Demography and Dispersal Ability of a Threatened Saproxylic Beetle: A Mark-Recapture Study of the Rosalia Longicorn (Rosalia alpina)

Abstract

The Rosalia longicorn or Alpine longhorn (Coleoptera: Cerambycidae) is an endangered and strictly protected icon of European saproxylic biodiversity. Despite its popularity, lack of information on its demography and mobility may compromise adoption of suitable conservation strategies. The beetle experienced marked retreat from NW part of its range; its single population survives N of the Alps and W of the Carpathians. The population inhabits several small patches of old beech forest on hill-tops of the Ralska Upland, Czech Republic. We performed mark-recapture study of the population and assessed its distribution pattern. Our results demonstrate the high mobility of the beetle, including dispersal between hills (up to 1.6 km). The system is thus interconnected; it contained ∼2000 adult beetles in 2008. Estimated population densities were high, ranging between 42 and 84 adult beetles/hectare a year. The population survives at a former military-training ground despite long-term isolation and low cover of mature beech forest (∼1%). Its survival could be attributed to lack of forestry activities between the 1950s and 1990s, slow succession preventing canopy closure and undergrowth expansion, and probably also to the distribution of habitat patches on conspicuous hill-tops. In order to increase chances of the population for long term survival, we propose to stop clear-cuts of old beech forests, increase semi-open beech woodlands in areas currently covered by conifer plantations and active habitat management at inhabited sites and their wider environs.

Potential range of impact of an ecological trap network: the case of timber stacks and the Rosalia longicorn

“…The first relates to the radii of this impact. As mentioned earlier, these were taken from the study by Drag et al (2011). One may argue that less than 4% of individuals disperse over distances greater than 1000 m. However, this proportion applies only to recaptured individuals.…”

“…Regardless of the extent and the stage of decay, strong insolation is a feature common to the species' breeding substrate (Russo et al 2011). The Rosalia longicorn is highly mobile and its movement ability has been assessed at between 3000 m (Drag et al 2011) to more than 10 km (Lachat et al 2013). …”

“…8% of individuals; (B) 1000 m-the dispersal range of approx. 4% of individuals; (C) 1600 m-the maximum dispersal range found during a mark-capture-recapture trial; and (D) 3000 m-potential dispersal range based on modelling (Drag et al 2011).…”

Rural avenues as dispersal corridors for the vulnerable saproxylic beetle Elater ferrugineus in a fragmented agricultural landscape

“…Although our estimates are imprecise due to the lack of knowledge about the effective density and (possibly) its variability over the studied area, dispersal of several hundred meters is highly possible in this species. Zauli et al (2014) found that males of E. ferrugineus moved from the site of first capture covering a median distance of 214 m and approximately 50 % of individuals disperse not further than 250 m. Observed movement distances of other saproxylic beetles could comprise more than 700 m in a species which is believed to be poor flier (Dubois et al 2010;Oleksa et al 2013a) and even more than 10 km for species with high dispersal capacities (Jonsson 2003;Williams and Robertson 2008;Drag et al 2011). In this respect, E. ferrugineus can be regarded as a species with lower dispersal abilities, for which habitat continuity plays an important role.…”

Primer registro de <em>Rosalia alpina</em> (Linnaeus 1758) (Coleoptera, Cerambycidae) en <em>Prunus avium</em> (L.) (Rosaceae)

“…No trees meeting these habitat conditions were observed in the surroundings of the study area. The nearest records of R. alpina are from the Site of Community Interest of Hernio-Gazume (Castro et al, 2012), and located more than 2 km far away, exceeding the maximum dispersal distance known (=1628 m) of the species (Drag et al, 2011). However, recent genetic analysis suggests that R. alpina could have stronger dispersal abilities (Drag et al, 2015), allowing repeated colonizations of lowlands with less and more isolated available habitat (as it would be the case of the study area) from nearby mountains, where most part of the population would concentrate (case of Hernio-Gazume).…”