Summary1. Ecological processes in mixed-species assemblages are not always an additive function of those in monocultures. In areas with high ground cover of bryophytes, renowned for their considerable water retention capacity, non-additive interactions in mixed-species cushions could play a key role in the ecosystem water economy. 2. We investigated mixture effects on external water loss in natural cushions with different species pairs of mosses and liverworts and the underlying mechanism of any non-additivity through shoot characteristics and canopy traits. 3. Species mixtures in bryophyte cushions had both additive and non-additive effects on the water economy, and these interactions were dependent on the composition of species assemblages and on plant tissue mass. Non-additivity of species mixtures was positive, resulting in the improvement of water retention. 4. Our results suggest advantages for bryophyte species to grow smaller and denser when in mixtures. They appear to alter the surface exchange area to converge in size with their neighbours, thus controlling boundary-layer properties and evaporation to reduce water loss. 5. Synthesis. A shift in bryophyte assemblages thus may influence ecohydrological processes of various ecosystems that cannot be simply predicted from the water economy of the component species when in monospecific cushions. In contrast to vascular plants, bryophytes do not compete for water but share it, and trait plasticity amongst bryophyte mixtures acts as a critical physical strategy in the community water economy.

Questions Is there a shift from positive to negative biotic interaction effects on seedling recruitment along two different stress gradients, temperature and precipitation (the stress‐gradient hypothesis); do such interaction effects differ between species with different bioclimatic affinities? Location Boreal, sub‐alpine and alpine grassland in southern Norway. Methods We tested the stress‐gradient hypothesis by comparing seedling recruitment in bare‐ground gaps where vegetation has been removed vs in extant grassland vegetation in 12 boreal, sub‐alpine and alpine grassland sites along a precipitation gradient. This was tested in (1) a seed‐sowing experiment and (2) in naturally occurring recruitment of alpine, generalist and boreal species. Results Emergence of the sown alpine species was higher in the cold alpine than in the warmer sub‐alpine sites, with no effects of precipitation or vegetation removal. The sown generalists also decreased in emergence towards warmer sites, whereas there was no effect of temperature on the sown boreal species. Vegetation removal, interacting with precipitation, increased the emergence of the generalist and boreal species sown at intermediate precipitation levels. In contrast, interactions between temperature and vegetation removal regulated the emergence of all groups of naturally occurring seedlings. Alpine and generalist species emerged at the highest rate in alpine sites, whereas boreal species had highest emergence in the lowlands. Conclusion For all species groups, strong effects of vegetation removal show that competition from the extant vegetation dominates in controlling seedling emergence across all study sites and species. In generalist and boreal species, positive interactions between vegetation removal and temperature show that competitive interactions affect seedling emergence more strongly towards warmer climates, in line with the stress‐gradient hypothesis. In contrast, alpine species show no such interactions. This suggests that species’ adaptations to climate, in combination with environmental forcing, control seedling emergence along the bioclimatic gradients. Our results have implications for nature conservation, as we propose that disturbance from grazing animals can be useful to release competition and thereby increase seedling recruitment and biodiversity in boreal and alpine grasslands in a warmer future.

Bryophytes are widespread in terrestrial ecosystems but little is known about their infl uence on vascular species. Watersoluble leachates (0%, 1%, 5%, 10% concentration) derived from 18 species of bryophytes (mosses 11 species; liverworts 7 species) were tested on the germination and seedling growth of Lactuca sativa and two common trees Melicytus ramifl orus (Violaceae) and Fuchsia excorticata (Onagraceae) in southern New Zealand forests. Bryophyte water soluble extracts (BWSE) have minor impact on seed germination of Lactuca, stimulatory eff ects on radical growth at low (1%) concentrations and inhibitory eff ects at higher concentrations (5 -10%). For Melicytus the BWSE had variable eff ects, with evidence of strong stimulatory (Dendrohypopterygium fi liculiforme) and inhibitory (Lepidozia concinna) eff ects on germination, but generally inhibited radical growth. BWSE at all test concentrations consistently inhibit both germination and seedling radicle growth in Fuchsia. Th e toxicity eff ect of water-soluble leachates varies signifi cantly between bryophyte species but not consistently between mosses and liverworts. Bryophyte species exhibiting strongest inhibition eff ects under control conditions were associated with signifi cantly reduced densities of broadleaved tree seedlings in forest ecosystems. Our results demonstrate that some bryophyte species via allelopathic interactions can inhibit seedling establishment and growth of forest trees. Th is mechanism provides an additional factor constraining the spatial distribution of the regeneration niche in forest communities.

In France, municipal solid waste (MSW) is primarily incinerated. This study aims at providing a complete, up-to-date, description of French MSW incineration regarding its technological, environmental, and energy features, in a context where these features are decisive for robust life cycle assessments (LCAs) to be performed. Data relative to, respectively, air pollution control (APC) techniques, consumption of reagents, air emissions and energy consumption and recovery were collected with respect to 90 French MSW incineration plants, considering the period 2012-2015. The compiled data set is representative for approximately 73% of the total mass of MSW annually incinerated in France (10.65 million tonnes of MSW in 2012). The analysis of the collected data first enables to determine the most used APC techniques in the French MSW incineration sector, respectively distinguishing "dedusting + acid gas treatment" and "DeNOx + abatement of dioxins." Moreover, the statistical parameters that characterize the consumption of reagents in the French MSW incineration sector are provided as a function of APC techniques. Furthermore, regarding eight pollutants usually considered (at least partly) "process specific" in the LCA of MSW incineration (NOx, dust, dioxins, NH 3 , CO, volatile organic compounds, HCl, and SOx), this study discusses the significance-in a statistical point of view-of differences in incineration air emission factors from one APC technique to the other. Finally, average energy consumption and energy recovery efficiency of the French MSW incineration sector are provided and discussed. Keywords:air emissions APC energy industrial ecology LCI MSW incineration Supporting information is linked to this article on the JIE website Conflict of interest statement: The authors have no conflict to declare.