Translocation is an important tool in restoring biodiversity, particularly when species have been extirpated from an area. In the period just after release, the main objective of conservation managers is to keep as many of the translocated individuals in the release area as possible, in order to maximize the number of founders of the new population. Environmental and intrinsic factors, release conditions and social behaviour are likely to influence an individual’s propensity to move away from the release site (known as post‐release dispersal); however, few studies have explored the relative importance of these factors. The aim of this study was to evaluate how these four factors affected the post‐release dispersal of 169 Iberian ibex translocated from Spain to the French Pyrenees. We modelled the linear distance between the barycentre of each individual ibex’s monthly locations and the release site. Our results indicated that most individuals stayed close to the release site, but that inter‐individual variability was high. Post‐release dispersal was higher for males than females, with male breeders exhibiting higher exploration behaviour than juveniles. Release season played a major role, with dispersal being the lowest in spring and the highest during the rutting period. Dispersal was also found to be lower when conspecifics were present in the release area, probably due to their role as a cue for favourable habitat. These findings can be used by conservation managers to inform translocation strategies in order to enhance success: for example by releasing females and young males in spring and splitting a reintroduction project into successive release operations.
The diet of Miniopterus schreibersii was investigated by morphological analysis of prey remains in droppings from the spring to the autumn of 2000 from a bat roost in northeastern Slovenia (Central Europe). Lepidoptera dominated, having an average percent volume (APV) of 79% and constituting the bulk of the diet throughout the year. By decreasing importance in the diet, the insects identified were Neuroptera – mostly Chrysopidae (APV 9.2%), Diptera (APV 7.4%), Trichoptera (APV 2.2%) and Coleoptera (APV 1.4%). The diet was most diverse in late October. It seems that M. schreibersii is an aerial hawker that specialises in eating moths, but can opportunistically switch to other seasonably abundant prey. It hunts small- to medium-sized winged prey (wing length: 2–18 mm), of which most are tympanate insects.
Forests offer important refuge to bats by providing attractive roosting and foraging habitats. Their conservation is a major responsibility of forest managers. The use of tree cavities by bats in forests depends on the specific demands of each species, with a large range of different types of microhabitats utilised, from degraded cavities such as peeling bark to healthy hollows in live trees ensuring the temporal stability of the habitat. The conservation of tree-dwelling bats should not be dissociated from their fission-fusion behaviour which involves the use of many different roosts. Conservation measures must therefore take into account forest habitats suitable for feeding and in particular, forest parameters such as structure, composition, vegetation and foliage, among other elements such as deadwood, all upon which the forest manager can intervene. Acting in favour of bats requires close consideration of their complex individual responses concerning roost selection and foraging habitat selection, which is largely dictated by the reproductive status of individuals. Thereafter it is possible to evaluate the impact of wood harvesting on bats and to infer silvicultural conservation measures. The implementation of recommendations must then subsequently be based on a strong involvement on the part of the forest manager.
For studying the response of bat communities to urbanization in an area of the southern Mediterranean, acoustic and underground roost surveys were carried out in and around the city of Constantine. Echolocation calls of 10 species were recorded, with 6, 7 and 9 species in urban, suburban and rural areas, respectively. Pipistrellus kuhlii, P. pipistrellus, Tadarida teniotis, Hypsugo savii, Miniopterus schreibersii, and Eptesicus isabellinus were detected in all three area types. Myotis capaccinii was recorded only in a suburban site crossed by a permanent river. Activity of Rhinolophus ferrumequinum, Myotis punicus and M. emarginatus was restricted to a few sites in the rural area. The survey of underground roosts (mine, cave, tomb) added two bat species, Plecotus gaisleri and Rhinolophus hipposideros. Overall bat activity did not show an increase from urban to rural areas. The same pattern was reported for the most active species, P. kuhlii, whereas T. teniotis was more active in urban sites, and H. savii in rural sites. This first study of bat species richness and activity in a south-Mediterranean city should be extended to different periods, including winter, and different levels of urbanization.
31 October 2024 in Environmental Monitoring and Assessment