Evaluation of methods for establishing vegetation in created wetland mitigation sites in eastern Nebraska

EVALUATION OF METHODS FOR ESTABLISHING VEGETATION IN CREATED WETLAND MITIGATION SITES IN EASTERN NEBRASKA Andrew A. Miller, MS University of Nebraska, 2008 Advisor: Dr. Tom Bragg Seventeen wetland mitigation sites in eastern Nebraska were evaluated, by vegetative zone, to assess the relative success of active and passive wetland vegetation establishment techniques. For sites with available records of species introduced, 46% of the seeded species and 31% of the transplanted species were successfully established suggesting that the intentional introduction of species (i.e. active methods) provides some degree of success in wetland creation. No significant differences were observed within or among active or passive methods for Species Richness (S), Shannon-Wiener diversity (H′), or the Floristic Quality Index (FQI) (Kruskall-Wallis test P < 0.05). However, while not statistically significant, general trends showed that, in the temporarily flooded zones, seeding resulted in both the highest overall plant diversity and highest FQI (S = 20.2, H′ = 1.74, FQI = 8.99) and, among species with cover values > 0.5%, the lowest percent non-native species (6.2%). In the seasonally flooded zone, the highest diversity and highest FQI resulted from a combination of seeding and the addition of donor soil and transplants (S = 30.0, H′ = 2.598, FQI = 19.1). This combination of treatments also had the lowest percent of nonnative species with canopy cover values > 0.5 % for the