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Dynafor au congrès international de la SFE²

Dynafor a fortement participé à la conférence SFE² GFO Joint meeting, International Conference on Ecological Sciences -

Avec plus de 1000 sur place et d'autres en ligne, la conférence a été un moment fort pour les communautés d'écologie française et allemande. Les présentations devraient être disponibles prochainement en rediffusion vidéo sur le site de la conférence.

Il y a eu 5 communications orales faites par des dynaforien.nes dans plusieurs sessions de ce colloque, dont une session dédiée à l'écologie des paysages, et 4 communications dont des Dynaforien.nes étaient co-auteurs. En voici les résumés de présentation:

1°) The new assets of landscape ecology in the face of global challenges

Marc DECONCHAT 1 , Cécile ALBERT 2 , Audrey ALIGNIER 3 , Stéphanie AVIRON 3 , Laurent BERGES 4 , Sébastien BONTHOUX 5 , Solène CROCI 6 , Aude ERNOULT 6 , Cendrine MONY 6 , Clélia SIRAMI 1

1 Inrae - Castanet Tolosan (France), 2Cnrs - Marseille (France), 3 Inrae - Rennes (France), 4 Inrae - Grenoble (France), 5 Insa-Cvl - Blois (France), 6Univ Rennes1 - Rennes (France)

Abstract : In an ever-changing world threatened by multiple, wide-ranging and sometimes sudden crises, the ecological sciences need to assess how they can contribute to effectively addressing these emerging issues. Landscape ecology has evolved significantly in recent decades. Its concepts, methods, tools and results open new perspectives and are particularly relevant to address problems for which intermediate scales, such as landscapes, seem to be the most appropriate for action. Moreover, landscape ecology can be mobilized to address a wide range of interrelated issues such as global health, climate change, biodiversity conservation and food security. Spatio-temporal heterogeneity, at the heart of landscape ecology concepts, is now seen as a way of adapting to global changes. Remote sensing data and methods could also provide useful information for analyzing evolution trajectories and steering the socio-ecosystems. Developments in spatial modelling are contributing to society debates with increasingly refined scenarios of expected or desirable changes to guide realistic and fair transitions. However, the production of new, finer and more precise data and knowledge is not always enough to trigger the necessary changes and to anticipate future crises. Interactions between scientists and territorial stakeholders are often crucial to move from knowledge development to action. Because landscapes are socio-ecological systems, the social dimension of landscape analysis, such as developed through european landscape ecology is an important axis in which a development of tools and concepts is urgently needed. This presentation urges scientists to take up these issues, to develop transdisciplinary research questions and methods and to disseminate their results widely to accelerate the necessary transitions.

2°) Searching for optimal sampling design for landscape-scale biodiversity surveys

F. Laroche 1

1 Umr 1201 Dynafor University Of Toulouse Inrae Inpt Ei Purpan Castanet-Tolosan - Toulouse (France)

Abstract : Evaluating the spatial autocorrelation in species distribution is a necessary step for many applied ecological questions at landscape scale, like building a reserve network or implementing an efficient monitoring program. Autocorrelation range can be inferred from spatial sampling. However, there exists a trade-off between estimating of the autocorrelation range of a species distribution and estimating trends in the mean species abundance or occupancy among sites, which is also a question of interest in many studies. For instance, the random sampling design is a good heuristic to estimate autocorrelation range, as pairwise distances among samples cover a wide array of possible autocorrelation ranges. By contrast, the grid design is a better choice for estimating trends of the mean among sites as it eliminates small pairwise distances prone to pseudo-replication. Hybrid strategies mixing random and grid are thought to yield a polyvalent design able to cope with both conflicting objectives. Yet, fractal sampling designs could also show such intermediary performance, for it preserves some regularities associated to grid, but also contains various spatial scales browsing a wide array of possible autocorrelation ranges. Here, we studied for which questions fractal or hybrid design could be advantageous sampling strategies. We used optimal design theory to compare the accuracy of random, grid, hybrid and fractal designs at estimating mean and autocorrelation range of a field of values. We retrieved that the hybrid strategy is a Pareto-optimal intermediary strategy between grid and random designs. Fractal designs showed distinct properties : they performed better than both random and grid designs for estimating small autocorrelation ranges, but worse than other designs for estimating intermediate aurocorrelation ranges and mean value of a traget field. Overall, hybrid designs seemed appropriate when looking for a polyvalent design. Fractal designs could constitute a valuable alternative when specifically aiming at estimating of small autocorrelation ranges while tolerating a cost on other objectives. Thus, the interest of fractal designs appeared quite circumscribed in our study. More generally, harbouring explicit spatial scales may be a clear advantage of fractal designs for the analysis of biodiversity patterns when distinct biological processes occur at distinct spatial scales.

3°) How landscape heterogeneities could contribute to wild bees diversity and pollination in agricultural landscapes

Symposium: Diversification of agricultural landscapes to promote pollinator biodiversity and pollination service delivery

Ouin, A.1,x, Carrié, R., Desaegher, J., Rivers-Moore, J. 1,x, Sheeren, D. 1,x, Sirami, C. 1,x, Vialatte, A. 1,x, Andrieu, E. 1,x

1, UMR DYNAFOR, INRAE / Toulouse INP, Auzeville Tolosane, France

2, Center for environnemental and climate science, Lund University, Sweden

3, INRAE, UR 406 Abeilles et Environnement, Avignon, France

x, LTSER ZA PYGAR, Université de Toulouse, Auzeville Tolosane, France

Landscape heterogeneity support multiple ecosystem services, including the pollination of crops and wild flowers. In the Long Term Socio-Ecological Research (LTSER) site of Vallées et Coteaux de Gascogne (VCG), which is part of the LTSER platform ZA PYGAR located in south-west France, local features of the VCG and social systems have interacted with global drivers (like CAP) and lead to the maintenance of a high level of landscape heterogeneity. We show how the different components of landscape heterogeneity : composition (with a focus on wooded semi-natural habitats), configuration but also heterogeneity of practices contribute to wild bees diversity and potential of pollination. The modelling of pollinators and pollination allow us to propose some guidelines about the location of flower resource patches to ensure crop pollination.

4°) Crop diversity in the landscape favors bats and biological control of some pests

A. Tortosa 1 , B. Giffard 2 , L. Barbaro 1, 3, J. Froidevaux 3, 4, S. Ladet 1 , J. Delhommel 1 , A. Vialatte 1

1 Université De Toulouse, Inrae, Dynafor - Auzeville-Tolosane (France), 2Bordeaux Sciences Agro, Inrae, Isvv, Save - Villenave D'ornon (France), 3CESCO, Muséum national d'Histoire naturelle, CNRS, Sorbonne University - Paris/concarneau (France), 4University of Stirling, Biological and Environmental Sciences, Faculty of Natural Sciences - Stirling (United Kingdom)

Abstract : Agricultural landscapes mixing crop types can support higher biological pest control, while contributing to maintain farmland biodiversity. In addition to their status of protected species, bats have been recently shown to be efficient predators of many agricultural and forest pests. In our study, we investigated how diverse agricultural landscapes could promote bat richness, activity and biological pest control. We hypothesised that resource continuity may be ensured in diverse landscapes combining maize, vineyards and pine plantations, which are major crops of South-western France. Indeed, flight peaks of three associated moth pests follow one another in time and are known to be prey of several insectivorous bats. We therefore evaluated whether diverse landscapes with all 3 crops (maize, vineyard and pine, with the proportion of semi-natural habitats controlled) affect bat communities and their biological control activity, by comparing them with simplified landscapes dominated by only one of the three crops. Our study involved 37 landscapes (vineyards-, maize-, pine plantations-dominated landscapes and diverse landscapes) where abundance of the three lepidopteran pests were measured with specific pheromone baited-traps according to their first generation flight peak. Alternative preys were estimated with food traps. Bat activity was recorded two consecutive nights with passive detectors. Finally, specific damages were observed. We found that diverse landscapes have positive effects on bat species richness and activity. We also showed that grapevines and pine plantations benefit from a diverse landscape from the point of view of controlling their main pests by bats. Maize-dominated landscapes showed contrasting results, pest abundances and damage were positively related to bat richness and activity; assessing the actual efficiency of their biological control would require longer-term investigations. In addition, more diverse landscapes benefit to a large range of bat species and especially for species of conservation concern activity. This work highlights potential win-win strategies between differ