Guest Post: Repelling Invasive Species: Lessons from Around the World

Invasive species are bad news for native flora, fauna and even for humans. Animals, plants, and even microbes that aren’t native to an area can take over an entire ecosystem shortly after being introduced in this area and cause native species to disappear.

The only way to protect an ecosystem from the negative impact of an invasive species is to repel, or at least control, the invaders and support a diverse and healthy ecosystem where native species can thrive.

How Are Invasive Species Repelled?

Each ecosystem is unique. When an invasive species takes over an area, it is important to develop a solution that targets the alien species while preserving native animals and plants. The best solution depends on what the ecosystem was like prior to the introduction of the invasive species and on how the invasive species threatens local flora and fauna.

Here are a few examples of initiatives taken against invasive species.

Asian Carps in The Great Lakes

Asian carps have been present in the Illinois waterways for years. Ecologists are currently worried about three species of Asian carps taking over the Great Lakes.

Asian carps are an invasive species because they don’t have any natural predators in North American waterways and eat the phytoplankton and zooplankton that other native fish species need to survive. This invasion is a threat to several native species and for the Great Lakes fishing industry.

This invasive species is currently contained thanks to underwater electric barriers, but some fish manage to get through. There are other projects being developed to stop Asian carps. One of these projects consists in installing an acoustic fence on the bottom of the lakes. This acoustic fence would emit sounds that only the carps can hear but would be harmless to native species.  

The Amphibian Problem

Non-native amphibians are typically introduced to a new area for pest control purposes, but some frogs and toads are also inadvertently introduced via the pet trade or imports. Amphibians can reproduce very quickly and compete with local species for food sources.

American bullfrogs, cane toads, and Cuban tree frogs are considered as invasive species in the U.S. Brazil is currently seeing ecosystems threatened by six different species of amphibians and things could get worse.

Bullfrogs are particularly problematic. A female can lay as many as 20,000 eggs and these frogs easily adapt to a wide range of environments. Bullfrogs can eat birds, lizards, fishes and even snakes.

Controlling amphibian populations could become easier thanks to a study that looked at how cane toads reacted to different types of light. The study found that traps with ultraviolet lights attracted more toads and that toads tended to avoid fluorescent and incandescent lights.

These findings could help control amphibian populations with traps and keep frogs and toads away from certain areas by adding fluorescent or incandescent lights. Unfortunately, these findings aren’t used on a large scale to control amphibian populations.

Invasive Plants Are a Worldwide Issue

Non-native species like the floating pennywort, Azolla fern or the Japanese knotweed are wreaking havoc on British ecosystems. In fact, there were 3,000 non-native species present in the wild in the UK in 2005. Two-thirds of these species are plants.

This isn’t an isolated issue. Kudzu, a vine native to Japan, is smothering vegetation throughout the Southeast of the U.S. Invasive algae is an issue that threatens coral reefs and fishing industries worldwide.

The UK has launched a program that consists in educating people about invasive species and how they spread. The British government also created a special rapid response unit tasked with tracking the progression of invasive species and in taking action as early as possible to repel or control these species.

Global Warming Is Creating an Environment Favorable to Invasive Species

Plants and animals have always migrated to other areas and become a part of new ecosystems as a way of adapting to changing conditions. However, human activity is behind most invasive species.

Some invasive species end up in a different area because of stowaways in shipping containers. The pet trade is also responsible for the introduction of non-native species in new areas, and importing alien species to grow feed for animals or pest control purposes can result in an invasion.

Global warming is also reshaping some ecosystems and creating a warmer environment in several areas of the Northern hemisphere. Exotic species are often a lot more adaptable and will bloom earlier than their Northern counterpart thanks to rising temperatures linked to global warming. These species also benefit from the lack of natural predators in Northern ecosystems.

How to Stop Invasive Species

Invasive species are a serious issue. Non-native plants and animals might not sound like something that would directly have an impact on your life, but the increasing presence of invasive species could create a world where the ingredients for your favorite meals become difficult to find, or where native species that are common to your area become extinct.

Governments around the world need to take action to maintain diverse and healthy ecosystems. Monocultures are common in agricultural areas, but mixed forests would be a better way to sustain local ecosystems. There should also be programs to introduce natural predators to stop invasive species and some efforts made to protect some native species.

And because global warming is a part of the equation, everyone should make efforts to reduce their use of fossil fuels. Pollutants and insecticides should also be avoided since these chemicals can harm native species and cause alien species to adapt, become more resistant and spread at a faster pace.

Everyone can do something against invasive species. You can learn to identify the non-native species present where you live, clear your backyard of any invasive plants, and create a diverse ecosystem on your property.

If nothing is done, the ecosystems we grew up with could change forever. The flora and fauna we associate with the places where we live could disappear forever and be replaced by exotic species.

Author:  Dakota Findley