The impact of seed deficiency on productivity and on negative drought effect in semi‐natural grassland

Questions Vegetative re‐sprouting and recruitment from seed determine grassland recovery after severe drought, but the mechanisms determining vegetation composition are not fully understood. We ask how the timing of drought and seed availability modify the drought legacy effects on composition and function in a temperate, semi‐natural grassland. Location Negrentino, southern Alps, Switzerland. Methods Under automated rainout shelters, we simulated extreme seasonal drought events in a late summer and in the following spring, added rainwater to simulate normal conditions in no‐drought controls and maintained haymaking at times of normal practice. Towards the end of the summer drought, we added seeds of ten local species in a three‐factor split‐plot arrangement with seven blocks as the replicated unit. We measured fine‐scale variation in soil depth. We assessed the biomass of graminoids and forbs at regular harvesting dates and the species frequencies of established plants and recruits before treatment start, repeating these assessments for three years thereafter. We measured the biomass proportions of post‐drought annual recruit cohorts in year 4 after drought. Results One‐time seed addition augmented recruits, modified species composition and enhanced species diversity; these effects propagated to increased reproductive shoots of recruits and community biomass four years later. Single and repeated seasonal droughts only caused low adult plant mortality but clearly reduced recruitment from seed, while post‐drought establishment was slightly enhanced. Seed augmentation compensated the negative spring drought effect on forb recruits and in turn mitigated the negative impact of drought on species diversity after drought. Conclusions Our experiment shows that seed deficiency limits productivity and that seed deficiency compensation can help to stabilize diversity and productivity in semi‐natural grassland. Releasing the current constraints of management on seed supply in grassland would therefore assist in mitigating negative drought impacts

Apports et limites de la biographie langagière pour la recherche en appropriation des langues

Language biographies have been used for decades in order to document the construction of linguistic repertoires. However, the focus on the content of this narrative, instead of underlining the reflexivity inherent to such an approach, has veiled the role of subjectivity in this elaboration. This article aims to show how reflexivity can be analysed in order to better understand the sense one gives to his or her social experiences, and the benefit that the learner and/or the researcher can draw from such an approach. The lack of ethnographic data, the focus on a specific period of time and the sometimes great difficulty to induce narratives of the self will finally be evoked as limits for the biographical approach, both for the learner and for the researcher

Imaginaire colonial, empowerment et appropriation d’une L2

Se pencher sur la trajectoire d’apprenant-e-s en langue seconde implique, pour comprendre le sens qu’ils donnent à leur appropriation langagière en fonction de leur expérience migratoire, de prendre en considération leurs structurations socio-historiques. Le contexte post-colonial sera donc traité ici en tant qu’interne à l’apprenant, et non en tant que contexte d’apprentissage, et permettra une réflexion sur l’évolution des représentations sociales individuelles dans une démarche biographique réflexive

Language for integration, language as discipline? A Foucaltian perspective on L2 learning in the context of asylum

Between 2014 and 2016, like in other European countries, a substantial increase of asylum requests took place in Switzerland, which forced the professionals and politicians involved in this context to take urgent action. is crisis produced an effect of magnifying glass on power issues linked to language learning, or in other words on language learning as Foucaultian discipline. In this article, I will show that the common link socially constructed between ‘language learning’ and ‘integration’ allows the social actors encountered by asylum seekers to make them learn French as soon as possible for preparation for life in their new country. In doing so, the society sustainably disciplines and controls them: asylum seekers, once they reach the status of legitimate refugees, are namely concentrated in low-skilled jobs, officially because they lack the necessary language skills for finding a job corresponding to their actual qualifications and desires. Most of them thus live on welfare, a situation that gives arguments to strengthen the current immigration policy and, at the same time, lock them in a refugee identity, that is, of people indebted to a society where they have no other role to play. Meanwhile, this discipline that the State and the host society impose to asylum seekers articulates with social representations of learning the language of the host country, and with the general equivalence that asylum seekers make themselves between learning the host language and integrating the host society. Asylum seekers o#en conceive of L2 learning as a discipline they have to exercise, as they appreciate the language level they should reach to get ‘normalized’ in an apparent linguistically homogeneous society, even if they know that it will never be enough to level social inequalities

Positive diversity-invasibility relationship in species-rich semi-natural grassland at the neighbourhood scale

Background and Aims Attempts to answer the old question of whether high diversity causes high invasion resistance have resulted in an invasion paradox: while large-scale studies often find a positive relationship between diversity and invasibility, small-scale experimental studies often find a negative relationship. Many of the small-scale studies are conducted in artificial communities of even-aged plants. Species in natural communities, however, do not represent one simultaneous cohort and occur at various levels of spatial aggregation at different scales. This study used natural patterns of diversity to assess the relationship between diversity and invasibility within a uniformly managed, semi-natural community. Methods In species-rich grassland, one seed of each of ten species was added to each of 50 contiguous 16 cm2 quadrats within seven plots (8 × 100 cm). The emergence of these species was recorded in seven control plots, and establishment success was measured in relation to the species diversity of the resident vegetation at two spatial scales, quadrat (64 cm2) within plots (800 cm2) and between plots within the site (approx. 400 m2) over 46 months. Key Results Invader success was positively related to resident species diversity and richness over a range of 28-37 species per plot. This relationship emerged 7 months after seed addition and remained over time despite continuous mortality of invaders. Conclusions Biotic resistance to plant invasion may play only a sub-ordinate role in species-rich, semi-natural grassland. As possible alternative explanations for the positive diversity-invasibility relationship are not clear, it is recommended that future studies elaborate fine-scale environmental heterogeneity in resource supplies or potential resource flows from resident species to seedlings by means of soil biological networks established by arbuscular mycorrhizal fung