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

Evolution and networks in ancient and widespread symbioses between Mucoromycotina and liverworts

Like the majority of land plants, liverworts regularly form intimate symbioses with arbuscular mycorrhizal fungi (Glomeromycotina). Recent phylogenetic and physiological studies report that they also form intimate symbioses with Mucoromycotina fungi and that some of these, like those involving Glomeromycotina, represent nutritional mutualisms. To compare these symbioses, we carried out a global analysis of Mucoromycotina fungi in liverworts and other plants using species delimitation, ancestral reconstruction, and network analyses. We found that Mucoromycotina are more common and diverse symbionts of liverworts than previously thought, globally distributed, ancestral, and often co-occur with Glomeromycotina within plants. However, our results also suggest that the associations formed by Mucoromycotina fungi are fundamentally different because, unlike Glomeromycotina, they may have evolved multiple times and their symbiotic networks are un-nested (i.e., not forming nested subsets of species). We infer that the global Mucoromycotina symbiosis is evolutionarily and ecologically distinctive

Early divergence of an Azorean endemic species in the moss genus Rhynchostegiella (Brachytheciaceae)

Using the moss genus Rhynchostegiella (Brachytheciaceae) as a model, we address the question of whether taxonomic shortcomings account for the extremely low rates of endemism reported in the Azorean bryophyte flora. Eight accessions initially assigned to three of the four previously reported species in the Azores were identified as a distinct species using the Generalized Mixed Yule Coalescent method in the context of a molecular phylogenetic analysis of the genus. Rhynchostegiella azorica sp. nov. is therefore described as a new species that is endemic to the Azores. Its morphological features intergrade with those observed in other species, with a seta that ranges from almost smooth to rough; a length to width ratio of the laminal cells that matches the one of the R. curviseta group; but a leaf apex that is typical of the R. tenella group. This suggests that previous reports of four Rhynchostegiella species from Azores are erroneous and that a single, morphologically variable species, R. azorica, occurs in the archipelago. Rhynchostegiella azorica is sister to the remainder of the species of the genus, whose most recent common ancestor was dated at 4–20 Ma. This points to a more ancient origin in comparison with other Macaronesian endemic species of the genus. The unexpected discovery of an Azorean endemic species in Rhynchostegiella suggests that patterns of endemicity in the Azorean bryophyte flora are not well estimated from traditional taxonomic knowledge and point to the necessity of an extensive integrative taxonomic revision.</jats:p

Reinstatement of Plagiochila maderensis (Jungermanniopsida : Plagiochilaceae) based on chemical evidence and nrDNA ITS sequences

Plagiochila maderensis Gottsche ex Steph. is reinstated as a Madeiran endemic. This taxon was synonymized with P. spinulosa (Dicks.) Dumort. over 35 years ago and has been accepted under that name in recent years. Morphologically, P. maderensis, which is known only in the sterile state, differs from P. spinulosa in having a smooth leaf surface, larger leaf cells and an often broadly truncate leaf apex. Phytochemical analysis using NMR and GC-MS profiling demonstrated that the lipophilic secondary metabolites are strikingly and unambiguously distinct from those of P. spinulosa. The dominant constituent is 4- hydroxy-3'-methoxybibenzyl, present in exceptionally large amounts. Analysis of the ITS region of nrDNA of P. maderensis and incorporation of the sequence into a maximum likelihood analysis of a dataset comprising another 28 Plagiochila and two outgroup sequences revealed that P. maderensis is a member of Plagiochila sect. Rutilantes Carl. Plagiochila maderensis is placed sister to the Neotropical species P. gymnocalycina (Lehm. and Lindenb.) Mont. and P. trichostoma Gottsche, but in a clade that does not have bootstrap support. It is known already that 4-hydroxy-3'-methoxybibenzyl is the principal bibenzyl constituent of P. trichostoma and chemical analysis has now shown that this applies also to P. gymnocalycina