Changes in Community Composition and Biomass in Juncus roemerianus scheele and Spartina bakeri merr: Marshes One Year After a Fire

摘要

Fires occur naturally in many wetlands and are widely used for marsh management. We examined the responses to fire of Juncus roemerianus and Spartina bakeri marshes on Kennedy Space Center, Florida. In each marsh, we determined vegetation cover before burning on 5 permanent 15 m transects in the greater than 0.5 m and less than 0.5 m layers and sampled biomass on 25 plots (0.25 sq.m). One year after burning, we repeated the sampling. Species composition one year after burning was similar to that before the fire in both Juncus and Spartina marshes. Minor species tended to increase, but this was significant only in the less than 0.5 m layer. In mixed stands, fire appeared to favor Spartina bakeri. Total cover (sum of the cover values for each species) in both marshes reestablished by one year after burning. Biomass did not recover as rapidly. In the Juncus marsh one year after burning, live biomass was 47.2, standing dead 18.7, and total biomass 29.3 of that before burning. In the Spartina marsh, biomass one year after burning was live 42.3, standing dead 21.4, and total 30.7 of that before burning. Fire increased the ratio of live to dead biomass from 0.82 before burning to 1.85 one year after the fire in the Juncus marsh. In the Spartina marsh, the ratio of live to dead biomass increased from 0.80 before burning to 1.59 one year after burning.