Small zonal and fringing stands seem to be more vulnerable. 
Southern bulrush is thinned or destroyed in some localities, but 
only edges of stands are affected in other localities. Big cord- 
grass stands were eliminated by nutria on the transects. Rare 
cattail plants were heavily utilized and nutria are reported by 
others to damage and destroy cattaili stands. 
Extensive areas of openings did not develop on the transects 
with the higher populations of nutria, for saltmeadow cordgrass 
tended to occupy these openings and to replace other species that 
diminished in coverage. It is shown that many factors are changing 
in the dynamic marsh habitat, and these factors undoubtedly have 
effects, not assessed in this investigation, on the composition 
and density of marsh vegetation. 
It is concluded that the nutria did not have a primary or 
major effect by creating openings on the marsh vegetation as a 
whole in the areas represented by the transects. A general assess-~ 
ment of the value of the vegetation to desirable forms of wildlife 
suggests that the effect of the nutria, through vegetation, on 
this wildlife is less than a major one. 
