We're going in a slightly different direction this week. Usually on Mammal Monday we look at fascinating or endangered mammals. But sometimes mammals can be what we call "invasive non-natives." A recent article in the Morning Ag Clips about feral pigs got me thinking about this topic. Check out this article, which discusses the issue of feral pigs and proposed solutions.
If you're not familiar with the term invasive non-native species, here's a quick explanation. Over thousands of years, species in an ecosystem evolve together. An example of this "co-evolution" would be insects that begin to come out of winter sleep at about the same time that flowers begin to bloom -- this coordination ensures that the insects get nectar for food and that the plants get pollination. When these native species evolve together, this type of coordination helps the ecosystem remain healthy.
Sometimes, new species that didn't evolve in the ecosystem are introduced. These species are considered "non-native." Here in the Chesapeake Bay region, we often consider any species that was introduced after Europeans arrived in the area (let's say the 1600s) to be a non-native. Some non-natives stay where they're planted and really don't cause much trouble -- plants such as roses, tomatoes, and tulips are non-natives. Sure, non-native species may not be the greenest option, since they require more water or fertilizer than natives and often don't provide food sources to native species, but they aren't quite the problem that their cousins the "non-native invasive" are.
Non-native invasive species are plants or animals that are introduced into an ecosystem and quickly begin to outcompete native species. They may be a predator that eats everything in sight, such as the northern snakehead (see video below), or they could be a plant that outcompetes and kills other plants in the area (check your backyard for English ivy). Common non-native invasives include house sparrows and kudzu, but there are many, many more. And these species aren't just an ecological nuisance; they can have major economic impacts. Kudzu and bamboo can cost homeowners substantial amounts once it gets into their landscaping, and the invasive stink bug has already cost mid-Atlantic apple farmers millions of dollars in crop losses. The invasive emerald ash borer currently threatens ash trees. Why is that an issue? Think about America's past time -- wooden baseball bats are mostly made of ash wood. Zebra mussels were first introduced in the Great Lakes region, but have spread throughout the U.S. The Missouri Department of Conservation estimates that this small mollusk, responsible for clogging water intake pipes and power plant pipes, fouling boat hulls, and displacing native species, will cost the U.S. billions of dollars by the end of this decade.
But when we talk about mammal invasive non-natives (and yes, birds and fish too), animal lovers like me start to feel a little agita. On the one hand, we don't want to allow the ecological damage caused by non-natives, but on the other hand we don't want to see animals hurt or killed, although we know these organisms must be removed to protect native habitat. So what can a greenmomster do? First off, never set an unwanted pet (such as a snake or fish) loose into the environment. Check with a local nature center for proper ways to find them new homes. Second, try to encourage native plants and animals by choosing native plants for landscaping. Eradicating non-native species, particularly mammals like the nutria or feral pigs is a tough business. Prevention is our best, and most humane, weapon against non-native invasive species.