William F. Porter

Social organization in deer : implications for localized management

Populations of white-tailed deer (Odocoileus virginianus) inhabiting many state and national parks and suburban areas have grown to the point that they conflict with human activities. Conflicts range from destruction of vegetation through browsing to public perception that diseases carried by deer pose threats to human health. Traditional modes of hunting to control populations are inappropriate in many of these areas because of intense human development and activity. This article explores an alternative approach for population reduction based on deer social organization. Female white-tailed deer are highly philopatric and female offspring remain near their dams for life. This suggests that a population expands slowly as a series of overlapping home ranges in a form analogous to the petals on a rose. Incorporating the rose petal concept into a model of population growth shows that removal of deer by family unit can potentially alleviate conflicts in localized areas for as many as 10–15 yr.

Effect of Social Structure on Genetic Structure of Free-Ranging White-Tailed Deer in the Adirondack Mountains

The association between genetic structure and social structure was investigated in a free-ranging population of white-tailed deer ( Odocoileus virginianus ) in northern New York. Social groups were differentiated based on spatial aggregations and allozymic characteristics ( P < 0.05). Genetic structure was evident despite the high probability that males interbreed among adjacent and overlapping social groups on summer range. An excess of heterozygosity occurred within groups ( F IS = −0.25) relative to that expected from Hardy-Weinberg proportions. We suggest that the excess may be accounted for by a high turn-over rate among breeding males who lose their dominance between years. Genetic distances among groups were associated with the location of the social group on winter range. Groups that used the same winter range were more genetically similar even though in the central Adirondacks deer primarily breed on their summer range. We suggest that this association with winter range is due to the traditional use of winter yards by matrilineal groups and is maintained by female philopatry.

Effects of environmental pattern on habitat preference analysis

Changes in study area boundaries can affect inferences of habitat use by wildlife. In environments with regular patterns of cover dispersion, tests show delineation of study area boundaries has no effect on statistical indication of habitat use. In environments in which cover types are arranged in an aggregated pattern, traditional statistical approaches may yield spurious results. We present an analytical approach using grid cells, which offers an alternative way to examine habitat use patterns by wildlife. J. WILDL. MANAGE. 51(3):681-685 An objective of wildlife studies using radio telemetry is to determine the habitat compo- nents important to wildlife. However, the in- vestigative approach often used in these studies has serious limitations that do not appear to be widely recognized. Our intent is to illustrate some of these limitations and suggest an alter- native that merits further exploration in habitat preference studies. The analysis of telemetry data involves clas-

Movement behavior, dispersal, and the potential for localized management of deer in a suburban environment

Abstract We examined the potential for localized management of white-tailed deer (Odocoileus virginianus) to be successful by measuring movements, testing site fidelity, and modeling the effects of dispersal. Fifty-nine females were radiomarked and tracked during 1997 through 2000 in Irondequoit, New York, USA, a suburb of Rochester. We constructed home ranges for those deer with ≥18 relocations/season. Fifty percent minimum convex polygons (MCP) averaged 3.9 (SE = 0.53) ha in the summer and 5.3 (SE = 0.80) ha in the winter. Deer showed strong fidelity to both summer and winter home ranges, and 30 of 31 females showed overlap of summer and winter home ranges. Annual survival was 64%; the major cause of mortality was deer–automobile collisions. Average annual dispersal rates were <15% for yearlings and adults. Using matrix population modeling, we explored the role of female dispersal in sustaining different management objectives in adjacent locales of approximately 1,000 ha. Modeling showed that if female dispersal was 8%, culling would have to reduce annual survival to 58% to maintain a population just under ecological carrying capacity and reduce survival to 42% to keep the population at one-half carrying capacity. With the same dispersal, contraception would need to be effective in 32% of females if the population is near carrying capacity and 68% if the population is at one-half of carrying capacity. Movement behavior data and modeling results lend support to the use of a localized approach to management of females that emphasizes neighborhood-scale manipulation of deer populations, but our research suggests that dispersal rates in females could be critical to long-term success.

Sociospatial Dynamics of White-Tailed Deer in the Central Adirondack Mountains, New York

We compared the sociospatial behavior among and within kin groups of white-tailed deer ( Odocoileus virginianus ) inhabiting a contiguous forest environment of the central Adirondack Mountains, New York. This population had not been hunted since 1932 and contained females >10 years old. We estimate that 60–75% of all females were individually marked. Although actual genetic relatedness among females was uncertain, previous research on this population included genetic analyses of kin groups and our data showed long-term fidelity of individuals to kin groups. We hypothesize that although sociospatial behavior at the group level is relatively rigid, the sociospatial patterns of individuals within groups are more flexible. Specifically, we predict that sociospatial patterns within groups vary with age and reproductive status. Data from radiotelemetry and visual observations were used to delineate kin groups. Kin groups were classified using two techniques; distance between activity centers based on harmonic means on summer range, and grouping individual deer based on location on summer and winter range. Females in our study population exhibited a high level of philopatry to summer ranges inhabited by their kin group ( 5 years old maintained home ranges in spring and summer that were more exclusive than those of younger females. Pregnant females used smaller areas during spring than barren females.

Survival and Reproduction of Female Wild Turkeys in New York

Annual fluctuations of northern wild turkey (Meleagris gallopavo silvestris) populations often are attributed to high winter mortality. However, studies conducted in agricultural environments have demonstrated that seasonal survival can be highest during winter, suggesting other factors are more important to annual population change. We examined survival and reproduction of female eastern wild turkeys in south-central New York during 1990-93 and conducted a sensitivity analysis to determine the relative importance of demographic parameters to annual population change. Seasonal survival rates (n = 238) were 0.800 for spring, 0.855 for summer, 0.834 for fall, and 0.873 for winter. Fall survival rates varied by years (P < 0.01) and were higher during years of above average hen success. Annual survival rates averaged 0.498, and crude annual mortality rates (M) averaged 0.321 for predation and 0.117 for poaching, hunting, and wounding combined. Subadult females had lower nesting rates (P = 0.002, n = 201), lower renesting rates (P = 0.001, n = 115), and lower hen success rates (P = 0.02, n = 196) than adult females. Nest success averaged 37.9% (n = 232) and was highest (P = 0.005) during years with average to below average May rainfall. We observed annual variation in nest success (P = 0.001), hen success (P = 0.003), and hatching rates (P = 0.04). Poult survival averaged 40.0% (n = 605) and did not vary among years (P = 0.73). Nest success was the primary factor contributing to annual population change. We suggest that annual fluctuations of northern populations in mixed agricultural and forested environments rarely result from variability of annual survival and may result from variability of annual nest success and poult survival. Northern populations subjected to infrequent severe winters in mixed agricultural and forested environments likely would benefit more from enhancement of nesting and brood-rearing habitat.

The consistency and stability of abundance–occupancy relationships in large‐scale population dynamics

1. Abundance-occupancy relationships comprise some of the most general and well-explored patterns in macro-ecology. The theory governing these relationships predicts that species will exhibit a positive interspecific and intraspecific relationship between regional occupancy and local abundance. Abundance-occupancy relationships have important implications in using distributional surveys, such as atlases, to understand and document large-scale population dynamics and the consequences of environmental change. A basic need for interpreting such data bases is a better understanding of whether changes in regional occupancy reflect changes in local abundance across species of varying life-history characteristics. 2. Our objective was to test the predictions of the abundance-occupancy rule using two independent data sets, the New York State Breeding Bird Atlas and the North American Breeding Bird Survey. The New York State Breeding Bird Atlas consists of 5332 25-km(2) survey blocks and is one of the first atlases in the USA to be completed for two time periods (1980-85 and 2000-05). The North American Breeding Survey is a large-scale annual survey intended to document the relative abundance and population change of songbirds throughout the USA. 3. We found that regional occupancy was positively correlated with relative abundance across 98 (beta = 0.60 +/- 0.11 SE, P < 0.001, R(2) = 0.60) and 85 species (beta = 0.67 +/- 0.06 SE, P < 0.001, R(2) = 0.57) in two separate time periods. This relationship proved stable over time and was notably consistent between breeding habitat groups and migratory guilds. 4. Between 1980 and 2005, changes in regional occupancy were highly correlated with long-term abundance trend estimates for 75 species (beta = 5.73 +/- 0.24 SE, P < 0.001, R(2) = 0.88). Over a 20-year period, woodland and resident birds showed an increase in occupancy while grassland species showed the greatest decline; these patterns were mirrored by changes in local abundance. 5. Although exceptions existed, we found most changes in occupancy parallel changes in local abundance. These findings support the basic predictions of the abundance-occupancy rule and demonstrate its consistency and stability in species and groups of varying life-history characteristics.

OF ELEPHANTS AND BLIND MEN: DEER MANAGEMENT IN THE U.S. NATIONAL PARKS

Overabundant populations of white-tailed deer (Odocoileus virginianus) are becoming common in the eastern United States. Faced with burgeoning deer populations in eastern parks, the National Park Service (NPS) formulated policy based on its long experience with ungulate management in western parks. That the NPS failed to find a management solution acceptable to its many constituencies was inevitable. Like blind men touching different parts of an elephant and disagreeing about its form, those engaged in the debate about deer management in parks are viewing different parts of the ecological system. None has seen the entire system, and consequently, there is neither common agreement on the nature of the problem nor on the solutions. We explore the quandary of deer management in eastern parks by addressing three questions: (1) Can the National Park Service reconcile its management goals with those of its neighbors? (2) Can thresholds be identified for determining when to intervene in natural processes? (3) Is...

Temporal, Spatial, and Landscape Habitat Characteristics of Moose–Vehicle Collisions in Western Maine

Abstract We analyzed moose (Alces alces)–vehicle collisions (MVCs) in western Maine, USA, from 1992 to 2005 (n  =  8,156) using Geographic Information Systems to identify patterns of temporal and spatial distribution and develop predictive models based on road and landscape characteristics. We used chi-square and correlation analyses to assess temporal characteristics of MVCs, K-function and kernel analyses to identify spatial clusters of MVCs, and logistic regression to relate covariates for traffic, land-cover, land-form, and relative moose abundance to probability of MVC. We evaluated candidate models using Akaikes Information Criterion, area under the receiver operating characteristic curve (AUC), and the percentage of correctly classified observations. Most (81.6%) MVCs occurred from May to October, with peak monthly frequencies in June (18.6%). Moose–vehicle collisions were clustered spatially on roads at local (0–4 km) and regional scales (22–41 km and 45–54 km), but not at intermediate scales. Traffic-related covariates predicting MVCs included traffic volume and speed limit. For each additional 500 vehicles/day, odds of a location being an MVC increased by 57%. For each 8-km/hr increase in speed limit, odds of an MVC increased by 35%. Landscape composition covariates best predicted MVCs within a 2.5-km radius of the collision site. Mean percent cover within 2.5 km of MVCs was comprised of 36% more cutover forest, 10% more coniferous forest, 5% less deciduous–mixed forest, and 10% less nonwoody wetland than for random points. For every 5% increase in percent cutover and coniferous forest within 2.5 km of the road, predicted odds of MVC increased by 36% and 19%, respectively. Landscape configuration covariates best predicted MVCs within the 5.0-km radius. Moose–vehicle collisions were associated with areas of less interspersion of cover types; for each 5% increase in an index of interspersion–juxtaposition, predicted odds of MVC decreased by 11%. Our final model attained high predictive power (AUC  =  0.835) and validation accuracy (75.0%). The model also proved robust to physiographic variation, exhibiting high predictive power (AUC  =  0.828) and validation accuracy (68.8%). Managers seeking to prioritize resources for reducing MVCs or predicting future areas of high MVC probability should assess land-cover composition and configuration surrounding MVC hotspots at geographic extents out to 2.5–5 km and use this information to plan expensive roadside management practices such as fencing. The importance of traffic and landscape covariates in our modeling suggests that effective management to reduce MVCs will require a complex combination of driving speed reductions and modifications to forest management along roads.

AN ALTERNATIVE FIELD TECHNIQUE FOR ESTIMATING DIVERSITY OF SMALL-MAMMAL POPULATIONS

Abstract Sampling of populations of small mammals has traditionally focused on use of live traps, which are often costly and labor intensive. We tested track tubes as an alternative technique for assessing populations of small mammals. Track tubes record footprints of small mammals and allow determination of their presence or absence without live capture. We compared results from livetrapping against data from track tubes on 5 sites over 1-week periods in June 1999 and June 2000. Correlations between indices of abundance from the 2 techniques were significant in 1999 (rs = 0.656, P < 0.001) and 2000 (rs = 0.715, P < 0.001). Using track tubes we distinguished footprints of 4 species. We were not able to distinguish Peromyscus from Clethrionomys gapperi; species of Sorex could not be distinguished. In comparison with livetrapping, track tubes are inexpensive, are much less labor intensive for researchers, and can be run simultaneously on several sites. The technique has good promise where investigators seek only to identify composition and relative abundance of small-mammal species.