Deadwood enrichment combining integrative and segregative conservation elements enhances biodiversity of multiple taxa in managed forests

Abstract

Integrative management strategies that simultaneously aim for wood production and biodiversity conservation are considered crucial to protect biodiversity of forest species outside protected areas. In this study, we evaluated whether deadwood enrichment as an integrative strategy at a scale of 17,000 ha resulted in enhanced biodiversity of saproxylic and non-saproxylic taxa eight years after the implementation of the strategy. The strategy included active deadwood enrichment with harvest remnants, retention of deadwood, and nature forest reserves areas. The analysis was based on data on the occurrence of plants, fungi, beetles, true bugs and birds from directly before and after the implementation of the strategy. The implementation of the strategy resulted in an increase in the deadwood amount by an average of 90 ± 40 m3 ha−1 (mean ± SE) over this period. While deadwood amounts doubled in production forests (+90%), they increased even more in nature forest reserves (+160%). Multidiversity (species density of all taxa) increased with an increase in deadwood amount; this was a result of an increase in the multidiversity of saproxylic species as the non-saproxylic multidiversity did not respond. Among single taxon groups, fungal and beetle species density responded positively to the increase in deadwood amount, especially when only saproxylic species were analysed. Importantly, this effect was not only found in the nature forest reserves, but also in the production forests. We thus conclude that active deadwood enrichment in production forests and nature forest reserves is a promising tool to rapidly promote the protection of forest biodiversity.