Use of vegetation classification and plant indicators to assess grazing abandonment in Estonian coastal wetlands

Abstract

Question: What are the effects of grazing abandonment on the vegetation composition of Estonian coastal wetlands? Location: Vormsi Island and Silma Nature Reserve in western Estonia, Europe. Methods: Local knowledge and field reconnaissance were used to identify current and historical management levels of wetland sites within the west Estonian study area. Nine study sites, with varying management histories, were selected comprising an area of 287 ha. A total of 198 quadrats were taken from 43 distinct vegetation patches in five of the sites. TWINSPAN analysis was used to identify community type, and a phytosociological key was constructed for character taxa. This vegetation classification was then applied within a GIS-based context to classify all the study sites, using a ground survey technique and 1:2000 scale air photos. Results: We identified 11 different brackish coastal wetland community types. Indicator species were defined with community characteristics for the seven main vegetation types readily recognisable in the field. Coastal wet grasslands were most extensive in grazed sites, or sites that had been more intensively grazed, while abandoned sites were largely composed of Phragmites australis stands, tall grassland, and scrub. Site variations based on vegetation composition were significantly correlated with past grazing intensity. Plant community types showed significant edaphic differences, with particularly low soil moisture and high conductivity and pH for open pioneer patches compared to other vegetation types. Conclusion: Abandonment of traditionally grazed coastal grasslands threatens their characteristic biodiversity. This study found that grazing abandonment reduced the extent of coastal wetland grasslands of particular conservation value. Nevertheless, plant species of conservation interest were found across the sequence of community types described. The study shows that grazing is an important factor influencing coastal wetland plant communities but suggests that vegetation distribution is affected by environmental variables, such as topography.

Diversity distribution and floristic differentiation of the coastal lowland vegetation: implications for the conservation of the Brazilian Atlantic Forest

“…Although TWINSPAN has limited application to very complex frameworks (van Groenewoud 1992) it works well with simpler datasets and its hierarchic classification is very helpful, mainly when interpretations are made in comparison with DCA diagrams (McCune and Grace 2002; Tsiripidis et al 2007;Burnside et al 2007). It is one of few classification methods that provides a key for the identification of new samples; we propose this as a practical key for future use.…”

Improved modelling of the impacts of sea level rise on coastal wetland plant communities

“…The generally low relief of Baltic coastal wetlands (between -0.28 and ?1.2 m) means that they can be inundated during periods of elevated sea level. Burnside et al (2007) identified six main plant communities with indicator species for Estonian coastal wetlands. These were Clubrush Swamp (CS), Reed Swamp (RS), Lower Shore (LS), Upper Shore (US), Tall Grass (TG), and Scrub and developing Woodland (SW).…”

Distribution patterns of plant communities and their associations with environmental soil factors on the eastern shore of Lake Taihu, China

“…( 1) TWINSPAN is internationally accepted as a hierarchical classification method that can simultaneously complete plot and species classifications and is widely used in vegetation ecology (Niall et al 2007;Nkosi, Barrett, and Brown 2016). Ordination techniques reveal correlations between the spatial distribution of plant communities and environmental factors, which might have extremely important ecological significance (Kajsa and Johanna 2005).…”