A Triple-Isotope Approach to Predict the Breeding Origins of European Bats

Despite a commitment by the European Union to protect its migratory bat populations, conservation efforts are hindered by a poor understanding of bat migratory strategies and connectivity between breeding and wintering grounds. Traditional methods like mark-recapture are ineffective to study broad-scale bat migratory patterns. Stable hydrogen isotopes (δD) have been proven useful in establishing spatial migratory connectivity of animal populations. Before applying this tool, the method was calibrated using bat samples of known origin. Here we established the potential of δD as a robust geographical tracer of breeding origins of European bats by measuring δD in hair of five sedentary bat species from 45 locations throughout Europe. The δD of bat hair strongly correlated with well-established spatial isotopic patterns in mean annual precipitation in Europe, and therefore was highly correlated with latitude. We calculated a linear mixed-effects model, with species as random effect, linking δD of bat hair to precipitation δD of the areas of hair growth. This model can be used to predict breeding origins of European migrating bats. We used δ13C and δ15N to discriminate among potential origins of bats, and found that these isotopes can be used as variables to further refine origin predictions. A triple-isotope approach could thereby pinpoint populations or subpopulations that have distinct origins. Our results further corroborated stable isotope analysis as a powerful method to delineate animal migrations in Europe

Area mediated shifts in bird community composition: a study on a fragmented Mediterranean grassland

The effects of habitat fragmentation on birds have often been studied in forest specialist species. Here we aimed at comparing the response of open habitat birds within a range of habitat specialization. The study area was a Mediterranean pseudo-steppe, designated as important for conservation yet fragmented by tree encroachment. We defined bird species dependency on steppe-like habitat by a correspondence analysis, allowing us to distinguish between specialists, generalists and scrubland species. We studied species abundance in relation to fragment area, testing whether species representation in fragments differed from those in continuous habitat. This analysis showed a contrasted response to fragment size between "open habitat" specialist species and generalist ones. Open habitat species were under-represented in the smallest fragments, while generalist were over-represented in small fragments in comparison to their distribution in continuous habitats. We discuss how these results can be linked to species habitat requirements. We find that scrubland species seem to be favoured by encroachment of woody vegetation, as they are able to explore and use the wooded matrix; however specialist species are restricted to open patches and are sensitive to a reduction in patch size. This allows us to predict how different species can exhibit a different sensitivity to habitat fragmentation

Histoire des interactions entre les changements d’usage des terres et la biodiversité

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Naturalité ou biodiversité! Quels enjeux de conservation, quels modes de mise en œuvre ?

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Histoire des interactions entre les changements d’usage des terres et la biodiversité

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Le peuplement d’oiseaux du Causse Méjean (Lozère, France) : état actuel, évolution historique et perspectives d’avenir

Breeding avifauna of the Causse Méjean (Lozère, France) is known since the end of 19th century thanks to several publications ; these permit us to know its composition and to specify the status of many species. This paper brings additional information on the habitat and curent abundance of 55 species mostly related to open grasslands and scrub habitats. Basic parameters on birds and their habitats obtained from 150 points counts carried out by means of Frequential Sampling (EFP) have been submitted to a Correspondence Analysis with respect to Instrumental Variables (AFC-VI). The results of this Multivariate Analysis allow us to define 6 groups of species representative of the various sampled formations and to characterize the habitat they occupy within the studied gradient of vegetation structure which stretches from open grassland to forest. The composition of the breeding avifauna of the three most important formations, i.e. grassland (16 species), shrubland (32 species), and pine forest (31 species) is drawn up and their patrimonial value analysed using the criteria retained by Rocamora & Yeatman-Berthelot (1999). This analysis reveals that grasslands with 14 patrimonial species and shrublands with 18 species have a stronger patrimonial interest than pine forest (only one species). A comparison of the current and past composition of the Causse Méjean’s bird communities is carried out thanks to both published and unpublished previous data. Phenomena of extinction for 3 species (Grey Partridge Perdrix perdrix, Little Bustard Tetrax tetrax, and Woodchat Shrike Lanius senator) as well as expansion and colonization for 6 others species (e.g. Tengmalm’s Owl Aegolius funereus, Black Woodpecker Dryocopus martius, Collared Dove Streptopelia decaocto, and Starling Stumus vulgaris) are highlighted and commented on. Finally the future of the Causse’s avifauna is discussed following the large Pinus nigra plantations of the first half of 20th century and in relation with the recent evolution of stock farming practices. These provoke a regression of the open lawn grasslands previously maintained by an adequate sheep grazing pressure. Thus, more than 5,600 ha of grasslands have disappeared between 1948 and 1989 from the eastern part of Causse Méjean (naked Causse) in favour of shrublands and forests.Depuis la fin du XIXe siècle, Tavifaune nicheuse du Causse Méjean (Lozère, France) a fait l’objet de plusieurs publications qui ont permis d’en connaître la composition et de préciser le statut de nombreuses espèces. Cet article apporte des informations complémentaires sur l’habitat et l’abondance actuelle de 55 espèces, notamment celles qui composent le peuplement des milieux ouverts, herbacés et buissonnants. Les données de base obtenues sur les oiseaux et leur habitat grâce à 150 points d’écoute (méthode des E.F.P., Echantillonnage Fréquentiel Progressif) ont été traitées par analyse multivariée (AFC-VI, Analyse Factorielle des Correspondances par rapport à des Variables Instrumentales). Les résultats permettent de définir 6 groupes d’espèces représentatifs des différentes formations végétales échantillonnées et de caractériser leur habitat dans le gradient végétal étudié, allant des pelouses nues aux landes et à la forêt de pins. Un inventaire de l’avifaune nicheuse est dressé pour les trois formations végétales dominantes du Causse Méjean : les pelouses (16 espèces), les landes (32 espèces) et les forêts de pins (31 espèces). La valeur patrimoniale de ces trois milieux est analysée aux regards des critères retenus par Rocamora et Yeatman-Berthelot (1999). Il en ressort que les pelouses, avec 14 espèces patrimoniales et les landes avec 18 espèces sont des milieux beaucoup plus riches que la forêt de pins (une seule espèce). Une comparaison de la composition actuelle et passée de l’avifaune nicheuse du Causse est conduite grâce aux publications antérieures et à des données inédites. Des phénomènes d’extinction pour 3 espèces (la Perdrix grise Perdix perdix, l’Outarde canepetière Tetrax tetrax, la Pie-grièche à tête rousse Lanius senator), mais aussi d’expansion et de colonisation pour 6 autres espèces parmi lesquelles la Chouette de Tengmalm Aegolius funereus, le Pic noir Dryocopus martius, la Tourterelle turque Streptopelia decaocto et l’Étourneau sansonnet Stumus vidgaris, sont mis en évidence et commentés. Enfin, l’avenir de l’avifaune nicheuse du Causse est discuté en relation d’une part avec les importantes plantations en Pin noir Pinus nigra de la première moitié du XXe siècle et d’autre part avec l’évolution actuelle des pratiques pastorales. Celles-ci conduisent globalement à une régression des pelouses steppiques auparavant maintenues par une pression de pâturage importante. C’est ainsi que plus de 5 600 ha de pelouses ont disparu entre 1948 et 1989 de la moitié est du Causse Méjean (Causse nu) au profit des landes et des forêts.Fonderflick Jocelyn, Thévenot Michel, Destre Rémi. Le peuplement d’oiseaux du Causse Méjean (Lozère, France) : état actuel, évolution historique et perspectives d’avenir. In: Revue d'Écologie (La Terre et La Vie), tome 56, n°2, 2001. pp. 173-192

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Avifauna trends following changes in a Mediterranean upland pastoral system

Understanding the relationships between biodiversity and land-use is a key element for the development of effective conservation strategies. We studied a mid-altitude steppe-like area of Southern France, the Causse de Sauveterre, that has been grazed for many centuries. The decrease of human population during the 20th century, particularly since the end of 2nd World War, and the ongoing changes in agricultural practices may have dramatic effects on many biodiversity components of these landscapes. Our study assesses landscape change and modifications in bird community composition through the repeated sampling of a network of sites after an interval of 15-19 years. We paid particular attention to the possible consequences of recent changes in agricultural policy on these communities. Landscape changes were studied through remote sensing, and bird community and vegetation changes by field sampling on 183 sites. Correspondence Analysis showed an overall trend towards landscape closure. This results in a decrease of open-habitat species that are fairly rare in Europe (e.g. Tawny Pipit Anthus campestris, Linnet Carduelis cannabina, Ortolan Bunting Emberiza hortulana), and in an increase of common forest species (e.g. the Common Chiffchaff Phylloscopus collybita and Winter Wren Troglodytes troglodytes). Although most of the avifauna changes seem to be explained by local landscape changes, the decrease of certain bird species as Bullfinch Pyrrhula pyrrhula and Citril Finch Serinus citrinella may result from population changes at larger scales. The current closure of the landscape represents a threat for several steppe species whose conservation status is unfavourable in Europe. This closure does not result from a decrease in human population and/or in flock number, as observed in many Mediterranean hinterlands. It rather results from a shift from a former extensive pastoralism, where sheep grazed steppe-like grasslands (rangeland grazing), towards a more intensive herding that use hay and cereal foodstocks cultivated on the more productive areas of the farms. To alleviate the observed trends, subsidies should be oriented towards the compensation of a possible loss of income resulting from the maintenance of the traditional extensive pastoralism

Managing agricultural change for biodiversity conservation in a Mediterranean upland

In Europe, land use changes follow public policies, and particularly the Common Agricultural Policy. To predict the effect of policies on agricultural practices, landscape, and ultimately biodiversity, requires understanding of the interactions between social, economic and ecological dynamics at regional scale. We studied by means of prospective scenarios the possible effects of agricultural changes on biodiversity in a Mediterranean upland. This area is characterised by extensive grasslands that have been maintained for centuries by agriculture and are now threatened by tree and shrub encroachment. We built four scenarios that describe possible changes in agricultural EU policies by 2030. We selected 15 bird species on the basis of a high natural heritage responsibility of the study area for these species and 45 plant species on the same basis plus local rarity and habitat vulnerability. We analysed how these species were affected by the four scenarios by considering changes in their habitats. For each scenario, we analysed the driving forces that determine land use changes. Landscape dynamics was modelled with a Generalised Linear Model combining environmental and land use factors. Most of the 60 selected species depend on open habitats. Only the scenario where public support was only granted if it provided environmental services had a positive impact on open habitats and their associated biodiversity. This 'natural heritage' scenario was also rated positively by local stakeholders. This approach sheds light on the interest of inter/transdisciplinary studies, scenarios, and stakeholder involvement in the definition of public policies for biodiversity conservation

Suivi des tendances de l'occupation de l'espace et de l'abondance des chenilles d'Apollon Parnassius apollo lozerae dans le Parc national des Cévennes en lien avec le changement climatique.: Rapport méthodologique, protocole version 1

L’Apollon (Parnassius apollo) exige des espaces ouverts, pelouses ou éboulis ensoleillés entre 600 et 2 500 mètres d’altitude. Ce papillon a vu ses populations françaises régresser, voire disparaître sur certaines parties du territoire national ces dernières décennies, potentiellement en raison des changements climatiques. L’évolution des pratiques pastorales pourrait également expliquer une partie de ce déclin, notamment sur les causses méridionaux. Une étude-pilote a été lancée en 2018 sur plusieurs causses du Parc national des Cévennes. Elle se base sur un dénombrement des chenilles d’Apollon au cours de trois passages réalisés en mai sur 168 dalles à orpin. A partir des données collectées, nous avons estimé une probabilité d’occupation des dalles par les chenilles de 0,46 [IC95% 0,39-0,54] par une modélisation en site-occupancy et une abondance moyenne par dalle de 0,71 [IC95% 0,43-1,1] par des modèles en N-mixture. La probabilité de détection moyenne de l’espèce est de 0,77 [IC95% 0,71-0,83]. Elle augmente avec l’avancée de leur stade de développement. Sur la base de ces résultats, nous fournissons plusieurs recommandations pour le déploiement de ce protocole dans les prochaines années sur les causses du Parc national des Cévennes. Il permettra ainsi de renseigner les changements de répartition et d’abondance de cette espèce sur le long terme en lien avec le changement climatique. Certaines mesures pour maintenir les populations relictuelles pourraient être encouragées. Ce document justifie les choix méthodologiques réalisés et propose un cadre pour le recueil, le stockage et l’analyse des données. Il fixe également les moyens logistiques nécessaires à la mise en oeuvre du protocole proposé. L’ensemble de ces informations garantit la pérennité de l’étude sur le long terme. L’élaboration de ce protocole s’inscrit dans le cadre d’une coopération entre l’Office Français de la Biodiversité et le Centre d’Ecologie Fonctionnelle et Evolutive. Cette coopération lancée en 2018 vise à mettre en place un appui méthodologique et statistique pour un transfert continu de compétences, de savoirs, de méthodes, vers les gestionnaires des parcs nationaux et des autres aires protégées