Species ecological preferences predict extinction risk in urban tenebrionid beetle guilds

A number of studies have attempted to investigate which species traits influence species proneness to extinction in vertebrates. By contrast, studies involving insects are scarce, because of difficulties in obtaining complex assessments of species extinction risk and measures of species traits. In this paper, a simple (binary) codification based on literature data and field observations was used to determine the importance of various traits (notably ecological preferences) in determining species vulnerability of the tenebrionid beetles inhabiting urban Rome (Italy). Vulnerability scores were calculated from measures of geographical, habitat and population rarity. Vulnerable species were distributed with similar proportions among different tenebrionid guilds, which suggests that conservation programs in urban ecosystems should be more addressed to the development of species-oriented actions than to the identification of priority `habitats'. Species traits accurately predicted species assignment to vulnerability classes, with some traits being particularly important in determining species vulnerability. Species associated with ruins and cellars, and which are typically fairly common in Rome, tend to be moderately or middle vulnerable. The identification of important sites for these species and definition of measures for population management would be useful strategies to preserve them.