Invasive Species: Study of Nitellopsis Obtusa

Background

Nonindigenous species establishment has increased with the growing frequency and magnitude of transportation networks worldwide (Rothlisberger & Lodge, 2013). Some nonindigenous species establish populations and become invasive, threatening native biodiversity and impairing ecosystem services. (Rothlisberger & Lodge, 2013). Furthermore, these ecological impacts can result in large economic and human health consequences (Rothlisberger & Lodge, 2013; Glisson et al., 2018; Larkin et al., 2018). There are over 180 aquatic invasive species that have been documented across the Great Lakes basin (Midwood, Darwin, Ho, Rokitnicki-Wojcik & Grabas, 2016). One such species is the green alga, Nitellopsis Obtusa, a member of the Characeae family and is native to Europe and Asia (Midwood et al., 2016; Glisson et al., 2018; Larkin et al., 2018). N. obtusa was first discovered in the Great Lakes in 1978 and was likely introduced through ballast water from interoceanic shipping (Midwood et al., 2016; Rothlisberger & Lodge, 2013). Epizoochory, dispersal through the attachment to the fur and feathers of animals, is another possible way that N. obtusa has expanded its range (Midwood et al., 2016; Pullman and Crawford 2010). The species’ tolerance for a wide variety of conditions, fast-growing nature and morphology, favours its efficient and rapid spread (Midwood et al., 2016; Larkin et al., 2018). It can now be found in the Huron-Erie corridor, Lake Ontario and across inland lakes in New York State and Michigan (Midwood et al., 2016; Sleith, Havens, Stewart & Karol, 2015). Characeae species are highly productive, alter water chemistry and nutrient cycling, which in large quantities can restrict nutrient availability to native plants (Larkin et al., 2018).

Objectives

The impacts of N. obtusa on the state of lake bottom fish species, has not been thoroughly researched. This study will compare the species richness and abundance of lake bottom fish in areas where N. obtusa has invaded, and areas where the species is not yet present.

Methods

The distribution of N. obtusa has been mapped out extensively in Presqu’ile Bay, Lake Ontario, and thus is a suitable setting for a study of this nature (Midwood et al., 2016). This will be an observational, in-situ study where an equal number of random points will be established within areas of N. obtusa presence and absence. Areas of N. obtusa absence will function as the control group. The lake bottom will be raked to determine the presence or absence of N. obtusa. A randomized sample with a minimum 100 metre spacing will be established using GIS software (Meyer, Ingram & Grabas, 2006). (Midwood et al., 2016). Fyke nets will then be set up and left for an 18-hour period, after which the fish caught will be identified, recorded and released (Cooper et al., 2018). This data would then be analyzed using an analysis of variance (ANOVA) to compare the mean species richness and abundance.

Significance

This study will contribute to the state of knowledge on N. obtusa and its effects. Given the limited scope of research on N. obtusa and its effects on native species, it is a goal of this study to incite further research. Depending on the results of the study, the need for control measures may be established and require further action by the state. Overall, a study such as this can identify problems that need to be addressed or more research to be conducted.  

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