Bruce D. Leopold

A MULTI-RESOLUTION ASSESSMENT OF RACCOON DEN SELECTION

Abstract Many studies have been conducted on the ecology of raccoons (Procyon lotor), while few have examined raccoon den-site selection, particularly in agricultural and prairie landscapes. Furthermore, no studies have examined selection of den sites at multiple spatial scales. We examined den-site selection for 48 raccoons during 1997–1999 in an agricultural landscape in the Black Prairie physiographic region of east-central Mississippi, USA. Den types selected by raccoons differed by gender and season. Females used more cavity dens during young rearing, whereas males selected ground dens and brush piles. We found that den sites were located closer to crop fields, roads, and macrohabitat edges than random points. At the landscape level, den sites were associated positively with woody patch size, amounts of woody and grass edge, number of available patches of crop fields, and available area of lakes and ponds. Composition of habitats around den sites differed from composition of habitats within home ranges, and this difference also was noted by gender. Female raccoons selected crop fields, whereas males selected lakes/ponds relative to composition of habitats within their respective home ranges. Our results indicate the importance of tree cavities to females during young rearing, particularly on prairie landscapes. Furthermore, our findings suggest that on prairie landscapes, availability of foraging habitat and water may influence den-site selection. We suggest that raccoons select den sites based on a perceived arrangement of required resources and that landscape configuration is important in the den-selection process. Additionally, our findings offer evidence that managers may selectively remove den sites as a nonlethal means of managing predation by raccoons.

AFFORESTATION OF BOTTOMLAND HARDWOODS IN THE LOWER MISSISSIPPI ALLUVIAL VALLEY: STATUS AND TRENDS

The Lower Mississippi Alluvial Valley (LMAV) originally supported at least 10 million ha of bottomland hardwood (BLH) forests. Many of these forests were wetlands and provided a diversity of values that were not recognized fully until at least one-half of the original forested area had been converted primarily to row-crop agriculture. Efforts to restore these forests have expanded in proportion to growing recognition of their unique values. This paper provides a summary resulting from a survey of BLH afforestation by all agencies and private entities in Arkansas, Louisiana, and Mississippi, the three states in the LMAV with the most restoration activity and, more specifically, by the U.S. Fish and Wildlife Service, the U.S.D.A. Natural Resources Conservation Service, and state wildlife management agencies, the three entities responsible for approximately 95% of the afforestation in this region. There is a promising trend in the annual increase of BLH afforestation across the LMAV. Approximately 71,000 ha have been planted with BLH species through 1998; however, this represents <1% of the BLH forests that have been lost, and afforestation does not ensure restoration of all ecological functions. No clear choice between planting stocks (bareroot seedlings or direct seeding) or among planting seasons (Fall, Winter, Spring, or Summer) is prevalent among those involved in BLH afforestation. Much of the early afforestation used oaks (Quercus spp.) to accelerate replacement of mast-bearing species. Recently, mixtures of species have been incorporated into afforestation regimes. More light-seeded species and a more diverse component of oak species have been planted to mimic a more natural regeneration process. Successful widescale afforestation is a critical link in restoration of functional BLH ecosystems in this region.

Regulation of space use in a solitary felid: population density or prey availability?

Home range size in birds and mammals appears to be influenced by a number of factors including food availability, body mass and population density. However, few studies have convincingly shown population density to influence the extent of space use in a population of free-ranging carnivores without a corresponding increase in food availability. We investigated the relative effects of food availability, body weight and increased density on the size of adult bobcat, Lynx rufus, home ranges and core areas in Mississippi, U.S.A. during 1989–1997. We observed an increase in population density and a decrease in annual mean home range and core area sizes for males and females during this 9-year study. Population density explained 64% and 56% of the variation in home range size for males and females, respectively, whereas food availability and body weight failed to explain the observed reduction in bobcat home range size. Population density was also the most important variable explaining variation in core areas for both sexes, although food availability also appeared to contribute to variation, especially for females. We suggest that population density should be considered along with energy acquisition and metabolic factors such as food availability and body size when investigating variability in home range and core area sizes of mammals.

Denning ecology of black bears in the White River National Wildlife Refuge, Arkansas

Lack of adequate den sites may adversely affect cub survival and reproductive success in black bears (Ursus americanus). Management of remnant bear populations in the lower Mississippi floodplain necessitates understanding denning ecology. We monitored 23 radiotagged black bears for 33 den years from 1993 to 1995 in White River National Wildlife Refuge, Arkansas to investigate denning chronology and den requirements. Bears entered dens between 1 January-20 February and emerged between 12 March-28 April. Mean (±SE) denning duration was 92.9 ± 6.6 days and varied between sex-age classes (P = 0.002). Pregnant females denned longer (117.8 ± 5.2 days, P = 0.029) than males and non-pregnant females (84.2 ± 7.7 days). More than 44% of the bears that denned (n = 27) used >1 den during a denning season, and one female used 4 dens. Most (90.2%, n = 51) dens were elevated tree cavities with a hollow opening on the top or middle of the main trunk. Three species of trees were used with 77.8% (n = 46) being overcup oak (Quercus lyrata). Basal area of trees ≥10 cm diameter at breast height (dbh; P < 0.001) and number of stems ≥84 cm dbh (P < 0.001; the min. dbh of den trees documented in this study) differed among vegetation plots with and without den trees. For seasonally flooded habitats, our results suggest the need for maintenance or augmentation of trees ≥84 cm dbh to increase the number of potential dens and to enhance the quality of den microhabitat in the lower Mississippi Alluvial Valley.

Habitat use of eastern wild turkeys in central Mississippi

Most past studies of wild turkey (Meleagris gallopavo) habitat use were limited to 1 spatial scale. were of short duration, and had not simultaneously examined habitat use by both sexes. We used compositional analysis to describe habitat use of an castern wild turkey (M. g silvestris) population in central Mississippi at 3 spatial scales (study area, home range, within home range). We conducted the study on the 14,410-ha Tallahala Wildlife Management Area (TWMA), which was composed of hardwood, pine, and pine-hardwood stands of various ages. Overall, turkevs of both sexes preferred pine and hardwood sawtimber most, and poletimber stands least Throughout the vear, females primarily used hardwood sawtimber stands, but males tended to use pine sawtimber. Habital use by females during preincubation may have influenced subsequent nest success. Habitat use at 3 spatial scales was similar and was reflective of the adaptable nature of wild turkeys and the high degree of habitat heterogencity on the study area.

Space use and multi-scale habitat selection of adult raccoons in Central Mississippi

Raccoons (Procyon lotor) are important furbearers and ecological generalists that exist in a variety of landscapes. Numerous studies have examined raccoon space and macrohabitat use, but information detailing these parameters within pine-dominated landscapes is lacking. Furthermore, no studies using radiotracking have examined raccoon habitat use at multiple spatial scales. We radiomonitored 131 adult raccoons (99 M, 32 F) during 1991-1997 in central Mississippi, USA. We subsequently assessed space use and habitat selection at 3 spatial scales. Males maintained larger home ranges and core areas than females. Size of home ranges differed by season, but raccoons maintained similar-size core areas across seasons. Habitat use differed by gender only at the coarsest spatial scale. Raccoons consistently used mature (>30 years old) pine and hardwood habitats over other available habitats at all spatial scales. Although hardwood-dominated habitats were important to raccoons, our findings suggest that in pine-dominated landscapes, raccoons select multiple seral stages of pine. Raccoons also readily used ≤8-year-old pine habitats, likely because of increased foraging opportunities within these habitats, particularly, during spring and summer. Our findings illustrate the importance of juxtaposition of habitat types for raccoons in pine-dominated landscapes, specifically the availability of mature pine and hardwood habitats, as well as early-successional habitats capable of providing beneficial foraging resources. Additionally, our findings offer evidence that prescribed burning may alter landscape use by raccoons, providing the potential that manipulating burning frequencies may allow managers to manage raccoon habitat-use patterns.

Survival and cause-specific mortality of adult raccoons in central Mississippi

The raccoon (Procyon lotor) provides recreational, aesthetic, and economic benefits throughout its range. Knowledge of survival and cause-specific mortality is necessary to understand dynamics of raccoon populations and enable effective management. Additionally, sportsmen in many Southeastern states have expressed interest in a summer raccoon hunting season; however, information on effects of summer hunting on raccoon survival and cause-specific mortality are unavailable. Consequently, we radiotracked 176 adult raccoons in central Mississippi during 1991-97. Annual survival differed (P = 0.031) between males (0.63 ± 0.09; x ± SE) and females (0.50 ± 0.10). Annual survival varied among years for males (P < 0.01), but not for females (P = 0.117). Cause of death was known for 55% of raccoon mortalities; legal harvest accounted for most (58%) known deaths. Annual survival did not differ (P = 0.356) between raccoons in the summer hunting (0.60 ± 0.06) and control (0.69 ± 0.06) areas. However, patterns of mortality varied between the summer hunting and control areas (P < 0.001), and seasonally (P = 0.003). Our data suggest implementing a summer raccoon ting season with conservative bag limits will not reduce raccoon populations by reducing annual survival.

Space use, movements and habitat selection of adult bobcats (Lynx rufus) in Central Mississippi

Abstract Many factors influence bobcat (Lynx rufus) space use, movements and habitat selection, including prey distribution and density, season, breeding behaviors and intraspecific relationships. Knowledge of ranging behaviors and habitat selection is required to understand population dynamics and ecology of bobcats within temperate ecosystems. We radio-monitored 58 adult bobcats from 1989–1997 in central Mississippi. Males maintained larger home ranges and core areas than females, but sizes of these areas did not vary seasonally. Male bobcats moved at greater rates than females and bobcats moved at greatest rates during nocturnal periods. Movement rates were greatest during winter. Habitat selection at three spatial scales differed between genders and across seasons within gender. Our findings suggest that ≤8 y-old pine (Pinus spp.) habitats are important to bobcats, particularly females, as these habitats were selected by females at all spatial scales. However, our data also indicate that mature (>30 y) pine habitats are important to bobcats on our study area.

Diets of 3 Predators in Big Bend National Park, Texas

Le regime alimentaire de Felis concolor F. rufus et Canis latrans est etudie entre 1972-74 et 1980-81 dans le Parc National de Big Bend au Texas. Les modifications constatees entre les 2 dates resultent du declin significatif de la population de Odocoileus hemiomus crooki

Forest Management and Female Black Bear Denning

Abstract: Most habitats available to black bear (Ur,~usamericanus) in the Mississippi Alluvial Valley (M.4V) consist of seasonally flooded commercial forests where lack of suitable dens may limit population growth. \Ve studied interactions between forest management and flooding relative to female black bear denning. Denning behavior differed between commercial and noncommercial forests. Females used tree dens exch~sivelyon nonco~nmercialforests, whereas on commercial forests, most (83%) were ground dens. L7ariationsin ground den elevation resulted in differing inundation probabilities, altering survival prol.)abilities for neonates. On commercial forests, ground dens with similar inundation probabilities as tree dens allowed successful repro-duction to occur. Management practices that enhance suitable cover in areas of nlirlimal inundation probability may mitigate for lack of den trees in flood-prone landscapes. JOURNAL OF WILDLIFE MANAGEMENT 65(1):34-40 Key words: batture, black bear, denning, elevation, flooding, forest management, Misissippi Allu~ialValley, reproduction, topography, Ursus arnericanus.