Structure forestière et communautés de coléoptères dans les forêts wallonnes en libre évolution : Apport de la télédétection LiDAR à l'établissement d'un état de référence (T0) des Réserves Biologiques Intégrales du Parc National de l'Entre-Sambre-et-Meuse

Details

Supervisors

Pairon, Marie ; Bourdouxhe, Axel

Faculty

Faculté des bioingénieurs

Degree label

Master [120] : bioingénieur en gestion des forêts et des espaces naturels, à finalité spécialisée

Abstract

enEuropean temperate forests are among the ecosystems most heavily altered by human activity, which weakens the biodiversity they support ; particularly saproxylic beetles, which depend closely on deadwood and on the microhabitats characteristic of mature forests. In response, the establishment of Integral Biological Reserves (IBRs) based on the principle of free evolution within the Entre-Sambre-et-Meuse National Park represents a concrete answer, aimed at restoring the natural dynamics of Walloon broadleaved forests. This work documents the initial state of these reserves and assesses the contribution of airborne LiDAR remote sensing to characterising forest structure in relation to beetle communities. An entomological inventory was coupled with a LiDAR characterisation of the stands, then compared with alternative, more easily obtained descriptors ; topographic and hydrographic variables, and the Potential Biodiversity Index. The analysis sought to detect possible differences between reserve and managed plots, to identify the structural factors most explanatory of the communities, and to situate LiDAR relative to these alternative approaches. At this initial stage, no significant difference was found between reserves and controls, either in forest structure or in the diversity, abundance, or composition of the beetles — an expected result given the recent establishment of the reserves. The density of the intermediate stratum beneath the canopy nonetheless emerged as the most consistent structural factor explaining the communities. LiDAR proved best at accounting for local diversity, whereas the topographic and hydrographic context explained more of the composition and abundance; the three approaches appear complementary rather than substitutable, and a compositional signature specific to the reserves is already beginning to take shape. In conclusion, this initial similarity provides a solid baseline for the long-term monitoring of the reserves, and LiDAR establishes itself as a promising and reproducible monitoring tool, complementary to — but not a replacement for — field inventories.