I am particularly interested in determining if unimodal diversity-productivity relations might result from an interaction between the effects of interspecific competition for resources occurring within trophic levels, and the regulation of such interactions by predators between trophic levels. I have found that models based solely on resource competition are not likely explanations for observed positive inter-correlations among nutrient availabilities and overall nutrient levels in lakes. I have also documented that patterns of variation in species diversity in pond algae are closely linked to patterns of variation in density, composition, and diversity of zooplankton grazers. Here is a landsat pic of one of the areas we study. This area is called the Lux-Arbor Research Reserve at the Kellogg Biological Station.
Vegetation shows up red on here whereas ponds and lakes are dark.
We mostly sample the smaller ponds you can in the central peninsula as well as ponds in other sites in southern and central Michigan. These ponds are fishless and have a biota that is relatively distinct from the other nearby fish-containing ponds. Together they form what might be called a meta-community . However there is a lot of variability because this increase in diversity does not always occur at intermediate productivity levels. Right now, I m trying to understand why this might be so .