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Lichen harvest and trade are closely associated with the livelihood of most of the rural people in Western Nepal. The present study investigates the commercial collection of lichens, quantifies the traded volume and relates it to a market scenario, and discusses conservation measures in relation to established legal practices in Nepal. Data on lichen trade and revenue generated for the 12 years (2000–2011) were collected and analyzed from 74 districts of Nepal. Voucher specimens were deposited at TUCH (Tribhuvan University Central Herbarium) in Nepal. The lichens collected in West Nepal are mainly used in international trade, while those in East Nepal are used locally for food. A total of 20 commercially important species of lichens were identified from five trade centers and one local market. During 2000–2011, Nepal legally exported 2020 tons of lichens and collected NRs 25,293,305 (USD 240,000). The average annual quantity of turnover was 168 tons, though it is estimated that much was exported illegally. The hill districts in Nepal, which traded 1774 tons, were more important for the collection of commercial lichen species than the Mountainous and inner-Tarai districts, which traded 167 and 108 tons, respectively. Through the Forest Act, Forest Regulations and its amendment in 2011, the collection of lichens for harvest, trade and export in any crude or processed form was banned. However, the legislation lacks an effective implementation strategy, and sustainable harvest of lichen resources based on scientific data would better serve local livelihood and lichen conservation in Nepal.

Riparian areas and their plant communities are threatened due to human exploitation and habitat loss. Conservation of riparian vegetation requires knowledge on limiting factors in the biology of species preventing its spread along suitable areas. It needs to be assessed if an endangered species is trapped in an extinction vortex or whether it can recover from its current bottleneck situation by management measurements. We investigate the recovery potential of an endangered riparian shrub species of European rivers, the German tamarisk, Myricaria germanica, by combining field and lab experiments on seed production, germination and wind dispersal with a modelling approach on species distribution. While the seed potential is high, wind-mediated dispersal is average, with a majority of seeds falling next to the mother shrub. The modelled dispersal kernel shows highest goodness-of-fit with a polynomic function. Including this kernel in a model on the future distribution of the species based on identification of suitable habitat, limited spread to new areas in Switzerland after 20 and 50 dispersal events is predicted. Given the current limited distribution of the German tamarisk in Switzerland, conservation efforts are required to allow for the formation of new riparian habitat. Additionally, connectivity along river networks has to be enhanced to help the species to escape the extinction vortex it is trapped in.

Tree crowns typically cover the vast majority of the surface area of trees, but they are rarely considered in diversity surveys of epiphytic bryophytes and lichens, especially in temperate Europe. Usually only stems are sampled. We assessed the number of bryophyte and lichen species on stems and in crowns of 80 solitary sycamore maple trees (Acer pseudoplatanus) at six sites in wooded pastures in the northern Alps. The total number of species detected per tree ranged from 13 to 60 for bryophytes, from 25 to 67 for lichens, and from 42 to 104 for bryophytes and lichens considered together. At the tree level, 29 % of bryophyte and 61 % of lichen species were recorded only in the crown. Considering all sampled trees together, only 4 % of bryophyte, compared to 34 % of lichen species, were never recorded on the stem. Five out of 10 red-listed bryophyte species and 29 out of 39 red-listed lichen species were more frequent in crowns. The species richness detected per tree was unexpectedly high, whereas the proportion of exclusive crown species was similar to studies from forest trees. For bryophytes, in contrast to lichens, sampling several stems can give a good estimation of the species present at a site. However, frequency estimates may be highly biased for lichens and bryophytes if crowns are not considered. Our study demonstrates that tree crowns need to be considered in research on these taxa, especially in biodiversity surveys and in conservation tasks involving lichens and to a lesser degree also bryophytes.

Occupancy and density of the epiphytic lichen L. pulmonaria were studied in the mountains of Uholka–Shyrokyi Luh (Ukraine), which include the largest primeval beech forest in Europe. The lichen occupancy was assessed on 314 plots laid out on a systematic grid. Additional data on population density were collected from 483 trees growing both, on and between these plots. The trees harbouring L. pulmonaria were distributed very sparsely within Uholka–Shyrokyi Luh, and occupy nearly 10 % of the studied perimeter. The generalized linear models showed that area of occupancy of L. pulmonaria was significantly influenced by altitude and canopy cover, whereas the species’ density was explained by habitat types and slope exposition. Population density is higher at the timberline than in the interior forest or on lowland meadows. We found a bimodal altitudinal distribution of L. pulmonaria, with maxima below and above 900 m a.s.l., where it prefers forest stands with loose or scattered canopy. The preferred position of L. pulmonaria on host tree trunks depends on stand density and allows the species to get the necessary level of insolation also in shaded sites where it grows higher up on the trunk than in open stands. While L. pulmonaria occupied trees with various diameters, juvenile individuals are more frequent on small trees, but mature lichen individuals are predominantly found on trees of average or large sizes. Fertile individuals require specific environmental conditions, which are available at intermediate altitudes, related with sheltered light, and horizontal terraces on slopes with eastern exposition. In general, the primeval beech forest of Uholka–Shyrokyi Luh harbours a high percentage of juvenile thalli of L. pulmonaria, which lack vegetative propagules. Mature individuals have a low frequency of fruit bodies and reproduce mainly with vegetative diaspores. We interpret this as an indication of a currently growing population of L. pulmonaria within the area. We hypothesize that transboundary air pollution has decreased the lichens’ population frequency and density and has altered the ratio of developmental stages in L. pulmonaria during earlier decades.

The Uholka-Shyrokyi Luh area of the Carpathian Biosphere Reserve is considered the largest and the most valuable primeval beech forest in Europe for biodiversity conservation. To study the impact of different topographic and forest-stand variables on epiphytic lichen diversity a total of 294 systematically distributed sampling plots were surveyed and 198 epiphytic lichen species recorded in this forest landscape, which has an uneven-aged structure. The obtained data were analysed using a non-metric multidimensional ordination and a generalized linear model. The epiphytic lichen species density at the plot level was mainly influenced by altitude and forest-stand variables. These variables are related to both the light availability i.e. canopy closure, and the habitat diversity, i.e. the developmental stage of the forest stands and the mean stem diameter. We found that lichen species density on plots with a relatively open canopy was significantly higher than on plots with a fairly loose or closed canopy structure. The late developmental stage of forest stands, which is characterized by a large number of old trees with rough and creviced bark, had a strong positive effect on lichen species density. In the Uholka-Shyrokyi Luh primeval forest the mean stem diameter of beech trees significantly correlated with lichen species density per plot. Similar trends in the species diversity of nationally red-listed lichens were revealed. Epiphytic lichens with a high conservation value nationally and internationally were found to be rather abundant in the Uholka-Shyrokyi Luh area, which shows its international importance for the conservation of forest-bound lichens.

Fragmentation represents a serious threat to biodiversity worldwide, however its effects on epiphytic organisms is still poorly understood. We study the effect of habitat fragmentation on the genetic population structure and diversity of the red-listed epiphytic lichen, Lobaria pulmonaria, in a Mediterranean forest landscape. We tested the relative importance of forest patch quality, matrix surrounding fragments and connectivity on the genetic variation within populations and the differentiation among them. A total of 855 thalli were sampled in 44 plots (400 m 2 ) of 31 suitable forest fragments (beeches and oaks), in the Sierra de Ayllon in central Spain. Variables related to landscape attributes of the remnant forest patches such as size and connectivity and also the nature of the matrix or tree species had no significant effects on the genetic diversity of L. pulmonaria. Values of genetic diversity (Nei's) were only affected by habitat quality estimated as the age patches. Most of the variation (76%) in all populations was observed at the smallest sampled unit (plots). Using multiple regression analysis, we found that habitat quality is more important in explaining the genetic structure of the L. pulmonaria populations than spatial distance. The relatively high level of genetic diversity of the species in old forest patches regardless of patch size indicates that habitat quality in a highly structured forest stand determines the population size and distribution pattern of this species and its associated lichen community. Thus, conservation programmes of Mediterranean mountain forests have to prioritize area and habitat quality of old forest patches.