Transplanting the leafy liverwort Herbertus hutchinsiae : A suitable conservation tool to maintain oceanic-montane liverwort-rich heath?

Thanks to the relevant landowners and managers for permission to carry out the experiments, Chris Preston for helping to obtain the liverwort distribution records and the distribution map, Gordon Rothero and Dave Horsfield for advice on choosing experimental sites and Alex Douglas for statistical advice. Juliane Geyer’s help with fieldwork was greatly appreciated. This study was made possible by a NERC PhD studentship and financial support from the Royal Botanic Garden Edinburgh and Scottish Natural Heritage.Peer reviewedPostprin

The natural exclusion of red deer from large boulder grazing refugia and the consequences for saxicolous bryophyte and lichen ecology

Large boulder grazing refugia permitted comparison of saxicolous bryophyte and lichen assemblages with those boulder tops accessible to red deer (Cervus elaphus) on a sporting estate in northwest Scotland. Plant succession was predicted to occur unchecked by grazing on the tops of these large boulders with cascading effects on bryophytes and lichens—assuming boulders had been in place over the same time period. Fifty pairs of boulders (one ≥2 m and the other accessible to red deer) were selected at random from various locations below north-facing crags. Percentage cover of each bryophyte and lichen species was estimated from three randomly placed quadrats on each boulder top. Due consideration was given to the influence of island biogeography theory in subsequent model simplification. Mean shrub cover and height, leaf-litter, bryophyte cover and bryophyte species richness were significantly higher within quadrats on large boulder tops that naturally excluded red deer. Lichen cover and lichen species richness were significantly higher on boulder tops accessible to red deer. Lichen cover was in a significant negative relationship with bryophyte cover, shrub cover and litter cover. Bryophyte cover showed a significant positive relationship with shrub height but there was an optimum shrub cover. Natural exclusion of red deer from the tops of large boulders has facilitated plant succession. The results suggest that grazing arrests the lithosere on boulder tops accessible to red deer at an early plagioclimax favouring saxicolous lichens. The results are relevant to situations where red deer might be excluded from boulder fields that hold lichen assemblages of conservation value

The impact of red deer on liverwort-rich oceanic heath vegetation

Background: There is concern about increasing numbers of large herbivores including red deer (Cervus elaphus) but little is known about their impact on bryophytes. Aims: This study set out to determine the effect of different localised densities of red deer on the internationally important Northern Atlantic hepatic mat, characteristic of oceanic heath vegetation, at four locations in the Scottish Highlands where sheep have been absent for decades. Methods: Thirty 7 m x 7 m plots were randomly located in each study area. The standing crop dung pellet group count method was used to estimate red deer density. Species richness, diversity and cover of hepatic mat liverworts were obtained from 1 m x 1 m quadrats placed at random within the sample plots. Calluna vulgaris cover, ericoid height, rock cover, gradient and altitude were also recorded. Results: Model simplification in ANCOVA revealed a consistent pattern of decreasing cover of hepatic mat and Calluna with increasing red deer density at all four study areas. Northern Atlantic hepatic mat cover, diversity and species richness were positively correlated with Calluna cover. Conclusions: The data suggest that Calluna cover is reduced (through trampling and browsing) at high local densities of red deer which has had cascading effects on the Northern Atlantic hepatic mat. Alternative explanations are discussed