Wednesday, August 5, 2009: 1:30 PM
Grand Pavillion III, Hyatt
Background/Question/Methods Removal of invasive and undesirable vegetation often results in highly degraded conditions. Ecosystem recovery can be accelerated by means of active revegetation, or planting. Despite the critical need for rapid plant community establishment, little is known about the factors that control revegetation success. In these studies, Salix caroliniana was removed from two historic ponds at Florida Panther National Wildlife Refuge (FPNWR), Naples, FL and Imperata cylindrica was treated in phosphate mine at Tenoroc Fish Management Area (TFMA), Lakeland, FL. Following invasive species treatments, native plant species were utilized for revegetation. To ensure appropriate ecotypes were used for revegetation studies, native plant material was aquired via propagation from seedlings that emerged from a seed bank assay of the study site (FPNWR), or was purchased at a local native plant nursery (TFMA). At FPNWR, we tested the effects of hydrology (high and low elevation), propagule type (1” plug and 5” pot), and planting density (0.457 m and 0.914 m centers) on plant survival and growth. At TFMA, we tested the effects of canopy complexity (no planting, low complexity: grasses only, and high complexity: grass/forb/shrub combination) and post-planting herbicide treatments (control, treat) on plant survival, plant growth and reinvading I. cylindrica.
Results/Conclusions Response to all factors tested was species-specific, though some general trends emerged. At FPNWR, planting at different elevations with respect to the littoral zone of the ponds had little effect on overall plant growth and survival for either density. Of the native species planted, Verbena hastata was the only species to have a significantly high (>90%) mortality rate. Plant survival was significant (decrease by ~99%) six months after planting for all species except Verbena hastata and 12 months after planting for all species except Eleocharis atropurpurea, Fuirena breviseta, and Proserpinaca palustris . Generally, the transplants from 5” pots had a greater survival rate than 1” plugs, but there were exceptions to these trends. Of the species selected for revegetation at TFMA, Eragrostis spectabilis in high complexity plots and Aristida stricta in low complexity plots had the highest percent survival and greatest plant volume. Panicum virgatum and Andropogon glomeratus had the lowest percent survival and plant volume. Canopy complexity had no effect on I. cylindrica reinvasion. Our results suggest that designing effective revegetation strategies for these two ecosystems and likely others rely on a species-specific knowledge of plant characteristics, and recommendations for revegetation are unlikely to follow simple rules.
Results/Conclusions Response to all factors tested was species-specific, though some general trends emerged. At FPNWR, planting at different elevations with respect to the littoral zone of the ponds had little effect on overall plant growth and survival for either density. Of the native species planted, Verbena hastata was the only species to have a significantly high (>90%) mortality rate. Plant survival was significant (decrease by ~99%) six months after planting for all species except Verbena hastata and 12 months after planting for all species except Eleocharis atropurpurea, Fuirena breviseta, and Proserpinaca palustris . Generally, the transplants from 5” pots had a greater survival rate than 1” plugs, but there were exceptions to these trends. Of the species selected for revegetation at TFMA, Eragrostis spectabilis in high complexity plots and Aristida stricta in low complexity plots had the highest percent survival and greatest plant volume. Panicum virgatum and Andropogon glomeratus had the lowest percent survival and plant volume. Canopy complexity had no effect on I. cylindrica reinvasion. Our results suggest that designing effective revegetation strategies for these two ecosystems and likely others rely on a species-specific knowledge of plant characteristics, and recommendations for revegetation are unlikely to follow simple rules.
