By Hannah Beckett
I’m sure most people have heard the terms “native” and “nonnative” when referring to the plants and animals that inhabit the area. But, what exactly do those words mean? And, why are they so important?
Native species are considered species that have existed historically in a certain region or ecosystem. They were here long before civilization and boast a stable, self-perpetuating population. These native species have evolved and adapted to the local climate, soil conditions, and other environmental factors to fill a specific ecological niche.
Non-native species do not originate in the area of region they are found. These species are introduced due to human activities in an ecosystem, intentionally or accidently. Non-natives don’t necessarily pose a threat to local ecosystems, so long as they do not have a measurable negative impact. However, if a non-native plant has a significant negative impact in the local region, it is considered an “invasive” species.
Invasive species are non-native to an ecosystem and their introduction causes harm to the environment. Species that are invasive succeed because of their ability to grow in favorable conditions and lack of natural predators, competitors and diseases that would normally regulate their populations in their native range. If left unchecked, invasives can outcompete and reduce native species populations. This, in turn, can cause a negative cascade effect among other organisms that rely on the outcompeted native species.
There are countless examples of both non-native and invasive species found in Brazoria County. I’ve chosen a few to highlight and describe how these species affect our local environment.
Chinese tallow trees are extremely invasive to Texas. It’s a prolific seed producer and adapts well to many conditions, easily outcompeting native vegetation. Native to China and Japan, it was introduced into the US as ornamental plantings. It quickly spread by birds and water transporting seeds creating monospecific (single species) tallow forests in the absence of land management practices.
Zebra mussels are small mussels about the size of a dime with zebra-like striping on their shells. Originally from the Black and Caspian Sea, they were likely introduced into the US from shipping. These quick-breeding mollusks are transmitted through improperly cleaned boats and boat trailers. Zebra mussels have caused alarming declines in fish, birds, and native mussels by over-absorbing phytoplankton, an essential food source for many aquatic species. Additionally, zebra mussels will attach to any hard surface they settle on including native mussels. Excessive growth on and around native mussel beds suffocate them over time. They adhere to just about any surface and once they do, they’re permanently secured.
Red fire ants pose a major threat to what little remains of the original Coastal Prairie along the Texas and Louisiana coast. These insects are believed to cause dramatic reductions in native species. Insects, lizards, birds, mammals, or amphibians that disturb a fire ant’s mound run the risk of being immediately attacked and even killed. Red imported fire ants often outcompete and even attack the ants that are originally from Texas. The resulting reduction of native ants is thought to be a reason for the decline of the horned toad populations.
So how can we help mitigate the harm of invasive species? Learning about the invasive species and native species of your area can allow you to locate and identify those that do or don’t belong. You can remove invasive plants from your yard and use more native plants in your gardening. Volunteering with local conservation groups to remove invasives from public land is another great option to help. Our native species are well-suited to their environment, and their presence is essential for maintaining a balanced and resilient ecosystem. We should do our best to understand and support these intricate relationships of native species within ecosystems.
Photo: Invasive Species Alert – Infested Waters – Zebra Mussels – Minnesota
Credit: Tony Webster, Public Domain via Wikimedia Commons
