Effects of Nutrients and Hydroperiod on Typha, Cladium, and Eleocharis: Implications for Everglades Restoration

摘要: The recent expansion of Typha domingensis (Typha) into areas the Ev- erglades previously dominated by Cladium jamaicense (Cladium) communities has led to competing hypotheses about importance nutrient concentration vs. hydroperiod in controlling distribution these species. In this study, experimental mixtures domingensis, jamaicense, and Eleocharis interstincta (Eleocharis), a member community, were subjected two levels three contrasting hydroperiods determine how variables might affect Typha's ability displace community. Mixtures species established outdoor tanks containing soil from northern Everglades region where experiment was con- ducted. Nutrient treatments consisted additions adjust ambient water centrations either 50 ,ug/L phosphorus (P) or 100 pug/L P plus nitrogen (N). achieved maintaining depths within ranges observed Everglades. Maximum 15, 30, 60 cm through- out wet season (May-November) followed lowering 5 during dry season. Over 2-yr period, biomass monitored nondestructively aboveground material harvested at end experiment. Analysis changes over time showed that differences between developed first growing had initial growth rates substantially higher than those for Cladium. responded positively both elevated nutrients (by as much 45%) well increased depth 60%), while did not increase response variables. Tissue concentrations found be under nearly all conditions. Net accu- mulation shoots 2-3 times greater other en- hancement flooding is associated with syndrome life history characteristics includes rapid rates, high tissue P, tall leaves, environmental Cladium, contrast, slow rate, low capacity resist invasion shallow waters, less conditions, traits would seem suited nutrient- poor, hydrologically unstable conditions natural Results study suggest attempts limit spread should consider hydrologic restoration reduction surface nutrients.