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Collecting quantitative data on insect species occurrence and abundance is a major concern to document population trends. This is especially the case to assess the conservation status of species listed in the European Habitats Directive and to assess the efficiency of mitigation measures with a view to achieve the "no net loss of biodiversity" goal for protected species. However, at present, populations of riverine dragonflies listed in the Habitats Directive and protected under French national law are poorly quantified and monitored. Exuviae collection could be used for such monitoring but a standardised protocol is lacking. We here proposed and tested such a protocol to monitor riverine dragonfly populations through exhaustive exuviae collection along river bank transects. To define the optimal transect size and number of visits, ninety-eight 100 m-long transects divided into 10 m-long plots were monitored on three rivers in southern France. Each transect was visited three times over the emergence period. In the course of each visit, all the exuviae along transects were collected and identified. From our results, we recommend collecting exuviae along 100 m of river bank in the course of two visits in order to both maximise the species detection and minimise the monitoring cost. [ABSTRACT FROM AUTHOR]

Aim: Animal movement determines home range patterns, which in turn affect individual fitness, population dynamics and ecosystem functioning. Using temperate bats, a group of particular conservation concern, we investigated how morphological traits, habitat specialization and environmental variables affect home range sizes and daily foraging movements, using a compilation of 30 years of published bat telemetry data. Location: Northern America and Europe. Time period: 1988–2016. Major taxa studied: Bats. Methods: We compiled data on home range size and mean daily distance between roosts and foraging areas at both colony and individual levels from 166 studies of 3,129 radiotracked individuals of 49 bat species. We calculated multi‐scale habitat composition and configuration in the surrounding landscapes of the 165 studied roosts. Using mixed models, we examined the effects of habitat availability and spatial arrangement on bat movements, while accounting for body mass, aspect ratio, wing loading and habitat specialization. Results: We found a significant effect of landscape composition on home range size and mean daily distance at both colony and individual levels. On average, home ranges were up to 42% smaller in the most habitat‐diversified landscapes while mean daily distances were up to 30% shorter in the most forested landscapes. Bat home range size significantly increased with body mass, wing aspect ratio and wing loading, and decreased with habitat specialization. Main conclusions: Promoting bat movements through the landscape surrounding roosts at large spatial scales is crucial for bat conservation. Forest loss and overall landscape homogenization lead temperate bats to fly further to meet their ecological requirements, by increasing home range sizes and daily foraging distances. Both processes might be more detrimental for smaller, habitat‐specialized bats, less able to travel increasingly longer distances to meet their diverse needs. [ABSTRACT FROM AUTHOR]

Organisms associated with dead wood (i.e. saproxylic species) are threatened by intensified forest and agricultural management. For a majority of saproxylic beetles the detailed information on their habitat requirements is still lacking, thus hindering efficient conservation information. This also applies to the violet click beetle ( Limoniscus violaceus), one of the umbrella species of European saproxylic beetle fauna. This specie needs basal tree hollows for its larval development., We studied habitat preferences of L. violaceus in basal tree hollows using emergence traps installed on 208 trees located in five sites in France. We used logistic regressions and recursive partitioning methods to understand the species-habitat relationships and to identify key environmental variables to predict the occurrence of L. violaceus., The probability of occurrence of L. violaceus in basal hollows increases with increased tree circumference at 30 cm above ground and with increased hollow decay stage. The analysis of threshold values shows that the occurrence of the beetle is relatively high in trees that have a circumference greater than 360 cm, uncertain for those between 235 and 360 cm, and improbable for circumferences lower than 235 cm. Similarly, the occurrence of L. violaceus was probable in advanced stages of hollow decomposition and improbable in early stages., Our results provide non-specialists with helpful habitat features of an umbrella species which is hard to detect. This will increase the ability of conservation managers to identify sites that deserve protection and better monitor the habitat of many saproxylic species associated with basal hollow trees. [ABSTRACT FROM AUTHOR]

European forest managers are implementing set-aside measures in managed forests to restore key structures for forest biodiversity such as tree-related microhabitats (TreMs). However, the time required to regenerate these structures is little known. We assessed the patterns of thirteen TreM types on 282 plots in 24 lowland forests in southwestern France. We applied a synchronic sequence ranging from 1 to 80 years after the last harvest, a time frame which is considered long enough to observe significant changes in the TreM profile. We sampled lowland beech–oak coppice-with-standards stands representative of the different forest ownerships and management regimes occurring in France; our assessment included both public and private forests with or without formal management plans. We found that both TreM density and diversity just after harvesting were lower, though not significantly so, in private stands without any management plan than in the other management regimes. We observed both significantly higher TreM density and diversity in plots harvested 10–15 years ago than in plots harvested 1–5 years ago. The next marked difference did not occur until stands had been harvested 70–80 years ago. Globally, time since last harvest was the best explanatory variable for variations in both TreM density and diversity. We therefore recommend: (1) conserving more habitat trees in harvested areas, particularly cavity trees, since the densities we observed were much lower than the densities required by cavity-dwelling species, and (2) letting set-aside patches freely complete several full silvigenetic cycles. This latter practice would avoid the inefficacy (or possibly even negative effects) of a temporary conservation network, and would also simplify management of the network over time. Further research should assess TreM occurrences in a permanent reserve network. Diachronic observations would make it possible to highlight the drivers of TreM profile development. [ABSTRACT FROM AUTHOR]