Nitrogen effects on Spartina foliosa and Salicornia virginica in the salt marsh at Tijuana Estuary, California

Abstract

Nitrogen effects were examined by experimentally enriching plots of pure Spartina foliosa and mixed Spartina-Salicorniavirginica at Tijuana Estuary, California. Even with large inputs of organic nitrogen from sewage spills in 1983, plants responded to experimental urea enrichment. In pure plots, the addition of nitrogen increased Spartina growth (as measured by total stem length and August biomass) and foliar nitrogen (TKN) concentration. In mixed plots, enrichment had no apparent effect on Spartina but increased the growth of Salicornia. The experimental removal of Salicornia from mixed stands increased Spartina production, but removal of Spartina did not affect Salicornia. Salicornia is a superior competitor for nitrogen and checks the growth of Spartina in enriched and unenriched conditions. © 1988 Society of Wetland Scientists.