Invasive Plants on the Rise

Photograph of Tiffany Feebish and Abear Awada standing examining plant specimens.
Photo courtesy of Abear Awada and Tiffany Feebish

Using invasive plant impact research written by Jacob N Barney, Daniel R Tekiela, Eugene SJ Dollete, and Bradley J Tomasek we sought out the impact of the potential threat of invasive plants in our local community. We collected local plant specimens surrounding our community, plant pressed them, and placed them into Riker Mounts to preserve them for purposes of identification to genus and species, and to establish a herbarium collection of local plants for Henry Ford College. Obtaining the genus and species for each specimen would allow us to categorize them to native, alien non-invasive, or alien invasive plants. We predicted the concentration of invasive species would be greater than that of native species.

While many may neglect the consequences invasive species represent, ecologists are concerned with the rapid spread and growth of such species. As the author of the article “What is the “real” impact of invasive plant species” argue, lack of quantitative data and predominance of anecdotal data are contributing to the intrusiveness of invasive species; as a result of observational and subjective data, ecologists’ abilities to manage invasive species, or identify the consequences of species growth is limited (Barney, Tekiela, Dollete, and Tomasek 2013). Therefore, efforts of quantifying invasive species are encouraged. The uncertainty of invasive species impact due to lack of data contributed to listing invasive species as one of the “big five” environmental issues of the 21st century (Sala et al. 2000). Therefore, as more data is collected to quantify invasive species ecologists will have the ability to identify invasive species and limit their intrusiveness. As the federal website suggests, the longer we neglect this problem rising through invasive species, the solutions will become harder to attain and more expensive (2014). For instance the United States spends approximately one billion dollars per year toward controlling invasive species.
The definitions of invasive species are vast; the Britannica Encyclopedia defines invasive species as introduced species, alien species, or exotic species, any nonnative species that significantly modifies or disrupts the ecosystems it colonizes (2014). It is crucial to distinguish that not all alien, nonnative, species are invasive as some may not pose a threat to the ecosystem, therefore are labeled as alien non-invasive. Furthermore, as the ecosystem is changing some native species that posed no past threat are becoming of a concern to ecologists due to the rapid increase in their population’s size. Accordingly, for our research concern invasive species are any species that poses a threat to the ecosystem it inhabits.

The purpose of introducing invasive species could have been beneficial to the environment, as the case of Phragmites introduction as a counter affect to erosion. However, Phragmites are considered invasive as they have evolved in areas where they were able to survive longer, with the capability of rapid means of multiplication, for they “Produce abundant, easily dispersed seeds that can withstand adverse conditions” ( 2014). Intrusiveness caused by invasive species affects plants and animals. Invasive species compete for ecological space and resources, crowding out other native species. “Approximately 42% of threatened or endangered species are at risk due to non-native, invasive species” ( 2014).They can tolerate a variety of habitat conditions to which natives would not be tolerant. As they are newly introduced to an ecosystem invasive species lack competitors or consumers. Effects of invasive species ultimately lead to decreased biodiversity. For example, organisms that consume or use invasive plant species as habitats, would be able to survive and reproduce more efficiently, unlike other organisms that do not consume or occupy invasive species. These organisms would face hardships trying to cope with the presence of invasive species, as invasive species crowd out other species.

Our procedures were to quantify invasive species, and differentiate them among three categories known as alien invasive, alien non-invasive and native species. The process of conducting our research took a vast amount of time that was dedicated to collecting, pressing, mounting, and identifying species to genus and species. As a start to our research we collected around 70 specimens from 15 randomly selected 1 meter2 quadrats. We uploaded an altimeter onto a cell phone to determine the longitude and latitude coordinates for each quadrat. The areas we studied included iconic places such as Hines Drive, The Rouge River, landscapes on HFC’s campus, and a horse pasture. After collecting the plant specimens we pressed them and then mounted them in Riker Mounts, to help preserve the characteristics of the plants for identification. Afterwards, we started to identify each plant to genus and species. In the process, we further identified which species were native, alien invasive, or alien non-invasive. It is necessary to differentiate among all three categories, realizing that not all alien species are invasive. In other words, the alien non-invasive species do not pose a threat to the community currently. Afterwards, we measured the species richness as the number of different species present in the quadrats we examined. Of these different species in each quadrat we took the percent of invasive species to get a quantitative measure of invasive species present in the areas we studied.

The graphs from the Rouge Riverside (Figure 1&2) indicate the presence of alien invasive species within the area. However, they have not out-competed the natives yet, but if action is not taken to stop alien invasive species from rapidly multiplying it is likely they will eventually choke out the native plants of that area in the future. With 49% of the Rouge River side being native the area is not overwhelmed with alien invasive plants. The graphs of the Rouge River flood plain (Figure 3&4) show that both native and alien invasive each cover 25% of that area making it clear to see that this area’s native plants are struggling to survive with the increasing number of alien invasive species. However, identifying around 70 plant specimens to genus and species took much longer than expected; as it was not possible to identify all specimens due the plants’ lack of flowering since their flowering season had past. The graphs made from the data obtained from the horse pasture (Figure 5&6) show us that the alien invasive is more abundant than the natives within the entire area. Although some quadrats that made up the flood plain had more native than alien invasive, the horse pasture area as a whole has an overwhelming number of alien invasive species compared to the native plants. Our overall goal was to determine how well native plants are competing with alien species, some of which might be invasive. Then we would be able to make recommendations as to how to proceed in attempts to control invasive species in our area.

As a result of our research we recommend further identification of plants by collecting more species. Secondly, we recommend the use of additional measures including species abundance. Thirdly, we suggest determining the impact that each invasive species is having on its ecosystem. Due to the rapid growth of invasive species we should raise awareness of their potential negative presence on the overall environment. Now that we have established a baseline of plants in each of the four ecosystems, with many identified to genus and species, we recommend follow up work on the quadrats we studied in the four ecosystems. Future researchers should continue to attempt to identify the plants in the quadrats we studied by obtaining specimens when the plants are flowering; then assess the species richness in future years to determine if invasive plants are outcompeting our native plants. Finally, we recommend national attention toward invasive species potential risk on biodiversity. Left unattended invasive species can become a national threat as the case of Purple Loosestrife, which was introduced to Michigan 160 years ago and now occupies wetlands in all states except Florida.

Barney, J.N., Tekiela, D.R., Dollete, E. SJ., & Tomasek, B.J. (2013). “What is the real impact of invasive plant species?” The Ecological Society of America, 11(6), 322-329. Retrieved from
Invasive species. (2014). In Encyclopædia Britannica online. Retrieved from
Michigan Technological University. (2012, December 17). Density of invasive reed, Phragmites australis, mapped in Great Lakes. ScienceDaily. Retrieved from
Sala OE, Chaplin III FS, Armesto JJ, et al. 2000. Global biodiversity scenarios for the year 2100. Science 287: 1770-74. US Forest Service - Pacific Northwest Research Station (2014, November 18). Invasive Species. Retrieved from