RESTORATION OF WETLAND VEGETATION WITH TRANSPLANTED WETLAND SOIL - ANEXPERIMENTAL-STUDY

Restoration of drained wetlands requires the re-establishment of a nat ive wetland plant community. This can be difficult in areas where long -term drainage has eliminated wetland vegetation and significantly red uced the number of viable wetland plant seeds in the seed bank. This s tudy of U.S. Fish and Wildlife Service wetland restoration sites in no rthern New York examines the effectiveness of transplanting wetland so il from small remnant wetlands in the drainage ditches to the area tha t becomes shallow marsh following reflooding. The results of two exper iments are reported, including a small-scale study of transplantation techniques using small plots with treatments and controls established by hand, and a large-scale application of soil transplantation and sit e-preparation techniques using heavy equipment to establish large plot s across entire wetland basins. In the small-scale study, the transpla nt plots had significantly lower wetland index values, indicating grea ter dominance of wetland plants, after one growing season but not afte r two. Transplant plots also had more wetland plant species and more w etland plant cover than natural control plots, and these differences p ersisted through the second growing season. Litter removal and soil di sturbance also lowered the wetland index values and increased wetland plant species number and cover, but only for the first growing season. In the large-scale study, soil transplantation significantly increase d both the number of species and the amount of cover of wetland plants and of plants valuable as wildlife food sources. Mowing and plowing t reatments increased wetland plant establishment, but much less than so il transplantation, and plowing significantly increased the establishm ent of cattail (Typha spp.), an undesirable invasive species in small wildlife marshes. Soil transplantation should be a particularly effect ive technique for improving wetland plant establishment and limiting c attail encroachment in areas disturbed by dike construction.