title: Communities of saproxylic beetles associated with the White-backed Woodpecker (Dendrocopos leucotos) in temperate forests of central Europe
Creators: name: Angeleri, Romain
Publisher: name: Universität Bern
Year: 2025
Subjects: subject: 570 Life sciences; biology
subject: 590 Animals (Zoology)

description: To answer the consequences of the Anthropocene and its associated erosion of biodiversity, response time, accuracy, and cost-effectiveness must be strongly considered when developing biodiversity conservation programs. Because of limited human and financial support, conservationists must prioritize relevant ecological areas, ideally with a high buffering capacity accounting for species loss. Among other conservation tools, indicator species help in assessing a specific environmental condition. From a conservation perspective, species used as indicators of naturalness would also endorse the role of an umbrella species, in the hope that the protection of the surrogate’s habitat will simultaneously benefit the array of species encompassed within it.
In Fennoscandia and Eastern Europe, the White-backed Woodpecker (Dendrocopos leucotos) was proposed as an umbrella species for the saproxylic guild, including beetles. While the bird species went locally extinct due to intensive logging activity, it is now recolonizing its former habitat by expanding its breeding home range to extensively managed forest stands of central Europe. Because the bird species is often referenced as an old-growth deciduous forest specialist, conservationists questioned its role as a surrogate species for saproxylic beetle diversity in this specific anthropized context. The aim of the presented study is to fill in the knowledge gap regarding the relation between the central European White-backed Woodpeckers population and the saproxylic beetle communities.
From 2018 on, I characterized saproxylic beetle communities found in the White-backed Woodpecker habitat using three different sampling methods. First, passive and non-attractive flight interception traps were used to quantify flying beetle communities occurring at the woodpecker’s breeding home range scale. Second, in situ eclector traps were used to directly quantify communities emerging from dead standing trees, informing on the beetle species associated to this type of dead wood, referenced as of prime importance in the bird’s foraging strategy. Third, standardized fresh dead wood items were exposed for colonization along the vertical axis of the forests and set in rearing traps, informing on the colonization potential of the woodpecker’s habitat by the pioneer saproxylic beetle guild. While the first two methods were capitalizing on local radio-frequency data to quantify the White-backed Woodpecker’s activity, either in its breeding home range or in absence sites, the vertical stratification experiment was conducted in presence/absence sites distributed in along the western-Eurasian distribution of the woodpecker and as a collaboration between several research institutes.
I found the number of flying threatened saproxylic beetle species to be positively correlated with the White-backed Woodpecker’s activity. In addition, multiple saproxylic beetle species – including threatened ones – were to be associated with the bird’s breeding home range, emphasizing the importance of its habitat for saproxylic beetle diversity. Saproxylic beetle communities emerging from dead standing trees were highly heterogeneous, regardless of the White-backed Woodpecker activity, emphasizing the overall importance of this type of dead wood items in supporting local saproxylic beetle diversity. Experimental study of dead wood colonization along the three forest strata revealed strong partitioning of the community as a function of elevation above ground and exposure time, highlighting the importance of a diversified dead wood resource, both along a temporal continuum and in the vertical gradient of the forest.
In addition to evidencing the role of the White-backed Woodpecker as an umbrella species for threatened saproxylic beetles and indicator for forest naturalness, I propose an extensive framework for conservation programs aiming at supporting dead-wood dependent biodiversity. We believe this work will contribute to opening new opportunities for using the White-backed Woodpecker as a meaningful surrogate species for central European saproxylic diversity.