Craft, C.B. and C.J. Richardson. 1993. Response of plant communities to nitrogen and phosphorus additions. P. 460 in: Landin, M.C. (ed.), Wetlands: Proceedings of the 13th Annual SWS Conference, New Orleans, LA, June 1992. SWS South Central Chapter, Utica, Mississippi. 990 pp.

Nutrient-enriched agricultural drainage has been implicated in changes in plant species composition and community structure in areas of the northern Everglades that receive run-off from the Everglades Agricultural Area.

Three Everglades plant communities, sawgrass (Cladium), mixed sawgrass-cattail (Cladium-Typha), and slough (Eleocharis-Utricularia) were fertilized with N and P to study this enrichment. N and P were applied singly and in combination every two months at rates of 5.6 and 22.4 g N/msg/yr and 1.2 and 4.8 g P/msg/yr.

After 12 months, there was no significant change in aboveground biomass in the sawgrass and mixed plots in response to the fertilizer treatments. However, additions of P to the slough resulted in significantly less biomass in the Utricularia-periphyton mat. In all three communities, the phosphorus concentration in the plant tissue increased in response to the P and N+P treatments.

These findings are similar to the results of field studies by other researchers that show increased P uptake by macrophytes and degradation of the periphyton mat in areas of the Everglades receiving agricultural drainage.

Reproduced by permission

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