Journal of Insect Conservation

Bengtsson, V.; Wheater, C. P.; Hedin, J.; Appelqvist, T.; Niklasson, M.

doi: 10.1007/s10841-026-00788-7pmid: N/A

Veteran oaks are vitally important for saproxylic beetles due to the diversity of tree-related microhabitats they contain which have developed over centuries. Veteran oaks are however in decline across Europe. Veteranisation is a conservation tool that aims to create or speed up the formation of these rare microhabitats, potentially helping to mitigate losses, although empirical studies on the effectiveness of veteranisation are still very rare. We compared flight interception trapped beetle assemblages from 2-year old veteranised cavities in young oaks (2 methods: ‘nestbox with topping’ – NBT (n = 28) and ‘woodpecker hole’ – WPH (n = 26), with untreated control trees (n = 29) across 14 sites in southern Sweden. In total, 13010 individuals representing 493 beetle species were identified, of which 315 were saproxylic. The trapped beetles were assigned into one of four guilds with respect to their ecological association with wood (‘wood-living’, ‘partly wood-living’, ‘associated with wood living fungi’ and ‘other, non-saproxylic’). Both NBT and WPH supported significantly higher numbers of species and individuals than controls, particularly within the wood-living guild. Species such as Cryptarcha undata, Haploglossa villosula, and Quedius mesomelinus were abundant, reflecting an early-successional community. The presence of Lymexylon navale (NT) and Carphacis striatus (VU) indicates that the cavities provide ecologically relevant cues, even though reproduction could not yet be confirmed. No significant differences were detected between the two cavity types, suggesting that exposure of fresh wood and cavity creation alone are key drivers of early attraction. Our findings demonstrate that artificial cavities can rapidly increase habitat value for saproxylic beetles in young oaks, contributing to the restoration of oak sites.Implications for insect conservationArtificially created cavities in young oaks can rapidly attract saproxylic beetles. Such interventions can help alleviate the current scarcity of natural tree hollows, thereby reducing future extinction risks for saproxylic beetles associated.

Habel, Jan Christian; Schmitt, Thomas; Stockl, Barbara; Hailay, Gebreegziabher; Bezabih, Azmeraw Alemkere; Ulrich, Werner; Teucher, Mike; Eberle, Jonas

doi: 10.1007/s10841-026-00780-1pmid: N/A

Ecology and habitat demand of species determine their population structure and dynamics as well as their behaviour and responses to habitat changes. Species specialised to forest ecosystems are assumed to behave differently in these ecosystems than generalist species, which also occur in open ecosystems. For assessing how species with different ecological performance thrive in a small remnant forest, we selected two butterfly species with different degrees of habitat specialisation. We conducted a mark-release-recapture study in a church forest in northern Ethiopia to investigate the population ecology of these two species. As model species we selected the forest species Junonia terea and the habitat generalist Phalantha phalantha. We found for both species that one generation was fading out in the second half of the dry season but was substituted by the onset of eclosion of a follow-up generation. This population dynamic was also supported by population size dynamics, capture probability and survival probability. Life spans were comparatively short for both species, except for some few individuals. Dispersal behaviour of P. phalantha was very low, while J. terea was more dispersive, a common feature in forest butterflies. P. phalantha preferred habitats characterised by ground cover, litter, flowering plants and little shade. It thus preferred light spots inside the forest confirming the typical ecological niche of a generalist species being more common in open habitats than in forests. No habitat preferences were obtained for the euryoecious forest species J. terea, which thus occurs virtually anywhere in wooded habitats.Implications for insect conservationOur study clearly shows that the ecological performance of these two species had a significant influence on habitat selection, population dynamics, and behaviour. Our findings underline the high conservation value of still intact forest ecosystems to hold typical and highly specialized forest species.