Leonardo Ancillotto

Sensitivity of bats to urbanization: a review

In this article we review the current knowledge of the effects of urban expansion on bats and assess the potential of these mammals as bioindicators of urbanization. The response of bats to this process is highly species-specific: some species tolerate urban habitat or are even favoured by its roosting or foraging opportunities, others are affected by the loss or fragmentation of key natural habitat, or by the physical and chemical pollution associated with urbanization. Species responses generally translate into altered community structures, with few markedly dominating species. We propose different hypothetical models of bat fitness along an urbanization gradient and discuss why bat population density may not be an effective fitness proxy to assess the reactions of these mammals to urban expansion. We also suggest that urban habitat may act as an ecological trap even for apparently synurbic species. Overall, bat sensitivity to urbanization makes these mammals promising candidates to track the effects of this process of land use change on the biota, but more studies, specifically tailored to explore this role, are needed.

The post-release fate of hand-reared orphaned bats: survival and habitat selection

Although bats are frequently admitted to rescue centres — mainly as orphans — very little information is available on their survival after release. Our study answered the following questions: i) do hand-reared bats survive over a short time; ii) which activities and habitat selection do they exhibit; iii) are bats loyal to the release area; and iv) are they able to join local colonies? We radio-tracked 21 hand-reared Pipistrellus kuhlii over a two-year period released on a site that differed from that where they were rescued. At the study site they were provided with the same bat boxes used in the rehabilitation room. Nineteen bats were confirmed to survive, stay in the area and actively forage over 4–14 days. Fourteen day roosts in buildings (nine of which hosted a local colony) were used by 12 subjects. Bats travelled less than 5 km in total each night; their most frequent activity was night roosting, followed by foraging and commuting. We recorded typical foraging behaviour, including hunting around street lamps at sites exploited by many conspecifics. A comparison of habitats available within individual home ranges with those within the study area showed that urban areas, riparian vegetation and farmland were equally important and preferred to woodland. When the foraging time spent in each habitat was compared with habitat composition within individual home ranges or within the study area, urban sites were preferred for foraging over all other habitats, followed by farmland and woodland and finally riparian vegetation. Overall, we showed that hand-raised orphaned P. kuhlii may readily adapt to environments they are not familiar with, exhibit a high short-term survival and select key resources in the release area, provided appropriate rehabilitation and training techniques are adopted.

Rose-ringed parakeet **Psittacula krameri** populations and numbers in Europe : a complete overview

Alien species are considered one of the major causes contributing to the current loss of biodiversity. Over the past few decades, a large and increasing number of alien species have become invasive in many parts of the world. Their impacts range from competition for resources with native species to damage of urban infrastructure. In Europe, over a thousand alien species are now established, of which 74 are birds. Among 12 established alien parrot species in Europe, the Rose-ringed Parakeet (RRP) Psittacula krameri (Scopoli, 1769) is the most abundant and widespread. Since the 1960s, RRPs have established more than 100 wild populations in several European countries. For Western Europe, long-term demographic data indicate the species has grown considerably in number, although some populations have failed to persist. Data is scarce and dispersed for countries in Central, Eastern and Northern Europe. Therefore, here we present detailed demographic data of RRP for 90 populations in 10 European countries. Furthermore, we present information on the status of the species in another 27 European countries, for which previously no data were published. Our synthesis reveals a positive demographic trend across the continent, although locally, some populations appear to have reached carrying capacity.

The fancy city life: Kuhl's pipistrelle, Pipistrellus kuhlii, benefits from urbanisation

Abstract Context. Urbanisation is often regarded as a major threat to global biodiversity. Although wildlife is frequently affected by urbanisation, some species may actually benefit from it. Bats are among the commonest wild mammals in human-modified areas, and some species seem particularly well suited to exploit urban habitats where they find roosting and foraging opportunities. Aims. We investigated habitat selection around roosts of synurbic Kuhl’s pipistrelles, Pipistrellus kuhlii, in Italy. Methods. We measured the effects of the amount of urban habitat on bat reproductive timing and success in human-modified environments. Key results. We found that P. kuhlii selects roosts surrounded by areas featuring urban habitats, especially those subject to urban development. Colonies in cities and suburbs advanced parturition time and produced more pups than those in rural areas. Permanent water sources and artificial lights in the surrounding habitats also seemed to favour the species reproductive success, particularly in developing urban areas. Conclusions. Our results showed that this bat benefits from urbanisation and provided new insights on the effects of this major process on animal ecology and conservation in urban environments. Implications. Although the ecological flexibility and positive response to urbanisation of P. kuhlii may help explain its recent range expansion, the role of climate change as a potential driver of this process has yet to be tested.

The importance of non-forest landscapes for the conservation of forest bats: lessons from barbastelles (Barbastella barbastellus)

Although open landscapes are typically regarded as inhospitable matrix for several species of forest bats, their role may be crucial for maintaining gene flow among otherwise isolated populations occurring in distant forest fragments. The barbastelle (Barbastella barbastellus) is a bat species previously known to depend on mature forest and dead trees in its wide yet fragmented range. We tested the general hypothesis that viable populations of this bat may persist in open landscapes whose current structure is the result of historical deforestation. We unveiled the roosting and foraging ecology of B. barbastellus in a clay badland area of central Italy where forested habitats are absent and woody vegetation is scarce. Bats in badlands used rock crevices in lieu of the typical maternity tree-roosts and largely foraged in non-forest habitat, alongside riparian vegetation, where they found moth-rich hunting sites. Body condition and sex ratio did not differ from those documented in a source population found in mature forest in the same region. Our study identifies the hitherto overlooked importance of apparently unsuitable landscapes for the conservation of bats regarded as forests specialists and highlights that such environments and the associated occurrence of favoured prey should be carefully considered in management plans.

Selective aggressiveness in European free-tailed bats (Tadarida teniotis): influence of familiarity, age and sex.

Bats are highly social mammals that often form large groups and represent good models to test the role played by individual status in shaping social relationships. Social cohesion relies on the ability of group and individual recognition, which is mediated by a range of sensorial cues. In this study, we selected the European free-tailed bat Tadarida teniotis as a model species to test the effects of familiarity, sex and age on aggressiveness and mutual tolerance. We hypothesize that T. teniotis is able to recognize group members and exhibit selective aggressiveness, and thus we predict fewer aggressive events and more amicable encounters between colony mates than between strangers. As female bats are generally more sociable and perform prolonged parental care to juveniles even after weaning, we hypothesize that sex and age of bats have significant influences on aggressive behaviours and thus predict that females will perform more amicable behaviours than males and that adults of both sexes will be less aggressive towards juveniles. Our results confirm that T. teniotis is able to discriminate between familiar and stranger individuals, showing higher rates of aggressive behaviours towards the latter. Females are more prone to exhibit amicable behaviours, particularly during same-sex interactions, while males show higher level of aggressiveness. Juveniles are subjected to fewer aggressive behaviours by adults of both sexes. Familiarity appears crucial for T. teniotis in determining the degree of aggressiveness during social interactions but the rate of aggressive events is also influenced by intrinsic individual factors such as sex and age.

Coastal cliffs on islands as foraging habitat for bats

Small islands usually show simplified ecosystems with limited availability of suitable foraging habitats for bats, thus habitat selection on islands may differ compared to the mainland. Habitats that are marginal on the mainland may be important on islands. The island of Capri consists, to a large extent, of steep limestone cliffs and Mediterranean shrubland, with virtually no forests or other habitats preferred by bats on the mainland. In this study we tested the hypothesis that in resource-limited systems, such as islands, habitats generally deemed of minor value for bat foraging, such as cliffs, may become important. We conducted an acoustic survey of bats in Capri (SW Italy), comparing their use of Mediterranean shrubland and limestone cliffs. We found that cliffs provided the preferred foraging habitat in four of the five species tested. Noticeably, even the barbastelle bat Barbastella barbastellus, normally considered a forest specialist, selected coastal cliffs as foraging habitat. Our observations indicate that the paucity of foraging habitats on islands may strongly alter the habitat use by bats. This has important implications for conservation of bats in insular environments.

Macroparasites of introduced parakeets in Italy: a possible role for parasite-mediated competition

Alien species are considered a cause of biodiversity loss throughout the world. An important but often overlooked form of competition with native species is the parasite-mediated one. Introduced species may bring their own parasites from their native ranges (spillover) or get native parasites from native species, thus increasing the parasites’ spread and transmission risk (spillback). Thus, a complete knowledge of parasites hosted by introduced species is important to assess and to possibly prevent impacts. Ring-necked and monk parakeets have been introduced in many European countries, where they established a number of alien reproductive populations. We sampled 21 ring-necked parakeets and 7 monk parakeets from Italy and identified 35 arthropod ectoparasites belonging to five species. Amongst those, one species was native to India (Neopsittaconirmus lybartota), where alien populations of ring-necked parakeet may have been originated, and one species from South America (Paragoniocotes fulvofasciatus), which is typically found of the monk parakeet in its native range. The other three species of arthropod parasites were native to Italy and commonly found on native species, suggesting the possibility of spillback processes.

How to Be a Male at Different Elevations: Ecology of Intra-Sexual Segregation in the Trawling Bat Myotis daubentonii.

Intra-sexual segregation is a form of social segregation widespread among vertebrates. In the bat Myotis daubentonii, males are disproportionately abundant at higher elevations, while females are restricted to lower altitude. Intra-male segregation is also known to occur yet its ecological and behavioural determinants are unclear. We studied male segregation along a river in Central Italy where we tested the following predictions: 1. Upstream ( > 1000 m a.s.l.) males will rely on scarcer prey; 2. To deal with this limitation and exploit a cooler roosting environment, they will employ more prolonged and deeper torpor than downstream (< 900 m a.s.l.) males; 3. Body condition will be better in downstream males as they forage in more productive areas; 4. To cope with less predictable foraging opportunities, upstream males will use more habitat types. Consistent with our predictions, we found that prey were less common at higher altitudes, where bats exhibited prolonged and deeper torpor. Body condition was better in downstream males than in upstream males but not in all summer months. This result reflected a decrease in downstream males’ body condition over the season, perhaps due to the energy costs of reduced opportunities to use torpor and/or intraspecific competition. Downstream males mainly foraged over selected riparian vegetation whereas upstream males used a greater variety of habitats. One controversial issue is whether upstream males are excluded from lower elevations by resident bats. We tested this by translocating 10 upstream males to a downstream roost: eight returned to the high elevation site in 1-2 nights, two persisted at low altitude but did not roost with resident bats. These results are consistent with the idea of segregation due to competition. Living at high altitude allows for more effective heterothermy and may thus be not detrimental for survival, but by staying at lower altitude males increase proximity to females and potentially benefit from summer mating opportunities.

Sociality influences thermoregulation and roost switching in a forest bat using ephemeral roosts

Abstract In summer, many temperate bat species use daytime torpor, but breeding females do so less to avoid interferences with reproduction. In forest‐roosting bats, deep tree cavities buffer roost microclimate from abrupt temperature oscillations and facilitate thermoregulation. Forest bats also switch roosts frequently, so thermally suitable cavities may be limiting. We tested how barbastelle bats (Barbastella barbastellus), often roosting beneath flaking bark in snags, may thermoregulate successfully despite the unstable microclimate of their preferred cavities. We assessed thermoregulation patterns of bats roosting in trees in a beech forest of central Italy. Although all bats used torpor, females were more often normothermic. Cavities were poorly insulated, but social thermoregulation probably overcomes this problem. A model incorporating the presence of roost mates and group size explained thermoregulation patterns better than others based, respectively, on the location and structural characteristics of tree roosts and cavities, weather, or sex, reproductive or body condition. Homeothermy was recorded for all subjects, including nonreproductive females: This probably ensures availability of a warm roosting environment for nonvolant juveniles. Homeothermy may also represent a lifesaver for bats roosting beneath loose bark, very exposed to predators, because homeothermic bats may react quickly in case of emergency. We also found that barbastelle bats maintain group cohesion when switching roosts: This may accelerate roost occupation at the end of a night, quickly securing a stable microclimate in the newly occupied cavity. Overall, both thermoregulation and roost‐switching patterns were satisfactorily explained as adaptations to a structurally and thermally labile roosting environment.