HAL Id: hal-02791658
https://hal.inrae.fr/hal-02791658
Submitted on 5 Jun 2020
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Contribution of wooded habitats to wild bee richness and pollen resources in agricultural landscapes
Justine Rivers-Moore, Annie Ouin, Aude Vialatte, Emilie Andrieu
To cite this version:
Justine Rivers-Moore, Annie Ouin, Aude Vialatte, Emilie Andrieu. Contribution of wooded habitats to wild bee richness and pollen resources in agricultural landscapes. World Congress on Agroforestry (WCA), May 2019, Montpellier, France. 1 p., 2019. �hal-02791658�
Contribution of wooded habitats to wild bee richness and pollen resources in agricultural landscapes
Justine RIVERS-MOORE 1,2 , Emilie ANDRIEU 1,2 , Aude VIALATTE 1,2 , Annie OUIN 1,2
1 DYNAFOR, Université de Toulouse, INRA, Castanet-Tolosan, France
2 LTSER Zone Atelier « PYRÉNÉES GARONNE », 31320 Auzeville-Tolosane, France
Context
• Wild bees (Hymenoptera), pollinators of entomophilous crops, are threatened by landscape simplification and loss of floral resources.
• Grasslands provide resources to pollinators (nectar, pollen, nest sites).
• There is a lack of knowledge about floral resource supplies provided by wooded semi-natural habitats (SNH) present in agricultural landscapes.
Study site
LTSER « Vallées et Côteaux de Gascogne ». 50 km South of
Toulouse, France.
Small forests, permanent grasslands and cropfields.
Experimental design and analyses Results
Discussion & perspectives
30 landscapes (selected on a gradient of % woods and % grasslands).
100 m / 10min May & June 2016
CR = Consumption Rate of each pollen species in the survey
PA = Pollen Availability of each pollen species in the pool of landscapes
𝑫 𝒊 = 𝑪𝑹 𝒊 − 𝑷𝑨 𝒊
𝑪𝑹 𝒊 + 𝑷𝑨 𝒊 − 𝟐(𝑪𝑹 𝒊 × 𝑷𝑨 𝒊 )
Aknowledgements : D. Genoud, R. Rudelle, J. Villenave-Chasset, A. Chemin, C. Bataillon, A. Dupuis, J. Willm, P. Caniot. Justine Rivers-Moore’s PhD is funded by the Fondation de France.
Aim of this study: To evaluate pollen supply of SNH in wooded habitats (forest edges and hedgerows) and herbaceous habitats (grasslands) for wild bees.
Toulouse Study site
Bee hunting
Botanical survey
Pollen
determination
(for more abondant bee species (N>4))
Bee
determination
Jacobs’s selection index of each species i:
529 wild bees of 77 species
462 pollen samples of 55 plant species – on 28 bee species
28% of pollen species found on bees are
found only in wooded habitats (woodland edges and hedgerows ) in the
botanical surveys.
Forest edge N=24
Grassland N=29
Hedgerow N=30
Herbaceous + wooded habitats
30 sp Wooded
habitats 15 sp Grasslands
6 sp
Crops 4 sp
Pollen species origin in the botanical survey
Grasslands 19 sp Herbaceous +
wooded habitats
26 sp
Hedgerows 8 sp
Forest edges 16 sp
Both 8 sp Wooded
habitats 32 sp
Bee species habitats of capture
Jacobs’s selection index of the pollen species found on wild bees in the study site
Grasslands
2 sp
Wooded habitats
7 sp Herbaceous
+ wooded habitats
12 sp Crops
1 sp
Habitat of capture of positive Jacobs’s index pollen species
Grasslands 4 sp
Wooded habitats 6 sp
Herbaceous + wooded
habitats 17 sp
Habitat of capture of negative Jacobs’s index pollen species
Vitis vinifera Lotus corniculatus
Carduus sp
Raphanus raphanistrum
Daucus carota
Cerastium fontanum
Jacobs’s selection index allows comparing for a particular species
its consumption frequency to its availability in the study site.
Botanical surveys have been done in May for grasslands and in June for wooded habitats. Flowering of species changes across season may influence Jacobs’s selection index.
Some pollen species found on bees didn’t appear in the botanical surveys. These species are mainly crop-specific (6 species).
Perspectives :
-To evaluate pollen supply at landscape scale (LP index).
-To use botanical species abundance (instead of presence/absence).
Over-selected species
Under-selected species
Clematis vitalba
Mélan ie R O Y
D. Genoud
