Zuzana Münzbergová

Ethnobotanical study of medicinal plants from the Humla district of western Nepal

AIM OF THE STUDY The present paper documents the uses of plants in traditional herbal medicine for treatment of human and veterinary ailments in four village development committees in the Humla district of western Nepal. It also determines the homogeneity of informants knowledge on medicinal plants suitable for different ailment categories and the most preferred plant species used to treat each ailment category in the study areas. MATERIALS AND METHODS The ethnobotanical information was collected through semi-structured interviews and key informant discussion. The data were analyzed through informant consensus factor (ICF), fidelity level (FL) and use value (UV). RESULTS We documented 161 plant species belonging to 61 families and 106 genera used for treating 73 human and 7 veterinary ailments. We also documented culinary uses and additional uses for 67 and 33 species of medicinal plant species respectively. Most medicines were prepared in the form of powder and used orally. Roots were most frequently used plant parts. The uses of 93 medicinal plants were not mentioned in any previous studies. Gastro-intestinal ailments have the highest ICF (0.40) whereas opthalmological uses have the lowest (zero) ICF. Mentha spicata and Rumex hastatus has the highest FL (100% each) both being used for gastro-intestinal ailments and Delphinium himalayai has the lowest (47.4%) for veterinary uses. CONCLUSIONS ICF values indicated that there was high agreement in the use of plants in gastro-intestinal ailment category among the users. FL or UV values indicated the most preferred plant species used in study areas. These preferred plant species could be prioritized for conservation and subjected to further studies related to chemical screening for their authenticity. Most of the medicinal plants of the region are collected in the wild and are often harvested for trade. Sustainable harvesting methods and domestication of the highly traded species is thus needed in the study areas.

INVASIBILITY AND SPECIES RICHNESS OF A COMMUNITY: A NEUTRAL MODEL AND A SURVEY OF PUBLISHED DATA

A widespread but controversial idea in ecology states that the number of invaders of a species assemblage depends on its species richness. Both negative and positive relationships have been reported. We examined whether a simple neutral model where assemblages are generated by drawing individuals from two pools of identical species (native and alien) can predict this relationship. We performed a meta-analysis of published data on this relationship. The neutral model showed that in communities with low and fixed numbers of indi- viduals, the relationship between the number of aliens and native species is strong and negative. This becomes weaker as the proportion of species from both pools already present in the community increases. The relationship between alien and native species richness becomes positive when the number of individuals is allowed to vary, because the richness depends on number of individuals and/or area sampled. The meta-analysis showed that scale-dependence of the relationship between alien and native species richness is universal and compatible with the neutral model. Unless more evidence is available to refute it, the relationship between native and alien species richness should be considered a result of a neutral processes due to constraints on the number of individuals in the community.

IMPORTANCE OF SPECIES TRAITS FOR SPECIES DISTRIBUTION IN FRAGMENTED LANDSCAPES

Knowledge of the relationship between species traits and species distribution in fragmented landscapes is important for understanding current distribution patterns and as background information for predictive models of the effect of future landscape changes. The existing studies on the topic suffer from several drawbacks. First, they usually consider only traits related to dispersal ability and not growth. Furthermore, they do not apply phylogenetic corrections, and we thus do not know how considerations of phylogenetic relationships can alter the conclusions. Finally, they usually apply only one technique to calculate habitat isolation, and we do not know how other isolation measures would change the results. We studied the issues using 30 species forming congeneric pairs occurring in fragmented dry grasslands. We measured traits related to dispersal, survival, and growth in the species and recorded distribution of the species in 215 grassland fragments. We show many strong relationships between species traits related to both dispersal and growth and species distribution in the landscape, such as the positive relationship between habitat occupancy and anemochory and negative relationships between habitat occupancy and seed dormancy. The directions of these relationships, however, often change after application of phylogenetic correction. For example, more isolated habitats host species with smaller seeds. After phylogenetic correction, however, they turn out to host species with larger seeds. The conclusions also partly change depending on how we calculate habitat isolation. Specifically, habitat isolation calculated from occupied habitats only has the highest predictive power. This indicates slow dynamics of the species. All the results support the expectation that species traits have a high potential to explain patterns of species distribution in the landscape and that they can be used to build predictive models of species distribution. The specific conclusions are, however, dependent on the technique used, and we should carefully consider this when comparing among different studies. Since different techniques answer slightly different questions, we should attempt to use analyses both with and without phylogenetic correction and explore different isolation measures whenever possible and compare the results.

Acacia trees as keystone species in Negev desert ecosystems

Abstract The only trees in most of the Negev desert are 3 native Acacia species. We tested the hypothesis that they act as keystone species as a result of the improved soil conditions under their canopies. Furthermore, because many Acacia populations suffer high levels of mortality due to water stress, we tested whether trees in high mortality populations had diminished effects on plant species and soil quality under their canopies. We show that plant species diversity beneath the tree canopies is higher than in the surrounding areas. There was also a clearly identifiable suite of species with higher occurrence under the trees. Plant species composition differed significantly between high and low mortality sites. However, there was higher species diversity in high mortality sites and under trees with higher water stress. Soil nutrient content was higher under the trees than in the open areas, especially under larger trees and trees with higher water status. The results indicate that there is a combination of positive and negative effects of Acacia trees on the under-canopy environment, which may include positive effects of higher soil nutrients and a negative influence of higher soil salinity. Abbreviations: MANCOVA = Multiple Analysis of Covariance; PAR = Photosynthetically active radiation; PCA = Principal Components Analysis. Nomenclature: Feinbrun-Dothan et al. (1991).

Determinants of species rarity: population growth rates of species sharing the same habitat

Determining differences between common and rare species is commonly used to identify factors responsible for rarity. Existing studies, however, suffer from two important drawbacks. First, studies compare species that are closely related phylogenetically but occupy different habitats. Second, these studies concentrate on single life history traits, with unknown relevance for population growth rates. Complete life cycles of one rare and one common Cirsium species sharing the same habitat were compared. Population growth rate was slightly lower in the rare species, translating into a large difference in local extinction probability. Seed predation intensity did not differ between species. However, it can be demonstrated that in connection with the data on complete demography, seed predation is the key factor causing a lower population growth rate in the rare species. These results are the first estimation of factors responsible for commonness or rarity of plants in terms of population growth rate without confounding differences in ecology. They demonstrate that conclusions based on single traits may be misleading and that only a comparison based on a complete life cycle can provide unequivocal evidence for concluding which factors are really those responsible for species commonness or rarity.

Timing of flowering: opposed selection on different fitness components and trait covariation.

The timing of reproduction influences how organisms interact with the environment and can have important fitness effects. In plants, the evolution of flowering phenology is often interpreted as the response to selection from mutualists, although antagonistic interactions may also be important. We examined direct and indirect phenotypic selection on the start of flowering via mutualistic and antagonistic interactions in the perennial herb Lathyrus vernus over 7 years. Flowering start influenced seed set, predispersal seed predation, and risk of grazing. These effects were in opposed directions and partly influenced different components of fitness. Combining information about effects on fitness components with information about links between fitness components and average lifetime fitness, in terms of population growth rate, showed that earlier flowering was associated with higher lifetime fitness in all years. These relationships were, however, mediated largely by variation in flower number, and direct selection on first flowering date was more variable among years. We conclude that long‐term studies correcting for indirect selection and environmental covariance are needed to understand selection on reproductive phenology and that demographic approaches are necessary to assess selection mediated by several agents and influencing several components of fitness.

Niche differentiation between diploid and hexaploid Aster amellus

The maintenance of separated diploid and polyploid populations within a contact zone is possible due to both prezygotic and postzygotic isolation mechanisms. Niche differentiation between two cytotypes may be an important prezygotic isolating mechanism and can be studied using reciprocal transplant experiments. We investigated niche differentiation between diploid and hexaploid Aster amellus in their contact zone in the Czech Republic. Diploid populations are confined to habitats with low productivity, whereas hexaploid populations occur in habitats with both low and high productivity. Thus, we chose three diploid populations and six hexaploid populations, three in each of the two different habitat types. We analyzed habitat characteristics and carried out reciprocal transplant experiments in the field using both seeds and adult plants. Sites of diploid and hexaploid populations differed significantly in vegetation and soil properties. The mean number of juveniles was higher at sites of home ploidy level than at sites of foreign ploidy level, suggesting niche differentiation between the two cytotypes. On the other hand, transplanted adult plants survived at all sites and juvenile plants were able to establish at some sites of the foreign cytotype. Furthermore, the mean number of juveniles, survival, and flowering percentages were higher at home sites than at foreign sites, indicating local adaptation. We conclude that niche differentiation between the two cytotypes and local adaptation within each cytotype may contribute to the maintenance of diploid and hexaploid populations of A. amellus in their contact zone. Moreover, further factors, such as differences in flowering phenology and exclusion of minority cytotypes, should also be considered.

POPULATION VIABILITY AND REINTRODUCTION STRATEGIES: A SPATIALLY EXPLICIT LANDSCAPE-LEVEL APPROACH

The effect of habitat destruction on the likelihood of species survival is often estimated based on the assumption that colonization and extinctions are in balance. This assumption is not sustainable in species where the dynamics of colonization and extinctions is slow in relation to landscape changes, such as in most plants. Here we use an alternative approach, a realistic, dynamic landscape-level model that does not rely on this assumption. It enables estimation of the effect of habitat destruction using field data on the biology of a species and on real landscape structure. Because our approach relies on direct comparisons of changes in population size and survival probability due to habitat changes, it can be easily extended to other conservation questions, such as assessing the effects of events causing the extinction of populations but allowing for re- colonization, or identifying optimal reintroduction strategies. We applied this method to a perennial herb, Succisa pratensis, that is a typical grassland species. We combined detailed demographic data with information on the spatial distribution of suitable habitats to model species dynamics in the landscape under different scenarios. The results show that habitat destruction alone has little effect on regional survival. How- ever, the effect of habitat destruction increases when combined with factors causing ex- tinctions of the existing populations that are expected to play a significant role in the study system. Our results further show that an optimal reintroduction strategy at the landscape level depends on the number of available seeds. The approach presented here was designed for studying systems where species colo- nization-extinction dynamics is slow compared with landscape changes. Such time lags and nonequilibrium dynamics have been suggested to be important features of many eco- systems and life forms, and this approach is thus likely to be useful for a wide range of future studies. The approach also allows the estimation of short-term effects of habitat destruction, i.e., situations that are nonequilibrium by definition. This is never possible with equilibrium models, giving the model a wide applicability for all types of organisms.

Morphometric and genetic differentiation of diploid and hexaploid populations of Aster amellus agg. in a contact zone

The aim of this study is to determine the origin, genetic relationships and morphological differences between diploid and hexaploid cytotypes of Aster amellus aggregate (Asteraceae) at their contact zone in the Czech Republic. We collected data on morphological and isozyme variation in a range of populations of the two cytotypes. We also studied the plasticity of the morphological traits in a common garden. The results suggest that hexaploid individuals of Aster amellus aggregate are of autopolyploid origin. The isozyme data indicate that diploids and hexaploids have different evolutionary histories. This, together with previous detailed cytological and ecological analyses, suggests that there is a secondary contact zone between the two cytotypes in the Czech Republic. The results of multivariate morphometric analyses and data on plasticity of the morphological traits indicate that it is not possible to distinguish the two cytotypes morphologically. The previously published morphological distinction between the cytotypes is thus not supported.

Rheum australe D. Don: A review of its botany, ethnobotany, phytochemistry and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE Rheum australe D. Don (Polygonaceae) has been commonly used in traditional medicine for a wide range of ailments related to the circulatory, digestive, endocrine, respiratory and skeletal systems as well as to infectious diseases. AIM OF THE REVIEW To provide the up-to-date information that is available on the botany, traditional uses, phytochemistry, pharmacology and toxicology of Rheum australe. Additionally, to highlight the possible uses of this species to treat different diseases and to provide a basis for future research. MATERIALS AND METHODS The present review covers the literature available from 1980 to 2011. The information was collected from scientific journals, books, theses and reports via a library and electronic search (Google Scholar, Web of Science and ScienceDirect). RESULTS Ethnomedical uses of Rheum australe have been recorded from China, India, Nepal and Pakistan for 57 different types of ailments. The phytochemical studies have shown the presence of many secondary metabolites belonging to anthraquinones, stilbenes, anthrones, oxantrone ethers and esters, chromones, flavonoids, carbohydrate, lignans, phenols and sterols. Crude extracts and isolated compounds from Rheum australe show a wide spectrum of pharmacological activities, such as antidiabetic, anti-inflammatory, antifungal, antimicrobial, antioxidant, anticancer, hepatoprotective and immune-enhancing activities, as well as a usefulness for improving renal function. CONCLUSION Rheum australe has been widely used source of medicine for years without any adverse effects. Many studies have provided evidence for various traditional uses. However, there is a need for additional studies of the isolated compounds to validate the traditional uses in human models. The present review on the botany, traditional uses, phytochemistry and toxicity has provided preliminary information for further studies and commercial exploitations of the plant.