INVASIVE SPECIES EFFECT AND IT'S IMPACT ON ENVIRENMENT

       invasive species, also called introduced species, alien species, or exotic species, any nonnative species that significantly modifies or disrupts the ecosystems it colonizes. Such species may arrive in new areas through natural migration, but they are often introduced by the activities of other species. Human activities, such as those involved in global commerce and the pet trade, are considered to be the most common ways invasive plants, animals, microbes, and other organisms are transported to new habitats.

Most introduced species do not survive extended periods in new habitats, because they do not possess the evolutionary adaptations to adjust to the challenges posed by their new surroundings. Some introduced species may become invasive when they possess a built-in competitive advantage over indigenous species in invaded areas. Under these circumstances, new arrivals can establish breeding populations and thrive, especially if the ecosystem lacks natural predators capable of keeping them in check. The ecological disruption that tends to follow such invasions often reduces the ecosystem’s biodiversity and causes economic harm to people who depend on the ecosystem’s biological resources. Invasive predators may be so adept at capturing prey that prey populations decline over time, and many prey species are eliminated from affected ecosystems. Other invasive species, in contrast, may prevent native species from obtaining food, living space, or other resources. Over time, invading species can effectively replace native ones, often forcing the localized extinction of many native species. Invasive plants and animals may also serve as disease vectors that spread parasites and pathogens that may further disrupt invaded areas.

        Most scientists agree that the most effective way to thwart further invasions of exotic species and contribute to the protection of biodiversity is to prevent the new species introductions in the first place. Although international trade and travel continue to provide opportunities for “exotic stowaways,” ecologists note that governments and citizens have the power to reduce the risk of the release of such organisms into new environments. Closer inspection of pallets, containers and other international shipping materials at ports of departure and arrival could uncover insects, seeds, and other stowaway organisms. Some ecologists and government officials have advocated for tougher fines and the threat of incarceration to deter buyers, sellers, and transporters of illegal exotic pets.

What Makes a Species Invasive?

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. For example, many fish species have been introduced into the Great Lakes for sport fishing.² They have no documented negative impacts and provide recreational opportunities and a food source. 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.

Where Do Invasive Species Come From?

invasive species may enter new environments through many routes. Some are transported to new places and established intentionally, but with unforeseen consequences. Beach vitex was planted in coastal North Carolina in the 1980s as an ornamental plant for coastal homes.⁶ However, the plant began to overtake native species after it became established. The plant also does not have the extensive root system that holds the sand in place as native plants do. As it spreads, the plants hasten dune erosion by removing plants that secure the sands of the dunes.

Some invasive species were actually brought in as unsuccessful attempts to control other invasive species. In the 1800s, rats that came to the Virgin Islands on ships infested the sugar cane fields on the islands, causing massive crop damage.⁷ Farmers brought in mongoose as a predatory control for the rats. However, the rats are nocturnal and sleep in trees, whereas the mongoose are diurnal and cannot climb trees, so they were not successful at eradicating the rats. As a result, the islands now have two invasive species.

Impacts On Environment

Invasive species impact agriculture, forestry, and fishing. Plants and animals can take over these areas and cause irreparable harm to local or global economies and the surrounding ecosystems, and can even harm humans. These species can kill off native crops and animals. Farmers may have to downsize their land, and fishing markets may catch less viable fish to sell. Supply chains then see less business, throwing supply and demand out of sorts. Communities often depend on the natural resources around them. Some cultures need naturally growing plants and animals for food and medicine. If invasive species like Japanese beetles eat crops, people won’t have access to the resources they need.

Invasive species can also significantly harm human health. For instance, zebra mussels are not naturally found in the Great Lakes but instead are native to Russia and Ukraine. These mussels have a toxin that can cause health issues for people after consumption. Similarly, a plant like sumac is common throughout the United States and becomes invasive quickly, with potentially poisonous iterations spawning. These effects often go hand-in-hand, negatively affecting all three areas at the same time. Such drastic impacts require immediate action.

All credit goes to John P. Rafferty And Jacob Hill.