Spatial analysis of the habitat and distribution of Osmoderma eremita (Scop.) in trees outside of woodlands

Abstract

The endangered and specialised saproxylic beetle Osmoderma eremita occurs in veteran trees, a habitat particularly threatened by changes in agricultural landscapes. Its conservation requires information about populations and key features of host trees. Surveys of 8,014 trees (pollarded or in hedgerows) were carried out and analysed, based on habitat description (tree level) and spatial information (hedgerow length and distance to the nearest inhabited tree). A suitable cavity was present in 61% of the trees and O. eremita was detected in 42 trees, mainly in Salix (30 observations), the most common tree amongst those surveyed. A small or absent crown was a significant factor in explaining the beetle's presence, as was the distance to the nearest inhabited tree. The largest population of O. eremita, 19 inhabited trees, was found in a wide and continuous area formed by trees with suitable cavities, with distances of less than 250m from each another. Seven smaller areas, with 7, 5 or 1 inhabited trees, were also found. When analysing inhabited trees on a 1km² grid, 17km 2 hosted O. eremita, corresponding to a dense network of 63km of hedges. The presence of O. eremita significantly increased per km² with increasing length of hedges and this variable was thus used to guide forthcoming investigations directed toward Osmoderma. As the hedgerows existing in 1999 had decreased by 6.1% in 2009, it is concluded that the long term survival of O. eremita is under threat. The preservation of trees outside woodlands is urgent and has already started, in connection with Natura 2000 policies. Regeneration and creation of new hedgerows is also ongoing and can be reinforced both by using Salix and by promoting pruning to increase formation of cavities. RESEARCH ARTICLE Launched to accelerate biodiversity conservation A peer-reviewed open-access journalBenoît Dodelin et al.

Ecological network for species dependent on ancient broadleaf trees using Osmoderma barnabita as a model species: a new approach

“…Although O. barnabita is considered to be poorly flying, it is assumed that its individuals mainly fly no more than a few hundred meters (Ranius & Hedin, 2001;Hedin et al, 2008;Dubois & Vignon, 2008;Dodelin et al, 2017). This study used hexagons, which size is based on the maximum flight range of the beetle in the study area of 2.09 km (Valainis et al, 2015).…”

“…Such corridors promote movement and genetic exchange between populations that have become isolated through habitat loss and fragmentation which facilitates the conservation of protected species (Drag et al, 2011;Alexander et al, 2016). The distance to the nearest tree inhabited by O. barnabita is one of the most important variables determining fragmentation (Dodelin et al, 2017). Different techniques yield different ranges of hermit beetle dispersal: 0.19 km (Ranius & Hedin, 2001) and 2.09 km (Valainis et al, 2015) in mark-recapture studies; about 0.50 km calculated with DNA markers (Oleksa et al, 2013); and a maximum single flight distance of 1.45 km and a maximum cumulative flight distance of 2.36 km obtained with a flight mill (Dubois et al, 2010).…”

“…Radio-tracking yielded maximum flight distances of 0.18 km (Hedin et al, 2008), 0.70 km (Dubois & Vignon, 2008), and 1.50 km (Chiari et al, 2013). According to Dodelin et al (2017), 39% of dispersing individuals reached distances greater than 0.25 km. The O. barnabita relocation distance, which was taken as the hexagon's radius, determines the integrity of ecological corridors.…”

Distribution and habitat suitability of two rare saproxylic beetles in Croatia - a piece of puzzle missing for South-Eastern Europe

“…All these are pointing that MaxEnt habitat suitability models spatially coincide with areas in which management practice should promote sustainability of the microhabitats suitable for the saproxylic beetles. Furthermore, hermit beetle is "not an easy to record" species, which can use even nonwoodland habitats (Dodelin et al 2017). Hence, knowledge of its populations, in particular in forest stands, may provide information for appropriate management of the forests that should ensure hermit beetle survival.…”

First Data on the Investigation of Gut Yeasts in Hermit Beetle (Osmoderma barnabita Motschulsky, 1845) Larvae in Lithuania

“…It is worth noting that dead or decaying wood actually represents a significant pool of organic C, energy, and other nutrients [1]. The Osmoderma chafers are a type of saproxylic insect that can be found inhabiting hollows in deciduous trees, including oaks, ashes, limes, and beeches [2][3][4][5][6][7]. They belong to the family Cetoniidae (order Coleoptera).…”