BackgroundThis study seeks to better understand the human-nature interface and to measure the variability of plant use knowledge among cultures, through inter- and intracultural analyses. We compared plant collection, use, and management of two culturally distinct groups (Baitadi and Darchula) of the Nepal Himalaya. They inhabit different physiographic regions, yet share the same ecological landscape, environmental resources, and livelihood challenges. We hypothesized that the elderly, native, and traditional healers living in remote and rural places possess more diverse and detailed knowledge of plant use and conservation than young, non-native, and non-healers.MethodsA total of 106 people were contacted for interviews, and 100 (68 men and 32 women) agreed to share ethnobotanical, demographic, and socioeconomic information. They were asked about the three most important plants for their socioeconomic benefit, culture, primary health care, and livelihood.ResultsThe knowledge of plant collection, use, and its transfer was strongly associated with the cultural heritage whereas the ecogeographical condition influences the ways in which plants are collected and used. The divergent knowledge of plant collection, use, and transfer between the participants of Baitadi and Darchula was significantly (p < 0.001) attributed to the cultural heritage of the area. The low consensus of plant use (FiC 0–0.87; IASc 0–0.67) between Baitadi and Darchula district could be due to cultural divergence, varied accessibility, physiographic heterogeneity, and biodiversity uniqueness.ConclusionsDifferences in plant use knowledge may help in diversifying the strategies of plant use in accordance with the livelihood, culture, and environment, and therefore, more studies measuring these aspects can further the ecosystem and cultural health of the region.Electronic supplementary materialThe online version of this article (10.1186/s13002-018-0242-7) contains supplementary material, which is available to authorized users.

The Stress Gradient Hypothesis (SGH), which predicts increasing ratios of facilitative:competitive interactions with increasing stress, has long been a guiding framework for conceptualizing plant-plant interactions. Recently, there has been a growing recognition of the roles of microbes in mitigating or exacerbating environmental stress for their plant hosts. As such, we might predict, based on the SGH, that beneficial microbial effects on plant performance should be positively associated with stress. Specifically, we hypothesized that support for the SGH would depend on the host plant's habitat specialization such that species that specialize in high stress habitats and thus likely coevolved with the resident microbes would exhibit stronger support for the SGH than non-specialist plant species. We further hypothesized that support for the SGH would vary with germination frequency, since boosting germination of low-frequency germinators is one effective means by which microbes can benefit plant species performance. Here, we explore whether plant-microbial interactions support the SGH using 12 plant species native to the Florida rosemary scrub. We conducted factorial experiments that manipulated the presence of microbes in nine soils collected along an elevational stress gradient, and recorded germination frequency and biomass. Microbes increased the germination frequency of four species, all of which had relatively low germination rates. Furthermore, we found support for the SGH in nearly one-half of the species examined, with soil microbes facilitating germination with increasing stress for 5 of the 12 species tested, and none of the species exhibiting the opposite trend. Support for the SGH was not predicted by either the plant hosts' habitat specialization or germination frequency. In contrast to germination, biomass results showed little support for the SGH, with four of 12 species refuting and one species supporting SGH predictions. Taken together, our study documents that interactions between the soil microbial community and plant species along a stress gradient can support the SGH, but emphasizes that these effects are life-history-stage dependent. This work also identifies a common mechanism (germination facilitation) by which microbes can benefit plant species in stressful habitats.

Abstract. A key challenge to understanding microbiomes and their role in ecological processes is contextualizing their effects on host organisms, particularly when faced with environmental stress. One influential theory, the Stress Gradient Hypothesis, might predict that the frequency of positive interactions increases with stressful conditions such that microbial taxa would mitigate harmful effects on host performance. Yet, equally plausible is that microbial taxa could exacerbate these effects. Here, we introduce the Mitigation-Exacerbation Continuum as a novel framework to conceptualize microbial mediation of stress. We (1) use this continuum to quantify microbial mediation of stress for six plant species and (2) test the association between these continuum values and natural species' abundance. We factorially manipulated a common stress (allelopathy) and the presence of soil microbes to quantify microbial effects in benign and stressed environments for two critical early life-history metrics, seed germination and seedling biomass. Although we found evidence of both mitigation and exacerbation among the six species, exacerbation was more common. Across species, the degree of microbial-mediated effects on germination explained >80% of the variation of natural field abundances. Our results suggest a critical role of soil microbes in mediating plant stress responses, and a potential microbial mechanism underlying species abundance.

Indigenous plant use-systems have evolved under, and constantly adapted to human and non-human impacts. In the last decades however, increasing socioeconomic and cultural transformations, including land-use change, outmigration, globalized markets, the introduction of new species, and climate change have led to a decreasing availability of indigenous resources, and are ultimately leading to a reduction of local use-knowledge. Participant observations, discussions, walks-in-the-woods, semi-structured interviews and informal meetings were carried out in 12 villages of far western Nepal between 2011 and 2015 to assess how sociocultural changes have affected the sustenance of indigenous systems and local biodiversity, when compared to studies carried out in the previous decades. Our findings show that there were no statistically significant differences in subject variable means, but differences were relatively important to plant parts-use and plant growth-forms (p = 0.183 and 0.088 respectively). Cissampelos pareira, Acorus calamus, Calotropis gigantea were found to have the greatest relative importance, whereas Ageratina adenophora, Melia azedarach, Carum carvi were most important based on use values. Among them, C. pareira and A. adenophora were introduced. The spatial distribution of species collected for medicine showed that all habitats were important for collection however, habitats close to villages were more favored. The use of non-indigenous and easily available species and more accessible habitats is becoming more prevalent as primary forests become increasingly overexploited, indigenous species become limited, and sociocultural cause of land use change expand. The utilization of indigenous and non-indigenous species and nearby habitats, although possibly affecting the quality of medicinal species, nonetheless reveals the dynamism of indigenous medicines as an adaptive asset mitigating human and non-human environmental changes.

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Aim Much of what is known about invasion biology is based on research conducted in North America and Europe, leading to limitations and potential biases in our knowledge. We address these limitations by conducting a systematic review to assess the literature on ecological studies of two major tropical and subtropical invasive plant species, Ageratina adenophora and Chromolaena odorata. Our goals were to: (1) collect the literature on the invasion biology of these species by broadly searching five databases (one international and four regional); (2) determine limitations to the international literature available in the ISI Web of Science (WOS); (3) quantitatively summarize the scope of the invasion literature on the two species; and (4) propose future studies based on what we found.Location Global.Methods Using specific search terms, we searched the literature for A. adenophora and C. odorata in the ISI WOS, Chinese National Knowledge Infrastructure (CNKI), Indian Journals, Nepal Journals Online and African Journals Online (AJOL). We extracted information on journal titles, publication years, study area locations, habitats investigated and study focus.Results We found 101 papers for A. adenophora and 61 papers for C. odorata, published from 1987 to 2015. A high percentage of the studies were conducted in China, western and southern Africa, and India. Studies from WOS most frequently focused on the mechanism of invasion, while studies from CNKI and AJOL focused on the impacts of the invader.Main conclusions Web of Science is not sufficient for generalizing about the invasion biology literature, particularly if the goal is a comprehensive assessment that includes areas other than North America, Hawaii, Europe, Australia, South Africa and New Zealand. In future systematic reviews, other databases should be used if possible, including those in languages other than English. For future research, several research areas should be studied more thoroughly for A. adenophora and C. odorata invasions, including possible multiple factors responsible for invasion, and impacts of co-occurring invasive species.

With the intent to better management human wildlife conflict (HWC) and wildlife conservation in mid-hills outside protected areas of Gandaki province, Nepal, we analyzed the patterns and drivers of HWC. Using data collected from literature, government records and questionnaire survey, we investigated temporal, seasonal and spatial distribution of human casualties caused by wildlife attacks. We also appraised the perception of local people towards wildlife conservation. We have recorded 77 cases (69 human injuries and 8 mortalities) during the period of nine year between 2011 and 2019. The number of wildlife attacks increased over this period. Wildlife attacks were more frequent in winter with 50% (42) of attacks occurred between September and December. Common leopard (Panthera pardus) and Himalayan black bear (Ursus thibetanus laniger) were the major species involved in these conflicts. Common leopard was the most feared species that causes highest number of human mortalities (87%, n = 67); the most severe type of HWC outcome. Forty-eight percent (n = 37) attacks were reported at human settlement areas followed by 27% attacks in agriculture land (n = 21) and 24% (n = 19) in forest. Generalized linear model analysis on spatial variables showed that the probability of human attacks increases with decreasing elevation (β = -0.0021, Z = -1.762, p = 0.078) and distance from the forest (β = -0.608, Z = -0.789, p = 0.429). We recommend to decrease habitat degradation / fragmentation, carry out habitat management program within forest to increase prey availability to decrease the wildlife invasion into human settlement area, and decrease dependency of people on forest resources by providing alternative livelihood opportunities. Simplified relief fund distribution mechanism at local level also helps alleviate the impact of HWC. The knowledge obtained by this study and management measures are important for better human-wildlife co-existence.

Community forests of developing countries are eligible to participate in the Reducing Emissions from Deforestation and Forest Degradation (REDD+) scheme. For this, estimation of carbon stock and the sequestration is essential. The carbon stock in the living biomass of nine community managed Shorea robusta forests of the mid hill regions of central Nepal (managed for 4-29 yr) were estimated. The carbon stock of trees and shrubs was estimated using an allometric equation while the biomass of herbaceous vegetation was estimated by the harvest method. The carbon stock in the living biomass of the studied forests ranged from 70-183 Mg ha −1 (mean: 120 Mg ha −1 ) and it increased with increasing soil organic carbon. However, the carbon stock did not vary significantly with species richness and litter cover. The biomass and carbon stock in the forests managed for >20 yr were significantly higher than in the forests managed for < 20 yr. The carbon stock increased with the management duration ( p < .05) with sequestration rate of 2.6 Mg C ha −1 yr −1 . The local management has had positive effects on the carbon stock of the forests and thus the community forests have been acting as a sink of the atmospheric CO 2 . Therefore, the community managed forests of Nepal are eligible to participate in the REDD+ scheme.