Fifty years of vegetation change in oceanic-montane liverwort-rich heath in Scotland

Abstract

AbstractBackground: 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 diversitybryophytesdissimilaritygraminoidshepatic mathomogenisationleafy liverwortsre-visitation studiessemi-permanent plotsvegetation change AcknowledgementsWe are grateful to Alison Averis, Donald McVean and the late Derek Ratcliffe for collecting the original data, to Gordon Rothero, Alison and Ben Averis for useful information, and Martin Hermy, Eduardo Moreno and three anonymous referees for valuable comments on the manuscript. We also thank the relevant landowners and managers for access to the sites, and Juliane Geyer for assistance in the field. M.F. was funded by a NERC Ph.D. studentship (CASE studentship with Royal Botanic Garden Edinburgh), and the project also received funding from SNH.Additional informationNotes on contributorsMaren FlagmeierMaren Flagmeier is a plant ecologist with a special interest in bryophytes and their response to environmental change.David G. LongDavid Long is a bryophyte taxonomist with research interests in Sino-Himalayan bryophytes and liverwort taxonomy, phylogeny and biogeography.David R. GenneyDavid Genney's main research interests are monitoring and conservation management for fungi, lichens and bryophytes.Peter M. HollingsworthPeter Hollingsworth is a biodiversity scientist interested in population genetics, systematics, and biodiversity responses to environmental change.Louise C. RossLouise Ross is a vegetation scientist interested in understanding and explaining changes in plant community composition as a result of climate change, land management practices and invasive species.Sarah J. WoodinSarah Woodin is a plant ecologist with interests in the influence of environmental change, land management and herbivory on (semi) natural vegetation in the British uplands and the Arctic.