Studies on the production and decomposition of Spartina alterniflora Loisel in a Galveston salt marsh
Sears, Norman Evans
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Annual net aerial primary production of Spartina alterniflora was estimated by several methods which are compared and critiqued. Annual loss of dead vegetation was measured by the Wiegert and Evans (1964) litter bag method (1,211 g/m2) and by a leaf loss method (1,081 g/m2). The peak standing crop (October) was 1555 +- 160 g/m2. The standing crop at the end of sampling (Dec. 1979) was significantly higher than at the beginning (Dec. 1978), which may mean production was higher in 1979. Annual losses from the litter bag method plus changes in standing crop (method of Wiegert and Evans, 1964) gave 1863 +- 617 g/m2 annual production. Annual losses from the leaf loss method plus changes in standing crop gave 1847 +- 523 g/m2 annual production. Growing season losses plus peak standing crop gave 2078 +- 222 g/m2 annual production. In laboratory experiments, juvenile fiddler crabs, Uca, were found to ingest partly decayed S. alterniflora at the rate of 36% of dry body wt/day. The amphipod, Orchestia ingested about their own weight per day of the same material.