Tree spade transplanting of Spartina pectinata (Link) and Eleocharis macrostachya (Britt.) in a prairie wetland restoration site

Clonal vegetation was transplanted in an attempt to increase plant species diversity at a wetland restoration in northeast Kansas, USA. A total of 107 plugs of wetland sod were relocated to the 6.9ha floodplain site from a local wetland in April 1994, using a 60cm tractor-mounted tree spade. Perennial and clonal species were selected based on their regional suitability for prairie wetlands and their presence in adjacent wetlands. Four growing seasons after transplanting, the survival of the plugs was over 90%. Of the 107 transplants, 27 plugs were Spartina pectinata L. (eastern cordgrass) and 18 plugs were Eleocharis macrostachya Britt. (spikerush). The objective of our study was to determine the extent of transplant spread, and effect of microtopography on this spread. The area of each transplanted plug was determined in October 1994, 1995, 1996 and 1997. Mean area of S. pectinata plugs was 0.51m2 in 1994 and increased annually to reach 1.57m2 in 1997. Mean area of E. macrostachya was 2.19m2 in 1994 and increased annually to reach 26.4m2 in 1997. Elevation and the resulting water depth affected transplant spread of both species (P< 0.05), with S. pectinata spreading most at shallow (maximum depth 0.11-0.20m) water levels within the site and E. macrostachya spreading most in medium (maximum depth 0.210.30m) and deep (maximum depth 0.31-0.40m) water levels. Survival and spread of these transplants indicate that the tree spade technique is useful for enhancing vegetation in restorations, especially for restoring clonal species that may be difficult to establish via seeding.