BIOFORDIV - Taxonomic, functional and phylogenetic diversity of forest biocenoses along a gradient of naturalness

The BIOFORDIV project aims to analyze the response of forest biodiversity to the history of silvicultural management and the naturalness gradient of ancient native fir forests, using a multi-taxonomic and interdisciplinary approach. It comes at a time of high societal and operational expectations regarding sustainable forest management and biodiversity conservation, particularly in mountain ranges with contrasting histories of exploitation.

Approaches

The work was carried out in two mountain ranges in the Pyrenees, Canigou and Burat, within beech and fir forests representative of three categories of forest corresponding to a gradient of anthropization: (i) currently exploited production forests, (ii) formerly exploited forests that have been left to evolve freely for at least 50 years, and (iii) old forests with very few traces of exploitation, dating back more than 100 years. BIOFORDIV relied on the study of three complementary indicator groups (forest birds, saproxylic beetles, and vascular flora) to characterize biodiversity in different dimensions (taxonomic, functional, and phylogenetic) and analyze its determinants.

Biological communities and environmental components were characterized using standardized inventories, coupled with the evaluation of innovative biodiversity monitoring methods, such as passive acoustics, automated data analysis, and molecular tools based on environmental DNA (eDNA). Comparison with conventional methods allowed for testing their complementarity, performance, and operational limitations.

Results

Biological communities respond differently to forest management history. At the multi-taxonomic level, species richness appears to be determined mainly by the specific context of each forest, while community composition, abundance, and certain aspects of diversity are strongly influenced by the degree of naturalness and maturity of the stands. This is the case, for example, with saproxylic beetle communities (which live on dead wood), which are clearly structured by silvicultural history, highlighting the importance of habitat quality and continuity rather than just the quantity of resources. The richness, abundance, and phylogenetic diversity of bird communities increase with the structural complexity of stands and the density of tree microhabitats, which have been identified as key elements. The vascular flora reveals significant differentiation between mountain ranges and a marked influence of local conditions, while highlighting a floristic specificity associated with old-growth forests.

Innovative approaches have proven their value. Passive acoustics, coupled with the BirdNET automated identification tool, has shown performance comparable to standardized listening points. eDNA analyses detected a significant proportion of insect species and genera identified morphologically, as well as species complementary to conventional approaches, and provided access to fungal diversity that had previously been poorly documented.

Overall, BIOFORDIV highlights the importance of integrating qualitative indicators of forest structure, such as dendro-microhabitats and ecological continuity, into forest assessment and management. The project thus reinforces recommendations in favor of silvicultural practices aimed at preserving or enriching these elements, including in production forests. The results and limitations identified have directly led to the development of the SALUD project (2025–2029), which extends BIOFORDIV by broadening the spatial scope and the taxa studied, and by integrating a “One Health” approach in order to strengthen the scientific and operational scope of the work.

Participants

INRAE units involved

• URFM - Unité de recherche Écologie des Forêts Méditerranéennes
• URZF - Unité de recherche Zoologie Forestière
• UMR RECOVER - Risques, écosystèmes, vulnérabilité, environnement, résilience - Aix Marseille Université
• UMR DYNAFOR - Dynamiques et Écologie des Paysages Agriforestiers

Partners

• CEN - Conservatory of natural areas Occitanie
• CRPF - National Center for Forest Property

Contacts - coordination