Heritage Trees as an Important Sanctuary for Saproxylic Beetles in the Central European Landscape: A Case Study from Litovelské Pomoraví, Czech Republic

Abstract

Intensive forest and agroforestry management has greatly reduced the biodiversity of saproxylic organisms. Large trees are one of the most important refuges of saproxylic beetles. These large trees that grow outside and inside the forest are declining in the wider landscape. Heritage trees are one of the essential groups of beneficial trees in the landscape. We investigated saproxylic beetles associated with 35 selected oak heritage trees in Litovelské Pomoraví in the eastern Czech Republic. The study aimed to investigate the distribution of saproxylic beetles on trees growing inside or at the edge of forest stands, or on free-growing heritage trees. The other studied variables were the height, DBH, and light condition (sunny or shady) of heritage trees. The results showed that sunny habitats were the only significant factor found for all saproxylic species. However, the significance of increasing tree trunk dimension was found for the endangered species. Diversity indices q = 0 (species richness) and q = 1 (exponential of Shannon entropy index) were also higher for sunny trees, while solitary trees showed a high Shannon index value despite the low number of samples. Redundancy analysis of saproxylic species showed that the preferred habitats of most species were sunny massive solitary oaks. The results indicated that strictly protected heritage trees scattered in the landscape are crucial sanctuaries for many species—especially in landscapes where there are not enough suitable habitats for saproxylic beetles. Finding, conserving, and protecting these rare types of massive trees in the landscape has a significant impact on the conservation of saproxylic beetle biodiversity.

Understanding the Coleoptera community at the tree‐line using taxonomic and functional guild approaches

“…Our results are generally consistent with those of Wermelinger et al (2007), Seibold et al (2016), Vogel et al (2020) and Oto et al (2022). These studies showed high affiliation between Coleoptera and open space, forest edges and/or sunlight.…”

“…Plots at higher elevations had lower levels of basal area and were more open (Table 2). While the mechanisms driving higher abundance at higher elevations do not necessarily include the higher levels of open space at higher elevations, the affiliation of saproxylic Coleoptera to both open space and edge habitat is supported by other studies (Oto et al, 2022; Seibold et al, 2016; Wermelinger et al, 2007). Open space and edge habitat can be a proxy for sunlight, and higher amounts of sunlight‐exposed substrate are known to be important predictors of saproxylic biodiversity (Jonsell et al, 1998; Lindhe & Lindelöw, 2004; Thorn et al, 2016; Vogel et al, 2020).…”

“…Moreover, a visual inspection of the datasets revealed that month had a parabolic‐shaped response for abundance and richness, which led us to also include month‐squared as a predictor (in R syntax, I (month 2 )) in those analyses. These landscape and stand variables were chosen as they are characteristics often found to be influential in saproxylic species distributional patterns (Müller & Bütler, 2010; Oto et al, 2022; Schiegg, 2000; Thorn et al, 2016). Plot was inserted as a random factor.…”

Trapping liquids may bias the results of beetle diversity assessment

“…A higher number of species was recorded in sunny plots, which implies that beetles prefer sunny habitats ( e.g. , Lettenmaier et al, 2022 ; Nakládal et al, 2022 ). Beer and wine consistently captured higher numbers of beetle species than vinegar and water in sunny plots.…”

“…Besides aqueous solutions with different preservatives, fermenting (attractive) liquids are also used to study beetle communities ( Ruchin, Egorov & Khapugin, 2023 ). Some studies have used beer, wine, and vinegar as trapping fluids to assess beetle biodiversity in relation to surrounding environmental conditions ( Ruchin & Egorov, 2021 ; Nakládal et al, 2022 ; Spina et al, 2023 ) or to monitor target groups, e.g. , stag beetle (Lucanidae) ( Bardiani et al, 2017 ), flower chafer (Scarabaeidae: Cetoniinae), longhorn beetle (Cerambycidae) ( Touroult & Witté, 2020 ) or social wasps (Hymenoptera: Vespidae) ( Dvořák & Landolt, 2006 ).…”