Factors influencing cattail abundance in the northern Everglades

Since the early 1900s, the Everglades have been influenced by anthropogenic actions including altered hydrology and increased nutrient loading. In the northern Everglades an apparent effect of Ž . these disturbances has been the development and proliferation of dense cattail Typha spp. stands Ž . in areas previously dominated by sawgrass Cladium jamaicense Crantz and sloughs. Cattail cover, soil nutrient concentrations, topography and fire history were determined for the Holey Land and Rotenberger Wildlife Management Areas, located in the northern Everglades. These data were analyzed using multiple regression to assess the relative influence of fire, hydrology and soil nutrients on cattail abundance. Holey Land and Rotenberger were overdrained over recent decades which resulted in soil compaction and nutrient accumulation, illustrated by increased soil bulk densities and elevated nutrient storage. Average bulk densities were 0.13 g cm for Holey Land y3 Ž . and 0.22 g cm for Rotenberger. Average total P TP stored in the surface 10 cm of soil in Holey Land and Rotenberger were 7 and 13 g m, respectively. In contrast, Everglades soils uninfluenced by nutrient enrichment and with less severe overdrainage have bulk densities of 0.07 g cm and TP storage of 4 g m. Typically, elevated soil P concentrations have been considered a primary factor influencing cattail growth and distribution in the Everglades. With the apparent absence of P limitation in Holey Land and Rotenberger, cattail abundance was influenced by either fire or hydrology. Forty-six percent of the variation of cattail cover in Holey Land was explained by elevation, indicating that increased water depth and duration of flooding have a ) Corresponding author. Tel.: q1 561 687 6608; fax: q1 561 687 6442; e-mail: [email protected] 0304-3770r98r$19.00 Published by Elsevier Science B.V. Ž . PII S0304-3770 97 00089-2 ( ) S. Newman et al.rAquatic Botany 6