A comparison of physicochemical variables across plant zones in a mangal/salt marsh community in Louisiana

摘要: Three vegetation zones were delineated in a mangal / salt marsh community at Bay Champagne, Louisiana — zone dominated byAvicennia germinans adjacent to the bay, an inland bySpartina alterniflora, and transition between two containing both species. Parallel transects that intersected each established perpendicular shore of bay sampled determine if these differed on basis soil texture, elevation, redox potential, selected interstitial water variables. Redox potential sulfide, ammonium, P, Ca, Mg, K, Fe, Mn, Cu, Zn, pH, salinity measured 5 times during year account for seasonal variation. Factor analysis identified five factors, accounting 80.6% variation data. These factors interpreted as representing seawater, nitrogen/phosphorus, Eh, copper scores theAvicennia significantly different than other sulfide with higher lower scores. Analysis variance revealed highly significant differences most individual TheAvicennia was characterized by highest relative elevation bulk density. Higher concentrations ions associated sea water, such potassium, calcium, magnesium, occurred zone, which also caused be zone. The andSpartina more biochemically reduced shown measurements, concentrations, factor former. Iron manganese zones, probably due precipitation sulfide. only potassium some additional TheSpartina had usually We hypothesize relatively high theSpartina may limit establishment ofAvicennia propagules there.