Below is my research paper regarding Invasive Species...


Invasive Species

            Today, there are countless invasive species in the world, reaching new areas every day through one of two ways: self introduction or with human assistance that may have been intentional or accidental. Invasive species are often not native to the area or environment of which they have invaded and are causing harm to and are then labeled as “invasive”.  Invasive species are often defined as species that reproduce and spread violently, with a high potential to cause harm (Nature Conservancy). They can be any kind of living organism including insects, fish, fungus, or bacteria. They can even be invasive as seeds, eggs, or larvae as long as the species is not native to the most current ecosystem to which it causes harm. Further characteristics include having a general diet, large genetic variation, the ability to adapt to a wide variety of conditions and climates, a continuous breeding season, and the production of numerous offspring per birthing cycle – a large factor in how fast they can take over an ecosystem (Berg, Linda R.). All these factors lead to invasive species causing a wide variety of economic, environmental, and human health related problems which almost always arise from rapid and uncontrolled invasive species population growth.

            Approximately 42% of threatened or endangered species are at risk primarily due to invasive species (Nature Conservancy). Invasive species have the ability to not only result in the extinction of naturally native species but alter an ecosystem so drastically that it is beyond reparable, meaning habitats are literally impossible to restore back to its original condition with original biodiversity. As stated by The Convention on Biological Diversity, “… invasive species [are held] as one of the direct drivers of biodiversity loss” (Bright, Christopher). Through competition, disease, parasitism, and predation, these species lead to the killing and crowding out of original species. In addition, they also radically modify natural ecological processes such as the water, nutrient, and energy cycles, leading to the distortion of land and displacement of animals affected by their alterations (Berg). Further loss of stability among the native populations can result from the creation of hybrid species that occurs when a species which is native mates with one which is invasive, which is the same as introducing a new invasive species into the same ecosystem fundamentally doubling the damage.

            There are direct and indirect costs as a result of invasive species impacting the economy. Direct costs are those related to controlling the spread of invasive species such as the use of pesticides applied in an attempt to contain the spread of pests. The financial impact of this is astonishing, for example in 2001 “total expenditures for pesticides in the U.S. were $11.09 billion dollars… worldwide, the cost of pesticides… in 2001 was $31.8 billion U.S. dollars [U.S. dollars]” (Lah, Katarina). Indirect costs relate to the ecosystem services lost through such destruction. Today, the annual worldwide cost of invasive species is still in the billions of dollars and rising. Today, the estimated 50,000 invasive species known in the United States -- pythons in the Everglades, Zebra Mussels in the Great Lakes -- cost over $138 billion dollars annually; an enormous amount of tax payer money and frustration (Berg).

            Invasive species can spread disease and other harmful ailments to human health. Due to the fact that humans are continuously innovating to transport goods quicker, easier and most importantly farther, the interaction between diseases and humans is becoming more and more common as a result of invasive species. This can be as simple as, “the pollen of some invasive species increasing the severity of respiratory allergies” to “cholera and toxic algae being moved by the ballast of ships” (National Invasive Species Council). Unfortunately, many non-native species can act as reservoirs for disease, including insects, rodents, and birds, which carry diseases such as yellow fever and malaria. For example, the West Nile virus spread across North America after it was carried over by non-native mosquitoes. The West Nile virus is one of many “zoonotic” diseases-- those that infect both humans and animals -- that are spread via invasive species and fatal to humans (National Invasive Species Council). Other concerns include issues with food and water supply. A limited 10% of the earth’s 33 billion acres are arable. Meaning that if that 10% is being reduced millions of acres at a time, by invasive plants and pests, the land available for food production begins to dwindle. Thus, the U.S. spends billions of dollars to fight back while developing nations, who cannot afford to fight such an expensive battle, have no choice but to starve.  

            Generally, invasive species have been held to the assumption that they are all bad for a new ecosystem, however due to a recent discovery this may not always be the case. The red swamp crawfish is an invasive species and is now the most common crawfish in the world, leading to the decline of native amphibians and invertebrates. However, the situation is not all bad. Researchers have discovered that in the Guadalquivir marches of Spain, “the red swamp crawfish is the sole reason for the rebound of numerous threatened bird species” (Goldstein). The crawfish has become an important food source for multiple bird species that are making a population comeback after centuries of over hunting and biodiversity loss. The reason this is so astounding is because this represents the “first study to show the positive effects of an otherwise detrimental invader on a community of predator species” (Goldstein). In other words, this is the first time an invasive species has proven to not only be good for an ecosystem but actually has the ability to restore biodiversity, a groundbreaking discovery.

            Though there is now evidence that makes the case of invasive species not all bad, if the situation is left alone there will still be serious negative effects. As stated earlier not all invasive species are animals, many are plants. The introduction of new plant species into an ecosystem can even alter our own health. For example, the “spotted knapweed out-competes native grass species… by producing poisonous compounds… It also degrades the quality of grazing available cattle” (Nature Conservancy).However, this case has even become as serious as contaminating the cow itself; making their meat inedible even giving food poisoning to its purchasers. Invasive plant species can even affect oxygen levels. The arrival of the chestnut blight to the United States in 1904 resulted in the near extinction of the American chestnut by the early 1950s (Nature Conservancy). This dangerous threat to such an old species of plant – and such a vital provider to clean air – literally dropped oxygen levels all over North America and even Southern parts of  Canada; affecting overall health and the quality of our crops and cattle (U.S. Department of Agriculture). Luckily, in this case, the chestnut blight was able to make a comeback. However the threat of this happening again is high as new plant species are imported and exported overseas continuously, increasing the possibility of spreading not only the plant itself but whatever pests or pathogens it may also be carrying.

            It is evident that invasive species can be a serious epidemic that continuously affects the environment, our economy, and human health.  Though there is now evidence that makes not all invasive species entirely bad, they still come with many negative affects which can be extremely detrimental to the livelihoods of other species and humans. Knowing ways to prevent further spread of invasive species is important in today’s society. The simplest thing anybody can do to help fight invasive species is to not plant or transmit and invasive species. Ensure research is done and information is up to date on the status of these and other pests. Further tips include reporting an occurrence of invasive species to federal or state natural resource or agricultural agencies. There is even volunteer work with those natural resource agencies that work to control and eradicate invasive species ( Most importantly, spread the word that the ever increasing population and variety of invasive species are harmful and everywhere.


Works Cited

·         "Invasive Species." National Wildlife Federation. N.p., n.d. Web. 20 Mar. 2014. 

·         Berg, Linda R. Raven Berg. 5th ed. N.p.: n.p., 2006. Print.


·         Bright, Christopher. "Invasive Species." Global Environmental Governance Project.       N.p., n.d. Web. 20 Mar. 2014. 
·         Lah, Katarina. "Pesticide Use Statistics." N.p., n.d. Web. 20 Mar. 2014. 
·         "What is an Invasive Species?" The National Invasive Species Council. N.p., n.d. Web.   20 Mar. 2014. 
·         Goldstein, Robert, ed. "When an invasive species is good for conservation..."   Conservation Maven. N.p., n.d. Web. 20 Mar. 2014.           
·         "Plants." United States Department of Agriculuture. N.p., n.d. Web. 20 Mar. 2014. 
·         "What can I do to fight invasive species?" N.p., n.d. Web. 20 Mar. 2014. 

·         "Impacts of Invasive Species." The Nature Conservancy. N.p., n.d. Web. 20 Mar. 2014.