Effect of legacy on hydric forest structure in a subtropical urban watershed
Hydric forest communities within the Tampa Bay Watershed were inventoried to assess the effect of urbanization on these systems. Based on aerial photography and site visits, 85 hydric plots were assigned a legacy class—remnant (forest, pre-1948), emergent (forest, post 1948), and managed (actively managed grass on plot). On each plot, diameter at breast height (dbh) and canopy width and species were recorded for trees ≥2.5 cm dbh. A hierarchical agglomerative cluster analysis identified community types within a legacy class and one-way AOV (α = .05) was used to compare structural features within and among legacy classes. Remnant plots (43 plots) were composed of six, natural community types as recognized by the Florida Natural Areas Inventory and no novel communities. Emergent plots (23 plots) were composed of four natural community types and one novel community. Managed plots (19 plots) contained only novel communities. Remnants had the highest species richness (41 species) and only one non-native species. Managed had the lowest species richness (33 species) but highest richness of non-native species (17). Remnant and emergent plots had similar densities for trees ≤32 cm dbh, (803 and 820 stems/ha, respectively), whereas managed plots had only 119 stems/ha. For trees >32 cm dbh, remnant plots had a significantly higher density (196 stems/ha) than emergent (99 stems/ha) and managed (40 stems/ha). These results suggest that legacy did not play a key role in differentiating between emergent and remnant plots but did play a key role in identifying managed plots.