L. Wes Burger

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.

Effects of the Conservation Reserve Program on northern bobwhite and grassland birds

The Conservation Reserve Program (CRP) has converted just over 36 million acres of cropland into potential wildlife habitat, primarily grassland. Thus, the CRP should benefit grassland songbirds, a group of species that is declining across the United States and is of conservation concern. Additionally, the CRP is an important part of multi-agency, regional efforts to restore northern bobwhite populations. However, comprehensive assessments of the wildlife benefits of CRP at regional scales are lacking. We used Breeding Bird Survey and National Resources Inventory data to assess the potential for the CRP to benefit northern bobwhite and other grassland birds with overlapping ranges and similar habitat associations. We built regression models for 15 species in seven different ecological regions. Forty-nine of 108 total models contained significant CRP effects (P < 0.05), and 48 of the 49 contained positive effects. Responses to CRP varied across ecological regions. Only eastern meadowlark was positively-related to CRP in all the ecological regions, and western meadowlark was the only species never related to CRP. CRP was a strong predictor of bird abundance compared to other land cover types. The potential for CRP habitat as a regional conservation tool to benefit declining grassland bird populations should continue to be assessed at a variety of spatial scales. We caution that bird-CRP relations varied from region to region and among species. Because the NRI provides relatively coarse resolution information on CRP, more detailed information about CRP habitats (spatial arrangement, age of the habitat (time since planting), specific conservation practices used) should be included in future assessments to fully understand where and to what extent CRP can benefit grassland birds.

Habitat use by cottontail rabbits across multiple spatial scales in Mississippi

Relative importance of different land-cover types is often inferred from studies of habitat selection in the context of availability. From 1 February 1997 to 31 January 1999, we examined seasonal (breeding and nonbreeding) habitat selection of cottontail rabbits (Sylvilagus floridanus) in an agricultural landscape in east-central Mississippi at multiple spatial scales (second-, third-, and fourth-order habitat selection; Johnson 1980). We characterized available land-cover types as woody, rowcrop, or grass. The composition of seasonal rabbit home ranges (95% Adaptive Kernel [HR]) and core areas (50% Adaptive Kernel [CA]; second-order selection) exhibited selection for grass patches, followed by woody and rowcrop patches. However, genders differed across diel periods for the composition of HR. Males selected woody patches during diurnal hours, and females selected grassy patches, whereas they both selected grassy patches during the nocturnal hours. Within HR, allocation of time among habitats (third-order selection) differed between seasons and genders. Males selected grass patches followed by woody and rowcrop during the breeding season, and females used them in proportion to availability, whereas they both used them in proportion during the nonbreeding season. Genders used HR land-cover types in proportion to availability for both diel periods. Two predictive models of fourth-order selection poorly discriminated (56.9% and 60.7%) between used and random locations. Cottontails exhibited habitat selection at the HR (second-order) and males at the patch scale (third-order); however, cottontails randomly used within a patch (fourth-order). Our results support the characterization of cottontails as vegetative community generalists at the patch scale (fourth-order); however, cottontails select among land-cover types at larger spatial scales (second- and third-order).

Avian community response to pine—grassland restoration

Abstract Habitat management for an endangered species may affect nontarget communities. We examined avian community response to pine—grassland restoration for red-cockaded woodpeckers (Picoides borealis) and traditional United States Forest Service pine sawtimber management at Homochitto National Forest, Mississippi from 1994–1996. Thirteen species were more abundant in pine-grassland restoration stands, whereas 5 species were more abundant in traditionally managed pine sawtimber stands. Mature restored pine-grassland stands had greater avian species richness, total bird abundance, and avian conservation value than traditionally managed pine sawtimber stands. We used logistic regression models in an exploratory analysis to predict occurrence of selected species using stand- and landscape-scale habitat characteristics. Probability of redeyed vireo (Vireo olivaceus) occurrence increased with increasing hardwood canopy cover, and probability of yellow-breasted chat (Icteria virens) occurrence increased with increasing grass ground cover. Species richness, total avian abundance, and occurrence of red-eyed vireos and Bachmans sparrows (Aimophila aestivalis) increased with increasing values of Shannons Habitat Diversity Index. Pine-grassland restoration for red-cockaded woodpeckers created vegetation composition and structure at the stand and landscape scales that may benefit numerous avian species of regional conservation concern.

Movements and home range dynamics of cottontail rabbits in Mississippi

Knowledge of movement rates with respect to habitat conditions is necessary to understand foraging strategies, breeding opportunities, and probability of predation. The cottontail (Sylvilagus floridanus) is an important small game animal, yet no previous study has simultaneously examined movement rates and home range dynamics with respect to gender, breeding season, diel period, and habitat use. We estimated home range (HR) and core use areas (CA) during the breeding seasons and diet periods for 94 cottontails. We determined breeding season, diel period, and habitat-specific movement rates for 103 cottontails in east-central Mississippi from 1 February 1997 to 31 January 1999. Overall movement rates (m/hr) did not differ between years (1997; x = 28.81 m/hr, SE = 1.67; 1998; x = 26.26 m/hr, SE = 2.34) or genders (male: x = 28.81 m/hr, SE = 2.24; female: x = 23.06 m/hr, SE = 1.49). However, diel period interacted with season to influence movements (diurnal breeding: x = 8.99 m/hr, SE = 0.83; diurnal nonbreeding: x = 3.23 m/hr, SE = 0.35; crepuscular breeding: x = 33.40 m/hr, SE = 2.47; crepuscular nonbreeding: x = 23.45 m/hr, SE = 1.90; nocturnal breeding: x = 43.12 m/hr, SE = 3.27; nocturnal nonbreeding: x = 29.12 m/hr, SE = 1.71). Movement rates differed among habitat types (>1 habitat patch: x = 41.7 m/hr, SE = 2.3; open fields: x = 35.5 m/hr, SE = 6.1; rowcrops: x = 25.5 m/hr, SE = 3.1; grass fields: x = 19.4 m/hr, SE = 0.9; woody areas: x = 15.7 m/hr, SE = 1.7). These differences were associated with differences in plant species richness (woody areas: x = 11.1 plant species/30 m, SE = 0.7; grass fields: x = 9.2 plant species/30 m, SE = 0.3; open areas: x = 8.5 plant species/30 m, SE = 1.1; rowcrops: x = 5.8 plant species/30 m, SE = 1.1) and percentage cover within habitats (0.0-0.9 m in height: rowcrop. woody areas, and grass fields had significantly greater cover than open areas; 0.9-1.8 m in height: rowcrop and woody areas had greater cover than grass fields and open areas). A significant gender-by-season interaction occurred for HR (95% adaptive kernel) (male breeding: x = 5.98 ha, SE = 0.57; male nonbreeding: x = 2.54 ha, SE = 0.65; female breeding; x = 3.04 ha, SE = 0.33; female nonbreeding: x = 2.11 ha, SE = 0.51) and CA (50%) (male breeding: x = 0.93 ha, SE = 0.10; male nonbreeding: x = 0.32 ha, SE = 0.08; female breeding: x = 0.41 ha, SE = 0.05; female nonbreeding: x = 0.26 ha, SE = 0.05). Home range (diurnal: x = 3.71 ha, SE = 0.47; nocturnal/crepuscular; x = 4.70 ha; SE = 0.43) and CA (diurnal; x = 0.52 ha, SE = 0.07; nocturnal/crepuscular; x = 0.69 ha, SE = 0.06) size differed between diel periods. Habitat specific movement patterns may be a function of forage availability and may influence fitness, particularly predation risk. Selection of habitats or habitat conditions that result in reduced movement rates by cottontails should reduce vulnerability to predation.

Effects of Burning and Discing Conservation Reserve Program Fields to Improve Habitat Quality for Northern Bobwhite (Colinus Virginianus)

Abstract Since 1985 considerable expanses of highly erodible cropland have been enrolled in the Conservation Reserve Program (CRP). Areas enrolled in CRP provide wildlife habitat; however, habitat quality and specific resources on these sites vary in relation to seasonal biological processes of target wildlife species, planted cover and vegetation succession. Throughout the southeastern United States habitat quality for early successional species, such as northern bobwhite (Colinus virginianus), may decline as CRP grasslands age. Although disturbance may enhance and maintain habitat quality for bobwhite, concerns regarding perceived conflicts between wildlife habitat and soil erosion objectives of the CRP persist. During 1995 and 1996 we evaluated effects of strip-discing or prescribed burning on vegetation structure and composition and soil erosion in fescue (Festuca arundiacea) dominated CRP fields in Mississippi. Fall discing generally increased percentage bare ground and plant diversity and decreased percentage litter cover and litter depth. Fall discing enhanced bobwhite habitat quality, but responses diminished by the second growing season post treatment. Burning increased plant diversity and improved quality of habitat for bobwhite. Soil loss for all treatments was within United States Department of Agriculture tolerable limits. Discing or burning intensity on CRP fields could be increased without compromising soil erosion provisions of CRP.

The role of farm policy in achieving large-scale conservation : Bobwhite and buffers

Abstract The Farm Bill provides a policy vehicle for implementing conservation programs with the potential to alter land use on a large spatial scale. The conservation payments under the Farm Bill dwarf the collective investment of the North American Wetlands Conservation Act, Endangered Species Act, Pittman-Robertson Act, and Conservation and Reinvestment Act. However, the ecological value of past policy has varied by program, practice, region, and wildlife species, resulting in a broad array of wildlife habitat and population effects ranging from positive to negative. We argue the conservation provisions of the Farm Bill can produce more consistent positive wildlife habitat benefits when policy (program statutes, rules, practices, and practice standards) is developed in the context of explicit goals identified as part of large-scale conservation initiatives. For example, initiatives like the North American Waterfowl Management Plan, Partners in Flight, and the Northern Bobwhite Conservation Initiative (NBCI) set science-based goals and objectives to facilitate wildlife species population recovery and sustainability at the landscape scale. We contend that the best ecological and societal cost/benefit ratio is achieved when Farm Bill conservation programs and practices are developed to address these specific habitat goals. We present a case study illustrating how a Conservation Reserve Program option (Conservation Practice 33—Habitat Buffers for Upland Birds) specifically addresses NBCI goals and objectives. We discuss the successes, failures, and lessons learned by NCBI in policy formulation, practice development, programmatic delivery, and evaluation.

Airports Offer Unrealized Potential for Alternative Energy Production

Scaling up for alternative energy such as solar, wind, and biofuel raises a number of environmental issues, notably changes in land use and adverse effects on wildlife. Airports offer one of the few land uses where reductions in wildlife abundance and habitat quality are necessary and socially acceptable, due to risk of wildlife collisions with aircraft. There are several uncertainties and limitations to establishing alternative energy production at airports, such as ensuring these facilities do not create wildlife attractants or other hazards. However, with careful planning, locating alternative energy projects at airports could help mitigate many of the challenges currently facing policy makers, developers, and conservationists.

Effects of Landscape Composition on Winter Survival of Northern Bobwhites

Abstract In a manipulative experiment, we tested effects of select elements of landscape structure and composition on winter survival of northern bobwhites (Colinus virginianus) at Ames Plantation, Tennessee, USA. We hypothesized that abundance of closed canopy forested habitats (52% of the landscape) on Ames diminished usable space for bobwhite and provided usable space for a suite of important predators, thereby contributing to low winter survival. To test this hypothesis we divided a 2,217-ha portion of the property into 4 approximately equal areas. We altered landscape structure and composition by converting approximately 33% of the timber to early successional herbaceous plant communities on 2 treatment sites, which reduced percentage of landscape and edge density of closed canopy forest and increased percentage of landscape in early successional herbaceous communities, and left 2 control sites in their former composition. During one pretreatment year (1998–1999) and 3 posttreatment years (1999–2000, 2000–2001, 2001–2002), we estimated winter (15 Oct–10 Apr) survival on treatment and control sites from a radiomarked sample of 920 bobwhites. We used Cox Proportional Hazard models to test for effects of treatment (forest conversion) and covariates describing landscape structure and composition (% closed canopy forest, % early successional herbaceous, wooded edge density) on winter survival at multiple spatial scales. Winter survival on the treatment sites pooled across the 4 winter seasons was 41% compared to 32% for control sites. Additionally, for each 1 m/ha increase in closed canopy woods edge density within winter covey ranges, risk of mortality increased 0.3%. Our results suggest composition at the landscape scale and landscape structure at the local scale influence winter survival of bobwhite. Management strategies that alter composition and structure and increase usable space may be effective in mitigating winter mortality thereby altering population trajectories. Typical bobwhite management plans focus on improving quality of herbaceous vegetation structure within existing herbaceous patches, however, population processes may work at larger spatial scales influencing design and implementation of conservation programs.

Creating Wildlife Habitat Through Federal Farm Programs: An Objective-Driven Approach

Abstract Conservation programs administrated by the United States Department of Agriculture under the Farm Bill have tremendous potential to impact wildlife habitat and populations on private land. Recent comprehensive reviews demonstrate that private landowners who participate in these programs have established habitats that may contribute to sustaining some regional wildlife populations. However, I argue that if Farm Bill conservation program lands are to consistently provide habitat that supports viable wildlife populations, conservation planners must have a better understanding of species-specific habitat requirements and ecological processes. Concomitantly, wildlife biologists also must have a working knowledge of the conservation programs, practices, and landowner needs and eligibility requirements. This understanding is then translated to changes on the landscape through comprehensive planning and implementation at the farm scale. I argue that, all too often, landowners selection of conservation practices is program-driven. Program-driven implementation is less likely to result in quality wildlife habitat. I contend that the consistent application of an objective-driven approach to farm-scale conservation planning is more likely to produce habitats that sustain viable wildlife populations. Under this approach, landowner conservation objectives drive management practices and management practices lead to program selection, instead of program requirements driving management practices.