



The graph below shows the relationship between the number of ELUs on 24 Audubon Refuges in RI and the total number of plants (herbaceous species, shrubs, and trees) that have been found on each refuge. For example, Ruecker Wildlife Refuge has 39 different ELU types. Because large refuges have more ELUs and plant species due to size alone, we removed this bias using standard statistical techniques (see Nichols et al., 1998 for a description of the method). On the graph below, each dot is an individual refuge. The graph shows that as the number of ELUs increase, so does the number of plant species. The Pearson Product Moment Coefficient of Correlation for this relationship is r=0.59 (p < 0.001). Audubon refuges are an excellent place to test this relationship because most of them have not been disturbed for many decades.

