, whereas it was positively related to the relative abundance and species richness of gulls and terns. Herons and egrets relative abundance and species richness were not related to long pier density. Obligate marsh birds were negatively affected by long piers, whereas herons, egrets, gulls, and terns appeared to benefit from perching opportunities. Based on the negative effects of long piers on obligate marsh birds, management should focus on reducing the presence and density of long piers in tidal marshes by requiring the removal of existing long piers, or reducing or eliminating permits for construction of new long piers.
Effects of silvicultural activities on birds are of increasing interest because of documented national declines in breeding bird populations for some species and the potential that these declines are in part due to changes in forest habitat. Silviculturally induced disturbances have been advocated as a means to achieve suitable forest conditions for priority wildlife species in bottomland hardwood forests. We evaluated how silvicultural activities on conservation lands in bottomland hardwood forests of Louisiana, USA, influenced species-specific densities of breeding birds. Our data were from independent studies, which used standardized point-count surveys for breeding birds in 124 bottomland hardwood forest stands on 12 management areas. We used Program DISTANCE 5.0, Release 2.0 (Thomas et al. 2006) to estimate density for 43 species with >50 detections. For 36 of those species we compared density estimates among harvest regimes (individual selection, group selection, extensive harvest, and no harvest). We observed 10 species with similar densities in those harvest regimes compared with densities in stands not harvested. However, we observed 10 species that were negatively impacted by harvest with greater densities in stands not harvested, 9 species with greater densities in individual selection stands, 4 species with greater densities in group selection stands, and 4 species with greater densities in stands receiving an extensive harvest (e.g., >40% canopy removal). Differences in intensity of harvest influenced densities of breeding birds. Moreover, community-wide avian conservation values of stands subjected to individual and group selection, and stands not harvested, were similar to each other and greater than that of stands subjected to extensive harvest that removed >40% canopy cover. These results have implications for managers estimating breeding bird populations, in addition to predicting changes in bird communities as a result of prescribed and future forest management practices.
The migratory population of the king rail (Rallus elegans) has declined dramatically during the past 40 years, emphasizing the need to identify habitat requirements of this species to help guide conservation efforts. To assess distribution and habitat use of king rails along the Illinois and Upper Mississippi valleys, USA, we conducted repeated call-broadcast surveys at 83 locations in 2006 and 114 locations in 2007 distributed among 21 study sites. We detected king rails at 12 survey locations in 2006 and 14 locations in 2007, illustrating the limited distribution of king rails in this region. We found king rails concentrated at Clarence Cannon National Wildlife Refuge, an adjacent private Wetlands Reserve program site, and B. K. Leach Conservation Area, which were located in the Mississippi River floodplain in northeast Missouri. Using Program PRESENCE, we estimated detection probabilities and built models to identify habitat covariates that were important in king rail site occupancy. Habitat covariates included percentage of cover by tall (>1 m) and short (≤1 m) emergent vegetation, percentage of cover of woody vegetation, and interspersion of water and vegetation (2007 only) within 50 m of the survey location. Detection probability was 0.43 (SE = 0.12) in 2006 and 0.35 (SE = 0.03) in 2007 and was influenced by observer identity and percentage of cover by tall herbaceous vegetation. Site occupancy was 0.11 (SE = 0.04) in 2006 and 0.14 (SE = 0.04) in 2007 and was negatively influenced most by percentage of cover by woody vegetation. In addition, we found that interspersion of vegetation and water was positively related to occupancy in 2007. Thus, nesting king rails used wetlands that were characterized by high water–vegetation interspersion and little or no cover by woody vegetation. Our results suggest that biologists can improve king rail habitat by implementing management techniques that reduce woody cover and increase vegetation–water interspersion in wetlands.
The decline of many snake populations is attributable to habitat loss, and knowledge of habitat use is critical to their conservation. Resource characteristics (e.g., relative availability of different habitat types, soils, and slopes) within a landscape are scale-dependent and may not be equal across multiple spatial scales. Thus, it is important to identify the relevant spatial scales at which resource selection occurs. We conducted a radiotelemetry study of eastern hognose snake (Heterodon platirhinos) home range size and resource use at different hierarchical spatial scales. We present the results for 8 snakes radiotracked during a 2-year study at New Boston Air Force Station (NBAFS) in southern New Hampshire, USA, where the species is listed by the state as endangered. Mean home range size (minimum convex polygon) at NBAFS (51.7 ± 14.7 ha) was similar to that reported in other parts of the species' range. Radiotracked snakes exhibited different patterns of resource use at different spatial scales. At the landscape scale (selection of locations within the landscape), snakes overutilized old-field and forest edge habitats and underutilized forested habitats and wetlands relative to availability. At this scale, snakes also overutilized areas containing sandy loam soils and areas with lower slope (mean slope = 5.2% at snake locations vs. 6.7% at random locations). We failed to detect some of these patterns of resource use at the home range scale (i.e., within the home range). Our ability to detect resource selection by the snakes only at the landscape scale is likely the result of greater heterogeneity in macrohabitat features at the broader landscape scale. From a management perspective, future studies of habitat selection for rare species should include measurement of available habitat at spatial scales larger than the home range. We suggest that the maintenance of open early successional habitats as a component of forested landscapes will be critical for the persistence of eastern hognose snake populations in the northeastern United States.
Mortality due to fisheries interactions has been implicated as a contributor to population decline for several species of sea turtle. The incidental capture of sea turtles in the coastal gillnet fisheries of North Carolina, USA, has received much attention in recent years, and mitigation measures to reduce sea turtle mortality due to gillnet entanglement are a high priority for managers and conservationists. Efforts to evaluate effects of gillnet entanglement on sea turtle populations are complicated by the lack of information on health status of turtles released alive from nets and postrelease mortality. We obtained blood samples from green (Chelonia mydas) and Kemp's ridley (Lepidochelys kempii) sea turtles captured in gillnets for 20–240 minutes to assess the impacts of gillnet entanglement on blood biochemistry and physiological status. We measured concentrations of lactate, corticosterone, ions (Na, K, Cl−, P, Ca2 ), enzymes (lactate dehydrogenase [LDH], creatine phosphokinase [CPK], aspartate aminotransferase [AST]), protein, and glucose in the blood and also performed physical examinations of turtles to document external indicators of health status (injuries, lethargy, muted reflexes). We evaluated the effects of entanglement time on blood biochemistry and to look for correlations between blood biochemistry and results of the physical examinations. We observed a significant increase in blood lactate, LDH, CPK, phosphorus, and glucose with increased entanglement time. Alterations in blood biochemistry were generally associated with a decline in health status as indicated by results of the physical examination. Although entanglement time plays an important role in determining the health status of sea turtles upon release from a gillnet, our results suggest that factors such as the depth and severity of entanglement may also have an effect on health status of turtles and the probability of postrelease survival. We were unable to set a maximum unattended gillnet soak time to minimize impacts on captured sea turtles, and therefore recommend that fisheries managers continue to enforce the net attendance regulations currently in place in the lower Cape Fear River, North Carolina, during the summer months.
The western pond turtle (Actinemys marmorata) is a species of conservation concern over much of its range and is listed as endangered in Washington State. From 2000 to 2004, we used radiotelemetry to document survival and mortality factors of head-started western pond turtles (n = 68) released into Pierce National Wildlife Refuge in southwestern Washington. Survival estimates for first year and older turtles ranged from 86% to 97% and overlapping confidence intervals indicated no detectible differences among age classes or among years. Subadult turtles released at ≥90-mm carapace length apparently avoided capture by most aquatic predators, indicating that terrestrial predators should be the focus of research and management where predation on larger age-classes is a concern. High annual survival combined with the documented nesting by ≥7-year-old female head-started turtles in Washington suggest that recruitment of adults is being achieved; however, head-starting is only practical as an interim solution and strategies for effective removal of aquatic predators must be developed and implemented where natural recruitment is inadequate to maintain populations.
KEYWORDS: black bear, human–wildlife conflict, New Jersey, New York, risk communication, risk perception, social amplification of risk, Ursus americanus
Managers and other stakeholders may rely on wildlife-related risk communication campaigns to prevent or reduce risks associated with human–wildlife conflict. The operating environment or the sphere of activity within which a campaign functions can influence a campaign's ability to achieve outcomes. Between 1 May 2005 and 30 October 2005, we studied human–black bear conflict in southeastern New York and the wildlife-related risk communication campaign, the New York NeighBEARhood Watch (NYNW). Based on the social amplification of risk framework, our goal was to determine whether mass media affected the operating environment of the campaign, and if so, identify the magnitude and direction of the effect. We used a self-administered mail survey (N = 2,800) in 4 southeastern New York, USA, towns to collect data about residents' perceived black bear-related risks, bear-related behavior, and exposure to the NYNW. We also conducted a content analysis of mass media coverage about black bears. Exposure to the NYNW from newspapers was positively correlated (R = 0.39, P < 0.01) with respondents' decreased acceptance of black bear-related risks. Our results showed a small social amplification of risk associated with black bears from exposure to mass media, specifically newspapers. Mass media can influence the operating environment of a wildlife-related risk communication campaign, including through amplification of risk perception. Characterizing the operating environment of campaigns is key to HWC-intervention planning, evaluation, and policy. Wildlife practitioners can consider media effects, as well as other biological and social factors, as potential influences on a campaign's operating environment and be aware that interaction effects may occur.
Nutria (Myocastor coypus) are an important part of the Louisiana (USA) fur industry, but high densities of nutria cause extensive damage to coastal marsh ecosystems. Hence, there is a need to develop improved methods for targeted management of nutria. We screened 14 olfactory cues as potential lures for nutria, first in controlled settings and then in the field, to see if nutria capture rates using foothold traps would increase. In Y-maze trials, nutria most frequently selected olfactory cues of a synthetic formulation of nutria anal-gland secretion and nutria fur extract. We examined the 3 most selected attractants in Y-maze trials and female nutria urine under field conditions to compare trapping success over untreated traps. Capture probability was nearly 2.5 times greater for fur wash than control and 2 times greater for urine than control (relative risk = 2.43 and 2.01, respectively). The results suggest that use of semiochemicals and synthetic formulations of semiochemicals increased nutria trapping success. Development and use of effective synthetic semiochemicals could benefit resource managers nationwide who are responsible for reducing damage caused by this invasive herbivore.
Accurately estimating large mammal populations is a difficult challenge because species of interest often occupy vast areas and exhibit low and heterogeneous visibility. Population estimation techniques using aerial surveys and statistical design and analysis methods provide a means for meeting this challenge, yet they have only rarely been validated because wild populations of known size suitable for field tests are rare. Our study presents field validations of a photographic aerial mark–recapture technique that takes advantage of the recognizable natural markings on free-roaming feral horses (Equus caballus) to accurately identify individual animals and groups of animals sighted on multiple occasions. The 3 small populations of feral horses (<400 animals each) in the western United States used in the study were all closely monitored on a weekly basis by local researchers, thus providing test populations of known size. We were able to accurately estimate these population sizes with aerial surveys, despite rugged terrain and dense vegetation that created substantial heterogeneity of sighting probability among horse groups. Our best estimates at the 3 sites were within −6.7%, 2.6%, and −8.6% of known truth (−4.2% mean error, 6.0% mean absolute error). In contrast, we found undercount bias as large as 32% before any statistical corrections. The necessary corrections varied both temporally and spatially, in response to previous sighting history (behavioral response), and by the number of horses in a group. Despite modeling some of the differences in horse-group visibility with sighting covariates, we found substantial residual unmodeled heterogeneity that contributed to underestimation of the true population by as much as 22.7% when we used models that did not fully account for these unmeasured sources. We also found that the cost of the accurate and validated methods presented here is comparable to that of raw count (so called, census) methods commonly employed across feral horse ranges in 10 western states. We believe this technique can assist managers in accurately estimating many feral horse populations and could be applied to other species with sufficiently diverse and distinguishable visible markings.
Sampling of feces for genetic studies of wild populations can be problematic because of the low quality and quantity of template DNA obtained. We used cotton swabs in the field to isolate the mucous layer on the surface of fresh wolf (Canis lupus, C. lycaon, and their hybrids) scats followed by immediate preservation, and compared microsatellite genotyping of DNA from these fresh field swabs (FS) to that of previously frozen laboratory swabs (LS). In single polymerase chain reactions (PCRs) of 2 multiplexes, amplification at 8 loci was higher in the FS samples (FS = 50%, LS = 15%; P = 0.02) because proportion, quantity, and quality of large fragment wolf nuclear DNA from these samples was greater (2.5–25%, 6.25–62.5 ng/swab, 35% amplified at 1,000 base pairs [bp]) than from the LS samples (1.9%–10%, 4.7–25 ng/swab, 10% amplified at 1,000 bp). Paired blood and fresh field-swabbed samples had identical genotypes. In 84 multiplex PCRs we found no evidence of allelic dropout associated with low template quality or quantity. We conclude that field swabbing of fresh wolf scat facilitates field storage and reduces the need for multiple amplifications at single microsatellite loci, thereby reducing the genotyping costs for wildlife projects that use noninvasive samples.
Detailed ecological data on the bush dog (Speothos venaticus) have been lacking, since standard field techniques, such as camera traps, have had little success recording their presence. This study eliminates dependence on visitation rate and switches the focus to locating evidence (e.g., olfactory) associated with the species' natural behavior and movement patterns. Over a 3-month period, a detection dog located multiple (n = 11, 4 confirmed and 7 potential) bush dog areas in Upper Paraná Atlantic Forest of Misiones Argentina. These positive results demonstrate that detection dogs can provide species-specific data on the bush dog despite the rugged terrain and dense forest vegetation they may occupy. The ecological data collected using this technique allow effective conservation strategies to be developed, wildlife corridors and biological crossings to be designed, and species distributions to be examined.
We compared injury rates among captured coyotes (Canis latrans) to determine if modifications to cable foot-restraints would decrease resulting injuries. Mean International Standardization Organization's injury scores of coyotes caught in 3 types of cable foot-restraints were 22.2, 37.9, and 60.4 (F2,41 = 4.63, P = 0.015) for a chain-loop, standard cable, and sleeved cable, respectively. These results may be important for trappers and researchers to consider when using a cable foot-restraint device to capture wildlife.
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