Céline Bellard: understanding biological invasions at the heart of the biodiversity crisis

Originally from northern France, Céline Bellard completed all her higher education at the University of Lille. From 2005 to 2008, she studied for an undergraduate degree in organism and population biology, followed by a Master's in terrestrial ecosystems from 2008 to 2010. During her Master's internship she discovered Université Paris-Sud (now Univ. Paris-Saclay) and the Ecology, Society and Evolution Laboratory (ESE - Univ. Paris-Saclay/AgroParisTech/CNRS), where she would go on to establish the foundations of her future scientific career.

A PhD focused on the effects of climate change

In 2010, Céline Bellard embarked on a PhD at the laboratory, focusing on the impact of climate change on biodiversity and species' responses. She defended her thesis in 2013. In the face of climate change, species react in one of three ways: through local adaptation, changes in phenology (the timing of seasonal events) or spatial redistribution. Céline Bellard chose to concentrate on this mechanism of spatial redistribution, with a particular focus on invasive species. "Across one hundred species, climate change encourages the expansion of insects, often northwards towards Europe or to higher altitudes, while many mammals are seeing their areas contract."

Postdoctoral studies and international perspective

Between 2014 and 2016, thanks to an AXA grant, Céline Bellard conducted postdoctoral research at University College London. It was there that she studied the ecological factors that either facilitate or hinder biological invasions, with a particular emphasis on island animal species (birds, mammals, reptiles, amphibians, ants, etc.). "80% of recorded extinctions since the year 1500 have been caused by invasive alien species." She also explored the resilience of ecological communities, which are stronger when they are rich in biodiversity.

From 2016 to 2017, the researcher worked at the University of Rome La Sapienza before joining the National Museum of Natural History (MNHN) in Paris, for a new postdoctoral position. In 2018, she joined the French National Centre for Scientific Research (CNRS) as a research fellow and returned to the ESE laboratory.

Decoding the mechanisms behind biological invasions

At the laboratory, Céline Bellard has continued her work on invasive species, focusing on the characteristics of species introduced by humans, often for a specific purpose such as hunting, and the species that become vulnerable due to such introductions. "It's no accident, invasive species often target prey with reduced defensive capabilities, for instance, small birds that have never had predators." The researcher is developing a functional and phylogenetic approach (which traces the evolutionary history of the species and their blood lines). This aims to identify what ecosystem functions are threatened (pollination, biomass production, population regulation) and to understand whether the species affected belong to ancient or more recent evolutionary lines.

Islands, laboratories of vulnerability

A large part of her research relates to island ecosystems, which are particularly exposed to the combined threats of climate change, biological invasions and land conversion. "We assessed the vulnerability of island biodiversity on over 17,000 islands, combining the exposure to threats, the sensitive of resident species and their capacity to adapt." This work also evaluated the effectiveness of protected area networks - size, location and connectivity - to determine whether current measures are sufficient to safeguard biodiversity in the face of global changes.

Céline Bellard obtained her accreditation to supervise research (HDR) in 2022, which led her to supervise three PhD candidates. "It's a hugely inspiring experience, I support them on the challenges of the biodiversity crisis and in return, they fuel my own thinking with their own ideas and fresh perspective."

Research related to public policies

The researcher regularly contributes to international expert assessments. In 2014, she was involved in the Intergovernmental Panel on Climate Change (IPCC) and the Global Biodiversity Outlook, a United Nations report. She also participated in the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) in 2023. She was interviewed by a French member of parliament on invasive alien species in 2022 and is routinely involved in the public debate regarding France's ecological planning and the setting of conservation targets.

At the same time, Céline Bellard is working with the MNHN and the French centre of expertise and data on natural heritage, PatriNat, to develop monitoring indicators for invasive species. These are designed to inform public decisions regarding biodiversity. "Under European legislation, France is required to have monitoring indicators. However, until now, we didn't have any for biological invasions."

Recognition and growing responsibilities

Her outstanding career was recognised in 2022, when she received the Irène Joliot-Curie Prize in the Commitment to Biodiversity Research category, a French award showcasing the role of women in science. Then, in 2024, she was presented with the CNRS Bronze medal. This is awarded to a researcher whose early work has been deemed particularly promising.

New action-oriented projects

Promoted to Research Director in 2025, Céline Bellard now co-leads a programme supported by the French Ministry of Higher Education and Research on nature-based solutions, working with the University of Montpellier. This programme aims to assess the effectiveness of French protected areas to respond to the challenges of climate change.

Another area of her work concerns the development of species prioritisation indicators. These are designed to identify species that have both a high risk of extinction and a key functional role, along with those where the population status remains poorly understood despite their ecological importance. "These lists make it possible to target our conservation efforts, especially in national parks and nature reserves."
Biodiversity and global challenges

For Céline Bellard, ecological research is connected to major societal challenges, particularly in France, which ranks sixth in the world for species richness, due specifically to its overseas territories. The current sixth mass extinction, in which invasive species play a central role, demands both scientific and political mobilisation. "Without biodiversity, we no longer have food or medicines. For example, over half the molecules used in healthcare are derived from natural resources. Preserving biodiversity also means giving ourselves a chance to discover future new treatments for serious diseases," concludes Céline Bellard.