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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; 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; 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.