Does niche partitioning explain spider richness in vacant lots?

This project is testing urban ecologic theories, specifically seeking to learn:

1) Does increased management intensity reduce prey availability and increase Linyphiidae competition?

2) Does increasing niche breadth and reducing niche overlap support more rich and abundant Linyphiidae communities?

Urbanization largely contributes to biodiversity loss, however, cities can support rich arthropod communities. Shrinking cities such as Cleveland, Ohio are gaining greenspace through the creation of vacant lots and management decisions regarding these lots, such as mowing frequency, can influence their value for biodiversity. The species richness of arthropod generalist predators able to coexist within a habitat patch is predicted to be driven by their extent of niche partitioning. Management of vacant land could influence the breadth of prey available for generalists and influence the intensity of exploitative competition that occurs among them.

To understand how niche partitioning affects the species richness and abundance of sheet web spidersĀ (Linyphiidae) we tested the hypotheses that (1) increased management intensity will reduce prey availability and increase competition among Linyphiidae and (2) increased dietary niche breadth and reduced dietary niche overlap will support increased Linyphiidae species richness and abundance.

In 2014, four focal competitors (Glenognatha foxi, Calymmaria emertoni, Erigone autumnalisand Tenuiphantes tenuis) were hand collected and their DNA was extracted, amplified with universal primer and tested for prey with gut-content analysis. Community traits for the Linyphiidae spiders were gathered from data collected with pitfall traps in the same year. The abundance and richness of the communities was determined with these identified spiders from a mix of control (mowed monthly) and meadow sites (mowed biannually). I predict that increased management will result in more niche overlap and less niche breadth. I also predict that increased breadth and decreased dietary overlap will result in richer and more abundant spider communities. Understanding if ecological theories like niche partitioning hold true in urban areas is critical to properly conserving and working in urban areas.