Insect Conservation and Diversity (2012) 5, 186–191 doi: 10.1111/j.1752-4598.2011.00149.x

Habitat requirements of the endangered schneideri (Panzer, 1796) (Coleoptera: ) _ _ LAIMA BLAZ ˇ YT E-C ˇ ERES ˇ KIEN E and VIDMANTAS KARALIUS Institute of Ecology of Nature Research Centre, Vilnius, Lithuania

Abstract. 1. To further knowledge regarding habitat requirements of the threatened species , a total of 1522 dead standing Scots pine ( Pinus sylvestris ) were checked for the presence of B. schneideri larvae. For the 245 trees inhabited by larvae (16% of all examined trees), tree characteristics and occupancy patterns were measured. 2. As most of the investigated forests were 40–80 years old and were dominated by comparatively thin dead trees (5–20 cm diameter at breast height), B. schneideri larvae were mainly found under the bark of trees with a diameter in the range of 10–20 cm. However, the probability of a tree being inhabited by B. schneideri increased progressively with tree diameter and forest age. 3. Most of the trees with B. schneideri (79%) were in medium-dense and sparse- growth pine forests where the canopy cover was 60–80%. The presence of Norway spruce ( Picea abies ) in Scots pine forests was an important factor affecting the proba- bility of trees being inhabited by B. schneideri . Only 6% of trees inhabited by B. sch- neideri were found in mixed Scots pine-Norway spruce forests, where the shadowing was higher than 80%. 4. All dead trees inhabited by B. schneideri had loose and at least slightly frag- mented bark. A bark area of 0.08 m 2 was found to be sufficient for the survival of B. schneideri . The critical bark thickness for B. schneideri larvae was 5 mm. 5. The data obtained are important for the optimisation of conservation measures implemented during forest management operations. Key words. Boridae, Boros schneideri , conservation, habitat, Pinus sylvestris , saproxylic beetle.

Introduction Success ofthe European network of conservation areas Natura 2000 depends on broad biological knowledge of the designated Dead wood is one of the most important substrata for maintain- protected species. To devise management plans and develop ing biodiversity in forest ecosystems (Esseen et al. , 1997). Inten- protected areas, it is necessary to carry out in-depth analysis of sive forest management has reduced the volume of dead wood habitat requirements of the target species. For this purpose, stud- and its diversity in many regions (Kaila et al. , 1997; Simila et al. , ies of habitat requirements of a few endangered saproxylic beetle 2003). As a result, due to a lack of suitable breeding substratum, species, such as Osmoderma eremita (Scopoli, 1763) (Cetoniidae) many saproxylic species (species that are dependent on decaying (Ranius & Nilsson, 1997), Cerambyx cerdo (Linnaeus, 1758) wood) have declined, and in the last few decades many have (Cerambycidae) (Buse et al. , 2007), Pytho kolwensis (Sahlberg , become threatened (Jonsell et al. , 1998; Tikkanen et al. , 2006). 1833) (Pythidae) (Siitonen & Saaristo, 2000) and Cucujus haema- Numerous ecological studies aimed at conserving the biodiver- todes (Erichson, 1845) (Cucujidae) (Horak et al. , 2010) have been sity of saproxylic species have been conducted (Ranius & Jans- conducted. son, 2000; Jonsson et al. , 2005; Lindhe et al. , 2005; Johansson, Boros schneideri (Panzer, 1796) is the only species in the family 2006; Tikkanen et al. , 2007; Alexander, 2008). Boridae occurring in Europe (Levkanic ˇ ov i˛, 2009). It is an endan- gered saproxylic beetle species listed in Annex 2 of the European Union Habitat Directive (Council Directive, 2006) and occurs Correspondence: Laima Blazˇyt e-C_ ˇ eresˇ kiene,_ Institute of Ecol- mostly in the Baltic area. The species has decreased in number ogy of Nature Research Centre, Akademijos 2, LT-08412 Vilnius- 21, Lithuania. E-mail: [email protected] over the past century. B. schneideri is extremely rare in the

Ó 2011 The Authors 186 Conservation and Diversity Ó 2011 The Royal Entomological Society