A comparison of physical characteristics between transplanted and natural Spartina alterniflora marshes in lower Galveston Bay, Texas

Abstract

Five natural and ten transplanted Spartina alterniflora marshes in the Lower Galveston Bay System were compared to determine if there were significantly different physical characteristics associated with each type of marsh. The transplanted marshes were categorized into young, old, dredge spoil, and shoreline type marshes. The saltinarshes were compared on the basis of microhabitats, length-width ratio, areaperimeter ratio, marsh-water interface, total size of S. alterniflora habitat, fetch distances, angle of exposure, orientation, and elevation. All physical measurements, except for elevation, were obtained with the use of a Geographic Information System. The natural marsh sites in this study were characterized by highly undulant edges, island type land segments, concave shorelines, and low elevations. Transplanted marshes were characterized by relatively smooth interfaces, a large intact shoreline morphology, convex to straight shoreline configurations, and elevations higher than those of natural marshes. Younger marshes were typified by having relatively smooth edges, large intact morphologies, and elevations higher than those of natural marshes. Older transplanted marshes had long thin marsh morphologies with relatively smooth interfaces and longer fetch distances and higher elevations than both natural and young marshes. Transplanted shoreline marshes were depicted by long thin marsh morphologies possessing linear edges with marsh elevations similar to those of natural marshes. Transplanted dredge material marshes were characterized by having linear edges, large intact areas, and elevations higher than natural marshes.