Invasive Species


Invasive species or invasive exotic are a term or a categorization phrase deployed for flora and fauna. According to Agrawal & Kotanen (2003), invasive species refer to introduced, non-indigenous or non-native species that adversely interfere with the bioregions or habitats they invade. The issue of invasive species has attracted the attention of various environmental bodies such as the California Native Plant Society and International Union of Conservation of Nature (IUCN). The European Union has also defined the invasive species as species that are outside their natural distribution and threaten biological diversity. This paper focuses on the advantages and disadvantages associated with the invasive species. It also attempts to provide a remedy for dealing with invasive species.

Invasive species can have substantial benefits to the environment and human beings. For example, the Asian oysters have better capabilities of filtering water pollutants than the native oysters. In addition, some invasive species including the Asian oysters grow extremely faster and can withstand disease. According to biologists such as Grosholz (2005), releasing the mollusk in the Chesapeake Bay will substantially assist in helping in restoring the numbers of oysters and removing pollution. A research by Beckstead & (Parker) revealed that such Asian oysters could significantly improve the water quality in the Chesapeake Bay (Rouget & Richardson, 2003).

Invasive plant species can help provide habitat for creatures (Ricciardi & Atkinson, 2004). Native plants typically assist in safeguarding the alarming threat of diminishing habitat for animals. With the trees being cut down to pave the way for building house, many creatures are left without habitats. Through planting invasive plant species, human can provide good habitats for these animals. Besides, birds and mammals can feed on fruits, nuts and seeds of the invasive plants.

Beautification of the landscape is another benefit associated with invasive plant species. This is because they can attract hummingbirds, songbirds, insects and butterflies. However, one will have to prune the weeds constantly because to keep the environment tidy. As such, planting invasive plant species can be time consuming (Prenter, MacNeil, Dick, & Dunn, 2005).

Research findings have also shown that many of the invasive plant species are readily available (Lee, 2002). This makes them less expensive than native plant species. The ability of these species to adapt to various regions also implies that it is not logical to spend a lot of money expensive pesticides, topsoil, fertilizer or new plants. In addition, many of these invasive plant species can withstand desert conditions. As a result, one does not need to install an irrigation scheme. The ready availability of these species plays a crucial role in influencing people to plant them.

According to Jiang & Morin (2004), invasive species can help in restoring native ecosystems on ruined land. For example, in Puerto Rico, farming caused much of the destruction to the native forest. In the recent years, biologists have attempted to restore the abandoned land by planting native trees. However, they were not successful until they planted invasive plant species. Invasive species such as the rose apple and African tulip have restored this Puerto Rican ecosystem.

Another advantage of the invasive species is the promotion of biodiversity (Keane & Crawley, 2002). Through acting like the engineers of the ecosystem, these species can modify their new habitat. For example, off Chile’s coast, the Pyura praeputialis invertebrate forms massive mats providing crevices and corner in which other species survive. A research by Keane & Crawley (2002) found out that about 100 species of algae and invertebrates live in these crevices developed by the Pyura praeputilias. In addition, some invasive species such as the honeybees pollinate the plants. Other species can also help native plants in various ways. The Japanese white-eye bird in Hawaii spreads seeds of other plants in the habitat.

On the flipside of the coin, invasive species have certain disadvantages (Lee, 2002). Invasive plant species such as weed substantially reduce agricultural yield, although they can provide nutrients. These plants species have deep roots that can absorb essential nutrients from the subsoil. As a result, they deprive of the native plants nutrients through competition. According to Keane & Crawley (2002), many of these species are unpalatable since have spines and thorns. As a result, herbivores cannot feed on them. Therefore, the production of animal products such as meat and milk reduces.

Introduced species have substantial effects on recreation and tourism. These species can negatively affect outdoor recreations such as hunting, fishing wildlife viewing, hiking and water-related activities. Some species can damage various environmental services, which are essential for recreation, including, though not limited to quantity and quality of water, species abundance and animal diversity.

Exotic species can affect human health. The encroachment of human beings into the initially remote environments has exposed various diseases such as the AIDs virus to extremely wide population (Jiang & Morin, 2004). Exotic rodents, insects and birds such as the pigeons can act as reservoirs for human afflictions and vectors. The invasive Chinese mitten crabs are reservoirs of the Asian lung fluke. Through human history, diseases such as yellow fever, typhus, malaria and bubonic plague spread through these vectors. The spread of the west Nile virus that killed birds, mammals, humans and reptiles is one of the recent effects of invasive species. Waterborne illnesses agents such as cholera bacteria are frequently transported through ballast water.

Genetic pollution is also another negative impact of the invasive species. According to Klironomos (2002), exotic species threatens poses the risk of extinction to the native species through the process of genetic pollution. This process refers to the unintentional hybridization and introgression that result in the replacement of the existing genotypes because of fitness of numerical advantage of the exotic species. Hybrids from the invasive species that interbreed with the native species can swamp gene pool of the rarest species. An instance of genetic pollution is the interbreeding between the red wolf and the coyotes in the North Eastern parts of North Carolina.

Two significant solutions can help combat the effects of invasive species. The first solution is screening any intentional imports (Beckstead & Parker). Presently, the US law does not require the checking of screening imported organisms. As a result, revising the Lacey Act that gives the US Fish and Wildlife the authority to identify the invasive species will restrict their importation. Under the present system, the Act does not require the screening for invasiveness. This might pose threats to the native wildlife, human health and the economy. The US Department of Agriculture needs to revise the laws for plant importation. Some countries have reduced weed importation by adopting screening laws (Agrawal & Kotanen, 2003).

The second solution is the prevention of the unintentional introductions (Jiang & Morin, 2004). The pathway-based approach can prevent inadvertent introductions of organisms hitchhiking with others. For invasive plants, the government needs to revise the Quarantine Act of the US Department of Agriculture. Horticultural importations are key pathway for the invasive plant species that are causing economic and ecological damage. The quarantine should be reinforced to alleviate further introductions.

In conclusion, invasive species have both advantages and disadvantages. Some of the benefits of invasive species include the beautification of the landscape, provision of habitat for creatures, restoration of native ecosystems on ruined land, and promotion of biodiversity. The disadvantages of these species include reduction of agricultural yield, effects on recreation and tourism, and genetic pollution.












Agrawal, A., & Kotanen, M. (2003). Herbivores and the success of exotic plants: a phylogenetically controlled experiment. Ecology Letters, 6(2), 712–715.

Beckstead, J., & Parker, M. (n.d.). Invasiveness of Ammophila arenaria: release from soil-borne pathogens? Ecology, 84(1), 2824–283.

Grosholz, D. (2005). Recent biological invasion may hasten invasional meltdown by accelerating historical introductions. Proceedings of the National Academy of Sciences, 102(1), 1088–1091.

Jiang, L., & Morin, P. (2004). Productivity gradients cause positive diversity–invasibility relationships in microbial communities. Ecology Letters, 7(2), 1047–1057.

Keane, R., & Crawley, M. (2002). Exotic plant invasions and the enemy release hypothesis. Trends in Ecology and Evolution, 17(1), 164–170.

Klironomos, N. (2002). Feedback with soil biota contributes to plant rarity and invasiveness in communities. Nature, 417(4), 67–70.

Lee, C. (2002). Evolutionary genetics of invasive species. Trends in Ecology and Evolution, 17(1), 386–391.

Prenter, J., MacNeil, C., Dick, A., & Dunn, A. (2005). Roles of parasites in animal invasions. Trends in Ecology and Evolution, 19(1), 385–390.

Ricciardi, A., & Atkinson, S. (2004). Distinctiveness magnifies the impact of biological invaders in aquatic ecosystems. Ecology Letters, 7(1), 781–784.

Rouget, M., & Richardson, D. (2003). Inferring process from pattern in plant invasions: a semimechanistic model incorporating propagule pressure and environmental factors. American Naturalist, 162(4), 713–724.

Type of paper Academic level Subject area
Number of pages Paper urgency Cost per page: