Infodoc : Sciences, Techniques et Culture

Tropical forests are threatened by logging activities. To understand the impact of this disturbance on forests, several studies conducted functional composition measurement on different logging intensity treatments, focusing on the leaf and wood economic spectrum.Their findings reveal a shift in the tree community right after the disturbance, fromslow-growing species, with lower acquisitive traits and higher conservative traits, to fast-growing species, with opposite traits. They therefore reveal the importance of accounting for the scale and spatial pattern for the interpretation, with trait values showing different tendencies. However, almost no studies have taken into account the hydraulictraits. That is why we investigated the impact of logging intensity on 8 functional traitsrela[...]

Tropical forests are threatened by logging activities. To understand the impact of this disturbance on forests, several studies conducted functional composition measurement on different logging intensity treatments, focusing on the leaf and wood economic spectrum.Their findings reveal a shift in the tree community right after the disturbance, fromslow-growing species, with lower acquisitive traits and higher conservative traits, to fast-growing species, with opposite traits. They therefore reveal the importance of accounting for the scale and spatial pattern for the interpretation, with trait values showing different tendencies. However, almost no studies have taken into account the hydraulictraits. That is why we investigated the impact of logging intensity on 8 functional traitsrelated to light, nutrients and water use, at two scales (25*25m and 250*250m) in theParacou site in French Guiana in both 1998 and 2015. We also used the Moran eigenvector method (MEM) as proxy for underlying bigger processes impacting the functional traits. Wefound a mixed effect of the logging impact at the bigger scale, but a more intense impact at the smaller one. Our results did not follow the expected tendencies and suggested a latter effect on conservative traits and an effect that is still present for acquisitive traits even after30 years of disturbance. In particular, hydraulic traits did show variation with logging intensity variation; stomatal density was very sensitive to logging where gmin and pltp were only impacted at smaller scales. The MEM proxy revealed several auto correlations at the quadras scale. This work opens new perspectives to add the hydraulic traits in logging impact studies, to put a particular attention to scale and time, and to explore under lying mechanisms structuring functional composition across space and time.