Spartina Alterniflora Die-Back in Louisiana: Time-Course Investigation of Soil Waterlogging Effects

Abstract

SUMMARY (1) Transplantation of streamside Spartina alterniflora swards into the more waterlogged and less productive inland marsh caused rapid decreases in soil redox potential and increases in interstitial water sulphide and NH4 concentrations and root alcohol dehydrogenase activity. (2) One year later, standing crops in these transplanted swards were significantly reduced compared to their streamside controls. (3) Reciprocal transplantation from inland to streamside resulted in the amelioration of the detrimental conditions associated with the waterlogged inland marsh and in an increase in standing crop to levels equivalent to streamside controls. (4) Soil salinity and pH were not significant factors in causing reduced growth of S. alterniflora. (5) Sulphide toxicity, in combination with extended periods of anaerobic metabolism in the roots, appeared to be a major factor associated with reduced growth of S. alterniflora and may be a cause of dieback in these marshes.