Delmas, Chloe , Escaravage, Nathalie , Pornon, André .
The effect of fragmentation on pollinator failure and the potential rescue of flowering communities.
It has been largely shown that habitat fragmentation can affect plant reproduction by pollen limitation through a breakdown of plant-pollinator mutualisms. However, other studies yield contradictory results and additional experiments are required to test whether plant reproduction limitations may be generalized to all plant species and habitat types. We examined the pollination and subsequent reproductive output of 119 Rhododendron ferrugineum L. (Ericaceae) shrubs growing in 32 Pyrenean populations (France) varying greatly in structure, size, and isolation. We recorded the abundance and diversity of pollinators foraging on R. ferrugineum and meadow community flowers. Flower emasculations and supplemented pollinations were performed to quantify R. ferrugineum reproductive limitations, i.e. pollinator failure. The abundance of R. ferrugineum pollinators (mainly Hymenoptera) declined with increasing fragmentation. However, floral display in R. ferrugineum populations decreased much faster than pollinator visits. Pollinator failure was significantly higher in isolated individuals. Even isolated shrubs covering less than 5% of large flowering meadows received 50% of total community pollinator visits. These results show that flowering meadows provide additional resources to pollinators and allow isolated R. ferrugineum individuals to continue to receive some pollinator visitations and subsequent reproductive output. Indeed, emasculated flowers from highly fragmented populations produced only half as many seeds as those from non fragmented populations. Our study included both the fragmentation effect and observations on plant-pollinator interactions at the community level. We emphasized that plant-pollinator response to fragmentation was dependent on both intra- and inter-specific plant interactions and the biodiversity in surrounding meadows have the potential to reduce the negative impact of fragmentation.
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1 - Université Paul Sabatier/CNRS 5174 , Lab Evolution et Diversité Biologique , 118 route de Narbonne , Bâtiment 4R3 , Toulouse, 31062, France
2 - Université Paul Sabatier / CNRS 5174 , Lab Evolution et Diversité Biologique, 118 route de Narbonne, Bâtiment 4R3 , Toulouse, 31062, France
Presentation Type: Oral Paper:Papers for Topics
Location: 553A/Convention Center
Date: Monday, August 2nd, 2010
Time: 2:45 PM