The biomechanical and ecophysiological properties of plant seed/fruit structures are fundamental to survival in distinct environments. Dispersal of fruits with hard pericarps (fruit coats) encasing seeds has evolved many times independently within taxa that have seed dispersal as their default strategy. The mechanisms by which the constraint of a hard pericarp determines germination timing in response to the environment are currently unknown. Here, we show that the hard pericarp of Lepidium didymum controls germination solely by a biomechanical mechanism. Mechanical dormancy is conferred by preventing full phase-II water uptake of the encased non-dormant seed. The lignified endocarp has biomechanically and morphologically distinct regions that serve as predetermined breaking zones. This pericarp-imposed mechanical dormancy is released by the activity of common fungi, which weaken these zones by degrading non-lignified pericarp cells. We propose that the hard pericarp with this biomechanical mechanism contributed to the global distribution of this species in distinct environments.

Anthropogenic environmental change disrupts interactions between plants and their animal pollinators. To assess the importance of different drivers, baseline information is needed on interaction networks and plant reproductive success around the world. We conducted a systematic literature review to determine the state of our knowledge on plant–pollinator interactions and the ecosystem services they provide for European ecosystems. We focussed on studies that published information on plant–pollinator networks, as a community-level assessment of plant–pollinator interactions and pollen limitation, which assesses the degree to which plant reproduction is limited by pollinator services. We found that the majority of our knowledge comes from Western Europe, and thus there is a need for baseline assessments in the traditional landscapes of Eastern Europe. To address this data gap, we quantified plant–pollinator interactions and conducted breeding system and pollen supplementation experiments in a traditionally managed mountain meadow in the Western Romanian Carpathians. We found the Romanian meadow to be highly diverse, with a healthy plant–pollinator network. Despite the presence of many pollinator-dependent plant species, there was no evidence of pollen limitation. Our study is the first to provide baseline information for a healthy meadow at the community level on both plant–pollinator interactions and their relationship with ecosystem function (e.g. plant reproduction) in an Eastern European country. Alongside the baseline data, we also provide recommendations for future research, and the methodological information needed for the continued monitoring and management of Eastern European meadows.

The Marsh Fritillary (Euphydryas aurinia) was once widespread in large parts of Central Europe. However, in the course of the last century, populations of the butterfly largely collapsed. Here, we surveyed patch and microhabitat occupancy and its drivers in one of the last vital populations in calcareous grasslands. Our study revealed that environmental conditions at the landscape and habitat level determined the occurrence of E. aurinia in a montane agricultural landscape with low land‐use intensity. Patch occupancy increased with the cover of Devil's‐bit Scabious (Succisa pratensis) grasslands in the surroundings of the patches, habitat heterogeneity and host‐plant cover. Microhabitat occupancy was driven by a warm microclimate and high availability of host plants. In the well‐connected landscape of nutrient‐poor grasslands, patch occupancy of E. aurinia was driven by parameters defining a high habitat quality. Habitat heterogeneity very likely buffers E. aurinia populations against environmental stochasticity and, hence, enhances long‐term viability. For the gregariously feeding caterpillars of E. aurinia, host‐plant biomass is essential. Due to their more luxuriant growth, S. pratensis plants were clearly preferred, although the Glossy Scabious (Scabiosa lucida) was also widespread. Additionally, the growth of large Succisa plants was favored by soil humidity and grassland abandonment. To cope with the adverse macro‐ and mesoclimatic conditions of the study area, females of the butterfly selected host plants growing in extraordinarily warm microhabitats for oviposition. To secure long‐term viability of E. aurinia populations, we recommend creating mosaics of traditionally managed grasslands and early stages of abandonment within the patches.

The decline of butterflies exceeds those of many other animal taxa due to their high sensitivity to habitat alterations driven by land‐use change. Moreover, cold‐adapted species frequently suffer severe range retractions due to rising temperatures at their trailing‐edge range margins. In this study, we aim to identify drivers of occupancy of the post‐glacial relict species Lycaena helle at three spatial scales – (i) landscape, (ii) habitat, and (iii) microhabitat – in one of its last refuges in central Europe. In our study in the Eifel low mountain range (western Germany), the occurrence of L. helle was mainly driven by the (i) isolation, (ii) size, and (iii) quality of habitat patches. Lycaena helle formed metapopulations that were dependent on networks of interconnected but often small habitat patches. Habitat quality within the semi‐natural grasslands was determined by (i) macro‐ and mesoclimate, (ii) host‐plant abundance, and (iii) vegetation structure, which was interrelated with microclimate. Lycaena helle preferred moist, nutrient‐poor grasslands in deep, narrow valleys at the highest elevations of the study area, which were characterised by (i) cold winters, (ii) high abundance of the host plant, and (iii) short and sparse swards providing a warm microclimate in summer. According to these findings, abandonment of traditional land use and climate change are considered the most severe threats for long‐term survival of the species. Hence, conservation measures should aim at maintaining and restoring networks of large and well‐connected habitat patches of high quality, preferably in cold‐air depressions within mountain systems.

Mougeotia scalaris is a filamentous streptophyte alga renowned for light-inducible plastid rotation and microtubule-dependent polarity establishment. As a first step toward transgenic approaches we determined the 5,825 base pair genomic sequence encoding the α-tubulin1 gene (MsTUA1) of M. scalaris (strain SAG 164.80). The subcloned MsTUA1 promoter facilitated strong transgene expression in M. scalaris and tobacco leaf cells, as shown by particle bombardment and the subsequent visualization of expressed fluorescent protein markers. Our results provide a route for the genetic transformation of the filamentous streptophyte alga M. scalaris based on the endogenous TUA1 promoter.