Abstract Introduction Acknowledgements Material and Methods Results Discussion - Changes in Salinity - Changes in SAV and Benthic Habitats > Other Indicators of Change - Correlation Between Sites Significant Findings, Implications And Future Work References Appendices PDF version

Other Indicators of Change

The benthic foraminifer Bolivina is an infaunal taxa typically associated with organic-rich sediments. The distribution of this group in the No Name core seems to correlate with human activities in south Florida. It is absent from 1856 to 1901 except for the period 1869-1888, which corresponds to the first major increase of European settlement in south Florida. The increase in Bolivina abundance, suggesting higher organic conditions, initially increased just after the population growth of the 1920s when Dade County's population increased six-fold from 30,000 to 177,000. The decline in Bolivina since 1975 may be related to decreases in freshwater pollution loads as a result of passage of the Federal Clean Water Act in 1972.

Patterns of molluscan faunal diversity and abundance are nearly identical in the No Name and 2002 Featherbed Bank (GLW402-FBB) cores (Figure 22). The highest abundance and diversity are found at the bottom of the cores and at approximately 25 cm depth. These differences are not due to taxonomic effects, because the data plotted have excluded worn and broken specimens. The 1997 Featherbed Bank core (SEI297-FB1) shows high diversity and abundance in the upper portion, similar to the other two, but not at the bottom. The differences in the lower portion of the core, however, are probably due to the age of deposition. Based on the current age models, the bottom of the 1997 core is several hundred years older that the bottom of the 2002 core. The increases in the upper portion of the three cores are particularly interesting because diversity and abundance increase at a time when epiphytal habitats were declining, and infaunal species were declining. Currently these patterns cannot be explained, but they raise a critical issue for restoration. The highest diversity and abundance occurs in an already altered system, therefore high diversity is not necessarily a good performance measure for restoration.