David A. White

Factors Incluencing Disappearances of Spartina Alterniflora From Litterbags

Marsh plant detritus is exported to nearby estuarine ecosystems by tides (Darnell 1967, Odum 1980). Characteristically, tidal marsh litter export and decomposition rates are determined by placing one set of litterbags into the field at study initiation to generate a single rate curve (Williams and Murdock 1972, de la Cruz and Gabriel 1974). These rates are controlled by many seasonal factors (Swift et al. 1979), among which are resource quality, tides, and faunal associations. Therefore a single data set may not entirely explain this important process of marsh energy flow. Recent studies in tidal creeks and estuaries have documented the importance of tides in the dynamics of estuarine particulate and dissolved organic matter fluxes (Heald 1971, Heinle and Flemer 1976, Settlemyre and Gardner 1977, Hackney and de la Cruz 1979). No work has elucidated the influence of tides on conversion of senescent plants to the particulate matter of the estuary. This study examines litter disappearance of Spartina alterniflora (Loisel.) to determine if loss of material varies according to the month of litterbag placement into the tidal marsh, and to determine the effect of tides on litter decomposition and disappearance.

An American beech-dominated original growth forest in southeast Louisiana'

WHITE, D. A. (Dept. Biol. Sci., Loyola Univ., New Orleans, LA 70118). An American beechdominated original growth forest in southeast Louisiana. Bull. Torrey Bot. Club 114:127-133. 1987.-An old-growth (more than 150 years old) forest in southeastern Louisiana was studied during 1982-1983 using nested quadrats to quantify the ecological importance of the woody species. The canopy of +35 m height is dominated by American beech (Fagus grandifolia Ehrhart) with 3 other co-dominants: spruce pine (Pinus glabra Walter), southern magnolia (Magnolia grandiflora L.) and sweetgum (Liquidambar styraciflua L.). The relict angiosperm star anise (Illiciumfloridanum Ellis) is a very common shrub. Twenty-eight woody species were found, within a forest basal area of 39.8 m2/ha. The overstory species were underrepresented in the smaller size classes, while the shrub and understory species showed typical reverse J-shaped size class distributions. The forest is thought to be climax.