Net productivity was determined from measurements of litter-fall and 

 stem growth of woody species and harvest samples of annual herbaceous 

 understory at two sites. Annual stem growth was calculated from biomass 

 estimates on two different dates. The annual increase in stem biomass 

 was 800 g dry wt/m^ for the bottomland hardwood site (BLH) and 500 g 

 dry wt/m^ for the baldcypress-water tupelo site (CT) . Litter-fall was 

 574 g dry wt/m2/yr for BLH and 620 g dry wt/m^/yr for CT. Harvest 

 samples within the two plots yielded 200 g dry wt/m^ and 20 g dry wt/m^ 

 for BLH and CT, respectively. Minimum net primary production was 

 calculated as the sum of the three and yielded 1574 g dry wt/m2/yr 

 for BLH and 1140 g dry wt/m^/yr for CT. 



The author poi 

 he did not take 

 Thus, he made es 

 consumption usin 

 was estimated to 

 caterpillar cons 

 84 g dry wt/m^/y 

 based on these e 

 wt/m^/yr for CT. 



nts out that his original estimates were low because 

 into account understory production and insect grazing, 

 timates of maximum herbaceous production and insect 

 g values from the literature. Herbaceous production 

 be equal to 312 g dry wt/m^/yr at both sites, and 

 umption was estimated at 47 g dry/m^/yr for BLH and 

 r for CT. Corrected total primary productivities 

 stimates were 1733 g dry wt/m^/yr for BLH and 1516 g dry 



A literature review of biomass and productivity studies of swamps 

 and forests is provided. (J.B.) 



Keywords: primary productivity, freshwater swamps, nutrient cycles, 

 detritus, Louisiana 



II-D-4 



Carter, M.R., L.A. Burns, T.R. Cavinder, K.R. Dugger, and P.L. Fore. 1973. 



Ecosystems analysis of the Big Cypress Swamp and estuaries. EPA-904/9-74-00; 



Environmental Protection Agency, Athens, Georgia. 379 pp. 



This was a 2-year study to obtain biological and hydrological infor- 

 mation for objective planning of the wise use of south Florida's land, 

 water, wildlife and fisheries resources. Field investigations during 

 1971-1972 intensively examined the details of biotic community inter- 

 actions with hydrologic conditions of disturbed and relatively unaffected 

 regions of the Big Cypress Swamp and contiguous tidal wetlands and 

 estuaries. Process studies and experimental and manipulation models 

 were formulated for the various components of the ecosystem. Study 

 results demonstrate the total dependence of the South Florida ecosystem 

 on the hydroperiod. Canal drainage of upland wetlands, which include 

 cypress swamps and wet-prairies, effected a ten-fold decrease in primary 

 productivity. Drainage also effected a thinning of the forest canopy 

 and induced a reduction in the rate of forest litter decomposition. 



78 



