Reestablishing Florida scrub in a former agricultural site: survival and growth of planted species and changes in community composition.
Scrub vegetation reestablishes poorly in former agricultural sites. Between 1992 and 1999, we followed the survival and growth of scrub oaks, saw palmetto (Serenoa repens), and other species planted in a former citrus grove on scrub soil adjacent to extant scrub in Florida, USA, and also followed the changes in community composition. Oaks (Quercus chapmanii, Q. geminata [Q. virginiana], Q. myrtifolia) were planted in the summer of 1992 with a second planting in the summer of 1993. S. repens, Pinus elliottii and ericads were planted in the summer of 1993. We relocated marked plants annually and determined survival and height growth. Mortality of oaks was concentrated in the first year. The survival and growth of Q. geminata were significantly greater than those of Q. myrtifolia or Q. chapmanii. Survival was lower but differences between species were similar in the second cohort of oaks. Initial survival of S. repens was high but declined due to rooting by feral pigs. S. repens grew slowly. The survival of P. elliottii was high and growth rapid. Soil (0-15 cm layer) of the former grove differed from that of adjacent, intact scrub, with higher pH, NO3-N, available Cu and Zn, but lower organic matter, NH4-N, available Al, and Fe. We determined changes in community composition by annual sampling of line-intercept transects. Cover of native, woody scrub species increased slowly. Herbaceous, weedy species remained dominant through 1999, and exotic grasses were an important component of the vegetation.