Land-use intensification threatens biodiversity, and restoring degraded ecosystems remains challenging due to the difficulty of identifying the rules governing community assembly and dynamics. Investigating the temporal dynamics of trait-abundance distributions (TADs) along long-term time series offers a promising approach to disentangle the influence of stochastic (e.g. climatic variability, ecological drift) and deterministic processes (e.g. biotic interactions, abiotic filtering) in shaping ecological communities and guiding biodiversity restoration. We used a long-term restoration experiment conducted in a species-poor, historically intensively managed grassland (Massif-central, France) to evaluate the relationships between land-use intensity, TADs dynamics, and the recovery of grassland plant species richness. TADs were quantified annually from 2004 to 2021 based on four traits related to plant architecture and leaf carbon economy. We analysed the temporal variability of TADs using the skewness-kurtosis relationship (SKR), a framework that explicitly accounts for stochasticity while revealing the imprint of deterministic processes on community assembly. TADs dynamics were not random, but were constrained according to trait- and land-use-specific SKR patterns. The cessation of fertilisation shifted TADs for all traits, from peaked distributions under fertilised management to more uniform distributions under unfertilised conditions. In the unfertilised treatment, TADs were also more stable than expected by chance and converged toward maximal trait evenness. Maximisation in trait evenness occurred during the early years of the experiment and preceded the long-term recovery of plant species richness. By explicitly accounting for stochastic community dynamics, our study reveals how plant communities reassemble during ecological restoration of grasslands historically degraded by intensive management and identifies the maximisation of trait evenness as a predictive benchmark linking early community reorganisation to long-term biodiversity recovery.

This chapter describes the diversity of data available about grasslands, and how such data may be analysed and fuel a variety of tools in order to support grassland management decisions at farm and territory scales, with a focus on EU countries. Specific attention is then drawn to the case of semi-natural grasslands that are more difficult to document but that are of high strategic importance. Based on different examples, the potential of combining different types of data and different tools is discussed, as well as the importance of multi-stakeholder networks.

Permanent grasslands have the ability to simultaneously provide numerous ecosystem services for the benefit of agricultural production and, more broadly, society. This multifunctionality results from strong interactions between animal and plant biodiversity and biogeochemical cycles. These links are, however, modulated by local pedoclimatic conditions, the biogeographic/landscape context and management practices, thus determining a great variability in the structures and dynamics of permanent grasslands. Today these balances are threatened due to rapid changes in climatic conditions and modifications in agricultural activities. We illustrate the complex links between practices, climate and biodiversity and their effects on the multifunctionality of grasslands through the synthesis of several studies conducted in the Massif central. We show that biodiversity is a major determinant of the capacity of grasslands to simultaneously ensure production, forage quality, stability, carbon stock, heritage value of grasslands and resistance to drought. By modifying the biodiversity of grasslands, practices impact their functioning (biological functions) and indirectly the ecosystem services they provide. Our results further illustrate how climate change could disrupt these relationships. More specifically, we show that rising temperatures could lead to deleterious effects of actual fertilization practices on biodiversity and thus on the provision of ecosystem services. Our findings invite to rethink our research devices to better anticipate the response of grassland ecosystems to global changes and adapt agricultural practices in favour of the conservation of their biodiversity.

Les prairies permanentes ont la faculté de fournir des services écosystémiques aux bénéfices de la production agricole et plus largement de la société. Ces services résultent d’interactions fortes entre la biodiversité animale et végétale et le fonctionnement des écosystèmes (e.g. les cycles biogéochimiques). Avec les changements climatiques et de pratiques agricoles en cours, ces liens entre biodiversité et fonctions sont susceptibles d’être modifiés, si bien que la capacité des prairies à fournir simultanément divers services (i.e. leur multifonctionnalité) pourrait être altérée. Nous illustrons les liens complexes entre pratiques, climat et biodiversité et leurs effets sur la multifonctionnalité des prairies par la synthèse de plusieurs études conduites dans le Massif central. Nous montrons que la biodiversité est un déterminant majeur de la capacité des prairies à assurer de manière simultanée la production, la qualité fourragère, la stabilité, le stock de carbone, la valeur patrimoniale des prairies et la résistance aux sècheresses. Les pratiques agricoles influencent alors directement cette multifonctionnalité, mais aussi indirectement en modifiant la biodiversité des prairies. Nos résultats illustrent également comment les changements climatiques pourraient bouleverser ces relations. Plus précisément nous montrons que la hausse des températures pourrait rendre les pratiques de fertilisation actuelles fortement délétères pour la biodiversité et ainsi la fourniture simultanée de nombreux services écosystémiques. Ces travaux invitent à repenser nos dispositifs de recherche pour mieux anticiper la réponse des écosystèmes prairiaux aux changements globaux et adapter les pratiques agricoles en faveur de la conservation de leur biodiversité et ainsi de leur multifonctionnalité.

Background Grasslands provide a wide range of ecosystem services (ESs). However, there is currently no method for easily diagnosing the level of ESs produced. Our aim was to develop ES indicators based on botanical surveys, which are readily available data and integrative of grassland spatiotemporal variability. Methods Based on academic knowledge and expertise, we identified several simple vegetation criteria that we aggregated using a multicriteria analysis tool to construct indicators of the level of ESs provided by grasslands. In this study, the indicators were calculated from over 2000 botanical surveys spread over a wide biogeographical gradient. Results Analyses of correlation between the various indicators show that “forage supply” and “diversity conservation” were not correlated. “Forage availability” and “nitrogen availability for the vegetation” were positively linked together and negatively linked to the robustness of the plant community to extreme events. A temporal approach highlights that the “biodiversity conservation” score decreased from 1970 to 2010 and that “nitrogen availability for the vegetation” was lower in 1970 and 1980 than in 2000 and 2010. Conclusions These results show that our aggregation method based on a large data set of botanical surveys could be appropriate for studying temporal dynamics of ESs.

Agroecosystems are facing new challenges in the context of a growing and increasingly interconnected human population, and a paradigm shift is needed to successfully address the many complex questions that these challenges will generate. The transition to providing multiple services within an agroecosystem is a starting point for heightened multifunctionality, however, there is still hesitation among stakeholders about moving towards multi-service systems, largely because of the lack of knowledge linking productivity and multifunctionality. We reason that much of this reticence could be overcome through a better understanding of stakeholder re-quirements and innovative transdisciplinary research extended in the dimensions of time and space. We assembled experts in France to identify priority research questions for co-constructing projects with stakeholders. We identified 18 key questions, as well as the obstacles that hinder their resolution and propose potential so-lutions for tackling these obstacles. We illustrate that research into agroecosystem multifunctionality and service production must be a hugely collaborative effort and needs to integrate knowledge from different sectors and communities. Promoting dialogue, standardization and data-sharing would enhance transdisciplinary progress. Biodiversity is highlighted as a key factor to explore and incorporate into modelling approaches, but major advances must be made in the understanding of dynamic changes in the biodiversity-function-service nexus across landscapes. Resolving these research questions will allow us to translate knowledge into decision objec-tives, identify adaptation and tipping points in agroecosystems and develop social-ecological economic pathways that are adaptive over time.

The dichotomy between temporary and permanent grasslands tends to exacerbate the opposition between an agronomic approach that favors management practices that promote biomass production at the expense of biodiversity and a more naturalist vision that favors the maintenance of biodiversity at the expense of forage performance. In fact, the functioning of grasslands results from the interaction between environmental factors (soil and climate, management) and the biological diversity present. It is necessary to consider these different factors (abiotic, biotic and anthropogenic) to identify the performance of agroecosystems and to deduce the services that humans can benefit from. The identification of interactions between management practices, biodiversity and ecosystem age provides a framework for deducing the levels of services that can be expected. Management and agricultural practices are fundamental in the management of the biodiversity-functioning-service relationship, because they reveal the role of the farmer as the pilot of the dynamics of these agro-ecosystems. Our proposal will be illustrated by analyzing the four main categories of service: support, supply, regulation, and cultural that can be expected from grasslands depending on their maturity (young vs. old). Even if biomass production and in some cases nutritional value decreases with age, allowing grasslands to age appears to be an effective lever for preserving the support, regulation and cultural services from which farmers and society benefit.

Grasslands, whether sown or permanent, grazed or mowed, are the basis of herbivore production systems aiming at economy and autonomy. With the uncertainties linked to climate change, to the socio-economic context, but also with regard to society's expectations in terms of ecosystem services, the sustainability of grasslands is becoming an important concern for farmers and land managers. However, the very notion of sustainability of grasslands is not explicit and needs to be clarified. Are we looking for the fact that temporary cover allows for quantitative and qualitative biomass production, or for the fact that a grassland cover can meet the farmer's objectives in the long term? This article presents some elements of reflection to better understand the objectives and expectations of the different actors, the biological components of grassland sustainability at different scales (plants, plant communities, farms), in order to better understand the keys to improving this sustainability. This panorama is an introduction to the theme "Valuing, Maintaining and Ensuring the Sustainability of Grasslands" that the papers that will be presented during these AFPF 2022 days will allow to develop, illustrate and deepen.

Cet article présente une étude de cas de recolonisation par la végétation de type pré salé continental après des travaux de suppression d’un remblai sur un marais salé continental dans la plaine de la Limagne (Puy-de-Dôme, France). Les plantes indicatrices des prés salés ont été suivies en présence/absence dans un réseau de 104 mailles de 10 m². Nous avons pu montrer la colonisation rapide et durable de Puccinellia distans et Juncus gerardi, mais aussi l’installation plus lente et variable de Spergula media et de Plantago maritima. Nous avons cartographié les évolutions spatiales et temporelles de cette colonisation pour 6 espèces différentes. Parmi les espèces halotolérantes, on notera l’augmentation de la population d’espèces menacées comme celle d’Inula britannica. Les résultats permettent de conclure sur l’intérêt de ce type d’opération de suppression de remblais pour restaurer les paramètres abiotiques et de la capacité de la flore de se réinstaller même après vingt-cinq ans pour reconstituer une communauté végétale caractéristique des « prés salés continentaux ».

This work addresses the dynamic of phenological development on mean stage weight (MSW), chemical composition, (ash, nitrogen (N), neutral detergent fibre (NDF) and acid detergent fibre (ADF) contents, and pepsin-cellulase dry matter digestibility (PCDMD) for cultivars of six perennial grass species (timothy, ryegrass, cocksfoot, sheep's fescue, red fescue and meadow foxtail), during their first growth cycle. The study was performed over two years along 3 sites distributed along an altitudinal gradient. The dynamics of MSW, N, NDF, ADF and PCDMD for the species differed according to the environment. For a given sum of temperatures, at Clermont-Ferrand (CL; 350 m), MSW was delayed (note of 2.37) compared with Saint-Gene`s-Champanelle (SG; 850 m; note of 2.97) and Laqueuille (LA; 1100 m; note of 3.02). Consequently, the NDF and ADF contents were lower and the PCDMD value was higher in the cultivars established at CL (575 g/kg dry matter (DM), 287 g/kg DM and 0.64 respectively) than in those at SG (653 g/kg DM, 349 g/kg DM and 0.51 respectively) and LA (653 g/ kg DM, 343 g/kg DM and 0.52 respectively). In all sites, and for the two years, the PCDMD content of timothy (0.60), ryegrass (0.63) and cocksfoot (0.59) cultivars were higher than that of sheep's fescue (0.47), red fescue (0.53), and meadow foxtail (0.51). The only exception was identified for CL site in the first year of the study, when the dynamic of PCDMD was similar for all cultivars. Sum of temperatures and MSW were closely related to nutritive value of forage, but neither indicator fully described the nutritive value of perennial grasses.

An educational game is a form of transfer that relies on a strong involvement of the targeted actors in the knowledge dissemination process. AEOLE-the-game is one ofthe deliverables ofthe AEOLEproject, which aims to raise awareness among stakeholders to enable them to better understand the main types ofgrasslands in the Massif Central. It is about "experiencing at first hand" the diversity of the types ofgrasslands and their interests in front ofexternal events, byplaying in particular various climatic or socio-economic scenarios. It helps to raise awareness of the impact of management practices on the services provided by grasslands at the farm and territorial levels. AEOLE -the-game is a collaborative game, each player incarnating a farmer belonging to the same territory that he has to develop in a sustainable way (with predetermined objectives to reach). Each ofthe 4 players will thus have to lead and maintain his farm by mobilizing individual choice criteria and concomitantly, maintain or develop a territory by jointly reasoning the 3 pillars of sustainable development. On this last point, the interactions between players will allow discussion and the emergence ofcollective decisions. By becoming an actor, the player becomes aware ofthe impact ofhis practices and decisions on the services provided by the grasslands, both on the farm and on the territory.

Increasing evidence suggests that agricultural intensification is a threat to many groups of soil biota, but how the impacts of land-use intensity on soil organisms translate into changes in comprehensive soil interaction networks remains unclear. Here for the first time, we use environmental DNA to examine total soil multi-trophic diversity and food web structure for temperate agroecosystems along a gradient of land-use intensity. We tested for response patterns in key properties of the soil food webs in sixteen fields ranging from arable crops to grazed permanent grasslands as part of a long-term management experiment. We found that agricultural intensification drives reductions in trophic group diversity, although taxa richness remained unchanged. Intensification generally reduced the complexity and connectance of soil interaction networks and induced consistent changes in energy pathways, but the magnitude of management-induced changes depended on the variable considered. Average path length (an indicator of food web redundancy and resilience) did not respond to our management intensity gradient. Moreover, turnover of network structure showed little response to increasing management intensity. Our data demonstrates the importance of considering different facets of trophic networks for a clearer understanding of agriculture-biodiversity relationships, with implications for nature-based solutions and sustainable agriculture.