Missions

Western European forest ecosystems are being hit hard by climate change. Rainfall and temperature patterns, which are major drivers of forest dynamics, influence tree fruiting, growth, aging, and decline, and consequently the rate of logging. Mechanistic models predict significant and rapid changes in the evolution of forest stands, food webs, and ecological interactions between animal and plant communities, with major repercussions on forest dynamics.
In this context, understanding and predicting the long-term effects of these changes on the functioning of animal and forest communities is a major challenge. To address this issue, a cooperation agreement was initiated in December 2022 between the French Biodiversity Agency (OFB), the Centre d'Etudes Biologiques de Chizé (CEBC), the Laboratory of Biometry and Evolutionary Biology (LBBE), and the National Forestry Agency (ONF). The main goals of this project are to 1/ Characterize the forest environment at different spatial scales, 2/ Assess the impact of climate change on the phenology of vertebrate organisms and the performance of their populations, 3/ Assess the influence of forest fruit production levels on vertebrate population functioning, 4/ Study the ecological interactions within animal and plant communities and their cascading effects, and 5/ Assess the effects of human activities on biodiversity.

The postdoctoral work will focus on axes 2 and 3 of the project, with the following objectives:
1) Using raw/original datasets, to estimate/re-estimate biological variables that describe the life history traits of the different vertebrate species studied (mammals, birds, reptiles), as well as their variation over time. These variables concern those describing reproductive calendars, individual performance (e.g., fertility, reproductive success) and population dynamics (abundance/population size, survival rate, recruitment, growth rate, etc.).
2) To develop an integrated model to assess the strength of the links between a) the biological variables mentioned above and variations in environmental conditions (e.g., weather conditions, forest fruiting levels), b) between the biological (or environmental) variables themselves, and c) between the biological variables of the different species/communities studied.

The successful candidate will primarily work on identifying and measuring the extent of climate change's impact on the vertebrate community (wild ungulates, snakes, forest birds) living in the forest ecosystem (e.g., reproductive phenology, phenotypic quality, performance, health status). Depending on progress, a second part of the work could seek to understand and document the effects of pulsed resources on population dynamics, the performance and phenotypic qualities of individuals, and the interactions between these elements. This work will be disseminated in the form of scientific publications in international journals and shared with local partners and stakeholders (managers, scientists, and administrations).

Activités

The candidate will play a leading role in developing scientific questions relevant to wildlife and forest managers. Interactions with those involved in the project, who are responsible for various research programs and belong to different organizations (OFB, ONF, CNRS), will therefore be very important.

For the first part (high priority), the initial task will be to characterize climate change based on meteorological data (temperatures and precipitation), distinguishing between directional change (e.g., increase in temperature or decrease in precipitation) and the increase in the frequency of extreme events (e.g., drought), which may affect the life history of vertebrates in different ways (2023 IPCC report).
The next objective of this postdoctoral research will be to study the demographic responses of the species monitored in two steps: a description of responses to climate change (pattern-based approach) followed by an investigation of the mechanisms involved (process-based approach). For the descriptive approach of the demographic response of vertebrates to these changes, four variables describing the biological cycle of the species concerned will be analysed: (a) reproductive phenology; (b) phenotypic quality measured by size, mass, or body condition; (c) performance measured by fertility or reproductive success; (d) health status measured by the intensity of external parasitism of individuals. For the mechanistic approach, we will try to differentiate the microevolutionary responses of phenotypic plasticity on (a) reproductive phenology and (b) phenotypic quality. This approach will be restricted to species for which we have medium-term individual data, i.e., over several identified generations (at least mother-daughter relationships). For this first part, the person recruited will be required to perform path analyses. Verifying and formatting some of the data will take up a significant portion of the time at the beginning of the contract.

If this first task is ended before the end of the contract, a second part could focus on estimating the degree of synchrony between the abundance of populations of different species and interannual fluctuations in forest fruiting levels. The calculation of values would be based on long-term monitoring of the abundance of nesting birds, reptile species, bats, small mammals, and wild ungulates, as well as their reproductive success. The assessment of fruiting levels would be based on several sources of information: (a) measurements of oak and beech fruiting carried out as part of a Wild Boar Reproduction Observatory, (b) measurements of airborne pollen from various species collected by the National Aerobiological Monitoring Network. The person recruited could then assess the consequences of interannual fluctuations in fruiting levels on the phenotypic quality of individuals (body condition and external parasite load).

Compétences

- In-depth knowledge of population dynamics and vertebrate ecology (wild ungulates, forest birds, or reptiles);
- Knowledge of/interest in wildlife and forest management and applied scientific issues;
- Data analysis using generalized linear models, preferably in R environment (hierarchical models);
- Analysis of structural relationships in data (path analysis), preferably in R environment;
- Analysis of longitudinal data (in particular abundance monitoring and capture-recapture data in the broad sense);
- Modelling of population dynamics (Leslie matrices);
- Knowledge of Bayesian statistics would be appreciated (BUGS, JAGS, NIMBLE, etc.);

- Ability to work actively in collaboration with local and remote partners;
- Autonomy in data management and analysis;
- Very good command of English (level C1 of the Common European Framework of Reference for Languages) and proven writing skills in English (production of scientific articles);
- Understanding of French appreciated
- Ability to present results to an audience of non-scientists/biodiversity managers;

Contexte de travail

The Centre d'Etudes Biologiques de Chizé (CEBC) is a joint research unit located in Villiers-en-Bois (79), bringing together researchers from the CNRS and La Rochelle University. It is one of the CNRS Ecology and Environment's flagship laboratories due to its international reputation and its research topics closely linked to the ecological crisis. Its main objective is to identify the mechanisms and processes that regulate biodiversity dynamics: understanding how species adapt—or disappear—in the face of natural changes or those induced by human use of nature. Fundamental research contributes directly to environmental solutions and measures to protect ecosystems and biodiversity.
The CEBC has a long history of scientific collaboration with partners involved in wildlife and forest studies and research, such as the French Biodiversity Agency and the National Forestry Agency. The CEBC's international scientific reputation is the result of collective work based in particular on unique long-term series of animal populations.

The successful candidate will play a key role in close and ongoing collaboration with Maryline PELLERIN (OFB, Conservation and Sustainable Management of Exploited Species Department), Cyril ERAUD (OFB, Conservation and Management of Species at Risk Department), Charles-André BOST (CEBC, Director, member of the “Marine Predators” team), Xavier BONNET (CEBC, “Ecophy” team), Jean-Michel GAILLARD (LBBE, “Evolutionary Biodemography” team), and Clayre GRUMIAUX (CEBC, Project Manager).

Contraintes et risques

No particular risk.

The CEBC is a relatively isolated worksite, in the heart of the Chizé forest, at 25kms of Niort, where you can find a high-speed train train station.