Arthropod diversity across burn plots of Northern Lower Peninsula: University of Michigan Biological Station.

Abstract

The purpose of our study was to examine relationships between the plant diversity and arthropod diversity in forests with different successions. In our study we examined seven burn plots: 1911, 1932, 1948, 1954, 1980 and 1998. We hypothesized that forests, with later burns would have smaller tree species diversity and therefore would have less arthropod species diversity. We also hypothesized that the more recently burned forest would have less leaf litter and therefore, would have fewer species of arthropods. Additionally, we hypothesized that there will be a positive correlation between the amount of groundcover and arthropod diversity. For our sampling method we used pit fall traps, which consisted of a cup (16oz) filled with 70% ethanol (3oz) placed into the ground. Five traps were placed on each burn plot in a 30x30 square meters area with a buffer zone of 30 meters into the forest from each edge of the burn plot. We also collected soil samples (top 10 cm of soil layer) to analyze the organic matter and moisture. We counted the groundcover (shrubs and seedlings) at each sampling point (around each pit fall trap) in 2x2 squared meters in each plot and all tree species in 900 square meters area. Leaf litter was collected on one square meter area around the center pit fall trap. Data analysis showed that overall arthropod diversity was positively correlated with the tree species richness. However, no signficant correlation was found with the forest successions. All orders (Coleoptera, Diptera, Araneida and Hymenoptera) that were found in the burn plots had a strong positive correlation with increased plant species richness. No correlation was found between percent moisture and percent organic matter across forests. We also did not find a correlation between the leaf litter mass and plant diversity. Overall our results support our hypothesis on increasing arthropod species richness with increasing plant diversity.