Using Sex Pheromone and a Multi-Scale Approach to Predict the Distribution of a Rare Saproxylic Beetle

Najihah Musa,Fredrik Andersson,Klas Andersson,Erik Hedenström,Inis Winde,Karl-Olof Bergman,Heidi Paltto,Joseph Burman,Per Milberg,Nicklas Jansson,Lars Westerberg,Mattias C Larsson

doi:10.1371/journal.pone.0066149

Najihah Musa, Fredrik Andersson + Show 10 more

Open Access

https://doi.org/10.1371/journal.pone.0066149

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Abstract

The European red click beetle, Elater ferrugineus L., is associated with wood mould in old hollow deciduous trees. As a result of severe habitat fragmentation caused by human disturbance, it is threatened throughout its distribution range. A new pheromone-based survey method, which is very efficient in detecting the species, was used in the present study to relate the occurrence of E. ferrugineus to the density of deciduous trees. The latter data were from a recently completed regional survey in SE Sweden recording >120,000 deciduous trees. The occurrence of E. ferrugineus increased with increasing amount of large hollow and large non-hollow trees in the surrounding landscape. Quercus robur (oak) was found to be the most important substrate for E. ferrugineus, whereas two groups of tree species (Carpinus betulus, Fagus sylvatica, Ulmus glabra, vs. Acer platanoides, Aesculus hippocastanum, Fraxinus excelsior, Tilia cordata) were less important but may be a complement to oak in sustaining populations of the beetle. The occurrence of E. ferrugineus was explained by the density of oaks at two different spatial scales, within the circle radii 327 m and 4658 m. In conclusion, priority should be given to oaks in conservation management of E. ferrugineus, and then to the deciduous trees in the genera listed above. Conservation planning at large spatial and temporal scales appears to be essential for long-term persistence of E. ferrugineus. We also show that occurrence models based on strategic sampling might result in pessimistic predictions. This study demonstrates how pheromone-based monitoring make insects excellent tools for sustained feedback to models for landscape conservation management.

Highlights

Temperate ecosystems in Europe have been heavily altered by human disturbances to the extent that natural ecosystems are absent or fragmented over large areas [1]
The Effect of Hollow Tree Stage for Elater Ferrugineus The occurrence of E. ferrugineus was significantly explained by the density of trees in all three tree hollow categories, and the relationships were increasingly stronger at larger spatial scales (Figure 2)
The occurrence of E. ferrugineus was better explained by the density of large trees in the surrounding landscape, regardless of presence/absence of hollows in the trees, compared to small hollow trees

Summary

Introduction

Temperate ecosystems in Europe have been heavily altered by human disturbances to the extent that natural ecosystems are absent or fragmented over large areas [1]. (Coleoptera: Elateridae), the red click beetle, is one of the species associated with wood mould of old hollow deciduous trees, and is negatively affected by the massive loss of hollow deciduous trees caused by forestry and changing agricultural practices [3]. This beetle is classified as vulnerable in the Swedish Red List [4]. In conservation management, it might function as an umbrella species, and knowledge about its habitat requirements might be generally applicable to other species. For example, considered a main predator on another umbrella species, Osmoderma eremita [5,6]

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