La pollinisation, un élément central du masting chez les chênes de région tempérée

Abstract : “Masting” designates a fruiting dynamics common in many perennial plants and characterized by seed production that is highly variable over the years and strongly synchronized among trees within populations. It is expected to strongly impact the population demography of seed consumers, and by cascade effect, the dynamics of forest ecosystems as a whole. Our lack of knowledge of the proximate causes of “masting” currently prevents any reliable prediction about the frequency and the intensity of fruiting, or about their consequences, under climate change. In this work I aimed to test the hypothesis that the pollination process is playing a key role in “masting” in temperate oak forests (Quercus petraea and Q. robur), which would make masting highly sensitive to climate change. By combining an empirical multi-site approach at large spatio-temporal scale in France and a theoretical approach based on a mechanistic model, I found that (i) fruiting dynamics depends on the annual amount of airborne pollen available for reproduction. This amount could be limited some years due to either low amounts of pollen produced at the population level, or harsh weather conditions affecting pollen release and aerial diffusion; (ii) pollen phenology is a key character of “masting”: pollen release takes place in early spring when weather conditions are typically unfavorable to pollination, which leads to frequent fruiting failure and explains thereby why mast years are rare and unpredictable; (iii) “masting” should become less stochastic in the upcoming decades because of the increase of spring temperatures, which should markedly influence the dynamics of seed consumers, and by cascading effect, oak forest regeneration
Document type :
Theses
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-02283651
Contributor : Abes Star <>
Submitted on : Wednesday, September 11, 2019 - 8:49:07 AM
Last modification on : Friday, September 13, 2019 - 1:20:10 AM

File

TH2019SCHERMERELIANE.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-02283651, version 1

Collections

Citation

Éliane Schermer. La pollinisation, un élément central du masting chez les chênes de région tempérée. Ecosystèmes. Université de Lyon, 2019. Français. ⟨NNT : 2019LYSE1081⟩. ⟨tel-02283651⟩

Share

Metrics

Record views

68

Files downloads

19