- Mitchell Marsh, a tidal salt marsh in the Salmon River Estuary, was diked in the
early 1960s. Restoration of the marsh, which began in late 1978, consisted of partial dike
removal. Several studies have been conducted in the marsh, addressing the status of the
developing salt marsh plant communities. Species composition data have been collected
inthemarsh forthe years 1978,1979,1980,1984,1988,1993,1999, and 2004.
Previous studies used multivariate methods, which did not address the spatial
variation present in the developing communities. This study introduces an innovative
method for representing spatial and temporal variation present in plant community
distributions. To achieve this, several methods were used. First, cluster and indicator
species analyses were performed in PCORD to identify plant assemblages for each year.
Second, universal kriging was performed using the Geostatistical Analyst in ArcGIS.
This resulted in a prediction map representing the spatial distribution of the plant
assemblages. Third, an animation of the kriged plant assemblages was created to display
continuous spatial plant assemblages from 1978 through 2004.
The vegetation analysis results were very similar to those found in previous yearby-
year studies conducted in the marsh. Initially the marsh was composed of wet pasture
assemblages that mostly died off by 1980. The only assemblage that persisted beyond
1980 was a high marsh assemblage identified by Argentina egedii. By 1984 the salt
marsh assemblages identified by Carex lyngbyei, Distichlis spicata, and Argentina egedii
were developing. These assemblages varied slightly in composition and distribution over
the years but presently appear much like they did in 1984.
The innovative methods introduced in this study allow the interpretation of
spatial and temporal distributions of plant communities. The results from this
study may be added to the wealth of data on salt marsh ecosystems and will
provide a building block for creating and interpreting visual representations of
landscapes, ecosystems, and communities. In combination with many other
studies, this one may help in the management and protection of this highly