ABSTRACT
Bryophytes play important role in forest ecosystem functioning and their distribution and diversity are driven by numerous environmental factors. The aim of the present study was to bring new insights in deeper understanding of terrestrial bryophytes diversity in temperate forests, as well as to determine the environmental factors which have predominant influence on ground-floor bryophytes. The survey was conducted in Fruska Gora Mountain (Serbia) across seven forest sites where ground-bryophytes were sampled. Soil moisture, temperature, and pH were measured as soil characteristics, while herbaceous cover, litter cover, stream distance, number of trees and shrubs were used as characteristics of stand structure. Species richness, Shannon diversity index, and evenness index were used as diversity measures. Generalised linear model and canonical correspondence analysis (CCA) were used to test the influence of environmental variables on bryophyte diversity. Litter cover was the most important explanatory variable, followed by soil moisture, stream distance and tree number, respectively. Overall, the stand structure was found to have a greater impact on ground-floor bryophyte diversity compared to soil characteristics. Identification of the most significant ecological factors affecting the diversity and distribution of bryophytes in forest ecosystems is of great importance in forest ecology with the aim of defining adequate management methods to preserve the biodiversity of forests, with particular emphasis on endangered and rare bryophyte species.
Subject(s)
Bryophyta , Ecosystem , Forests , Biodiversity , Trees , SoilABSTRACT
We hypothesize that the physical features of river habitats and anthropogenic hydromorphological alterations influence macrophyte communities and lead to habitat fragmentation. Sampling included 1081 contiguous survey units positioned in the main channel and side arms along 588km of the Danube River, along its middle course. To identify habitat fragments, Multivariate Regression Tree analysis (MRT) was applied on macrophyte and environmental data. Indicator species analyses were combined with MRT. To identify habitat fragments on a scale larger than final MRT groups, we set thresholds for an MRT complexity parameter. We identified 20 fine, 7 medium, and 3 large scale habitat fragments. Damming was the main fragmentation agent. Macrophyte communities show continuous variation at all scales of habitat fragmentation. High species diversity indicates major anthropogenic alteration of the river's hydrology and decline of the natural riparian zone. Future studies of the macrophyte communities, and their habitat fragmentation must include more factors (e.g. nutrient status, physicochemical quality of the water, etc.), as well as assessment of the importance of tributaries.
ABSTRACT
The taxonomical relationship between Salvia pratensis and S. bertolonii has been unclear for a long time. Salvia bertolonii has alternatively been considered a synonym, a subspecies, a problematic subspecies and a form of Salvia pratensis. However, both these two species are sometimes used in traditional medicine instead of sage (Salvia officinalis) or as an adulteration for the same drug. In order to confirm the status of S. bertolonii, together with the potential identification characteristics for differentiation from sage, both taxa were analyzed through the analysis of their essential oils, together with the micromorphological characteristics of the leaf surface and the anatomy and morphology of the leaves. The obtained results show that there are clear differences in the quantity of essential oil (0.073% for S. pratensis and 0.0016% for S. berolonii). The major compound in the essential oil of S. pratensis was E-caryophyllene (26.4%) while in S. berolonii essential oil caryophyllene oxide was the major component (35.1%). The micromorphological differences are also pronounced in the leaf indumentum (density and distribution of certain types of non-glandular and glandular trichomes). Clear distinction between the investigated Salvia species is also observed in the leaf anatomy (in S. pratensis leaves are thinner, palisade tissue is made of 1-2 layers of cells, and leaves of S. bertolonii are characterized by 2-3 layers of palisade tissue cells, and consequently thicker).
