Silviculture-driven vegetation change in a European temperate deciduous forest

Abstract

Forest management consists in anthropogenic disturbances that are able to modulate ecological features, resource availability and successional patterns. Plant communities are thus expected to react differently to contrasted silvicultural systems. We compared plant species composition between stands submitted to a traditional management since many centuries (i.e. coppice-with-standards treatment, stands intensively but infrequently disturbed) and stands recently converted into a selective cutting system (stands moderately but frequently disturbed), over uniform edaphic and topographic conditions. We found significant differences in species composition between both systems. Despite a strong shift in species composition among different stages of the coppice cycle, coppice-with-standards stands supported the highest number of true forest species. Selectively-cut stands were more homogeneous and characterized by ruderal "generalist" species. These fast changes in vegetation composition were related to differences in a group of factors that are directly or indirectly linked to the silvicultureassociated disturbance regime, including soil moisture, soil fertility, forest microclimate, light and game predation. We conclude that the conversion of a silvicultural system which has patterned plant communities since many centuries, induces early major changes in vegetation composition. The most negatively impacted species are the so-called "true forest species" that may be better labelled "coppice-woodland species". disturbance / microclimate / forest management / plant diversity / true forest species Rsum -Changements de la composition floristique induits par la sylviculture dans une fort tempre caducifolie europenne. La sylviculture est une perturbation anthropogne capable de moduler les facteurs environnementaux, la disponibilit des ressources et la dynamique forestire. La vgtation spontane est donc susceptible de ragir diffremment des systmes sylviculturaux contrasts. La composition floristique de parcelles forestires traites en taillis-sous-futaie depuis plusieurs sicles a t compare celle de parcelles rcemment converties en futaie irrgulire coupe pied--pied , en conditions daphique et topographique uniformes. Malgr des diffrences importantes en fonction du temps coul depuis la dernire coupe, la partie de la fort traite en taillis-sous-futaie hbergeait un nombre plus important d'espces forestires. Les parcelles en futaie irrgulire taient plus homognes et caractrises par des espces rudrales gnralistes . Ces changements prcoces de la composition spcifique ont pu tre relis des modifications du contexte environnemental, directement ou indirectement induites par la sylviculture, incluant l'humidit et la fertilit du sol, le microclimat forestier, la lumire et la prdation par le chevreuil. La conversion d'un type sylvicultural, qui a faonn les communauts vgtales durant des sicles, induit donc rapidement des changements majeurs dans la composition floristique. Les espces les plus affectes sont les espces considres comme forestires, qu'il conviendrait plutt d'appeler espces des taillis . perturbation / microclimat / sylviculture / biodiversit vgtale / espces forestires vraies / taillis-sous-futaie