Génétique et Ecologie Evolutive
- Publication : 6 octobre 2011
Blue tit project: Evergreen and deciduous forests in Southern France and Corsica
In the Mediterranean region, blue tits (Cyanistes caeruleus) breed in habitats dominated by broad-leaf deciduous downy oak (Quercus humilis) and in habitats dominated by evergreen holm oak (Q. ilexI). The two oak habitat types generally differ in timing and amount of food available for breeding tits, which, as we have shown in our long-term blue tit study, has major consequences for the expression of life-history traits and reproductive success. The core of our blue tit project is very much centered around evolutionary consequences of this habitat heterogeneity.
Deciduous study site of Muro, in Corsica
Evergreen study sites of Arinelle and Pirio, in Corsica
Artemia: salterns in Southern France
Artemia are small crustacean found in hypersaline environments. Along the mediterreanean coest they can be found mainly in salterns. Our main field study is Aigues-Mortes saltern near Montpellier. The saltern is a unique ecosystem with a rich bird community and a specific aquatic community.
Aigues-Mortes saltern near Montpellier, Southern France
Aigues-Mortes fortified city seen from the saltern. The pink color is due to the bloom of Dunaliella salina, a unicellular algae which is major food source for artemias.
Flock of flamingos that are one of the main predators of artemias in the saltern.
From left to right: sampling cysts floating on the surface of water - sampling brine shrimp from the water column - dilling a core for cysts stored in the sediment.
Metacommunities of freshwater snails Martinique and Guadeloupe (West Indies)
For more than 10 years, we have performed yearly surveys of freshwater habitats and associated mollusc communities in Guadeloupe and Martinique (French Antilles). These communities are extremely dynamic, subject to both long-term and short-term changes. Long-term variation relies on environmental change (anthropization, climate change) but also, to a great extent, on successive waves of invasions by introduced species. Short-term variation is driven by natural cycles of habitat perturbations (dessication, floods) which result in an extinction-recolonization dynamics of local snail populations. We refer to these systems as metacommunities to describe, by analogy with metapopulations, both spatial fragmentation and temporal instability in these species assemblages.
Questions we ask
- what are the rules of coexistence within a set of species, and in what way are they dependent on species traits ? What processes maintain biodiversity within sites and in the whole metacommunity ? Are genetic diversity within species and community diversity (species richness) governed by similar processes ?
- What role does the evolution of life-history traits and mating systems play in the success or failure of an invasive species, and in the response of local species to invasions ?
Two sites among 250 surveyed yearly in Grande-Terre (Guadleoupe) and the neighbouring island of Marie-Galante : the Saint-Félix pond (left) and Grande-Ravine, a freshwater mangrove swamp.
All the habitats we survey in Martinique are rivers; yet they are very different from one another. From left to right, a stream within pristine forest habitat, an open and anthropised river, and an artificial urban channel. All these habitats have been reached by successive waves of invasion of snails of the Thiaridae family.
Below are some images of snail searching, sampling, counting ... and 10 minutes of rest at the beach.
Amphibian communities in Mediterranean ponds
Many amphibian communities throughout the globe have been deeply altered by a combination of direct human actions and indirect factors such as climate change, pathogens and invasive species. We have since a long time been maintaining a low-intensity monitoring of amphibian communities in a network of ponds around Montpellier, which shows a reassuring global stability in species abundance. We have also recently examined the evolutionary basis for polymorphism on breeding time in the parsley frog Pelodytes punctatus (PhD of Hélène Jourdan, supervised by Patrice David and Pierre-André Crochet; program currently interrupted). We currently focus on the ecological factors that allow or prevent the invasive marsh frog Pelophylax ridibundus invading the local green frog communities, currently the greatest threat to the conservation of the near-endemic Pelophylax kl.grafi.
Man-made drinking place for cattle on Causse d’Aumelas (NW of Montpellier). Such very artificial habitats are of great importance for amphibian in Mediterranean landscapes (photo Yoann Mansier).
A more “natural” pond on Causse d’Aumelas. Although less artificial, such ponds have also been excavated to provide cattle with water. This pond (locally famous as “La Fertalière” pond) holds many of the Mediterranean species of amphibians. It has been colonised by Marsh Frog Pelophylax ridibundus in the past 10 years (photo Yoann Mansier).
A map of the ponds included in the detailed study of the breeding phenology of the Parsley Frog Pelodytes punctatus. Each green frog represents a pond. Brown areas are the “causses” (dry calcareous plateau) included in the study (from Hélène Jourdan’s PhD thesis).
Speciation patterns and biodiversity assessment in amphibians and reptiles around the Mediterranean
These programs involve a detailed mapping of contact areas between evolutionary lineages of the Iberian Wall Lizards (Podarcis hispanicus species complex) in the Iberian Peninsula, and broad-scale sampling of arid-habitats reptile communities in North Africa and the Middle East.
Map of all male samples of Podarcis hispanicus complex in the BEV-CEFE collection. The various grey levels correspond to position along the first two axis of a PCA on morphology that was used to asses geographic variation in morphology. Black dots correspond to Podarcis hispanicus sensu stricto.
Recent field trips (yellow) where herptile specimens or tissue samples have been collected. These samples are usually combined with those from other teams, covering missing areas, to provide more complete coverage of the region.
An example of combined coverage: dark green dots = distribution of the genus Stenodactylus based on museum specimens. Red dots = tissue samples available for genetic analyses through field work of CIBIO / Univ of Porto, CSIC – Univ of Barcelona, Crete Natural History Museum, R. Sindaco, S Baha El Din and BEV & GENEV teams at CEFE (from Metallinou et al. 2010, XI Congreso Luso-Español de Herpetologia / XV Congreso Español de Herpetologia, Sevilla, Octobre 2010).
A fishing rod with a slipknot remains the best non-destructive method to catch lizards (here an Acanthodactylus dumerili). Near Awserd, Morocco (Western Sahara), March 2010 (photo Eric Didner).
When no voucher specimen is collected, each tissue sample is linked to a series of photos of the live specimen to serve as a “digital” voucher. Kuwait, February 2009 (photo Eric Didner).
Tissue sampling of an adult Rhagerhis moilensis, Kuwait, February 2009 (photo Eric Didner)
Some species are trickier to handle than others... Cerastes cerastes, Awserd road, Morocco (Western Sahara), March 2010 (photo Eric Didner).