White-tailed deer are overpopulating regions across Michigan. As their population grows, they can cause decreases in biodiversity. Deer consume large amounts of resources, reducing the availability of grass and foliage not only for their own species, but also for the other animals that depend on these plants for survival. Additionally, white-tailed deer have recently been major carriers of disease, which spread easily to other species with more controlled populations, such as moose. To combat this issue, The Michigan Department of Natural Resources has encouraged the hunting of white-tailed deer as a method for slowing down their exponential population growth and their impact on the local environment. The state is allotting permits to hunt white-tailed deer in order to restore foliage and encourage biodiversity.
Over 600,000 hunting permits for white-tailed deer were sold in Michigan in 2019. Over 561,000 deer were harvested within the hunting season of 2019, out of that year’s deer population of 1.75 million. Outside of the hunting season, the deer population is still increasing yearly, although hunting has helped to slow the rate. While white-tailed deer are found in every county of Michigan, the highest population is in the northwestern portion of the state. Deer head north in the autumn, as they prefer snow cover. Hunting season is October to December, and sometimes January, depending on the type of weapon used. During these months, hunters follow the deer and head north to maximize the outcome of the hunting season.
Though there is a well defined hunting season, there are cases where hunting can occur throughout the year. Agriculture is one of the main sources of income across Michigan, and white-tailed deer consume some crops. They eat grasses, fruits, and browse, which are the leaves and twigs of certain plants. Northwest Michigan is a major exporter of cherries, which are easily and often consumed by deer. Farmers can be granted special “Deer Damage Permits” if they can prove the destruction was done by deer, allowing them to hunt during the off-season. Farmers are only allowed to hunt one deer per day during this time. Deer Damage Permits help to lessen the harm on valuable crops for farmers, while the cap on one deer per day helps to sustain deer populations. The balance keeps the white-tailed deer population running parallel to the economic growth of farms in Michigan.
Permitting hunting deer in Michigan also came about due to the destruction of local grass and foliage. Lack of biodiversity due to overpopulation of white-tailed deer was originally studied in the 1990s in Midwestern states. In 1997, when research was taking off, the relationship between biodiversity and deer was examined in Wisconsin. They discovered that areas with higher deer population density lost more than 60% of their plant species, while sites with lower populations only lost around 16%. This was 23 years ago, and deer populations in the Midwest have since grown. Studies in the area have shown that just 20 deer per square mile can cause significant damage to local biodiversity. Without containing the populations to some degree, exponential growth can significantly decrease biodiversity. By over-consuming grass and foliage, deer have the potential to impact other animals. The North American Breeding Bird Survey, a government run program that tracks bird populations, found that 73 species of bird populations decreased as white-tailed deer populations increased. Deer consume vegetation layers that birds use to build their nests, damaging their reproductive success. This is just one example of animals impacted directly by the growing population of deer in Michigan.
Hunting in Michigan can also help to eliminate disease. Chronic Wasting Disease (CWD), for example, is a degenerative neurological disorder caused by an abnormality in a cellular protein, called a prion, and causes odd behavior and loss of motor function. It always results in death. CWD presents similarly to Mad Cow Disease but is currently less common, as less deer is consumed by humans than beef. However, even though there are currently no human cases of CWD, there is a risk of contracting these prions from the bodies of infected deer by routes that are not consumption. If a hunter touches the deer and then their eyes or nose, there is a chance that they can be infected. Though the risk of transmission is low, the CDC has recommended that hunters do not shoot deer that appear to be acting abnormally. However, the main issue with these prions is that they can be spread easily to other organisms such as elk and moose, which can be found in northern Michigan. Therefore, it is not always discouraged to hunt deer that may have CWD in order to preserve elk and moose populations. For this to work without infection to humans, the CDC recommends wearing gloves to handle the deer as well as having meat tested for CWD. The Department of Natural Resources has set up testing sites across Michigan that are open throughout the hunting season. Hunters bring the heads of deer in to be tested, and results are posted on an online portal. If the deer tests negative for CWD, hunters are free to consume the meat. This system also helps to track the spread of the prions around the state.
While hunting can be detrimental to certain species, it can also help biodiversity. Plant diversity and bird species can reappear in areas once too barren for them to thrive. Hunting can be done in an ecologically safe manner if people are aware of pros and cons, follow the law, and organize the process correctly.
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