Resistance, emigration, or adaptation? Phylogeography and ecology of European alpine plant species
Till-Bottraud, Irène , Gaudeul, Myriam .
Reproductive biology and genetic structure in a conservation context. The example of Eryngium alpinum L. (Apiaceae).
Eryngium alpinum L. is an endangered Alpine plant growing in hayfields or avalanche corridors between 1500 and 2100 m a.s.l. Only 40 populations are known in France, and several have disappeared in the last 50 years. Most of the decline of the species is due to changes in land use or picking. Doubts remain about the long-term viability of the extant populations, especially with regard to the breeding system and genetic diversity.
We studied the reproductive biology of E. alpinum in a large population (Vallée du Fournel, France) using direct methods (flowering phenology, controlled crosses, fluorescent powder as pollen analogue, pollinators and pollination efficiency, primary seed dispersal) and compared the results to those obtained using indirect genetic methods (selfing rates using genotyping of progeny arrays, inbreeding depression, estimates of gene flow using genetic differentiation among populations) and to population structure data. Although the direct methods suggested a high potential selfing (important geitonogamous pollination), restricted gene flow (fluorescent powder transported over short distances, short seed dispersal distance) and a strong genetic structure within the population (restricted pollinator movement), the species is actually almost fully outcrossed, and no significant genetic differentiation could be detected over the 8 Km long valley, despite a noticeable habitat fragmentation due to forested areas between patches of open habitats where the species lives. This discrepancy could be explained by the longevity of the plants (over 20 year, and probably much more) and the recent recolonisation of the valley by forest that mostly occurred in the last 50 years. Our conclusions are that reproductive biology and genetic diversity and structure are important to understand the "functioning" of a population. However, they give information that operate at different time scales, and thus may not always be comparable.
1 - Laboratoire d'Ecologie Alpine, UMR CNRS 5553, Université Joseph Fourier, BP 53, Grenoble, 38041, France
Presentation Type: Symposium
Location: Ballroom 2 (Cliff Lodge)
Date: Wednesday, August 4th, 2004
Time: 1:15 PM