Landscape heterogeneity as an ecological filter of species traits

International audienceLandscape heterogeneity is a major driver of biodiversity in agricultural areas and represents an important parameter in conservation strategies. However, most landscape ecology studies measure gamma diversity of a single habitat type, despite the assessment of multiple habitats at a landscape scale being more appropriate. This study aimed to determine the effects of landscape composition and spatial configuration on life-history trait distribution in carabid beetle and herbaceous plant communities. Here, we assessed the gamma diversity of carabid beetles and plants by sampling three dominant habitats (woody habitats, grasslands and crops) across 20 landscapes in western France. RLQ and Fourth Corner three-table analyses were used to assess the association of dispersal, phenology, reproduction and trophic level traits with landscape characteristics. Landscape composition and configuration were both significant in explaining functional composition. Carabid beetles and plants showed similar response regarding phenology, i.e. open landscapes were associated with earlier breeding species. Carabid beetle dispersal traits exhibited the strongest relationship with landscape structure; for instance, large and apterous species preferentially inhabited woody landscapes, whereas small and macropterous species preferentially inhabited open landscapes. Heavy seeded plant species dominated in intensified agricultural landscapes (high % crops), possibly due to the removal of weeds (which are usually lightweight seeded species). The results of this study emphasise the roles of landscape composition and configuration as ecological filters and the importance of preserving a range of landscape types to maintain functional biodiversity at regional scales

Ecologie du paysage : recherche et application à la gestion des territoires

Journée de rencontres « Ecologie et écosystèmes : comment ça marche ?

Ecologie du paysage : recherche et application à la gestion des territoires

Journée de rencontres « Ecologie et écosystèmes : comment ça marche ?

Connectivité biologique et connectivité structurale : comprendre les patrons de distribution des espèces à l’échelle régionale.

National audienc

Species richness of hedgerow habitats in changing agricultural landscapes: are alpha- and gamma-diversity shaped by the same factors?

Understanding the determinants of hedgerow plant diversity in agricultural landscapes remains a difficult task, because the potential drivers affect the complete range of biodiversity components (alpha to gamma diversity). We surveyed herbaceous plant communities (of a height\1.5 m) in 84 hedgerows in the Seine river floodplain of France. Two types of potential drivers for species richness, accounting for landscape mosaic and hedgerow network, were recorded at both hedgerow and site scale. The distribution of species richness through the components of alpha hedgerow diversity (i.e. the average diversity within a habitat) and gamma hedgerow diversity (i.e. the total diversity across habitats) were assessed using additive partitioning methods, while the relationship between species diversity and its potential landscape drivers at both scales was modeled using Generalized Additive Models. Our results indicated that gamma hedgerow diversity is explained by the heterogeneity of the landscape structure, which is correlated with the mosaic of agricultural land use. At this scale, intrinsic properties of the configuration of the hedgerow networks have a weak influence on species richness. Alpha hedgerow diversity is also explained by landscape variables, accounting for both the configuration of agricultural mosaics and hedgerow networks, but to a lesser extent. Time lags for species responses are shown at both scales, and for the two types of drivers. Extinction or colonization debt may be indicated at both scales, while the remnant effects of former practices may also be responsible for such patterns at a local scale. We suggest that hedgerow management should take the specific parameters of both scales into account. At a local scale, management actions should aim to decrease the influence of adjacent land use when the impact is negative, through the implementation of extended buffer zones, while at the landscape and farm scales, agri-environmental schemes should be dedicated to the conservation of specific agricultural land uses

Connectivité biologique et connectivité structurale : comprendre les patrons de distribution des espèces à l’échelle régionale.

National audienc

Les apports de l'histoire récente dans l'étude des relations paysages – biodiversité

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Les apports de l'histoire récente dans l'étude de la biodiversité-paysage (Le cas de la plaine alluviale de la basse vallée de Seine)

L'objectif de la thèse est de caractériser la dynamique des paysages de la plaine alluviale de la vallée de Seine depuis 1963 et d'en déduire les conséquences sur la biodiversité. L'approche est basée sur une analyse comparative multi-sites (échelle du kilomètre carré) visant à comprendre le rôle des patrons spatiaux actuels et passés sur certaines composantes de la biodiversité (structure et composition). Pour cela, deux modèles biologiques sont retenus : les oiseaux et les plantes vasculaires. Pour les plantes, deux habitats sont étudiés : les prairies et les haiesROUEN-BU Sciences (764512102) / SudocSudocFranceF

Advances in landscape ecology in urban areas.

International audienc