The European spruce bark beetle Ips typographus in a national park: from pest to keystone species

Abstract

The influence of natural disturbance on biodiversity is poorly known in the intensively cultivated landscape of Europe. As an example of insect disturbance we studied effects of gaps generated by outbreaks of the spruce bark beetle (Ips typographus) on biodiversity in the area of the National Park ''Bavarian Forest'' and compared them with openings (e.g. meadows) created by humans in these forests. Insects were sampled using flight interception traps across twelve ecotones between edges of closed forest, six bark beetle gaps and six meadows. The diversity and species density of true bugs and of bees/ wasps increased significantly from the closed stand to the edge, and continued to increase inside the openings at interior and exterior edges. Species density in saproxylic beetles also increased significantly from closed forest to opening, but only across ecotones including bark beetle gaps. Similarly, the number of critically endangered saproxylic beetles increased significantly in bark beetle gaps. Using indicator species analysis a total of 60 species were identified as possessing a statistically significant value indicating preference for one of the habitat types along the ecotones: 29 of them preferred gaps, 24 preferred meadows, three were characteristic for edges of meadows, three for edges of bark beetle gaps, but only one was typical of closed forest. Most of our results support the thesis that I. typographus fulfils the majority of criteria for a keystone species, particularly that of maintenance of biodiversity in forests. Our results emphasize the value for the study and conservation of insect diversity of the policy of non-interference with natural processes pursued in some protected areas. As a recommendation to forest management for increasing insect diversity even in commercial forest, we suggest that logging in recent gaps in medium aged mixed montane stands should aim at retention of a part of the dead wood. Planting should be avoided, to lengthen the important phase of sunlit conditions.

Modelling Forest α-Diversity and Floristic Composition — On the Added Value of LiDAR plus Hyperspectral Remote Sensing

“…Temporally and spatially distributed monitoring of biodiversity patterns at landscape scales is especially important in the Bavarian Forest national park because of its highly dynamic environment created by the European spruce bark beetle Ips typographus, which has contributed to a rapidly changing landscape of different successional stages [51].…”

First report of three scolytid species (Coleoptera: Curculionidae, Scolytinae) in Romania

“…They initiate the process of decomposition of bark and wood tissues by feeding on them directly, and also by facilitating penetration by other in-sects, fungi and bacteria (Kirisits 2004, Persson et al 2011, Hulcr et al 2012, Stokland & Siitonen 2012, Six 2013. While a few species are important pests (Postner 1974), some are even regarded as keystone species in forest ecosystems (Müller et al 2008).…”

The Evaluation of the Bark Beetles Populations on Spruce Logging Debris

“…At the same time, the estimation of bark beetles population density is of high theoretical and practical significance for nature and forest conservation (Borkowski and Podlaski, 2011). In the last years, more and more authors pay attention to ecological role of bark beetles as ecosystem engineers and keystone species, influencing forest regeneration and conversion (Müller et al, 2008).…”

“…Bark beetles (Coleoptera, Curculionidae, Scolytinae) are of fundamental importance for forest ecosystems because they are the first in decomposing wood of dying or recently dead trees and are an important rejuvenating agent in natural forests (Dworschak, 2013). By creating dead wood and forest gaps, they facilitate fungal, insect and plant diversity (Müller et al, 2008;Müller et al, 2010;Wermelinger, 2004).…”