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Fifty years of vegetation change in oceanic-montane liverwort-rich heath in Scotland |
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| Authors: | Maren Flagmeier David G Long David R Genney Peter M Hollingsworth Louise C Ross |
| Institution: | 1. Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK;2. Royal Botanic Garden Edinburgh, Edinburgh, UK;3. Royal Botanic Garden Edinburgh, Edinburgh, UK;4. Scottish Natural Heritage, Inverness, UK |
| Abstract: | Background: Liverwort heath is considered in Scotland to be one of the vegetation types most vulnerable to environmental change, yet detailed insights into its dynamics are lacking. Aims: To assess the nature and extent of plant compositional changes in liverwort heath over 50 years and relate this to environmental change drivers. Methods: Vegetation plots previously recorded 20 and 50 years ago were re-surveyed to assess changes in species composition, plot-level species richness and between-plot variability, using several β-diversity indices and partitioning. The environmental indicator values of the species that showed most change were used to identify the environmental drivers of change. Results: Liverwort heath in north-west Scotland has undergone compositional changes over 50 years, becoming more heterogeneous, and losing some of its distinct character. Dwarf shrubs and specialist liverworts have decreased, while graminoids have increased. Partitioning of change in β diversity indicated that mainly changes in species richness, rather than species turnover, have driven the taxonomic differentiation over time. Grazing, eutrophication and warmer and drier conditions were found to be potentially important drivers of the observed vegetation change. Conclusions: Our results highlight the vulnerability of liverwort heath to environmental change. |
| Keywords: | beta diversity bryophytes dissimilarity graminoids hepatic mat homogenisation leafy liverworts re-visitation studies semi-permanent plots vegetation change |