Distribution of epiphytic bryophyte species was studied in Woodland Key Habitats (WKH) and in managed forest stands in the NorthEast Latvia (district Gulbene). In total, 32 epiphytic bryophyte species were found in six WKH stands. Five endangered/threatened bryophyte species (Anomodon longifolius, Homalia trichomanoides, Jamesoniella autumnalis, Lejeunea cavifolia, Neckera pennata), that are listed in the Red Data Book of Latvia were recorded. The relation between the total and endangered/threatened epiphytic bryophyte species richness and composition with substrate factors (phorophyte species, diameter at breast height (DBH), shading, and tree bark pH) was studied. The most important factors regarding epiphytic bryophyte species cover, composition and richness were found to be tree species, DBH, bark pH and forest shading. WKH indicator species richness showed significant relationship only with tree species. Tree species was one of the most important factors explaining epiphytic species distribution.
QuestionsThe importance of tropical rainforest gap dynamics in biodiversity maintenance is not fully understood, in particular for taxa other than trees and lianas. We used epiphylls on rainforest leaves to study the importance of leaf‐ and forest‐scale succession in determining biodiversity patterns by characterizing community change with leaf age in gaps and closed‐forest habitats. We asked: (1) Do epiphylls show specialization for leaf and forest successional stages? (2) Can early‐ and late‐successional epiphyllous species be recognized at these two scales? (3) How do epiphyll presence, species richness, and cover change with leaf and forest successional stages?LocationBarro Colorado Island, Panama.MethodData were collected from 420 leaves, in three age groups and at two heights on shrubs in gaps and closed forest. We calculated turnover and nestedness components of dissimilarity to evaluate the importance of species replacement or accumulation during leaf and forest succession. Using generalized linear mixed models we determined what factors explain epiphyll species occurrence, richness and cover.ResultsClosed forest contained more liverwort and lichen specialist species than gaps. Specialist species were identified for older leaves only. Dissimilarity between leaves within age groups was dominated by turnover within and between forest successional stages. Dissimilarity between leaf age groups, at the site level, was dominated by nestedness, i.e., species accumulation. Both in forest and gaps, epiphyll presence and cover increased with leaf age for all taxa except fungi, while species richness increased only for lichens.ConclusionEarly and late forest successional stages both contribute to epiphyll species richness by harboring specialized species. Among leaf successional stages, young leaves contain a mere subset of the species found on older leaves. Epiphyll communities do not follow classic succession, in the sense of changes being driven by species replacement, but are characterized by species accumulation through time.
1. The spatial structure of biotic communities can be shaped by niche-based or stochastic processes, and the importance of both can change through time. Nichebased processes include neighbour interactions, which can change in intensity and quality as communities develop in dependence of environmental conditions. Epiphylls, miniature communities of liverworts, lichens, algae and fungi on leaves, develop only in relatively moist forests, but their leaf-surface habitat is still characterized by moisture stress, especially in more exposed parts of the forest. As neighbours may alleviate moisture stress, we expected that in forest gaps (dryer, brighter), epiphyll communities would show more positive neighbour interactions, resulting in more clustered spatial patterns, than in closed forest, in accordance with the stress-gradient hypothesis.2. To understand how the processes shaping epiphyll communities change through time and differ between gaps and closed forest, we examined the fine-scale spatial structure within and between epiphyll functional groups (algae, fungi, lichens and liverworts) during 12 months on 60 leaves across 12 sites in a tropical rainforest in Panama. We analysed changes in spatial positions and spatial associations within and between functional groups using spatial point pattern analysis based on repeated photography.
Epiphyll densities increased through time for most epiphyll functional groups.However, although epiphyll groups changed their positions through time, the general types of spatial patterns remained similar for most groups: only lichen patterns shifted from mostly random to mostly aggregated through time. We found only random and aggregated spatial patterns within groups, while among groups we additionally found segregated spatial associations, but no consistent temporal trend. Patterns did not differ between gaps and closed forest, thus not supporting the stress-gradient hypothesis. 4. Synthesis. Our results only weakly support the assumption that communityshaping processes change from neutral to niche-based as communities develop. We do provide empirical evidence that epiphyll communities are dynamic
Fifty five species of lichens and lichenicolous fungi are reported from the Southern Ural (Republic of Bashkortostan and Chelyabinsk Region). Graphis betulina, Micarea micrococca, and Ramonia chrysophaea are reported for the first time in Russia. Abrothallus microspermus, Arthopyrenia grisea, Biatora pontica, Collema ligerinum, Puttea margaritella, Rinodina granulans, Rinodina malangica, Syzygospora physciacearum and Xylographa trunciseda are new to Ural Region. Calicium glaucellum, Chaenotheca gracillima, Microcalicium disseminatum, Parmeliella triptophylla, Ramalina obtusata and Sphaerellothecium reticulatum are new to Southern Ural. 21 species are new to the Republic of Bashkortostan and the Chelyabinsk Region, and 50 species are reported for the first time from the protected areas of the Southern Ural. Brief comments on the most interesting species and their ecology (habitat and substrate preferences) and chorology are given. Fig 1. Landscape around Nurgush Mountain range. Foto S. A. Gorodilov.
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