Epsilon Archive for Student Projects

Abstract

Saltmarshes worldwide are under threat from anthropogenic activities and has been so for the last centuries. In UK, land reclamation for agriculture has been a driving factor for the loss of these habitats. During recent decades, efforts has been made to restore areas to saltmarsh by moving sea defenses landwards and by doing so, allowing tidal inundation to cover previously reclaimed land. In 2005 the tidal River Glaven, located at Blakeney, north Norfolk coast, England, was realigned and as a result, an area previously shielded from the sea became subject to tidal inundation. This study aimed to investigate how the abundance and distribution of vascular plants has developed in the restored area since the restoration. Due to the zonation of plants, which characterize saltmarshes, a sampling methodology based on transects was developed. Both the restored area and an adjacent saltmarsh regarded as pristine was sampled at 10 metre intervals along transects. The result showed a clear zonation of species in the restored area, identified as a low/middle marsh plant community. No zonation was found in the reference saltmarsh, which was characterized by middle marsh communities and located at a higher elevation than the restored area. Fewer saltmarsh species was found in the restored area than in the reference. However, due to the presence of saltmarsh and grassland species, the restored area was found to have higher species diversity than the reference. The species data recorded showed a large skew due to a high amount of zeros. This was explained by the homogenous structure of the saltmarsh vegetation where many sampling squares were dominated by only one or two species. This suggests the need for an updated survey methodology in future surveys where more transects and samples are used. It is further suggested that the sampling effort in terms of transects are put in the restored area since no zonation was observed in the reference saltmarsh. A combination of transect sampling and the sampling strategy used in National Vegetation surveys is suggested.