There are many reasons in our world why plant and animal species become rare and endangered, or under the threat of extinction. However, environmental scientists and naturalists – like we educators here at the NEW Zoo – have noticed that there are five main reasons that can account for the majority of species becoming threatened. We use an acronym to help us remember – and teach people– about these five core reasons for animal endangerment. That acronym is the word HIPPO, meaning that every letter in “HIPPO” stands for something that is causing species to become endangered.
In our last Blog entry, we introduced you to the “H” in HIPPO, which stands for Habitat Loss. This time, we’re going to focus on the “I:” INVASIVE SPECIES, the second “big reason” why species in our world are becoming threatened and endangered.
According to the United States Department of Agriculture, an invasive species is “a species that is both non‐native (or “alien”) to the ecosystem under consideration, and whose introduction causes (or is likely to cause) economic or environmental harm or harm to human health.” In other words, it is a species that can wreak havoc on an ecosystem, because the plants and animals that already live within that system are not adapted to living with it. The native species either cannot compete well enough with the new invasive species to get food, or the natives may not be able to avoid becoming food for the invasive, or some combination of the two.
Both plants and animals can be considered invasive species, and they can be found in nearly every ecosystem around the globe. Invasive species are usually introduced to a region through human activities and can cause extensive damage to many aspects of an environment, including its structure, function, and economic value.
Take several invasive species that have found their way into Wisconsin’s landscapes and bodies of water for example. The emerald ash borer is a type of beetle that is dark green in color and usually grows up to half an inch long. They are native to Asia and may have come to North America through ash wood used in cargo ships or in consumer packaging. This species is a threat because of the way it invades ash trees – their presence results in the death of the tree after the beetles destroy the water and nutrient conducting tissues under the bark. The beetles simply don’t have enough predators here in North America to control their populations. As they move into an area, they thrive on the vulnerable ash trees, moving on to new, live trees as each one they inhabit dies.
Another invasive species here in Wisconsin is the sea lamprey. These are eel‐like fish without jaws that are now found in the Great Lakes, including Lake Michigan. Sea lampreys are most likely native to Lake Ontario, although this is debated. It is also debated as to how they arrived in Lake Michigan, but the most common explanation is the improvements done to the Welland Canal in 1919, which allowed lampreys to migrate into Lake Erie and then on to the rest of the Great Lakes. This species is devastating other fish populations – they perform a sort of parasitic feeding on other fish, which results in death. The fish that are native to the Great Lakes simply don’t have adaptations to avoid the lampreys, and again, the lampreys don’t have enough predators to control their populations, and so the native fish fall victim.
It has been estimated by The Washington Post that economic losses and environmental damages in the United States due to invasive species total nearly $120 billion every year! In order to help combat the negative effects of invasive species, the Wisconsin DNR has created the Invasive Species Identification, Classification and Control Rule. This comprehensive invasive species law helps to prevent new invaders from getting to Wisconsin in the first place and also allows the DNR to move more rapidly to contain new invasive species before they are established in an ecosystem. With continued time and effort, our state is attempting to cease the spread of these threatening invasive species in our area.
The Wisconsin DNR’s website has a very helpful list of things that you can (and should!) do to help avoid spreading invasive species in our area, and consequently, across the country. A few of their suggestions include things as simple as inspecting your boat, trailer, and other equipment and removing any attached aquatic plants and animals before launching, after loading, and before transporting on a public highway. They also recommend that campers only burn firewood that was purchased within a 25-mile radius of the campsite, and to burn all wood during a trip – don’t take any home with you. Landowners are encouraged to only use native seeds and plants in your yards and gardens whenever possible, and to respond aggressively to rid your land of new invasive species when you encounter them. Most importantly, we should always leave native tree and plant species alone – as natural landscapes can often offer the best defense against invasive species. For more information and more details on how to protect our lands from alien invaders, please visit the Wisconsin DNR’s website, at http://dnr.wi.gov/topic/Invasives/prevention.html. The suggestions provided may seem like small steps – but every step we take makes a difference. And that is all that matters.Tags: animals, conservation, endangered, HIPPO, species