부산대학교 도서관

Litterfall was measured in an impounded swamp and a managed wooded crayfish pond swamp in S central Louisiana from mid-December 1976 through mid-December 1981 and in a natural swamp and a 'restored' swamp from mid-December 1977 through mid-December 1981. Hydrological patterns were different from area to area and water depths (measured from May 1977 to May 1981) varied considerably in three of the areas depending upon rainfall. In the crayfish pond, the water regime was maintained by pumping. Average leaf litterfall was greatest in the crayfish pond swamp (579 g/m2/yr) and least (293 g/m2/yr) in the impounded area. Average litterfall values were intermediate and similar in the natural swamp and the 'restored' swamp areas (405 and 401 g/m2/yr, respectively). Yearly litterfall declined throughout the study in the impounded swamp until 1981. The progressive decline is likely related to permanent flooding conditions which have caused tree mortality. The increase in litterfall in 1981 in all areas was probably related to drought conditions that year which for the first time in many years allowed the sites to dry out, thus improving growing conditions. These results suggest that productivity of Louisiana coastal forested wetlands will decrease in the future due to waterlogging related to regional subsidence.