Predator-Prey Relationships in West Virginia - Essay Example

Predator Prey Interactions and the West Virginia White Tailed Deer Problem West Virginia is dealing with a deer population problem that has major stakeholders worried about the preservation of an entire ecosystem. In January of 2000, Gary Alt, a preeminent bear biologist was put on the task of managing the dear overpopulation problem in West Virginia (Williams 2005). The problem has far reaching effects on every aspect of the eastern ecosystem, including vehicle collisions, which were 1.5 million on the nation's highways in 2000 (Williams 2005). For over 80 years, there has been pressure on game commissioners to produce more deer for hunting than the ecosystems of the area can maintain (Broache 2005). Many believe the carrying capacity, the maximum number of animals the environment can support has been reached this can have devastating outcomes (Grafton 2008). There are major problems with deer populations in many states; however, in West Virginia populations can run as high as 75 deer per square mile (Williams 2005). In all cases, the root of the problem stems from a lack of natural predators and an ecological negative feedback loop that involves declines in forest health and composition. White tailed deer populations in excess of 20 per square mile are largely responsible for lack of woody and herbaceous regeneration (Grace 2008). Habitat impacts from such extensive deer overpopulation range from destruction of native understory, as deer are mostly browsers, eliminating low growing shrubs and herbaceous material to loss of small mammals and their predators. They are also responsible for dramatic changes in the hardwood diversity of eastern forests when they browse on immature hardwoods, killing them and thereby changing the fundamental structure of the canopy (Grace 2008). This affects every species in the system. The US Forest Service determined at more than 20 deer per square mile, there is a loss of many common bird species such as cerulean warblers, yellow-billed Cuckoos, indigo buntings, eastern peewees, and even robins disappear (Williams 2005). With the loss of these botanical species and associated birds, there is also a loss of small mammals due to lack of adequate cover and food resources (Broache 2005). Interestingly, it has been shown that silvicultural practices in managed hardwood forests of West Virginia have contributed to an initial increase of small mammal abundance diversity, usually until succession returns to the forest area (Kirkland 1975). This is thought to be due to an increase in consumption of seeds and seedlings, which in the long term has a deleterious impact on forest regeneration. In addition to anthropological restructuring of the forest's ecosystem, deer overpopulation has compounded the problem. Habitat alteration contributes to what still may be the root of the problem, which is the loss of the deer's natural predators from the system; bear, wolves and cougar that began in the 1700s. Numbers of the eastern timber wolf, black bear, and eastern cougar and all at historic lows since the area was first settled in the 1700s. Black bear in the state are estimated to be fewer than 8,000 individuals and both the wolf and cougar are listed on the Endangered Species list (Weaver 2007, USFWS 2008). Studies in Yellowstone have shown that large predators actually increase herd fitness by 30-40 percent when the herd has good quality habitat in which to bed, hide and feed upon (Brown 2006). Large predator prey relationships were studied over the long term at Michigan's Isle Royale National Park, where wolf and moose populations were shown to rise and fall in connected cycles (Milhill, 2008). The lack of predators in National Parks such as Yosemite and Zion has lead to large deer populations where stream bank erosion and loss of habitat for amphibians and butterflies have occurred (Milhill, 2008). With the lack of these large predators to help maintain deer populations, the deer are beginning to overpopulate the landscape, which hurts not only the ecology of the region, but also hurts the quality of the herd, with members being weaker and unable to withstand tough winters and disease. Large predators in a system take weak and old members of the herd, thereby increasing the overall fitness of the herd. The lack of large predators in the landscape has added to the cumulative effects of deer population historical mismanagement and the current status of the problem. During the last 50 years, the coyote whose range was mainly concentrated in the Great Plains and western states, has expanded it's range to the east and now occupies all 50 states of the country. Coyote deer predation has been extensively studied, where it has been found they take a majority of deer fawns (up to 70 % in some seasons) (Brown 2006). The coyote has also served to lessen the populations of red fox where they are able to out compete the fox for resources (Brown 2006). Bobcat populations, which do affect deer predation, do not seem to be affected by coyote colonization in West Virginia (Brown 2006). The overall effect on coyote colonization on deer populations is seen as beneficial in keeping the herds at carrying capacity and assisting in maintaining fitness levels. However, coyote also prey on small mammals, a species group that is already struggling due to the damage already done by deer overpopulation in forested areas (Woleslagle, 1994). Small mammals actually do better after a clear cut than in the stages of ecological decline set up by deer over browsing, as previously stated. The lack of small mammals in these areas contributes to a further decline in forest health due to the loss of their contribution to maintaining soil permeability and structure. It has been shown that vole activity is a major contributor to soil health (Woleslagle 1994). Again, changes in small mammal populations contribute to the overall decline in forest health, with deer overpopulation being the main driver caused by a lack of their natural large predators that have been effectively removed from the system. With the decline in small mammal populations and bird populations due to forest structural and compositional restructuring caused by deer and man, effects have been observed in some species of raptors (Venable 2008). However, these effects are mostly noted as a change in hunting ranges with a shift from forest ranges to agricultural and clear cut areas where small mammals are more easily found. Raptors seem to be adjusting to the rapidly changing ecosystem by feeding in areas that are provided for my man's activities. However, owls and forest hunting raptors that are not acclimated to man's activities are fairing less well in West Virginia's forested areas (Broache 2005). Numbers are declining as forest health declines, and the Audubon Society is concerned with loss of species diversity and richness. With possible overall decline in raptor and small mammal feeding birds, an effect can be felt across the entire landscape of West Virginia eventually with an increase in small mammals to pest proportions in more populated areas. The effect of forest health decline due to the deer population can have far reaching economic effects if small mammal's pest numbers are increased, affecting agriculture output and disease control. There is concern in West Virginia about the lack of acorns in the hardwood systems. It is presumed that this lack could be caused by both small mammal consumption and deer consumption (Broache 2005). This, of course, will only negatively affect the canopy structure with the loss of white, red, and black oaks. However, this phenomenon is still in an anecdotal stage and has yet to be seriously studied by scientists. But the observations made during the last few seasons of this acorn loss may surely be connected to deer overabundance in the area. The main source of deer control now is hunting, with a larger percentage of does being taken in order to stabilize the buck/doe ratio and control fecundity (Brown 2006). This is satisfactory to hunters of the area, but not a solution to the current state of the problem, since herds are already beyond carrying capacity and forest ecology has been already been affected. Hunters seem to be at odds with Audubon supporters who are concerned about the losses of bird species that are being observed (Williams 2005). Of course, hunters are not connecting the loss of birds, plants with botanical significance and forest ecological restructuring with the long term affect on the quality of their take. They are mostly concerned only with their ability to bag more deer. But increased and properly managed hunting may be a viable and immediate solution to the problem of bringing the entire ecosystem back into balance. This and the controversial reintroduction of wolves increase in bear and cougar populations and increased protection for large predators may have far reaching effects on the status of deer overpopulation and the economic impacts it is having in the state of West Virginia. Economic impacts include; impacts on farming viability, impacts on suburbia, watershed problems due to riparian zone overgrazing, and impacts to water quantity (Potomac Highlands Watershed School 2008). Attempting to maintain the current status of large predators in the state is the only management activity occurring right now, with bear hunting still allowed in many counties (Grace 2008). Reintroduction of large predators in this area is highly contentious due to possible effects on livestock resources and this has yet to be pursued in West Virginia. Currently, state wildlife biologists are working with all stakeholders in the problem, including the Audubon Society, various hunting organizations, and habitat conservation groups in an effort to implement an adaptive management plan that allows all parties to see improvement in the situation (Evans et.al. 2008). Various aspects of this plan include; 1) allowing a larger ratio of does to be harvested, 2) in counties with abundances of greater than 50 per square mile, reduce deer populations not only via hunting but with controlled harvesting by state officials by use of round up and possible euthanasia, 3) avoiding all further supplemental feeding programs during harsh winter conditions, 4) develop a year round monitoring awareness program in order to maintain quality statistics on population statistics, such as age cohort, number of breeding does, fecundity numbers, etc. and 5) promote better landowner, hunter relationships that will allow hunters to hunt on lands they previously did not have access to. This would discourage the congregation of deer in these safe zones and better control the population (Crum, 2008). A major problem in deer management in West Virginia is the high variability in deer counts and the inaccuracy inherent in those counts. You can never count all the deer at a certain location or farm. All techniques that are currently used to do mammal counts, including forward-looking infrared (FLIR), automatically triggered cameras, trapping and marking, and other techniques can only serve as indexes of population. These indexes can never give managers an accurate count. In addition, even with a count, this is not a good indicator of the interaction of the population with the habitat. The best indicator managers have of habitat and herd balance is antler beam diameters and weights of yearling bucks. Other indicators of herd and habitat health are the number of internal parasites and percentage of breeding fawns (Crum 2008). An adequate adaptive management program will require the use of all available technologies, cooperation of stakeholders, and adequate funding from state and local governments who need to recognize the need to control the problem and the severity of habitat and economic destruction that can occur if the problem is not adequately addressed. Adaptive management strategies are familiar to more state wildlife managers and predator prey relationships in West Virginia are key in understanding how reintroduction of large predators, however controversial, may indeed be a cost effective solution to the problem. A combination of liberalized hunting, monitoring of forest ecology, obtaining accurate indices of populations of all major species in the ecosystem, and the possible reintroduction of large predators may be what is needed to head off a potentially disastrous economic liability to the state of West Virginia. WORKS CITED Broache, Anne. 10/2005. Oh Deer! Accessed 12/01/08. http://www.smithsonianmag.com/science-nature/Oh_Deer.htmlc=y&page=2 Brown, Clifford L. Coyote. West Virginia Wildlife. 10/01/2006. Accessed 12/01/2008. www.wvdnr.gov. Crum, Jim WV DNR. In Successful Deer Management, Change is Good. Accessed 12/01/2008. http://www.wvdnr.gov/Hunting/SpecDeerMng.shtm Evans, et. al. DNR Wildlife Resources, Fundamentals of Deer Management. Accessed 12/01/2008. http://www.wvdnr.gov/Hunting/FundDeerMan.shtm Grace, Dr. James R. DCNR State Forest Resource Management Plan, Bureau of Forestry. Accessed 12/02/08. http://www.dcnr.state.pa.us/forestry/sfrmp/foresthealth.htm Grafton, William. Agronomist. West Virginia University. Oh Deer! Environmental Forum. Accessed 12/01/08. http://www.cacaponinstitute.org/PHSWR%20Chats/Oh%20Deer%20Native%20Guides/Native_Guide_Grafton.htm Kirkland, Gordon L. 1975. Responses of Small Mammals to the Clearcutting of Northern Appliachian Forests. Accessed 12/01/2008. http://www.jstor.org/pss/1380008 Mihell, Conor. Predator Prey Relationships. Sept 2008. Accessed 12/01/2008. http://www.backpacker.com/september_08_phenomenon_predator_prey/nature/12555 The Potomic Highlands Watershed School. Environmental Forum. Accessed 12/01/08. http://www.cacaponinstitute.org/hs_chat.htm Warner, David. Consulting Forester. Oh Deer! Environmental Forum Native Guides. Accessed 12/01/08. http://www.cacaponinstitute.org/PHSWR%20Chats/Oh%20Deer%20Native%20Guides/Native_Guide_Warner.htm Williams, Ted. Audubon Incite 07/2005. Accessed 12/02/08. http://audubonmagazine.org/incite/incite0507.html Weaver, Diana. USFWS News Release February 2007. Accessed 12/02/2008. http://www.fws.gov/news/newsreleases/showNews.cfmnewsId=0A18734E-C6A7-8977-200680E51EC6CB8FFC73 WOLESLAGLE, B.A. 1994. Survey of small mammals in northeastern Pennsylvania with an emphasis on six target species. Unpubl. M.S. thesis, Shippensburg University, Shippensburg, PA. 60 pp. WOOLAVER, L.G., M.F. ELDERKIN, AND F.W. Scott. Sorex dispar in Nova Scotia. Northeastern Naturalist 5:323-330. USFWS. American Black Bear. Accessed 12/01/08. http://www.richwooders.com/appalachian/wildlife/american/bears.htm Venable, Norma Jean et. al. West Virginia Hawks, West Virginia Extension Service. Accessed 12/01/2008. http://74.125.113.132/searchq=cache:BhnN0GfCccIJ:www.wvu.edu/agexten/wildlife/806.pdf+west+virginia+raptor+status&hl=en&ct=clnk&cd=7&gl=us Read More