Biodiversity is a foundational aspect of ecology. However, anthropogenic effects have impacted biodiversity across the globe. A type of anthropogenic effects that can disrupt biodiversity urbanization. As urbanization increases, less adaptable species may decrease. Additionally urbanization may cause behavioral changes in some organisms, and both results may lead to changes in community composition and species interactions. To further understand the effects of urbanization on species interactions we will look at the relationship between crayfish and branchiobdellidan worms. Crayfish and branchiobdellidan worms work well as a model system, because they have an established context-dependent relationship and are abundant in freshwater ecosystems. The objective behind this study was to see if there are any changes in the community structure of crayfish and branchiobdellidan worms depending on the amount of urbanization.
To complete the objective, crayfish and branchiobdellidan worms were sampled at different sites along Baltimore City, Baltimore County, and Howard County Maryland. Previous research has shown that as stream order increases so does the average amount of impervious surface cover. We sampled 24 sites with the sampling split up evenly between first, second, and third order streams. Crayfish and branchiobdellidan worms were sampled by using dip nets and the one person hour method. Along with crayfish and branchiobdellidan worms environmental samples were assessed as well. Results suggest an overwhelming negative effect on native crayfish abundance as well as the presence of worms due to non-native species. Additionally non-native crayfish increased in abundance as stream order increased. The implications of this work will provide researchers with further understanding on how species interactions within communities can be affected by urbanization.