1. Effect of Habitat Fragmentation on Red Fox (Vulpes vulpes) Population Health In Northern York County, Pennsylvania Jeremy M. Hamsher York College Department of Biological Sciences PROJECT SUMMARY The impact of expanding human populations on wildlife often has a negative and detrimental effect. York County has experienced population growth of 25.2% every ten years, but the effects this growth has on wildlife is unknown. The objective of this study is to assess the overall population health of the red fox (Vulpes vulpes) in northern York County, Pennsylvania and determine if habitat fragmentation has had an affect on fox populations. Foxes will be captured at locations of varying landscape types by using foothold traps. Population health will be assessed by examining occurrence of mange and age structure will be determined by counting cementum annuli rings in a canine tooth of adults and the lack of root closure in a juvenile canine tooth. The red fox helps maintain the delicate balance of predator and prey in ecosystems, but little is known about their population structure in Pennsylvania. The effects of population increase on these predators needs to be established to help with management and for the good of the species. INTRODUCTION The ever increasing suburbanization of the rural countryside of America leaves many questions about the future of wildlife in these areas. An effect of this rapid population increase is habitat fragmentation. Fragmentation separates populations of organisms from food sources, water and other con-specifics (Gaines 1997). However, while fragmentation detrimentally effects some species, it may allow others to exploit new resources (Gehring 2003). The organisms that can exploit a fragmented landscape can move from a population under control to an overpopulated burden on the ecosystem (DeStefano 2003). When fragmentation occurs, organisms get pushed into smaller and smaller parcels of land and while their overall numbers may not increase, their density does. A species which is adapted over a wide variety of environments may be better able to respond to landscape changes from human impact. Today, wildlife managers face many problems ranging from trying to retain biodiversity in a region to managing overabundant species in the same area (DeStefano 2003). In northern York County, Pennsylvania little is known about the effect of fragmentation on the red fox (Vulpes vulpes). Along with the effects of fragmentation, little is known about the population structure and overall health. The effect of fragmentation in York County is important because it could be used as a management model for other similar areas. The niche breadth of the red fox has yet to be characterized for this broken landscape. By determining the population dynamics in response to human-induced fragmentation, management plans can be developed to help maintain healthy populations of this species in human rich environments (Gehring 2003). REVIEW OF LITERATURE Morphological measurements such as those provided in Storm et al. 1976, Lefebvre et al. 1999, Pils 1978 gives clues as to how well the populations are doing physically. Stomach contents reveal food availability and what style of predation foxes are using. Using a canine tooth and counting the cementum annuli rings as described in Novak 1987 shows what the age structure of a population is and can indicate if there is a reproductive problem within a population. Mange is a key factor in determining population health. Mange caused by the mite Sarcoptes scabiei, is an important factor in the mortality of foxes (Storm et al. 1976). High incidence of mange occurs when fox density is high and may be a regulating force in the control of fox populations (Storm et al. 1976). Habitat fragmentation and the extent of fragmentation can be detrimental or beneficial to a species depending on its ability to adapt (Gehring 2003 and DeStefano 2003). Habitat fragmentation may affect predators such that it changes the spatial availability of resources (Gehring 2003). Species with a broader niche and adaptability impose fewer constraints on an organism and allow it to distribute itself throughout the fragmented landscape. The effect of fragmentation on large carnivores is not known (Gehring 2003). OBJECTIVES Assess population health Determine if habitat fragmentation has a detrimental effect on red fox distributions and densities METHODS 1. Locate various trapping locations by habitat type and levels of habitat fragmentation using digital photo-orthoquads 2. Trap foxes at each location using #1 ½ foothold traps and dirt hole sets 3. Take morphological measurements of foxes captured 4. Record incidence of mange and degree to which the animal is affected 5. Remove a canine tooth for age analysis 6. Examine stomach contents 7. Trap rodents using a mark-recapture survey to determine food availability at each location RESULTS LITERATURE CITED DeStefano, Stephen and DeGraaf, Richard M. 2003. Exploring the ecology of suburban wildlife. Frontiers in Ecology andEnvironment.1(2):95- 101. Gaines, M.S. et al. 1997. The effects of habitat fragmentation on the genetic structure of small mammal populations. Journal of Heredity. 88:294 304. Gehring, Thomas M. and Swihart, Robert K. 2002. Body size,niche breadth and ecologically scaled responses to habitat fragmentation:mammalian predators in an agricultural landscape. BiologicalConservation. 109: 283-295. Lefebvre, Christine et al. 1999. Prediction of body composition of live and post-mortem red foxes. Journal of Wildlife Diseases. 35(2): 161-170. Novak, Milan et al., ed. Wild Furbearer Management and Conservation in North America. Ontario. 1987. Pils, Charles M. and Martin, Mark A. 1978. Population dynamics, predator-prey relationships and management of the red fox in Wisconsin. Technical Bulletin No. 105 Department of Natural Resources Madison, Wisconsin. Storm, Gerald et al. 1976. Morphology, reproduction, dispersal and mortalityof midwestern red fox populations. Wildlife Monographs. 49:82 p. ACKNOWLEDGEMENTS: Dr. Karl Kleiner for mentoring me and input on the ecological perspectives of this project. Dr. Bradley Rehnberg for giving input on the physiological perspectives Jim Payne for the use of his foxes All of the landowners that allowed me to trap on their property Examining the morphological data, it appears that the foxes are not getting enough to eat at the current time. They are primarily feasting on carrion. The age structure is interesting because it does not coincide with the published literature of Storm et al (1976) and Pils (1978). Normal ratios are from 1.5-7.5 young for every adult. Here, the ratios have flip flopped to 4.7 adults for every juvenile. This, if in fact is the actual age structure of the population could illustrate a serious deficiency in breeding. The occurrence of mange for this population does appear to be consistent with the results of other published studies regarding mange occurrence rates. At this point, there can be no correlation made between amount of fragmentation and population health and density. There was no definitive data that showed one location had a higher population of foxes. More research needs to be conducted.