Abstract |
Partial recovery of vegetation in a damaged freshwater marsh (Arcadia Wildlife Sanctuary at the mouth of the Mill River in Northampton, Massachusetts) after major sources of pollution were eliminated is described. Vegetation diversity was measured by species richness, total number of species sampled, average number of species per quadrat, and the Shannon-Wiener function, an index of information content. Diversity by each of these criteria was greater in all zones in 1971 than in 1969. Total coverage also increased in all zones throughout this period. Those species initially present within each zone at the beginning of the study period accounted for much of the increase in cover while species formerly absent from sampled areas within each zone contributed most of the increased diversity. (Modified author abstract) |