Cannelle Moinardeau, L’écopastoralisme, un outil adapté pour la gestion conservatoire des écosystèmes très anthropisés ? Le cas des digues artificielles du canal de dérivation de Donzère-Mondragon dans la vallée du Rhône (Vaucluse-Drôme, France) / Ecopastoralism, an adapted tool for the conservation management of highly anthropised ecosystems? The case of the artificial dikes of the Donzère-Mondragon channel in the Rhône valley (Vaucluse-Drôme, France), Thèse de doctorat de l’université d’Avignon, soutenue le 12 décembre 2018

Moinardeau Cannelle. Cannelle Moinardeau, L’écopastoralisme, un outil adapté pour la gestion conservatoire des écosystèmes très anthropisés ? Le cas des digues artificielles du canal de dérivation de Donzère-Mondragon dans la vallée du Rhône (Vaucluse-Drôme, France) / Ecopastoralism, an adapted tool for the conservation management of highly anthropised ecosystems? The case of the artificial dikes of the Donzère-Mondragon channel in the Rhône valley (Vaucluse-Drôme, France), Thèse de doctorat de l’université d’Avignon, soutenue le 12 décembre 2018. In: Ecologia mediterranea, tome 45 n°1, 2019. pp. 106-107

L’éco-pastoralisme un outil adapté pour la gestion conservatoire des écosystèmes très anthropisés ? : le cas des digues artificielles du canal de dérivation de Donzère-Mondragon dans la vallée du Rhône (Vaucluse-Drôme, France)

The main objective of the thesis was to characterize the impacts of different types of pastoral management (cattle, horses, goats) on "new ecosystems" plant communities. Our experimentations were conducted in highly anthropized dykes and embankments of the Donzère-Mondragon reserve in the lower Rhone valley. Various tools were used (i.e. vegetation surveys, soil analyzes, grassland mineral analyzes, remote sensing, GIS, etc.), and at different spatial scales in order to identify the interrelationships between the different levels of vegetation organization and functions. Indeed, the emergence of "new ecosystems" requires managers to reconsider the initial principles of conservation management. Our study showed that, in the short term (3-5 years), grazing systems using herds of herbivores, whose organization is adapted to maintain open habitats, increase species richness, diversity and heterogeneity of plant communities compared to lack of management or mechanical interventions. Moreover, the annual species that appear are appetizing and contribute to increase the forage value of the site grazed by horses. These herbivores also have an impact on the permanent seed bank by increasing both its heterogeneity and the density of viable seeds under the most grazed patches. Grazing of cattle and horses confirm a correlation between the vegetation index (NDVI), biomass and plant species richness. Finally, we evaluated the efficacy of goats’ action on bramble via consumption indices calculated using GIS. Our different results are in the line with those already obtained in natural environments. Future experiments should test the effects of mixed grazing systems, particularly cattle, goats and horses, on the colonization dynamic of competitive shrubs such as brambles. Applied pastoral management should be considered in the medium term, via multi-year contracts to promote the sustainability of this management method and its effects over time.L’objectif principal de la thèse était de caractériser les impacts de différents types de gestion pastorale (bovins, équins, caprins) sur les communautés végétales de « nouveaux écosystèmes » fortement anthropisés que sont les digues et remblais de la réserve de Donzère-Mondragon dans la basse vallée du Rhône. Différents outils ont été utilisés (relevés de végétation, analyses de sols, analyses minérales des herbages, télédétection, SIG, etc.) à des échelles spatiales différentes afin de dégager les interrelations entre les différents niveaux d’organisation et fonctionnalités de la végétation. En effet, l’émergence des « nouveaux écosystèmes » oblige les gestionnaires à reconsidérer les principes initiaux de la gestion conservatoire. Dans notre étude, il a pu être démontré que les systèmes de pâturage faisant appel à des troupeaux d’herbivores dont l’organisation est adaptée pour maintenir l’ouverture des milieux, augmentent la richesse spécifique, la diversité et l’hétérogénéité de la végétation à court terme (3-5 années) par rapport à l’absence de gestion ou aux interventions mécaniques. Les analyses montrent également que les espèces annuelles qui apparaissent sont appétentes et contribuent à augmenter la valeur fourragère de certains faciès du site pâturé par les chevaux. Ces herbivores ont également un impact sur la banque de graines permanente du sol en augmentant son hétérogénéité et la densité de graines viables sous les faciès les plus pâturés. Le pâturage des vaches et des chevaux confirme une corrélation entre l’indice de végétation (NDVI) obtenu après l’analyse de photographies aériennes, la biomasse et la richesse en espèces végétales. Les estimations d’indices de consommation de la ronce sous SIG ont permis d’apprécier l’efficacité de l’action des chèvres. Ces différents résultats, pour les modalités testées, correspondent bien à ceux déjà obtenus lors d’applications de systèmes pastoraux en milieux naturels. Des expérimentations devraient également être menées à l’avenir via des systèmes de pâturage mixtes notamment bovin-caprin et équin-caprin pour accroître l’effet de la restauration aux dépens de la colonisation d’arbustes compétitifs dont la ronce. La gestion pastorale appliquée devrait néanmoins être pensée sur le moyen terme, si possible via des contrats pluriannuels, favorisant la durabilité de cette méthode de gestion et de ses effets dans le temps

Ecograzing, a tool adapted for the conservation of highly anthropised ecosystems? : The case of the artificial dykes of the Donzère-Mondragon canal in the Rhône valley (Vaucluse-Drôme, France)

L’objectif principal de la thèse était de caractériser les impacts de différents types de gestion pastorale (bovins, équins, caprins) sur les communautés végétales de « nouveaux écosystèmes » fortement anthropisés que sont les digues et remblais de la réserve de Donzère-Mondragon dans la basse vallée du Rhône. Différents outils ont été utilisés (relevés de végétation, analyses de sols, analyses minérales des herbages, télédétection, SIG, etc.) à des échelles spatiales différentes afin de dégager les interrelations entre les différents niveaux d’organisation et fonctionnalités de la végétation. En effet, l’émergence des « nouveaux écosystèmes » oblige les gestionnaires à reconsidérer les principes initiaux de la gestion conservatoire. Dans notre étude, il a pu être démontré que les systèmes de pâturage faisant appel à des troupeaux d’herbivores dont l’organisation est adaptée pour maintenir l’ouverture des milieux, augmentent la richesse spécifique, la diversité et l’hétérogénéité de la végétation à court terme (3-5 années) par rapport à l’absence de gestion ou aux interventions mécaniques. Les analyses montrent également que les espèces annuelles qui apparaissent sont appétentes et contribuent à augmenter la valeur fourragère de certains faciès du site pâturé par les chevaux. Ces herbivores ont également un impact sur la banque de graines permanente du sol en augmentant son hétérogénéité et la densité de graines viables sous les faciès les plus pâturés. Le pâturage des vaches et des chevaux confirme une corrélation entre l’indice de végétation (NDVI) obtenu après l’analyse de photographies aériennes, la biomasse et la richesse en espèces végétales. Les estimations d’indices de consommation de la ronce sous SIG ont permis d’apprécier l’efficacité de l’action des chèvres. Ces différents résultats, pour les modalités testées, correspondent bien à ceux déjà obtenus lors d’applications de systèmes pastoraux en milieux naturels. Des expérimentations devraient également être menées à l’avenir via des systèmes de pâturage mixtes notamment bovin-caprin et équin-caprin pour accroître l’effet de la restauration aux dépens de la colonisation d’arbustes compétitifs dont la ronce. La gestion pastorale appliquée devrait néanmoins être pensée sur le moyen terme, si possible via des contrats pluriannuels, favorisant la durabilité de cette méthode de gestion et de ses effets dans le temps.The main objective of the thesis was to characterize the impacts of different types of pastoral management (cattle, horses, goats) on "new ecosystems" plant communities. Our experimentations were conducted in highly anthropized dykes and embankments of the Donzère-Mondragon reserve in the lower Rhone valley. Various tools were used (i.e. vegetation surveys, soil analyzes, grassland mineral analyzes, remote sensing, GIS, etc.), and at different spatial scales in order to identify the interrelationships between the different levels of vegetation organization and functions. Indeed, the emergence of "new ecosystems" requires managers to reconsider the initial principles of conservation management. Our study showed that, in the short term (3-5 years), grazing systems using herds of herbivores, whose organization is adapted to maintain open habitats, increase species richness, diversity and heterogeneity of plant communities compared to lack of management or mechanical interventions. Moreover, the annual species that appear are appetizing and contribute to increase the forage value of the site grazed by horses. These herbivores also have an impact on the permanent seed bank by increasing both its heterogeneity and the density of viable seeds under the most grazed patches. Grazing of cattle and horses confirm a correlation between the vegetation index (NDVI), biomass and plant species richness. Finally, we evaluated the efficacy of goats’ action on bramble via consumption indices calculated using GIS. Our different results are in the line with those already obtained in natural environments. Future experiments should test the effects of mixed grazing systems, particularly cattle, goats and horses, on the colonization dynamic of competitive shrubs such as brambles. Applied pastoral management should be considered in the medium term, via multi-year contracts to promote the sustainability of this management method and its effects over time

Cannelle Moinardeau, L’écopastoralisme, un outil adapté pour la gestion conservatoire des écosystèmes très anthropisés ? Le cas des digues artificielles du canal de dérivation de Donzère-Mondragon dans la vallée du Rhône (Vaucluse-Drôme, France) / Ecopastoralism, an adapted tool for the conservation management of highly anthropised ecosystems? The case of the artificial dikes of the Donzère-Mondragon channel in the Rhône valley (Vaucluse-Drôme, France), Thèse de doctorat de l’université d’Avignon, soutenue le 12 décembre 2018

Moinardeau Cannelle. Cannelle Moinardeau, L’écopastoralisme, un outil adapté pour la gestion conservatoire des écosystèmes très anthropisés ? Le cas des digues artificielles du canal de dérivation de Donzère-Mondragon dans la vallée du Rhône (Vaucluse-Drôme, France) / Ecopastoralism, an adapted tool for the conservation management of highly anthropised ecosystems? The case of the artificial dikes of the Donzère-Mondragon channel in the Rhône valley (Vaucluse-Drôme, France), Thèse de doctorat de l’université d’Avignon, soutenue le 12 décembre 2018. In: Ecologia mediterranea, tome 45 n°1, 2019. pp. 106-107

Using Different Grazing Practices for Increasing Plant Biodiversity in the Dykes and Embankments Along the Rhne River (Southern France)

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Short-Term Effects on Diversity and Biomass on Grasslands from Artificial Dykes under Grazing and Mowing Treatments

International audienceFew studies document the impacts of conservation management practices such as extensive grazing or mowing on the new ecosystems created by industrial conversions. In southern France, the Rhône channelling led to the construction of dykes to protect the Tricastin industrialized area from floods. Aiming to control plant dynamics for safety reasons and to favour plant biodiversity, mowing or extensive grazing by cattle were recently tested. Monitoring from both permanent plots and aerial photographs shows that three years of extensive grazing and annual mechanical mowing have modified plant composition, significantly increasing plant species richness, evenness and heterogeneity. The increase in evenness and beta-diversity from grazing was significantly higher than from mowing. Only grazing was able to reduce the height and cover of the dominant tussock perennial grass species (Brachypodium phoenicoides), while increasing bare soil cover and thus the contribution of annual species. The Normalized Difference Vegetation Index (NDVI) obtained through aerial photographic analyses confirmed the correlation between NDVI, aboveground biomass and plant species richness for the grazed site alone, allowing the results obtained from quadrats to be generalized to the scale of the grazed site. On the Rhône's artificial dykes, extensive grazing appears to be a better management tool than mowing to enhance plant biodiversity and meet safety objectives

Extensive horse grazing improves grassland vegetation diversity, seed bank and forage quality of artificial embankments (Rhône River - southern France)

International audienceGrazing by herds of herbivores modifies plant communities in different ways, depending on the herbivore species. Horse grazing is already known to be effective in increasing plant diversity and maintaining herbaceous vegetation, creating different types of patches and thus ensuring spatial heterogeneity. On an artificial embankment at the Donzère-Mondragon hydroelectric facility in the Rhône Valley, extensive grazing by a rustic horse (Konik-Polski) was introduced several years ago to control shrub encroachment and to enhance plant grassland diversity. Vegetation monitoring surveys over a five-year period (2014-2018) showed that horse grazing maintained patches of open and short grasslands and increased species-richness, in particular of annual species, some of which have heritage value. In contrast, overly-low grazing pressure led to the dominance of an unpalatable perennial grass (Brachypodium phoenicoides) at the expense of the annual species that significantly enhance the forage value of the most heavily grazed patches. Horse grazing also had a positive impact on the permanent seed bank of the soil, increasing its heterogeneity and the density of viable seeds. Extensive horse grazing thus appears to be a relevant management tool to preserve the diversity and the forage quality of the most open and short grasslands. Nevertheless, grazing pressure here remained too low to allow restoration of grasslands already colonised by woody species. Combining different livestock species might be a better alternative to pure horse grazing, to increase heterogeneity and diversity. Our results are discussed in relation to extensive horse grazing on artificial ecosystems, such as the embankments bordering rivers and canals

Using mechanical clearing and goat grazing for restoring understorey plant diversity of embankments in the Rhône valley (southern France)

International audienceConsumption by animals remains one of the key points to assess the effectiveness of grazing impacts in woodland for increasing understorey plant diversity. To limit the spread of the brambles and restore understorey plant diversity on an artificial embankment an original system of clearings connected by paths was created by mechanically crushing brambles and allowing them to be grazed by rustic goats. The analysis of the indices of consumption of bramble under GIS has been used to provide an estimation of the volume ingested and an estimation of the effectiveness of the goats. The impacts of three different managements (goat grazing, brush clearing and grazing, clearing and exclusion of grazing) and control without management were then tested during a three-year period. The monitoring of the vegetation on permanent plots provided evidence that goat grazing significantly increased in the short term the species-richness and heterogeneity of herbaceous plants communities, in complement with prior clearing. Thus, the objectives of the managers to open up the area and reduce the bramble cover were achieved, but the prior introduction of goats and the installation of mobile enclosures would be advisable in order to ensure the sustainability of these measures on plant diversity in the long term

Grazing in temporary paddocks with hardy breed horses (Konik polski) improved species-rich grasslands restoration in artificial embankments of the Rhône river (Southern France)

International audienceExtensive horse grazing with hardy breeds is largely used in conservation management for restoring species-rich semi-natural grasslands in Europe. As an example, the Donzère-Mondragon Rhône river embankments (south-eastern France) where horse grazing with Konik polski succeeded to maintain high species richness in patches of open and short grassland, but failed for patches of tall grassland dominated by the grass tussock species Brachypodium phoenicoides. In response, an increase of herd density by the creation of temporary paddocks was applied in tall grassland patches. Grazing pressure over time between patches was estimated via GPS fixed to mares, biomass, plant species richness measurements and from multispectral photographs, the normalized Difference Vegetation Index (NDVI) was calculated. Finally, telemetric data were collected. We wondered if the use of extensive horse grazing with temporary paddocks occupation, increase plant species richness. After three years, our results show that the increase in stocking rate enabled a significant increase of plant species richness in the tall grassland patches, with a significant decline of B. phoenicoides in all paddocks. The NDVI was strongly correlated with herbaceous biomass and plant species richness, while the number of GPS points indicating the position of the mares was higher in areas where the NDVI was high. These results are discussed for improving horse grazing conservation systems efficiency on grasslands established in anthropized sites such as embankments and the use of the NDVI as an appropriate tool to help decision-making for large-scale applications

Impacts de l'éco-pastoralisme sur les communautés végétales

National audienc