Thesis (doctoral)--Swedish University of Agricultural Sciences, 2006. / Thesis documentation sheet inserted. Appendix includes reproductions of six papers and manuscripts co-authored with others. Includes bibliographical references. Also issued electronically via World Wide Web in PDF format; online version lacks appendix of papers; ill. in online version displays in color.

Thesis (Ph. D.)--Goteborg University, 2007. / Includes bibliographical references.

Univ., Diss.--Göteborg, 2007. / Enth. 5 Zeitschriftenaufsätze.

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2002. / Thesis documentation sheet inserted. Appendix reprints three manuscripts and one published paper, three of which are co-authored with others. Includes bibliographical references. Also issued electronically via World Wide Web in PDF format; PDF version lacks abstract, ack., and appendix. One ill. in PDF version is in col.

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2007. / Thesis documentation sheet inserted. Includes appendix with four papers co-authored with others. Includes bibliographical references. Issued also electronically via World Wide Web in PDF format; online version lacks appendix.

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2004. / Thesis documentation sheet inserted. Appendix reprints four papers and manuscripts co-authored with others. Includes bibliographical references. Also partially issued electronically via World Wide Web in PDF format; online version lacks appendix .

Pour répondre aux enjeux énergétiques et écologiques actuels, les pouvoirs publics prévoient une forte augmentation des prélèvements de bois à l'horizon 2020. Cependant, très peu d'études en milieu tempéré établissent clairement un lien entre les changements sylvicoles associés et la préservation de la biodiversité. L’enjeu de cette thèse est d’améliorer les connaissances sur lesquelles fonder des outils de conservation pertinents et favorables à la biodiversité, en adoptant les coléoptères saproxyliques comme modèle biologique. Le volume de bois mort a souvent été retenu comme un indicateur de gestion durable des forêts. Au travers d'une méta-analyse, nous avons cherché à appréhender son importance et ses limites en tant qu’indicateur de biodiversité. Nous montrons que toute augmentation du volume de bois mort est favorable à la biodiversité. Nous avons ensuite testé l'effet de la qualité de différents types de rémanents (essence, diamètre et stade de décomposition) sur la biodiversité afin d'identifier les principaux facteurs déterminant la composition des assemblages. Nos résultats montrent que les variables à l’échelle de la pièce de bois mort jouent un rôle important pour la biodiversité. Enfin, nous avons étudié la valeur écologique de zones abandonnées par la sylviculture(taillis-sous-futaie abandonnés depuis plus de 60 ans), et l'impact du raccourcissement ou de l'allongement de la durée de rotation en futaie régulière de chêne. Nous avons ainsi montré que les zones vieillies hébergent une plus grande biodiversité et que la diminution des rotations sylvicoles pourrait avoir un impact négatif. Par conséquent, la préservation des zones vieillissantes permettrait de favoriser la conservation de la biodiversité saproxylique.Cette étude est la première du genre en milieu tempéré. Malgré les résultats obtenus, de multiples questions se posent encore et de nombreux facteurs sont encore à étudier. / Facing current energetic and ecological issues, public authorities forecast a strong increase in wood harvesting by 2020. Nevertheless, in the temperate biome, very few studies clearly link sylviculture changes associated with such an increase and conservation of biodiversity. The main issue of this Phd thesis was to improve the knowledge on which managers could build relevant conservation tools to preserve biodiversity. For this purpose, we used saproxylic beetles as biological model. Deadwood volume has often been used as an indicator for sustainable forest management. Using meta-analysis, we tested the relevance of deadwood volume as biodiversity indicator. We showed that an increase in deadwood volume favours biodiversity, but this relationship remains weak for temperate forests. We then tested the effect of different logging residues qualities (tree species, diameter and decay class) on biodiversity in order to identify the main drivers of assemblages’ composition. Our results showed that piece of wood characteristics play an important role on biodiversity. Finally, we studied the ecological value of areas where management had been abandoned (coppices-with-standard where coppice had not been harvested for more than 60 years) and the influence of shortened or increased rotation lengths in oak high forest (160-300 years). We thus showed that overmature areas have higher levels of biodiversity and that shortened rotations lengths may have a negative impact on biodiversity. As a consequence, maintaining such overmature zones may help preserve saproxylic biodiversity. This study is the first to be conducted in the temperate biome. Despite the results obtained, many questions lay ahead and many factors remain to be studied.

Urban forests play key roles in animal and plant biodiversity and provide important ecosystem services.  Habitat fragmentation and expanding urbanization threaten biodiversity in and around urban areas.  Saproxylic beetles can act as bioindicators of forest health and their diversity may help to explain and define urban-forest edge effects.  I explored the relationship between saproxylic beetle diversity and distance to an urban area along nine transects in the Västra Götaland region of Sweden.  Specifically, the relationships between abundance and species richness and distance from the urban-forest boundary, forest age, forest volume, and tree species ratio was investigated Unbaited flight interception traps were set at intervals of 0, 250, and 500 meters from an urban-forest boundary to measure beetle abundance and richness.  A total of 4182 saproxylic beetles representing 179 species were captured over two months.  Distance from the urban forest boundary showed little overall effect on abundance suggesting urban proximity does not affect saproxylic beetle abundance.  There was an effect on species richness, with saproxylic species richness greater closer to the urban-forest boundary.  Forest volume had a very small positive effect on both abundance and species richness likely due to a limited change in volume along each transect.  An increase in the occurrence of deciduous tree species proved to be an important factor driving saproxylic beetle abundance moving closer to the urban-forest.  Overall, analysis showed inconsistent effects on both abundance and richness as functions of proximity to the urban-forest boundary.  Urban edge effects, forest volume, forest age, and forest tree species make up are all variables that may effect saproxylic abundance and species richness.  Forest managers should consider these variables when making management decisions.

Old hollow trees have declined in Europe and many saproxylic (wood-dwelling) beetles dependent on them are threatened. Several studies have been done on old hollow oaks and they have been shown to harbour a species-rich saproxylic beetle fauna. However, other broad-leaved trees might also be important to consider as supporting habitats. The aim of this study was to investigate to what extent saproxylic beetles are tree genus specialists. Pitfall traps and window traps were used to compare the saproxylic beetle fauna in oak, ash, norway maple and small-leaved lime in an area dominated by old oaks. 5,501 specimens of saproxylic beetles were found, belonging to 239 species of which 27 species were red-listed. There were significant differences in the saproxylic species composition between the four tree species, but with large overlaps. The saproxylic species found in oak overlapped to 66 % with norway maple, to 67 % with ash and to 70 % with small-leaved lime. About one third of the species in this study seem to be tree genus specialists. The conclusion is that other broad-leaved trees are important to consider in models as supporting habitats for oaks. However, to be able to save the whole fauna of saproxylic beetles, trees of all different tree species are needed.

Today many saproxylic species are threatened because of habitat decline in Europe. Hollow trees represent a great part of the habitats that saproxylic species use. Since hollows takes a long time to develop, management actions are needed to prevent the extinction of saproxylic species. The aim of this study was to investigate the succession of saproxylic beetle species in artificial habitats in the form of wooden boxes. Wooden boxes were filled with a potential substrate and placed at different distances (0-1800 m) from oak hollow hot spots. In addition to the start mixture, four different additional substrates were added. In total, 4510 specimens of 114 saproxylic beetle species were sampled in 43 boxes over ten years. The specimens of tree-hollow species, wood rot species and nest species increased with 38% from the fourth to the final year but species richness decline from 47 to 29, respectively. A dead hen had a tendency for attracting more species but the small effect of different added substrates diminished over the years and had no significant effect on species richness after ten years. There was a higher similarity in species richness after ten years between the boxes and real hollow oaks. In conclusion, the artificial habitat developed into a more hollow like environment, with fewer but more abundant wood mould specialists, during ten years. This study clearly shows that the wooden boxes are used as habitats for saproxylic species as the boxes seems to develop into a more hollow-like habitat with time.