Jacob Thomas
Mr. Defrank
Environmental Science
December 15, 2014
The Effect of Deer Overpopulation on the Environment
White-tailed deer have increased dramatically in population during the last two decades due to the combination of several factors. With the increase in population of deer, many changes have occurred to the habitat of the deer which has caused changes to the habitat of other species, as well. These changes cause concern regarding the impact the overpopulation has on the environment and other species of animals. There is also an increased human health and safety issue with the increase of deer. Deer overpopulation is causing many concerns, including human health and safety concerns, ecological impacts, and economic losses.
The human health and safety issues associated with deer are primarily deer-vehicle collisions and transmission of Lyme disease. “It is estimated that 29,000 people are injured and 211 lose their lives annually in deer-vehicle collisions in the United States.” (Curtis) This number continues to rise as the overpopulation of deer continues to increase. Deer are coming out of the woods for food and water which causes an increase in the number of deer in human populated areas and highways. Deer-vehicle collisions is also one of the many economic losses that is associated with the overpopulation of deer. The expense of vehicle repairs and, sometimes, medical bills, due to vehicle-deer collisions is very high.
There is also the human health and safety issue associated with the deer and the concern of the transmission of Lyme disease, as well as other more serious diseases by the “Black Legged” or “deer tick”. Lyme disease can cause arthritis or joint pain in humans and permanent damage if left untreated or a long period of time. Lyme disease “can also cause heart, brain and nerve problems” in humans if not treated. (David Zelman) Interesting, the deer do not become infected with the Lyme disease, but the adult deer tick prefers the deer as its host. With the increase in the number of deer, and the increase in the number of deer that live closer to human occupied areas, comes an increase concern and risk of the transmission of Lyme disease. “[A]ccording to the Centers for Disease Control, the number of cases of Lyme disease is on the rise, increasing from approximately 2,000 cases in 1987 to 12,901 cases in 1997.” (Curtis) Lyme disease is one of the many diseases that can be transmitted by the deer tick, some have even more grave consequences.
According to The Nature Conservancy (TNC), “the rapidly rising population of white-tailed deer pose a more significant threat to forest habitats across the eastern United States than global warming. In our opinion, no other threat to forested habitats is greater at this point in time — not lack of fire, not habitat conversion, not climate change. Only invasive exotic insects and disease have been comparable in magnitude”. (Pentland) The overpopulation of deer is affecting our woods more than global warming which is a major concern worldwide.
Deer can also affect their own habitat and the abundance of other species. Deer can damage even a relatively large track of land. Deer are primarily browsers and over-browsing in an area by deer can have a negative environmental impact. “Thick and diverse near ground cover provides the nesting sites needed by many species of birds. It also provides food for other animals”. (Curtis) The over-browsing by deer creates and unbalanced situation in the environment. An example of an unbalanced environment caused by over-browsing of the deer is when “browsing tolerant plant species flourish at the expense and even elimination of other less tolerant species”. (Curtis)
When the ground cover, or understory vegetation, is reduced the change in the habitat may affect bird life. Some bird species may leave the area in search of an environment where there are more places to nest in the vegetation. The deer destroy the habitat that some birds prefer so they look or an area where deer have not yet over-browsed or destroyed the ground cover. The deer also damage the small trees that have begun to grow in the forest which causes less trees to eventually grow in the forest. The birds nest in the ground cover or in forests with dense trees because they are not easily seen there. Nesting in more open forests make bird nests easier for predators to detect. Additionally, the decrease in vegetation also leads to less insects for birds to feed on. Other wildlife, such as squirrels, are also affected by the overpopulation of deer because they have to compete for acorns, which are a preferred natural food of deer.
The high deer population of today may shape how the country’s forests look decades from now. The deer are reducing the number of trees and seedlings and affecting which tree species will survive. “There are no saplings, no underbrush for ground nesting birds. There will be no regeneration of the forest. In 40 to 50 years, as the current forest dies, there will be nothing to replace it.” (Deer Eating Away at Forests Nationwide) Many studies show that deer affect woody plants, such as trees and shrubs, as well as the ground cover plants. The deer also browse on tree seedlings which prevent regeneration and changes the dominant tree species in an area. By feeding on tree seedlings and changing the dominant species in an area the deer also cause a reduction in the “potential for marketable timber”. (Chambliss)
Deer may also influence mammals. “For example, deer are carriers of the parasite brainworm” which affects moose and may reduce the number of moose. “Overall, deer may have degrading effects on ecosystems”. (Chambliss) The overpopulation of deer can result in extensive property damage. Deer often feed in populated residential communities’ home gardens and landscaping. Home gardens and landscaping are expensive in creating and maintaining. The natural foods in the deer’s natural habitat are limited by the natural pH and nutrients of the soil and are in competition with neighboring plants for sunlight. Therefore, “even when natural foods abound in local area, deer are often attracted to the rich succulent plants of the backyard landscape. In the backyard, trees, plants, and gardens are usually enhanced by things like pH normalization, fertilizer, and pruning”, which make them tastier for the deer. (Deer Problems and Issues) Also, when natural food supplies are limited either due to season or weather, or by over use by deer, this makes the home gardens and landscaping even more of a targeted feeding for the deer.
Deer may heavily browse agricultural crops, especially when competition for food is high. This can be very expensive to farmers who depends on the agricultural crops for income or to feed his livestock. The destruction of agricultural crops can affect the prices and availability of certain products in the grocery stores. The deer can be a nuisance to gardeners of fall sizes because off the difficulty in keeping the deer out of the garden. “White-tailed deer are adaptable and prolific animals equipped with keen survival instinct”. (Deer Problems and Issues) However, a contributing factor to the overpopulation of deer is the decrease or extinction in the number of natural predators of the deer. Predator/prey relationships play a big role in animal populations. “Wolves and other predatory animals were hunted, trapped, and poisoned to near extinction.” (Deer Problems and Issues) “Major predators such as the gray wolf (Canis lupus) and cougar (Puma concolor) have been extirpated from much of the deer’s range.” (Rawinski) While some predators of the deer remain, such as bobcats and coyotes, the deer’s main predators are gone. Hunters are now a deer’s main predator, “but the number of hunters are declining, especially among teenagers who today have more options to fill their time”. (Deer Eating Away at Forests Nationwide) The overpopulation of deer has become a significant issue for several reasons. However, wildlife habitat has been substantially changed as human populations expand and land is used for human needs. These human uses and needs often compete with those of wildlife which increases the potential for adverse human/wildlife interactions. As deer and other wildlife habitat is destroyed they must find somewhere else to live. Many times the deer remain or return to the area that was their habitat and can cause problems in areas that are now human populated. Destruction of the deer habitat increases the deer-vehicle collisions because the deer travel and move around as their habitats are destroyed. The deer often remain or return to the area that was once their natural habitat and try to live in the communities that are now human populated. The deer become a nuisance because they feed on small shrubs, tree saplings, gardens and landscaping created by the development of the land by humans. Overall, the deer overpopulations has an adverse effect on the environment in many ways. They can be destructive to crops, gardens and, of course, vehicles when a deer and vehicle collide on a roadway. Attempts are being made by many states to control the overpopulation of the deer but as more of the deer’s habitat is destroyed for human use, the more the overpopulation of deer will affect humans. Additionally, the deer overpopulation will continue to effect the habitat of other wildlife when they are forced to over-browse certain areas because of the lack of food. The overpopulation of the deer is made worse by the fact that humans continue the deer’s natural habitat which forces the deer to live in communities populated by humans, or move to other areas of the woods which results in overuse and destruction of the habitat.
Works Cited
Chambliss, Emily. web.duke.edu. 12 November 2013. 12 December 2014. <https://web.duke.edu/nicholas/bio217/ekc7/deer.htm>.
Curtis, Kristi Sullivan and Paul. How Deer and Beaver Affect You and Your Land and What You Can Do About It. 2013. 11 Month 2014.
David Zelman, M.D. Arthrtis and Lyme Disease. 19 October 2014. 2014 December 2014. <http://www.webmd.com/rheumatoid-arthritis/arthritis-lyme-disease?page=6>.
Deer Eating Away at Forests Nationwide. 18 January 2005. 14 December 2014. <http://www.nbcnews.com/id/6835501/ns/us_news-environment/t/deer-eating-away-forests-nationwide/#.VI4uAyvF80s>.
Deer Problems and Issues. 2014. 12 December 2014. <https://www.deerdamage.org/page/problems-and-issues>.
Pentland, William. forbes.com. 28 August 2013. 14 December 2014. <http://www.forbes.com/sites>.
Rawinski, Thomas J. Northeastern Area State and Private Forestry. 2008. 13 December 2014. <http://www.na.fs.fed.us/fhp/special_interests/white_tailed_deer.pdf>.