Written by Nicole Giles, Westfield State University, Environmental Science, November 2012
Humans have gradually introduced new plant species into ecosystems without understanding the repercussions for their actions. We have a tendency to buy plants based on our landscaping needs, whether it be a flower or known for its vine and erosion control. Unfortunately, some companies import plants from other countries and sell them based on their physical properties. These ‘new’ species are quick to adapt to their new environment, with no natural predators and can be disease resistant. According to the Massachusetts Division of Fisheries and Wildlife, these plant species are categorized as an invasive plant and if left unchecked, these organisms can quickly crowd native species and kill everything that is not suited to compete.
Invasive Plant Introduction
Invasive plants reproduce rapidly with the help of wind, water, and local wildlife for dispersal their seeds to other areas for easy colonization (Somers 5). For example, birds will eat the fruit from the plants and disperse the seeds in flight. People can act as dispersal mechanisms as well, spreading seeds on shoes and clothing, and by also introducing contaminated fill or mulch into areas during construction (Somers 5). It is the law in Massachusetts to wash boats before and after they are put into bodies of water, to help prevent the spread of invasive aquatic plants such Eurasian Water Milfoil.
Affects on Ecosystems
Phragmites australis also known as the Common Reed is an invasive species typically found in wetland areas. Introduced to the Atlantic coast during the late 1800s, this invasive can generate extensive damage in the areas in which it is growing (Blossey). Due to its extensive root system and structure, Phragmities alters the function of the wet ecosystem by changing the nutrient and hydrologic cycles of the soils (Blossey). Dense patches of Phragmities discourage native biodiversity because it is not the habitat of choice for native waterfowl and migratory birds; these birds prefer native short grass habitats (Blossey). Control programs such as the one in Primebrook National Wildlife Refuge in Delaware saw a recovery in bird communities after chemically controlling the invasive plant (Blossey).
Phragmities
Japanese Knotweed or Fallopia japonica is another example of an invasive species that is very difficult and expensive to control. Making its first challenging appearance in the United Kingdom, Knotweed quickly grows into dense thickets that crowds out native plants and are of no use to wildlife (Shaw). This invasive can also grow to great heights, shading out native plants thus reducing ecosystem biodiversity (Shaw). Flooding facilitates dispersal of Knotweed by spreading seeds and stems downstream which rejuvenate in spring months (Shaw). Removal efforts for this plant are extensive and may further inhibit the soil and native plants (Shaw).
Japanese Knotweed
Kudzu, a native plant to Asia, is a climbing semi woody vine found in Southern United States (DCNR). When Kudzu invades an area, it covers native vegetation with a blanket of leaves and prevents the natives from getting sunlight for photosynthesis (DCNR). Kudzu can also uproot entire trees and shrubs using its weight as an advantage (DCNR). Kudzu roots can grow to 7 or more inches in diameter and 6 feet or more in length, weighing 400 pounds (DCNR). This invasive is abundant throughout the southeastern United States but is being seen in Pennsylvania (DCNR).
Kudzu
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References
Blossey, B., et al. “Common Reed.” .” Ecology and Management of Invasive Plants Program. Cornell University: 2008. Web. 24 Nov. 2012. <http://www.invasiveplants.net/monitor/9CommonReed.aspx>.
“Boat Massachusetts: Your Guild to Boating Laws and Responsibilities.” Massachusetts Environmental Police. 2010. Print.
Britton, Kerry., et al. “Kudzu.” Ecology and Management of Invasive Plants Program. Cornell University: 2008. Web. 24 Nov. 2012. <http://www.invasiveplants.net/monitor/25Kudzu.aspx>.
“Kudzu.” DCNR Invasive Exotic Plant Tutorial for Natural Land Managers. Plant Conservation Alliance. 24 Nov. 2012. < http://www.dcnr.state.pa.us/forestry/invasivetutorial/kudzu.htm>.
Shaw, R. H., et al. “Japanese Knotweed.” Ecology and Management of Invasive Plants Program. Cornell University: 2008. Web. 24 Nov. 2012. <http://www.invasiveplants.net/monitor/12Knotweed.aspx>.
Somers, Paul. “Guide to Invasive Plants in Massachusetts.” Massachusetts Division of Fisheries and Wildlife. 2006. Print.
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