Relative contribution of soil, management and traits to co-variations of multiple ecosystem properties in grasslands.

Ecological intensification promotes the better use of ecosystem functioning for agricultural production and as a provider of additional regulation and cultural services. We investigated the mechanisms underpinning potential ecological intensification of livestock production in the Vercors mountains (France). We quantified the variations in seven ecosystem properties associated with key ecosystem services: above-ground biomass production at first harvest, fodder digestibility, plant species richness, soil organic matter content, soil carbon content, total microbial biomass and soil bacteria:fungi ratio across 39 grassland plots representing varying management types and intensity. Our analyses confirmed joint effects of management, traits and soil abiotic parameters on variations in ecosystem properties, with the combination of management and traits being most influential. The variations explained by traits were consistent with the leaf economics spectrum model and its implications for ecosystem functioning. The observed independence between ecosystem properties relevant to production (forage biomass, digestibility and nutrient turnover) on the one hand and soil stocks (organic matter, carbon and microbial stocks) on the other hand suggests that an intensification of fodder production might be compatible with the preservation of the soil capital. We highlight that appropriate choices regarding various practices, such as the first date of grazing or mowing being dependent on soil moisture, have important consequences on a number of ecosystem properties relevant for ecosystem services and may influence biodiversity patterns. Such avenues for ecological intensification should be considered as part of further landscape- and farm-scale analyses of the relationships between farm functioning and ecosystem services.

Assessing the Effects of Grassland Management on Forage Production and Environmental Quality to Identify Paths to Ecological Intensification in Mountain Grasslands.

Ecological intensification in grasslands can be regarded as a process for increasing forage production while maintaining high levels of ecosystem functions and biodiversity. In the mountain Vercors massif, where dairy cattle farming is the main component of agriculture, how to achieve forage autonomy at farm level while sustaining environmental quality for tourism and local dairy products has recently stimulated local debate. As specific management is one of the main drivers of ecosystem functioning, we assessed the response of forage production and environmental quality at grassland scale across a wide range of management practices. We aimed to determine which components of management can be harnessed to better match forage production and environmental quality. We sampled the vegetation of 51 grasslands stratified across 13 grassland types. We assessed each grassland for agronomic and environmental properties, measuring forage production, forage quality, and indices based on the abundance of particular plant species such as timing flexibility, apiarian potential, and aromatic plants. Our results revealed an expected trade-off between forage production and environmental quality, notably by stressing the contrasts between sown and permanent grasslands. However, strong within-type variability in both production and environmental quality as well as in flexibility of timing of use suggests possible ways to improve this trade-off at grassland and farm scales. As achieving forage autonomy relies on increasing both forage production and grassland resilience, our results highlight the critical role of the ratio between sown and permanent grasslands as a major path for ecological intensification in mountain grasslands.

Does flexibility in perceptual organization compete with automatic grouping?

Segregated objects can be sought simultaneously, i.e., mentally "re-grouped." Although the mechanisms underlying such "re-grouping" clearly differ from automatic grouping, it is unclear whether or not the end products of "re-grouping" and automatic grouping are the same. If they are, they would have similar impact on visual organization but would be in conflict. We compared the consequences of grouping and re-grouping on the performance cost induced by stimuli presented across hemifields. Two identical and contiguous target figures had to be identified within a display of circles and squares alternating around a fixation point. Eye tracking was used to check central fixation. The target pair could be located in the same or separate hemifields. A large cost of presenting targets across hemifields was observed. Grouping by connectedness yielded two types of target pair, connected and unconnected. Subjects prioritized unconnected pairs efficiently when prompted to do so, suggesting "re-grouping." However, unlike automatic grouping, this did not affect the cost of across-hemifield presentation. The suggestion is that re-grouping yields different outputs to automatic grouping, such that a fresh representation resulting from re-grouping complements the one resulting from automatic grouping but does not replace it. This is one step toward understanding how our mental exploration of the world ties in and coexists with ongoing perception.

Additive vs non-additive genetic components in lethal cadmium tolerance of Gammarus (Crustacea): novel light on the assessment of the potential for adaptation to contamination.

Questioning the likelihood that populations adapt to contamination is critical for ecotoxicological risk assessment. The appraisal of genetic variance in chemical sensitivities within populations is currently used to evaluate a priori this evolutionary potential. Nevertheless, conclusions from this approach are questionable since non-additive genetic components in chemical tolerance could limit the response of such complex phenotypic traits to selection. Coupling quantitative genetics with ecotoxicology, this study illustrates how the comparison between cadmium sensitivities among Gammarus siblings enabled discrimination between genetic variance components in chemical tolerance. The results revealed that, whereas genetically determined differences in lethal tolerance exist within the studied population, such differences were not significantly heritable since genetic variance mainly relied on non-additive components. Therefore the potential for genetic adaptation to acute Cd stress appeared to be weak. These outcomes are discussed in regard to previous findings for asexual daphnids, which suggest a strong potency of genetic adaptation to environmental contamination, but which contrast with compiled field observations where adaptation is not the rule. Hereafter, we formulate the reconciling hypothesis of a widespread weakness of additive components in tolerance to contaminants, which needs to be further tested to gain insight into the question of the likelihood of adaptation to contamination.