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International audience; Reconciling the well known benefits of shrubs for forage with environmental goals, whilst preventing their dominance, is a major challenge in rangeland management. Browsing may be an economical solution for shrubby rangelands as herbivore browsing has been shown to control juvenile shrub growth. Less convincing results have been obtained for adult plants, and long-term experiments are required to investigate the cumulative effects on adult plants. We therefore assessed the impact of different levels of browsing intensity on key demographic parameters for a major dominant shrub species (broom, Cytisus scoparius), focusing on adult plants.We assigned individual broom plants to one of three age classes: 3-5 years (young adults); 5-7 years (adults); and 7e9 years (mature adults). These plants were then left untouched or had 50% or 90% of their total edible stem biomass removed in simulated low-intensity and high-intensity browsing treatments, respectively. Morphological, survival and fecundity data were collected over a period of four years. Browsing affected the morphology of individual plants, promoting changes in subsequent regrowth, and decreasing seed production. The heavily browsed plants were 17% shorter, 32% narrower, and their twigs were 28% shorter. Light browsing seemed to control the growth of young adult plants more effectively than that of older plants. Reproductive output was considerably lower than for control plants after light browsing, and almost 100% lower after heavy browsing. Highintensity browsing had a major effect on survival causing high levels of plant mortality. We conclude that suitable browsing practices could be used to modify adult shrub demography in the management of shrub dominance and forage value.

Current agri-environmental schemes for reconciling agricultural production with biodiversity conservation are proving ineffective Europe-wide, increasing interest in results-based schemes (RBSs). We describe here the French "Flowering Meadows" competition, rewarding the "best agroecological balance" in semi-natural grasslands managed by livestock farmers. This competition, which was entered by about a thousand farmers in 50 regional nature parks between 2007 and 2014, explicitly promotes a new style of agri-environmental scheme focusing on an ability to reach the desired outcome rather than adherence to prescriptive management rules. Building on our experience in the design and monitoring of the competition, we argue that the cornerstone of successful RBSs is a collective learning process in which the reconciliation of agriculture and environment is reconsidered in terms of synergistic relationships between agricultural and ecological functioning. We present the interactive, iterative process by which we defined an original method for assessing species-rich grasslands in agroecological terms. This approach was based on the integration of new criteria, such as flexibility, feeding value, and consistency of use, into the assessment of forage production performance and the consideration of biodiversity conservation through its functional role within the grassland ecosystem, rather than simply noting the presence or abundance of species. We describe the adaptation of this methodology on the basis of competition feedback, to bring about a significant shift in the conventional working methods of agronomists and conservationists (including researchers).The potential and efficacy of RBSs for promoting ecologically sound livestock systems are discussed in the concluding remarks, and they relate to the ecological intensification debate.

International audience; Die Verbuschung von Weideland im Anschluss an die Änderung der landwirtschaftlichen Nutzung hat sich zu einem größeren Problem für die Biodiversität und den Schutz der Weideländer entwickelt. Die erfolgversprechendste Maßnahme um die Verbuschung zu kontrollieren scheint derzeit die Beweidung zu sein, doch ist der Einfluss von kleinen wiederkäuenden Haustieren auf die Populationsdynamik der dominanten Straucharten bisher kaum verstanden. Wenn wir die schnelle Verdichtung der dominanten Strauchpopulationen kontrollieren wollen, bedeutet das, dass wir uns auf die frühen Stadien der Ausbreitung der Sträucher konzentrieren müssen. In dieser Veröffentlichung präsentieren wir einen Modellansatz, der deterministische Matrixmodelle beinhaltet, um die demographischen Strategien genau zu Beginn des Populationswachsturms der Sträucher zu verstehen und mögliche Ziellebensstadien für eine Kontrolle zu identifizieren. Wir sammelten über eine Zeitspanne von fünf Jahren die demographischen Daten der dominanten, europäischen Strauchart Cytisus scoparius (Besenginster, Fabaceae), die häufig in den Heideländern ist, die sich auf den früheren permanenten Grünländern in Europa etablieren. Unser Ergebnisse lassen eine sehr große Variation in der Blühhäufigkeit zwischen den Jahren und einen großen Beitrag der Samenbank zur Gesamtanzahl der Keimlinge, die jedes Jahr auflaufen, erkennen. Die Modelle zeigen, dass das Populationswachstum sehr deutlich ist und nicht durch wiederholte, schlechte Jahre für die Samenproduktion gestoppt wird. Die Anfälligkeitsanalysen weisen darauf hin, dass das Überleben der frühen Lebensstadien (Keimling, Jungpflanzen) den größten Einfluss auf das Populationswachstum hat. Diese Ergebnisse ermöglichen es, Jungpflanzen als das beste Ziel für eine Kontrolle zu identifizieren, weil sie eine Kombination aus einem hohen Empfindlichkeitsgrad in Bezug auf die Populationsdemographie zeigen, für herbivore Haustiere gut fressbar und Managementplänen leicht zugänglich sind.; Shrub encroachment in pastoral areas subsequent to land-use changes has become a major problem for biodiversity and pastoral resource conservation.Controlling encroachment by grazing is the most promising prospect at this time, but the impact of small domestic ruminants on the population dynamics of dominant shrubby species is still poorly understood. To control the rapid densification of dominant shrub populations means that we have to focus on the early stages of shrub colonisation. In this paper, we present a modelling approach that includes deterministic matrix modelling to understand demography strategy at the very beginning of shrub population growth and to identify potential targeted life stages for control. We collected demographic data over a period of 5 years on the European dominant shrub, Cytisus scoparius (Scotch broom; Fabaceae), which is often part of the heathlands that establish themselves on former permanent grasslands in Europe. Our results reveal a very high variation in flowering frequency between years and a large contribution of the seed bank to the total number of seedlings that emerge each year. Modelling shows that population growth is very vigorous and is not stopped by repeated “bad years” for seed production. Sensitivity analyses indicate that early life stage survival (seedling, juvenile) has the greatest impact on population growth. These results make it possible to identify juveniles as one of the best targets for control since they combine a high degree of sensitivity in terms of population demography, good palatability for domestic herbivores and easy accessibility within a management schedule.

International audience; Concerns about biodiversity preservation through grazing have revived interest in feeding choices made by herbivores. In this article, we study the dynamics of behavioural intake response in heterogeneous vegetation, where the size and quality of edible plants is highly diverse and varies from day to day as a result of grazing. We conducted two experiments with ewes grazing in paddocks located in shrubby rangelands. A direct in situ observation method was used, with continuous observation of ingestive bites taken by a continuously monitored individual. A bite coding-grid enabled us to distinguish the extreme diversity between bites masses and structure, including the ones resulting from plant depletion. Flock activities were also scan-sampled. Observations were made throughout complete paddocking sequences, which lasted for about two weeks. Grazing seriously depleted the paddocks since 75–95% of the herbaceous species was consumed. No trend was detected either in daily activity patterns or in intake time-budgets. These two variables were well synchronised between the continuously monitored individuals and their respective flocks. No inter-day trend was observed for dry matter daily intakes, which was twice higher than predictions from existing models on sheep intake. Our data enabled us to explore the relationship between the diversity of instantaneous feeding choices and the quantitative daily intake. On the instantaneous scale (20 s), we confirmed the functional relationship between bite mass and bite frequency. Little variation was observed in daily averages of ingestive behaviour components. But these averages hide the extremely large range of instantaneous values (from 0.04 to 1.2 g DM for bite mass). When vegetation size and structure declined as a result of grazing, the ewes progressively took larger bite masses with equivalent nutritive quality, thus adopting a pattern of consumption that is not consistent with the general assumption that such bites are chosen during the first day, as a result of the behavioural quantity–quality trade-off. This article provides knowledge about which type of diversity in plant parts size, structure and composition offers a small ruminant satisfying behavioural leeway in composing its meals and reaching physical satiety.We tend to discard pastoral management practices focused on biomass evaluation, and encourage further studies that will help qualify the nature and structure of vegetation that offers adjustment possibilities at both the individual and flock levels.

International audience; Exploring key demographic parameters for establishment and growth of shrub populations enables us to identify the life stages or plant organs that browsers need to consume to effectively influence shrub population dynamics. However, there is a lack of concrete knowledge on how browsing can efficiently meet this goal. We therefore tested the impact of different levels of browsing intensity on a key demographic parameter (survival of juveniles) of a major colonizing shrub species (broom, Cytisus scoparius) in order to control population growth, and designed a browsing management strategy focused on this target stage. Three browsing intensities, representing pertinent management practices, were simulated on juveniles (2 years old) in a broom population. Juvenile broom plants were either left untouched (control treatment; n ¼ 126) or had 50% or 90% of their total edible stem biomass removed for “light-intensity browsing” (n ¼ 127) and “high-intensity browsing” (n ¼ 77) treatments, respectively. Survival and fecundity data were collected over 6 years. Standard matrix modeling was used to analyze the impact of browsing on changes in population growth rate (l), and the results were 6.34 (control), 2.26(light browsing) and 0.85 (heavy browsing). Therefore, the natural expansion of broom populations may be slowed by light browsing or even reversed by heavy browsing (l < 1). This multi-year survey confirms that focusing browsing on juveniles is an efficient strategy for controlling broom dominance. Shrub control strategies should therefore target early-growth-stage populations and repeat the browsing strategy at the same intensity over several years to achieve cumulative effects.

International audience; After several decades of marginalization within farming systems, European rangelands are now being challenged to contribute to the conservation of ecological habitats and biodiversity. One of the main challenges, supported by the European Union incentives, relates to the reconciliation of livestock farmers’ grazing practices and to the control of dominant plant dynamics, especially those of shrub species, which includes maintaining them at density levels appropriate for both habitat conservation and forage resources production. In this chapter, we aim to identify reasons for the difficulty in designing relevant management practices, with focus on the interlinkage of knowledge produced by animal sciences and plant population ecology. From the point of view of these two disciplines, we stress the importance of taking into account the reciprocal interactions between ruminants' foraging strategy and shrubs' demographic behavior. A series of results is given for our experiments on rangelands encroached by Scotch Broom shrubs (Cytisus scoparius L.Linck) and grazed by ewes. Considering the dynamics of ewes' behavioral patterns, we argue for a description of heterogeneous vegetation that recognizes feed items and their functionality for ruminants in maintaining their intake level in a fenced paddock. And considering the dynamic response of Scotch Broom shrubs to browsing, we also argue for demographic models that would recognize the importance of both the selective offtake of plant organs and the new browsing-induced demographic behavior of shrubs. These results enabled to identify the plant community as a mandatory intermediate object, and the plant organs as a key organization level at which these two processes interact. We propose an original conceptual framework that interlinks the two processes and recognizes the specific organizational levels and time frames. This framework should facilitate the identification of prospective research issues such as the differential impact of browsing on shrub demography according to plant organs and life stages consumed, or the effect of different vegetation states of a plant community on selective browsing among shrub organs. For rangeland management, the framework brings out the importance of greater precision in identifying the targets, and in particular the target plant organs and target life stages in shrub demography control

International audience; The foraging responses of ewes faced with a diversity of feed items and their effects on broom (Cytisus scoparius L.) consumption were examined. The experiment was conducted on a farm in the autumn with ewes (n = 33) grazing three small paddocks (0.44 ha on average, for at least 10 days each) located in broom shrubland. The effects of three different herbaceous covers on broom consumption were compared: 100% of paddock area previously grazed in summer; 50% of paddock area previously grazed in summer; and paddock area non-grazed during the year. The characteristics of herbaceous cover (availability and quality) and the ewes’ diet selection were encoded as bite categories. Flock activities were recorded through scan sampling. We used logistic regression to assess the relationship between feeding behaviour of sheep on herbaceous vegetation and on broom species, and calculated selectivity indices for this shrub. We showed that the presence of high-quality bite categories in the herbaceous cover affected the way ewes integrated broom into their diet. At the start of each paddock use period, ewes favoured high-quality larger and medium bites of the herbaceous cover. They gradually included larger bites of broom and reduced their bite size, but continued to seek out higher quality herbaceous plants, a pattern which suggested a stabilisation of their daily average digestibility and bite mass over time. A negative relation was observed between the percentage of ewes taking large and mediumbites on highly digestible plant parts and the percentage of ewes browsing broom. A maximum of 26% of the flock browsing broom was observed on any given day. Hence, ewes have a threshold for this target shrubby species that they do not exceed during any paddock utilisation period. This finding was interpreted as a mechanism to deal with post-ingestive consequences and complementary interactions between nutrients and toxins. When comparing broom selection between paddocks in autumn, we found an earlier and thus longer broom selection in areas with herbaceous cover that had not been grazed during the year (possibly because of a lower palatability). Our results provide new insights into ways to manipulate diet selection in order to stimulate the use of broom by ewes. Bite categories are proposed as functional feed indicators that facilitate prediction of the herbaceous cover state preliminary to initial broom integration in the sheep’s diet.

[Departement_IRSTEA]Territoires [TR1_IRSTEA]DTAM; Two agri-environmental measures (MAE) tied to an obligation of result aimed at pastureland management (Herbe_09) and preserving species-rich grassland (Herbe_07) were studied: genesis of these measures in Europe and in France, conditions of implementation in different areas and agroecological relevance. This type of MAE restores a sense of responsibility to farmers. Implementing these measures may generate a positive territorial dynamic in the sometimes contradictory debate over the best interests of farmers vs. ecological biodiversity conservation measures. Results show that their positive impact in terms of social, ecological and agricultural benefits supports the idea that they ought to be implemented on a wider scale, along with improved regulations, a better dialogue between farmers and environmental activists, and progress in technical and scientific knowledge.; Les mesures agri-environnementales (MAE) visant la gestion pastorale (Herbe_09) et le maintien de prairies à forte richesse spécifique (Herbe_07) sont analysées : genèse de ces mesures en Europe et en France, conditions de leur mise en oeuvre dans plusieurs territoires et pertinence agri-écologique. Ce type de MAE est susceptible de redonner aux éleveurs une responsabilité valorisante ; leur mise en oeuvre peut entraîner une dynamique territoriale positive dans le débat parfois contradictoire entre agriculture et conservation de la biodiversité ; enfin, elles permettent de concilier production et biodiversité, mais sont peu propices à d’autres fonctions écologiques (pollinisation, séquestration du carbone...). Au final, leur bilan social, écologique et agricole, positif, incite à les généraliser mais en faisant progresser réglementation, concertation entre acteurs agricoles et environnementaux, et connaissances techniques et scientifiques.

National audience; Grazing contracts designed to protect biodiversity are becoming common fare although the question of appropriate practices has not yet been settled. This inspired the study, undertaken by the HERBIVORIE research network, of the impact of herbivores on plant dynamics in mountain areas. We interviewed herders who rear dairy cows which they claimed were perfectly able to graze on steep, bushy slopes in the Bauges mountains (northern French Alps). The survey was carried out using comprehensive interviewing techniques. Several reasons encourage the herders to graze their animals on steep slopes: urbanisation, gentler grasslands reserved for haymaking and dairy cows milked in the pastures, financial incentives to use grazing as a method to control scrub encroachment. Yet, current technical models discourage farmers from grazing non-controlled areas except with specialised breeds. We observed herders using steep uneven, bushy terrain for grazing dairy breeds (from the Holstein to the Tarine). All of them feel that the capacity to make best use of these lands can be traced to appropriate animal rearing practices, far more than to breed characteristics. Some herders are careful to teach their young cattle to use steep sloped lands. They say this is important because cows raised on lowland pastures are clumsy in the mountains and are accident-prone. They consider "education" to mean taking calves as young as 6-8 months old, and then heifers, to graze on special plots. These educational techniques and the behavioural diversity described by the herders raise the question of the "culture" of domestic herbivores and the role of herders in inter-generational transmission of the herd's skills. It may be profitable to encourage these practices and to include these learning areas in agro-environmental contracts; La contractualisation du pâturage à fin de conservation de la biodiversité devient affaire courante, mais la question des pratiques appropriées demeure. C'est pourquoi nous avons enquêté auprès d'éleveurs revendiquant d'élever des vaches laitières compétentes pour le pâturage de terrains très pentus et embroussaillés dans les Bauges (Savoie et Haute-Savoie). Pour tous, indépendamment des races élevées - elles sont diverses -, l'aptitude des vaches à tirer parti de ces milieux résulte de pratiques d'élevage appropriées, bien plus que des caractéristiques raciales auxquelles se cantonnent les références en vigueur. Certains éleveurs veillent à apprendre spécifiquement à leurs jeunes bovins l'usage des fortes pentes. Ces pratiques d'apprentissage et la gamme des comportements évoqués incitent à s'interroger sur la "culture" des herbivores domestiques. Une perspective opérationnelle serait d'encourager ces pratiques et d'inclure dans les contrats agroenvironnementaux les espaces nécessaires aux apprentissages

National audience

National audience

National audience; La "Directive Habitats" de l'Union Européenne a instauré en 1992 le réseau de sites Natura 2000 avec pour objectif de "contribuer à assurer la biodiversité par la conservation des habitats naturels ainsi que de la faune et de la flore sauvage sur le territoire européen". Fondée sur les connaissances en écologie, elle prétend intervenir sur 5 % ou plus du territoire français situés entre cultures et forêts de production, sur les pelouses, landes et fourrés, marais et bords de rivières, espaces délaissés par la pensée agronomique. Cette procédure incite l'ensemble des usagers des territoires concernés, au premier rang desquels les éleveurs, à maintenir ou modifier en conséquence leurs pratiques. Mais ces derniers manquent cruellement de références...

National audience; Two agri-environmental measures (MAE) tied to an obligation of result aimed at pastureland management (Herbe_09) and preserving species-rich grassland (Herbe_07) were studied: genesis of these measures in Europe and in France, conditions of implementation in different areas and agroecological relevance. This type of MAE restores a sense of responsibility to farmers. Implementing these measures may generate a positive territorial dynamic in the sometimes contradictory debate over the best interests of farmers vs. ecological biodiversity conservation measures. Results show that their positive impact in terms of social, ecological and agricultural benefits supports the idea that they ought to be implemented on a wider scale, along with improved regulations, a better dialogue between farmers and environmental activists, and progress in technical and scientific knowledge.; Les mesures agri-environnementales (MAE) visant la gestion pastorale (Herbe_09) et le maintien de prairies à forte richesse spécifique (Herbe_07) sont analysées : genèse de ces mesures en Europe et en France, conditions de leur mise en ½uvre dans plusieurs territoires et pertinence agri-écologique. Ce type de MAE est susceptible de redonner aux éleveurs une responsabilité valorisante ; leur mise en oeuvre peut entraîner une dynamique territoriale positive dans le débat parfois contradictoire entre agriculture et conservation de la biodiversité ; enfin, elles permettent de concilier production et biodiversité, mais sont peu propices à d’autres fonctions écologiques (pollinisation, séquestration du carbone...). Au final, leur bilan social, écologique et agricole, positif, incite à les généraliser mais en faisant progresser réglementation, concertation entre acteurs agricoles et environnementaux, et connaissances techniques et scientifiques.

Thèse de Bachelor Diplôme : Diplôme d'Ingénieur; L'évolution des politiques agricoles suisse a mené à la mise en place progressive, de surfaces de compensation écologique, puis à la notion de qualité biologique et à la mise en réseau de ces SCE. Le but de la thèse de Bachelor est de comprendre l’intégration et le fonctionnement des SCE "pâturages extensifs" et "pâturages boisés", au sein du dispositif légal et des exploitations agricoles. Le terme de compensation écologique est définit au début des années 90 par des scientifiques et naturalistes. Elle met en valeur l’importance écologique des milieux naturels et semi-naturels dont les pâturages extensifs et boisés. Des espèces bioindicatrices sont alors utilisées pour appréhender la valeur écologique de ces milieux agricoles. La mise en place de cette bioindication a été mandatée par l’OFEV, puis vulgarisée pour les agriculteurs, par l’OFAG. L’agriculteur a donc un nouveau rôle, celui de gestionnaire d’espaces agricoles d’intérêts écologiques. Ces milieux semi-naturels sont ici caractérisés par une modalité de gestion extensive, une forte valeur paysagère et économique (pâturages boisés), ou encore une végétation particulière et diversifiée (PPS et pâturages embroussaillés). Les modalités d’exploitation de ces pâturages doivent respecter un cahier des charges défini par l’OFAG, exprimé en obligations de moyens. L’objectif de ces mesures est une amélioration des pratiques de l’agriculture en faveur de l’environnement. Mais les résultats de l’évaluation ‘‘biodiversité’’ globale des SCE sont mitigés car les exigences ne sont pas suffisantes. Depuis 2001, la contractualisation permet de combiner obligations de moyens et de résultats, par la notion de qualité et de mise en réseau selon l’OQE. L’enquête auprès de sept agriculteurs suisse montre qu’il existe des différences entre les volontés des politiques publiques et l’intégration des SCE « pâturages » dans les systèmes d’élevage. Cette intégration et l’évolution vers de nouvelles obligations varient suivant les cas rencontrés (enquête de terrains). La mise en place des SCE dépend, du système d’élevage, des conditions d’exploitations ou encore des motivations professionnelles et personnelles. La combinaison aux obligations de résultats n’est pas évidente pour tous. Dans un système mixte de plaine, la qualité et la mise en réseau sont plus difficile à obtenir qu’en zone plus rurale, de colline ou de montagne. L’étude reflète la diversité des possibilités d’intégration de ces mesures, de la plus simple à la plus complexe