Success of managed realignment for the restoration of salt-marsh biodiversity: preliminary results on ground-active spiders.

Since the early 1990s managed realignment, where formerly reclaimed fand is re-exposed to tidal inundation through breaching of coastal embankments, has been increasingly used throughout Northern Europe as a cost effective and sustainable response to biodiversity loss and flood management. This study aimed to evaluate the success of managed realignment schemes that resulted in salt-marsh development for the restoration of spider assemblages. Restoration of salt--marsh fauna was studied by comparing ground-active spiders between recently inundated land (3-14 years old) and pair--matched, adj acent natural salt marshes. Natural reference salt marshes were characterized by a relatively low species richness, the dominance of late-successional stage species such as Pirata piraticus (Clerck 1757), and the presence of species preferring a cloud vegetation canopy like Arctosa fulvolineata (Lucas 1846) and Pardosa nigriceps (Thorell 1856). Restored habitats were characterized by greater species richness than in reference habitat and by the presence of balophilic species (Enoplognatha mordax (Thorell 1875) and Erigone longipalpis (Sundevall 1830)) and abundance of Pardosa purbeckensis (Westring 1861 ). These preliminary results arctic for maintaining a maximum of successional stages in salt marshes, as they increase the diversity of halophilic spiders. [ABSTRACT FROM AUTHOR]