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DEPE | Stratégie scientifique » Ecophysiologie et changements environnementaux

Ecophysiologie et changements environnementaux

Coordinateur : Jean-Patrice Robin

From individual quality to ecosystem functioning

At a time when climate and man-made changes impact drastically our environment, our group aims at developping a mechanistic approach to the understanding of the capability of animal species to adapt to environmental changes so that they can serve as ecological indicators. To this end, we are exploring the adaptability to changes at 2 levels : individual and population.

- At the individual level, one of the key question we are trying to address is : why some individuals perform better than others (cf. T. Raclot and Y. Ropert-Coudert’s pages). Determinants of individual quality in both at-sea foraging and on-land breeding performances are examined through an eco-physiological pespective. Our questions range from : What roles hormones are playing in reproductive strategies ? How aging shape the ability to capture prey ? What factors constrains most the diving/hunting ability of predators and how the balance between these factors is modified when environmental conditions change ?

- At the population level, we are particularly interested in the effects of climate variability on the population dynamics of top predators, as indicators of the impact of climate on ressources (see Le Bohec et al. 2008). In this context, we have pioneered new approaches that enable to determine the main life-history traits, i.e. breeding success and survival, from the monitoring of many individuals. For example, our data base on king penguins involves 3,5 millions data for more than six thousand individuals of known age over twelve years. In addition, we are now focusing on the still poorly known processes that determine the distribution of individuals in their colony according to their individual history and in particular their breeding performance(cf. Y. Le Maho’s page).

Our models are varied, although there is a historical, strong seabird component to our work, especially penguins. We have expertise in cutting-edge methodologies that we use to conduct our projects, among which :

- Automatic Identification and Weighing Systems : these are based on Radio Frequency IDentification where transponders implanted in animals are read at a distance by antennae hidden on the natural pathways of the animals or through mobile antennae carried by remote-controlled robots.
- Bio-logging tools : this approach consists in animal-attached data recorders that monitor i) the performances of animals in the wild, ii) environmental parameters and iii) the relationship between the two (see Ropert-Coudert & Wilson 2005).
- Hormonal assay techniques and manipulations :This approach gives informations on and/or allows one to modify the endocrinological balance to further examine the physiological mechanisms underlying animal behaviour in the wild.

The weighbridge installed in the Adelie penguin colony of Dumont d’Urville, Antarctica in 2006, monitor automatically the weight and identity of the birds passing on it. About 300 chicks from this colony are implanted annually with a 32-mm long transponder that associates a unique number to each individual.

Our pluridisciplinary approach means that we constantly cross bridges between disciplines, e.g. trying to fill the gap between whole-individual and population studies, or between physiological processes and their resulting behavioural strategies. To this end we have strong collaboration link with colleagues at the IPHC, like the
team of compromis évolutifs et allocations d’énergie for example, but also with numerous national (Centre d’Etudes Biologiques de Chize, Centre d’Ecologie Fonctionnelle et Evolutive de Montpellier) and foreign institutions (the Australian Antarctic Division, the National Institute of Polar Research in Japan, the Phillip Island Nature Park in Australia, the Centre for Ecological and Evolutionary Synthesis in Oslo, the Percy FitzPatrick Institute of African Ornithology in South Africa... ).