Mile and Paurotis ponds to Watson, North, and Roberts rivers and into the headwaters 
of Gum, Dixons, Lostmans, and East Slough. 
1994 0 
Frederick, P. C., and G. V. N. Powell (1994) Nutrient transport by wading birds in the 
Everglades. In: Everglades: The Ecosystem and Its Restoration . S. M. Davis and J. C. Ogden 
(eds.) St. Lucie Press, Delray Beach, FL. 
[DATE OF SAMPLING UNKNOWN OR NOT APPLICABLE.] The effect of nutrient 
accumulation resulting from deposition of feces in colonies of colonially breeding and 
roosting wading birds is estimated in this chapter for breeding and non breeding 
ciconiiform birds in the Everglades ecosystem, by modeling energy consumption and 
feces deposition rates and by using existing measurements of size, energy, and nutrient 
content of prey items from the Everglades. Current populations of breeding and non 
breeding birds are estimated to consume 4.9 fewer tons of prey (dry mass) per year 
than the much larger populations of the 1930s and 1940s, equivalent to an estimated 
14.6 million fewer prey items per year. This difference translates into 455 fewer tons 
of feces deposited in roosts and colonies per year, roughly equivalent to 59 fewer tons 
nitrogen and 5.6 fewer tons phosphorus. Non-breeding birds are estimated to account 
for only 1.5% of the difference in nutrient flux attributable to birds between the two 
periods, indicating that the differences are due to reductions in energyintensive 
breeding attempts. Although even the largest historical populations are estimated to 
have redistributed only a very small fraction of the total annual deposition of 
phosphorus and other nutrients in the marsh, loading rates at colonies can be extremely 
high. Loading rates at historical colony sites could have been as high as 120 g P nrr 2 
yr' 1 (approximately 3000 times the estimated historic atmospheric deposition rate), 
while current colonies are estimated to have rates of only 0.9 g P nrr 2 yr 1 (more than 
20 times the historic atmospheric deposition rate). Evidence from the Everglades and 
other ecosystems suggests that high nutrient concentrations in the vicinity of colonies 
has a strong effect on the productivity and species composition of aquatic fauna and 
flora. This may have strong feedback effects for survival of young wading birds, which 
characteristically develop foraging skills at or near colony sites. Recent relocation of 
large colonies from the estuarine zone to the freshwater Everglades implies that 
nutrient input to the estuary has decreased significantly. Nutrient-rich colonies 
probably serve as islands of refugia for nutrient-tolerant species in the oligotrophic 
Everglades and may serve to significantly affect the variability in biodiversity of the 
marsh. Sources of error tend to be in the direction of overestimation of nutrients 
transported, and in this regard, the amount of food required by nestlings is a central 
and poorly understood variable. 
1994 0 
Guentzel, J. L., W. M. Landing, and C. D. Pollman (1994) Atmospheric deposition of mercury 
in Florida: the FAMS Project (1992-1993). Abs., ASLO/PSA Joint Mtg., Miami, FL. a-31. 
[ABSTRACT ONLY. DATE OF SAMPLING UNKNOWN OR NOT APPLICABLE.] A five year 
study focusing on the atmospheric deposition of Hg and other trace elements in central 
and south Florida has been initiated. One of the primary objectives of the study is to 
determine the total pluvial flux of Hg and its partitioning into wet and dry components. 
Total metal deposition is collected at monthly intervals using continuous bulk deposition 
samplers. Wet deposition is collected by hand during individual storm events and 
monthly using a modified version of the automated Aerochem Metrics wet\dry 
deposition sampler. Preliminary calculations suggest that the atmospheric flux of Hg is 
seasonal, with the highest fluxes occurring during the summer months. There does 
appear to be a slight geographic trend, with the depositional fluxes being lowest in 
central Florida and increasing towards the south. Annual volume weighted fluxes for the 
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