Forest management cessation and biodiversity: a synthesis of a nationwide French project

Extending the network of strict forest reserves is one of the conservation measures promoted by the French National Strategy for Biodiversity improvement. According to the scientific literature, strict forest reserves may help preserving a part of the biodiversity that is threatened by forestry. However, this strategy is based on poor knowledge in the temperate context and available studies may suffer from methodological shortcomings. The national-scale project named "Forest management, Naturalness and Biodiversity" aims at quantifying the effects on forest structure and biodiversity of management abandonment in strict reserves. Based on a meta-analysis of worldwide literature and original data from 213 study plots set up in 15 forest sites throughout France - around half of the plots in forests left unmanaged for from 8 to 148 years (mean: 46 years)- , we analyzed the response of 7 taxonomic groups to management abandonment. The meta-analysis demonstrates that forestry affects total richness of saproxylic taxa worldwide, which is verified in our national dataset. However, management abandonment per se is not always the best explanation of the differences between managed and unmanaged forests, but other variables, notably linked to deadwood, better explain the observed patterns for saproxylic groups. For other taxa, the response is weaker and depends more on structural features than on management abandonment. In terms of policy, our project has allowed methodological advances thanks to the development of inventory and remote sensing protocols, as well as statistical methods. The dataset we have gathered is also a first comparison of structure and biodiversity between strict forest reserves and managed forests for France. This network may therefore constitute a first basis for long term biodiversity monitoring in French forests

Quantifier la réponse de la biodiversité à l'exploitation forestière

Le projet Gestion forestière, Naturalité et Biodiversité a pour but d'étudier le lien entre biodiversité, exploitation forestière et naturalité en comparant des parcelles exploitées à des parcelles non-exploitées (Réserves Biologiques Intégrales ou parties intégrales de Réserves Naturelles). En partenariat avec l'ONF, RNF et l'INRA, nous travaillons depuis 2008 sur des réserves intégrales soustraites à l'exploitation depuis au moins 20 ans. L'étude repose sur l'échantillonnage de 7 groupes taxonomiques : plantes vasculaires, mousses, champignons, chauve-souris, oiseaux, coléoptères carabiques et saproxyliques

GNB: Projet de recherche finalisée à l’interface recherche-gestion et ses interactions avec BGF

La gestion durable des forêts repose largement sur la biodiversité dont le fonctionnement reste cependant encore très insuffisamment connu. Il en découle la nécessité d’améliorer, de manière générale, le socle de connaissances relatif à la biodiversité et, plus particulièrement, d’analyser les interactions entre changement climatique, productivité forestière et biodiversité en forêt. Par ailleurs, les stratégies et décisions des acteurs influent sur ces interactions et constituent également des objets d’étude à privilégier. C’est pourquoi le programme de recherche « Biodiversité, gestion forestière et politiques publiques » a lancé en 2013 un appel à projets de recherche avec deux entrées : - l’une par les sciences de la nature axée sur le changement climatique, les mesures de gestion et la dynamique de la biodiversité dans les écosystèmes ; - l’autre par les sciences humaines et sociales sur les stratégies et décisions des acteurs, la gouvernance et les politiques publiques correspondant à la première entrée. Le présent colloque a pour objectifs de : - présenter les résultats des cinq projets de recherche qui ont été sélectionnés à cette occasion sur chacune des deux entrées en les accompagnant en tant que de besoin de regards complémentaires et en illustrant l’un des projets par une visite sur le terrain ; - initier une réflexion sur le progrès des connaissances dans ce domaine, en s’inspirant du devenir de projets antérieurs et en identifiant les principales lacunes à combler. Il se déroulera en trois sessions, chacune introduite par des exposés d’une quinzaine de minutes et conclue par une table ronde permettant un débat avec les participants et les invités

Protection gaps and restoration opportunities for primary forests in Europe

Aims: Primary forests are critical for forest biodiversity and provide key ecosystem services. In Europe, these forests are particularly scarce and it is unclear whether they are sufficiently protected. Here we aim to: (a) understand whether extant primary forests are representative of the range of naturally occurring forest types, (b) identify forest types which host enough primary forest under strict protection to meet conservation targets and (c) highlight areas where restoration is needed and feasible. Location: Europe. Methods: We combined a unique geodatabase of primary forests with maps of forest cover, potential natural vegetation, biogeographic regions and protected areas to quantify the proportion of extant primary forest across Europe\u27s forest types and to identify gaps in protection. Using spatial predictions of primary forest locations to account for underreporting of primary forests, we then highlighted areas where restoration could complement protection. Results: We found a substantial bias in primary forest distribution across forest types. Of the 54 forest types we assessed, six had no primary forest at all, and in two-thirds of forest types, less than 1% of forest was primary. Even if generally protected, only ten forest types had more than half of their primary forests strictly protected. Protecting all documented primary forests requires expanding the protected area networks by 1,132 km2 (19,194 km2 when including also predicted primary forests). Encouragingly, large areas of non-primary forest existed inside protected areas for most types, thus presenting restoration opportunities. Main conclusion: Europe\u27s primary forests are in a perilous state, as also acknowledged by EU\u27s “Biodiversity Strategy for 2030.” Yet, there are considerable opportunities for ensuring better protection and restoring primary forest structure, composition and functioning, at least partially. We advocate integrated policy reforms that explicitly account for the irreplaceable nature of primary forests and ramp up protection and restoration efforts alike

Vers un suivi multi-dispositifs de la biodiversité en forêt en France métropolitaine

International audienceThe "Plateforme Biodiversité pour la Forêt" works to build a large biodiversity monitoring system in metropolitan french forests. The idea is to mobilize funders and to make existing monitoring system managers work together to fill the current gaps.Une réflexion sur la mise en place d'un vaste réseau de suivi de la biodiversité en forêt a été lancée par la Plateforme Biodiversité pour la Forêt, en France. L'idée est de mobiliser les financeurs et gestionnaires des réseaux de suivis existants tout en comblant les lacunes actuelles

Nothing else matters? Tree diameter and living status have more effects than biogeoclimatic context on microhabitat number and occurrence: An analysis in French forest reserves

International audienc

IMPACT OF DISCONTINUING LOGGING ACTIVITY ON THE DENDROMETRIC STRUCTURE OF MIXED BEECH FORESTS IN FRANCE

Based on a comparison between managed and unmanaged forests, the aim of our study is to provide managers with a tentative quantitative analysis of the structural differences between managed and unmanaged mixed beech forests in France from a sample of 213 plots located in 15 lowland and mountain forests. Most structural descriptors were significantly higher in unmanaged forests. There were more very large living trees (+ 105 %) in unmanaged than in managed forests. These trees were also bigger (+ 145 %). The volume of dead wood was four times higher in unmanaged forests. Because of its nationwide scope, our investigation is a first French benchmark study for biodiversity-oriented forest policy, and contributes additional knowledge to a poorly researched area in FranceBasée sur la comparaison de forêts exploitées et non exploitées, l’objectif de notre étude est de fournir aux gestionnaires forestiers une première analyse quantitative sur les différences structurelles des hêtraies mélangées exploitées et non exploitées de France, sur un dispositif d’échantillonnage de 213 placettes réparties sur 15 massifs de plaine et de montagne. La majorité des descripteurs de structure est significativement plus élevée en forêts non exploitées. Les très gros bois vivants sont plus nombreux (+ 105 %) et plus gros (+ 145 %) en forêts non exploitées qu’en forêts exploitées. Le volume de bois mort est quatre fois plus grand en forêts non exploitées. De par son ampleur, notre étude constitue une première référence française en soutien aux politiques de conservation de la biodiversité, et apporte une pierre supplémentaire au champ de connaissance jusqu’à présent lacunaire en Franc

How much does it take to be old? Modelling the time since the last harvesting to infer the distribution of overmature forests in France

International audienceAim: The distribution of overmature forests in metropolitan France is poorly known, with only a few well-studied prominent sites, and has never been evaluated coun-trywide. Here, we modelled French forest reserves' time since the last harvesting operation—a proxy for forest maturity—then inferred the current statistical distribu-tion of overmature forests (i.e., forests over 50 years without harvesting) in France.Location: Metropolitan France.Methods: We used inventories from forest reserves and managed forests to calibrate a generalised linear mixed model explaining the time since the last harvesting with selected structural attributes and environmental variables. We then projected this model on the independent National Forest Inventory dataset. We thus obtained an updated estimation of the proportion and a rough distribution of overmature forest stands in metropolitan France.Results: We found that high basal area of very large trees, high volumes of standing and downed deadwood, high diversity of tree- related microhabitats and more mar-ginally diversity of decay stages best characterised the time since the last harvest-ing. Volumes of stumps and high density of coppices translating legacy of past forest management also distinguished more overmature plots. Our projection yielded an es-timated 3% of French forests over 50 years without harvesting mostly located in more inaccessible areas (i.e., mountainous areas).Main conclusions: Our study showed that the time since the last harvesting could be derived from a combination of key structural attributes characterising overmature temperate forests. It gives the first robust statistical estimate of the proportion of overmature forests in France and may serve to report on their status. Our method could be extended in countries with accessible National Forest Inventory and calibra-tion data, thus producing indicators at an international leve

L’observatoire des forêts sentinelles : un réseau d’analyse des interactions entre climat, humains et écosystèmes forestiers

National audienc