Urbanization can affect biodiversity in a variety of ways, including habitat loss and fragmentation and the introduction of non-native species. While we predict that human disturbance should impact the distribution and abundance of species in urban areas, what the actual relationship between urbanization and biodiversity is often unclear and may vary between plant and animal groups and even within groups of species. There are three main hypotheses that predict how urbanization should impact overall biodiversity in habitats that are impacted by human development. The productivity hypothesis predicts that the increased resources available in urban environments will result in an increase in biodiversity. The ecosystem stress hypothesis predicts a decrease in biodiversity in urbanized areas due to the stress associated with living in an altered habitat. The intermediate disturbance hypothesis predicts that areas that are moderately disturbed/ urbanized should have the highest diversity compared to highly urbanized or undisturbed habitats. We used publicly available bird biodiversity data collected through the citizen science program Project eBird and land use data collected from LandSat to create a two week long case study evaluating these three hypotheses for a senior level undergraduate research capstone course for biology majors.
Results/Conclusions
Students in the undergraduate research course first developed graphical predictions for each of the three hypotheses described above. They were then given bird count data from 13 sites in Florida where birds were counted at two time points approximately 10 year apart. Students calculated the Shannon's Biodiversity Index for each of the 26 time points using Excel. Students were also given changes in land use and urbanization that has been calculated using land use data (LandSat and QGIS) in those same locations over the same 10 year period and asked to evaluate the three hypotheses using this data. None of the three hypotheses described above are supported by these preliminary analyses, which leads students to think about how real-world data does not always fit in easily with ecological theory and creates a jumping off point for their semester long research projects required for this class.