Tourism in protected areas can threaten wild populations: from individual response to population viability of the chough Pyrrhocorax pyrrhocorax

International audienceMany protected areas are now faced with increasing pressure from visitors and tourism development. There is thus an urgent need for conservation biologists to evaluate the full impact of human disturbance not only on individual responses but also on the viability of protected populations so that relevant management measures can be proposed. We studied the impact of tourism on the rare and endangered chough Pyrrhocorax pyrrhocorax on a protected french island to assess the relationship between visitor pressure, bird individual behavior and fitness, and population viability. During 8 years, we monitored foraging behavior and estimated monthly juvenile survival using mark-recapture data. Population viability was examined under different tourism scenarios, using a stochastic individual-based model that incorporated the impact of visitor numbers on juvenile survival. In summer, the foraging probability of choughs was negatively correlated with the number of visitors. As a result, the time allocated to foraging during peak tourist season, adjusted to day length and prey availability, was 50% lower than expected. Juvenile survival rates were lowest in August, the peak tourist season, and varied significantly across years. August survival rate and therefore annual survival were negatively correlated with the number of visitors on the island in August and, except for a minor negative effect of rainfall, were not influenced by other environmental variables. Sthochastic simulations predicted a low probability of extinction of the protected population if the number of visitors remains constant in the future. However, short-term viability would be dramatically reduced if the current rate of increase in visitor numbers is maintained. We show that a relatively minor human-induced disturbance (e.g. scaring individuals away) has dramatic effects on population viability in a protected area, even when breeding individuals are not directly affected. This suggests that the full impact of tourism in protected areas may be overlooked, and has direct consequences for the assessment of sustainable levels of human distrurbance and the design of quantitative management options compatible with tourist activities in protected areas. We specifically emphasize the need for more integrative approaches combining research at individual and population levels

Conséquences sur l'avifaune terrestre de l'île de Trielen (réserve naturelle d'Iroise, Bretagne) de l'éradication du Rat surmulot (Rattus norvegicus)

The Norwegian Rat (Rattus norvegicus) invaded the Trielen Island (Iroise Natural Reserve, Brittany, France) during the beginning of the XXth century and was eradicated in 1996. Breeding pairs of all terrestrial bird species were censused annually, from 1996 before the eradication operation to 2001. None of the 7 occasional breeding species (two being a priori exposed to Norwegian Rat predation) established as a regular breeder after the eradication operation. On the other hand, numbers of breeding pairs increased by a factor of 1.7 to 2.0 for the Dunnock (Prunella modularis), 2.2 to 2.7 for the Wren (Troglodytes troglodytes), and 5.5 to 7.0 for the Rock Pipit (Anthus petrosus). Many biological facts converged to identify the rodent disappearance as the major driving factor of these increases. This Norwegian Rat eradication was particularly pertinent as a biological conservation operation, because of its positive effect on the local Rock Pipit (Anthus petrosus) population as the French coast hosts near 50 % of the subspecies petrosus world population. The 2001 Trielen Island abundance index (26 to 46 breeding pairs per coastal km) was among the highest known ones for that species. The large and quick increase following the disappearance of the Norwegian Rat showed the high sensibility of the Rock Pipit to mammalian predationL'inventaire du nombre de couples nicheurs du peuplement d'oiseaux terrestres de l'île de Trielen (Réserve Naturelle d'Iroise, Bretagne) a été réalisé annuellement entre 1996 et 2001, suite à l'éradication, en 1996, de la population du Rat surmulot (Rattus norvegicus) installée sur l'île depuis le début du XXe siècle. La disparition du rongeur ne s'est accompagnée, ni d'apparition où de disparition d'espèces, ni de la pérennisation de la reproduction de 7 espèces réputées nicher occasionnellement sur le site, deux d'entre elles étant a priori vulnérables au comportement de prédation exercé par le Surmulot. Les effectifs de couples nicheurs de l'Accenteur mouchet (Prunella modularis), du Troglodyte mignon (Troglodytes troglodytes), et du Pipit maritime (Anthus petrosus), espèces a priori toutes vulnérables au comportement de prédation du rongeur, ont été multipliés respectivement par un facteur de 1,7 à 2,0, de 2,2 à 2,7 et de 5,5 à 7,0. Les faits convergent pour désigner l'éradication du rongeur comme le facteur de causalité majeur de ces augmentations. Cette opération qui relève de la biologie de la conservation est particulièrement pertinente vis-à-vis du Pipit maritime dont le linéaire côtier français accueille près de 50 % de la population mondiale de la sous-espèce petrosus. L'indice d'abondance relevé en 2001 sur l'île de Trielen (26 à 46 couples nicheurs par km de linéaire côtier) compte parmi les plus élevés connus à ce jour pour l'espèce. Son fort accroissement, suite à la disparition du Surmulot, témoigne de la sensibilité de l'espèce à la prédation mammalienne

DIET AND FUELLING OF THE GLOBALLY THREATENED AQUATIC WARBLER ACROCEPHALUS 1 PALUDICOLA AT AUTUMN MIGRATION STOPOVER AS COMPARED WITH TWO CONGENERS

International audienceThe effective conservation of aquatic warbler (Acrocephalus paludicola), one of the most threatened western Palaearctic migratory passerines, requires good knowledge of its ecological needs at stopover sites. In particular, identifying its diet, which controls the accumulation of fat reserves during migration, facilitates the selection and management of adequately protected areas. Further key information includes the relationship between prey species abundance and habitats of aquatic warbler on stopover. We performed standardised mist-netting in the Audierne marshes (western France) during 12 years, which resulted in the capture of 1,200 aquatic warblers, and provided measurements for mass gain and the collection of faeces to infer the birds’ diet. Invertebrate sampling was carried out in the three main Audierne marshhabitats(reedbed, fen mire and meadow). In order to go beyond prey digestibility bias,we also studied two closely related Acrocephalusspecies, present at migration stopover sites during the same period. We found that the diet composition of aquatic warbler observed at migration stopover sites is based on large-sizedprey (Odonata, Orthoptera, Lepidoptera).Likes edge warblers, aquatic warblers put on weight during migration stopovers (daily mass gain =0.38g). This increase in weight suggests that the aquatic warblers might have adopted a strategy for long-distance migration with few stopovers only. Due to great differences in diet, conservation management for the threatened aquatic warbler at stopover sites should not rely on existing knowledge abouts edge and reed warblers. Similarities in the diet of aquatic warbler between nesting areas and migration stopover areas and the relationship between habitat and prey abundance suggest that fen mires play an important role in the quality of the for aging habitat at stopover site

Plant and spider communities benefit differently from the presence of planted hedgerows in highway verges

International audienceRoad verges should play a crucial role as a refuge for native flora and fauna in human dominated landscapes. However, the influence of construction choices, such as plantation of woody species, on the biodiversity supported by roadsides has received little attention, although the presence of hedgerows in roadsides is likely to enhance their role as a refuge, notably for woodland species. Using standardised methods, we assessed the impact of planted hedgerows on two taxonomic groups (plants and spiders) inhabiting highway verges within an intensive agricultural landscape. We examined community richness, taxonomic and functional composition in sites with and without planted hedgerows. At the site level, the response of plant and spider communities to the presence of planted hedgerows differed markedly: hedgerows were associated with significantly higher plant richness (higher α-diversity), but similar spider richness. Plant communities in sites without hedgerows appeared as a subset of communities in sites with hedgerows, whereas spider communities in non-planted sites were complementary to that of planted sites (increased β-diversity). The presence of planted hedgerows was also associated with increased taxonomic and functional trait diversity at the landscape level (γ-diversity), through an increased β-diversity in both plants and spiders. Our results thus suggest that a mosaic of planted hedgerows and grassland habitats is crucial for the maintenance of biodiversity at a landscape scale. By providing information for road practitioners and policy makers regarding their potential impact on biodiversity, these results have important direct implications for the management of road networks

Applying trait-based community metrics of relevance to conservation for understanding community patterns of farmland birds in Northwest Russia

Use of community trait-based metrics has been increasingly implemented for achieving an integrated view of biodiversity in conservation planning. We examined the extent, to which the use of community metrics based on species traits reflecting plausible sensitivity to change would contribute to our understanding of landscape characteristics of importance to the conservation of farmland birds in a poorly studied region of Northwest Russia. We collected species data on farmland from 230 transects covering a total 215 km for each year of 2008, 2010 and 2011 and analysed them using generalised linear mixed modelling. We derived community indices from species traits of habitat specialisation, trophic position, relative brain size and body mass. By relating these indices to the numbers of all species regarded farmland and Species of European Conservation Concern (SPEC), and by analysing them against the type of field and occurrence in typical non-cropped landscape elements, we showed consistent, albeit weak, congruence among the taxonomic and trait-based community descriptors. All community descriptors had their lowest estimates in arable fields. Community specialisation was the highest in open abandoned fields, which confirms the importance of such fields as refuges for regionally specialised species. Pastures were characterised by the highest community biomass, which indicates a particularly good resource base. Presence of ditches, of all non-cropped elements, had the strongest positive relationship with the community descriptors. The SPEC number strongly correlated with the overall species richness of farmland birds. A relatively weak congruence between taxonomic and trait-based community descriptors highlights their cornplementarity in understanding the underlying mechanisms of community changes. However, similarity in patterns among field types means that, under the current level of production in the region, accounting for the species richness of farmland birds seems to be sufficient to rapidly assess community sensitivity to agricultural change.Peer reviewe

A species-level trait dataset of bats in Europe and beyond

Knowledge of species' functional traits is essential for understanding biodiversity patterns, predicting the impacts of global environmental changes, and assessing the efficiency of conservation measures. Bats are major components of mammalian diversity and occupy a variety of ecological niches and geographic distributions. However, an extensive compilation of their functional traits and ecological attributes is still missing. Here we present EuroBatrait 1.0, the most comprehensive and up-to-date trait dataset covering 47 European bat species. The dataset includes data on 118 traits including genetic composition, physiology, morphology, acoustic signature, climatic associations, foraging habitat, roost type, diet, spatial behaviour, life history, pathogens, phenology, and distribution. We compiled the bat trait data obtained from three main sources: (i) a systematic literature and dataset search, (ii) unpublished data from European bat experts, and (iii) observations from large-scale monitoring programs. EuroBatrait is designed to provide an important data source for comparative and trait-based analyses at the species or community level. the dataset also exposes knowledge gaps in species, geographic and trait coverage, highlighting priorities for future data collection.Additional co-authors: Lisette Cantú-Salazar, Dina K. N. Dechmann, Tiphaine Devaux, Katrine Eldegard, Sasan Fereidouni, Joanna Furmankiewicz, Daniela Hamidovic, Davina L. Hill, Carlos Ibáñez, Jean-François Julien, Javier Juste, Peter Kaňuch, Carmi Korine, Alexis Laforge, Gaëlle Legras, Camille Leroux, Grzegorz Lesiński, Léa Mariton, Julie Marmet, Vanessa A. Mata, Clare M. Mifsud, Victoria Nistreanu, Roberto Novella-Fernandez, Hugo Rebelo, Niamh Roche, Charlotte Roemer, Ireneusz Ruczyński, Rune Sørås, Marcel Uhrin, Adriana Vella, Christian C. Voigt & Orly Razgou

Biotic predictors complement models of bat and bird responses to climate and tree diversity in European forests

Bats and birds are key providers of ecosystem services in forests. How climate and habitat jointly shape their communities is well studied, but whether biotic predictors from other trophic levels may improve bird and bat diversity models is less known, especially across large bioclimatic gradients. Here, we achieved multi-taxa surveys in 209 mature forests replicated in six European countries from Spain to Finland, to investigate the importance of biotic predictors (i.e., the abundance or activity of defoliating insects, spiders, earthworms and wild ungulates) for bat and bird taxonomic and functional diversity. We found that 9 out of 12 bird and bat diversity metrics were best explained when biotic factors were added to models including climate and habitat variables, with a mean gain in explained variance of 38% for birds and 15% for bats. Tree functional diversity was the most important habitat predictor for birds, while bats responded more to understorey structure. The best biotic predictors for birds were spider abundance and defoliating insect activity, while only bat functional evenness responded positively to insect activity. Accounting for potential biotic interactions between bats, birds and other taxa of lower trophic levels will help to understand how environmental changes along large biogeographical gradients affect higher-level predator diversity in forest ecosystems

Relating Habitat and Climatic Niches in Birds

Predicting species' responses to the combined effects of habitat and climate changes has become a major challenge in ecology and conservation biology. However, the effects of climatic and habitat gradients on species distributions have generally been considered separately. Here, we explore the relationships between the habitat and thermal dimensions of the ecological niche in European common birds. Using data from the French Breeding Bird Survey, a large-scale bird monitoring program, we correlated the habitat and thermal positions and breadths of 74 bird species, controlling for life history traits and phylogeny. We found that cold climate species tend to have niche positions in closed habitats, as expected by the conjunction of the biogeographic history of birds' habitats, and their current continent-scale gradients. We also report a positive correlation between thermal and habitat niche breadths, a pattern consistent with macroecological predictions concerning the processes shaping species' distributions. Our results suggest that the relationships between the climatic and habitat components of the niche have to be taken into account to understand and predict changes in species' distributions

Dynamique et répartition de la diversité (contribution pour une meilleure intégration dans les actions de conservation)

La compréhension des processus contrôlant la distribution spatiale et temporelle de la diversité est un enjeu majeur dans le contexte actuel d érosion de la biodiversité, pour évaluer l'impact des facteurs anthropiques et proposer des mesures efficaces de conservation. Dans cette thèse, je me suis intéressée à l identification des mécanismes contrôlant différentes composantes de la biodiversité (populations et communautés, taxonomique et fonctionnelle) à l aide de divers outils de quantification de la biodiversité, avec deux objectifs : (1) mieux comprendre l influence relative des processus déterministes et stochastiques dans l assemblage des communautés et (2) proposer des stratégies de conservation dans deux types d espaces : les zones protégées (mer d Iroise) et la nature ordinaire (dépendances vertes des infrastructures autoroutières). Mes résultats montrent des patrons de diversité contrastés selon que l on s intéresse à la diversité taxonomique ou fonctionnelle (richesse spécifique vs. spécialisation des espèces par exemple), ou selon le groupe taxonomique considéré (plantes vs. araignées par exemple). Ceci a des implications directes pour identifier les mécanismes sous-jacents, mais aussi en termes de conservation. Je montre ainsi que, si les dépendances autoroutières (mares et talus) peuvent jouer un rôle fonctionnel pour le maintien de la biodiversité, ce rôle dépend des choix de gestion favorisant la diversité spatiale au sein de ces espaces (plantations de haies par exemple). Enfin, mes résultats soulignent l importance de prendre en compte les aspects dynamiques de la biodiversité pour affiner les recommandations de gestion. Dans les espaces naturels protégés (mer d Iroise), nous avons observé un impact des activités humaines sur la biodiversité (fréquentation touristique, déprise agricole), susceptible d aller à l encontre des objectifs de conservation fixés. Nous montrons cependant que certaines pratiques de gestion (gestion concertée des flux touristiques, éradication d espèces introduites), peuvent favoriser le maintien des espèces et écosystèmes protégés.In the current context of biodiversity erosion, understanding processes controlling spatial and temporal distribution of diversity is a major challenge if we are to evaluate the impact of anthropogenic factors and propose efficient conservation policies. In this thesis, I focused on identifying mechanisms controlling different biodiversity components (populations and communities, taxonomic and functional diversity), using various tools to quantify biodiversity. The two aims were to: (1) improve our understanding of the relative impact of deterministic and stochastic processes in community assembly and (2) propose conservation strategies for two types of areas: protected areas (Iroise sea) and wider countryside (highway verges). My results show contrasted diversity patterns, depending whether the focus is on taxonomic or functional diversity (e.g. specific richness vs. species specialisation), or depending upon the taxonomic group (e.g. plants vs. spiders). Those results have direct implications in identifying underlying mechanisms but also in terms of conservation. I show that, while highway verges (ponds and embankment) can play a functional part in maintaining biodiversity, this part mainly depends upon management choices enhancing spatial biodiversity within those areas (e.g. planting hedges). Finally, my results highlight the importance of taking into account the dynamic aspects of biodiversity to finetune management advices. In protected natural areas (Iroise sea), we have observed an impact of human activities on biodiversity (tourism, abandonment of farmlands) that can work against conservation objectives. However, we show that some management practices (concerted management of tourism, eradication of introduced species) can enhance the maintenance of protected species and ecosystems.PARIS-Museum Hist.Naturelle (751052304) / SudocSudocFranceF