Comparison of nekton use of Phragmites australis and Spartina alterniflora marshes in the Chesapeake Bay, USA

Throughout the eastern USA many Spartina alterniflora salt-marsh systems are being altered through the invasion of Phragmites australis. As a result, substantial declines in the areal distribution of S. alterniflora-dominated habitat have occurred in contrast to increases in P. australis dominated habitat. While information is scarce on nekton use of P. australis marsh, increases in the areal distribution of this species have concerned resource managers. Managers typically view the shift of S. alterniflora to P. australis marsh as a shift from a biologically diverse and productive marsh to one less biologically diverse and productive. We examined nekton use of P, australis marsh relative to S, alterniflora marsh with similar geographic location and physical conditions. We found no significant differences (p > 0.05) in the utilization of P. australis and S, alterniflora marsh by nekton in terms of abundance or biomass. Further, no significant difference (p > 0.05) in the total number of nekton species was evident between P. australis and S. alterniflora marsh. We postulate that under similar environmental and physical conditions these marsh types are equivalent in terms of nekton use. It may be necessary to reevaluate current wetland management practices which involve the elimination of P, australis in favor of S, alterniflora marsh in order to increase nekton use.