Restoration of inland brackish vegetation by large-scale transfer of coastal driftline material

QuestionDoes large-scale transfer of coastal driftline material enhance the establishment of inland brackish vegetation? LocationThe Klutenplas of 11ha, a formerly reclaimed agricultural field, north coast of the Netherlands. MethodsA large quantity of coastal driftline material of local origin was transferred to the restoration site in 2006 after top soil removal in 2005 leaving bare areas for control plots. A priori species composition of the driftline was analysed in a greenhouse germination study. Target species were assigned to saline and brackish ecological species groups and present and historic regional occurrences. Our procedure for selecting target species resulted in a list of 98 species characteristic of terrestrial salt and brackish ecological species groups. The establishment of plant species in the field was recorded annually from 2006 to 2009, with a final survey in 2012. A comparison between locations with and without driftline was made. The entire study site was grazed with sheep. ResultsDriftline material contained 39 species, including 26 target species. During the first 4yr, the mean number of target species in the established vegetation of driftline plots was significantly higher than in control plots. When corrected for spontaneous occurrence by natural colonization in control plots, 44% of the target species in the established vegetation of driftline plots during the first 4yr could be attributed to the transferred material. After 7yr driftline and control plots converged to similar levels, probably as a result of dispersal by wind and animals. ConclusionsTransfer of coastal driftline material enhanced the rate of establishment of inland brackish vegetation for at least the first 4yr.