Can species pool size and composition explain different productivity-diversity relationships?
Houseman, Gregory*,1, 2, 1 Michigan State University, East Lansing, MI2 Kellogg Biological Station, Hickory Corners, MI ABSTRACT- Although the influence of plant diversity on ecosystem function (i.e. productivity) has garnered much attention, understanding how diversity varies across productivity gradients remains an important way to examine how underlying differences in environmental conditions influence community dynamics. Recent reviews have found that, while unimodal patterns are common, positive, negative or no relationship between diversity and productivity also occur with surprising frequency. If species pools strongly affect local diversity, then different species pools found among sites may explain the disparate productivity-diversity results. I tested this idea by adding 0, 5, 15, 30, or 45 new species to low, medium and high productivity (146, 338, 556 g live biomass/m2 respectively) portions of a natural productivity gradient in a southwest-Michigan oldfield. I assumed that
