Invasive species

One consequence of globalization is that in addition to people and products moving across the globe, wildlife has been transported as well. This practice of transporting animals from their native regions to new areas dates back thousands of years.

In many cases, the transplanted animal or plant does not thrive in its new environment. A lack of proper food sources combined with the wrong climate can make for a short lifespan for the animal/plant in its new home. In other cases, however, the specimen thrives and is able to successfully reproduce and spread throughout its new habitat. When this happens, the plant or animal can cause damage on the new area and become an invasive species.

Introducing a species into a new environment may have a variety of outcomes. An exotic or alien species is one that has been introduced to a new place but does not necessarily have negative consequences. However, when these alien species begin to have negative consequences in the new habitat, they are called invasive species. Invasive species may cause environmental harm, economic harm, or impact human health. An invasive species can be any kind of living organism—an amphibian, plant, insect, fish, fungus, bacteria, or even an organism’s seeds or eggs.

A key factor that makes many species invasive is a lack of predators in the new environment. This is complex and results from thousands of years of evolution in a different place. Predators and prey often co-evolve in a phenomenon called the co-evolutionary arms race. What this means is that as prey evolve better defences, predators in turn evolve better ways of exploiting prey.

However, when a plant or animal enters a new environment, they will likely encounter predators who have not been evolving with them, which makes these predators unable to successfully exploit the prey. Defence mechanisms like venom, size or speed that have been matched by adaptation in predators are suddenly without match in the new environment. This can allow the species to proliferate rapidly as it no longer faces any predators.

Invasive species are among the leading threats to native wildlife. Approximately 42% of threatened or endangered species are at risk due to invasive species.

Examples of invasive species and their consequences:

Loss of habitat
- The hemlock woolly adelgid is an invasive insect from Asia that rapidly kills infested hemlock trees
Alteration of habitat
- Beavers from Canada were relocated to Tierra del Fuego. The trees in South America are not adapted to beaver activity as they are in North America, leading to the alteration of the habitat
Kill large numbers if endemic species
- Burmese pythons have decimated local mammal and bird populations in the Everglades
Impact Human health
- Invasive zebra mussels accumulate toxins in their tissues. When other organisms prey on these mussels, toxins are passed on the food chain and can also enter animals consumed by humans
Economic costs
- Zebra mussels in the Great Lakes can rapidly submerged surfaces, clogging up water intakes at water treatment facilities and power plants. Removing this invasive species has a high cost

What can we do to help?

Many strategies have been developed to stop the damage caused by invasive species and to prevention future invasions.

An important component is educating people about the dangers of transporting wildlife to new areas. Many laws and regulations have also been passed to combat the future spread of invasive species.
One way tocurb the spread of invasive species is to plant native plants and remove any invasive plants in your garden. There are many good native plant alternatives to common exotic ornamental plants. In addition, learn to identify invasive species in your area.
Regularly clean your boots, gear, boat, tires, and any other equipment you use outdoors to remove insects and plant parts that may spread invasive species to new places. When camping, buy firewood near your campsite instead of bringing your own from home, and leave any extra for the next campers. Invertebrates and plants can easily hitch a ride on firewood you haul to or from a campsite—you could inadvertently introduce an invasive to a new area.

Source:

https://www.environmentalscience.org/invasive-species

https://www.nwf.org/Educational-Resources/Wildlife-Guide/Threats-to-Wildlife/Invasive-Species