Phytosociology informs the conservation of species-rich meadows in hydrologically dynamic habitats: an example from British floodplains in a wider European context

Abstract

Nature conservation requires classification of vegetation types for site assessment and assignment. Species-rich floodplain meadows are a declining habitat in Britain and Europe yet their classification in Britain has been based on just a few samples and fails to describe community response to environmental change adequately. European classification, in opposite, has been based on samples from the wide geographical range with no environmental data/analysis supporting the choices. We propose a revised classification of the lowland meadow Alopecurus pratensis-Sanguisorba officinalis community of the British National Vegetation Classification (NVC) linked to variation in local water-table depth. Data have been collated from 58 British floodplain meadows. Based on botanical and hydrological data, four subcommunities within the Alopecurus-Sanguisorba community have been defined. Assessment of conservation sites at the subcommunity level allows temporal and spatial evaluation of the trends and suggests hydrological management towards desirable vegetation. This approach, developed on data from the British meadows, has much wider geographical applications if compared with European plant communities. Seventy-two British and European plant associations were compared via Canonical Correspondence Analysis (CCA). Species ordinations were used to study the coherence of floodplain syntaxonomic alliances across Europe from Ireland to Bulgaria. CCA confirmed the spread of the British subcommunities of the Alopecurus-Sanguisorba community along a strong hydrological gradient and highlighted their lower fertility compared to their Dutch counterparts. The hydrological gradient separating the British subcommunities should help inform site management for the conservation of the species-rich communities, especially where hydrological control is possible.