Can pinewoods provide habitat for a deciduous forest specialist? A two-scale approach to the habitat selection of Bechstein's bat (original) (raw)
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Acta Chiropterologica, 2008
Most of the little information available on the foraging ecology of the threatened Geoffroy's bat Myotis emarginatus refers to areas outside the Mediterranean Basin. In this study, we analysed habitat selection by this species in a typical Mediterranean landscape. We radio-tracked a breeding colony (adults and juveniles) in the Iberian Peninsula and analysed habitat selection patterns. Although we confirmed the species' preference for forest, olive groves also appeared an important foraging habitat for both adults and juveniles. Juveniles proved to be less mobile than adults, moving on average 1.6 km less than adults in displacements to foraging sites and preferred more accessible habitats. We highlight here the importance of traditionally managed olive groves as foraging sites for this threatened bat. The ripping-up of ancient olive groves and their replacement by intensively managed cropland, urban areas or shrubland represents a significant threat for this vulnerable species in Mediterranean landscapes.
Forest cover in Europe has substantially increased in recent decades, resulting in extensive secondary forest cover (ca. 10–20 years) that is too young for many specialist forest-dwelling species. In the Mediterranean region, forests have historically been logged with detrimental effects on local biodiversity. Only a few small forest patches remain untouched. Specialist forest-dwelling species are often less studied than other species due to their lower population densities and the inherent difficulties involved in sampling. In fact, some forests species have only recently been discovered or described such as the Myotis alcathoe (Alcathoe bat) and so there is a remarkable dearth of information regarding their natural history, habitat requirements and conservation status. A total of 18 M. alcathoe bats were captured and radio-tracked in a 100-year-old Mediterranean forest which led us to locate and describe 18 different tree roosts. The structural traits of each roost and the surrounding habitat were studied to unravel the factors involved in roost selection. Alcathoe bats were found roosting in a wide variety of sites (holes, cracks and under bark) and tree species. Around 70% of the roosts were found in dead or decrepit trees. However, except for roost height, no special traits were selected. Due to the maturity of some common holly Ilex aquifolium, this typically secondary bush species was often used as a breeding roost. Our results provide new insights into how old and small secondary tree species play an essential role in the conservation of certain forest species. Considering that in 20 years of bat surveys in the region, breeding colonies of this forest species have only been found in this forest characterized by its remarkable maturity (50–100 dead trees/ha), we suggest that current forest management guidelines (recommending densities of 5–10 dead trees/ha), might not be enough to ensure the presence of breeding colonies of these tree-dwelling bats.
Forests
Bats are primarily forest mammals and forest structure may affect their communities through the level of vegetation clutter. Pine plantations are typically even-aged managed forests that lack structural complexity. However, an understory layer can enhance the heterogeneity of these forests, making them suitable for several animal taxa. We hypothesized that species composition, richness, and foraging activity of insectivorous bats in pine plantations vary according to forest structure, specifically with the density of the understory. We measured pine density, Diameter at Breast Height (DBH), canopy closure, and vegetation cover of 29 pine (Pinus halepensis) plantations of the Judean Lowlands, Israel, and collected acoustic data on resident bats. We found that bat species richness and total activity increased in forests with large tree DBH and dense shrubs. Cluttered-habitat species foraged preferentially in forests with large tree DBH and high pine density, while open-habitat species...
Forest Ecology and Management 293: 161–170, 2013
Habitat loss and degradation are perceived as main factors threatening biodiversity. Historical rather than contemporary processes are often responsible for present patterns of species’ distribution, but their respective contributions are not always easy to disentangle. The strict forest specialist, sedentary, highly phylopatric Bechstein’s bat (Myotis bechsteinii) is an ideal model species to assess the effect of historical landscape transformations in the current distribution patterns of forest species. Although to date the species has been considered almost absent from the Mediterranean range (Southern Europe), recently it has been shown to be common in certain spots there. We test whether the present distribution and ecological preferences of the species in this area are related to biogeographical constraints or to clearance of forests from preferred areas. We assessed roost selection, spatial ecology, foraging habitat selection, and prey selection in Atlantic and Mediterranean domains of the Iberian Peninsula. Ecological requirements appeared conserved throughout, but roost selection appeared less constrained in the Mediterranean localities. Hunting occurred preferentially inside closed deciduous oak forest in both regions, but commuting distances and foraging areas were larger in the Atlantic, together with higher habitat fragmentation and lower prey availability. The same prey taxa were eaten in both regions, although their frequency in the diet varied, matching differences in availability. Consequently, scarcity of these bats in Mediterranean Iberia seems to be better explained by the retreat or loss of deciduous forests due to human impacts, coupled with climate change.
mamm, 2003
We have carried out a first research on habitat selection in Rhinolophus euryale with the aim of assessing if landscape changes may be involved in the current decline of this species. During May 2000 nine bats were tagged with small radio-transmitters, in a spring colony in Urdaibai Biosphere Reserve (Basque Country). We gathered a total of 133 locations in 23 tracking nights. Every night each bat moved to an individual feeding area, travelling as far as 10 km from the roost. Meadows were avoided. Forests were used extensively, where bats flew both along forest edges or within the canopy. Pine plantations were negatively selected with 25 % of fixes gathered in pine wood. Native deciduous forests and eucalyptus plantations were selected positively. The scarcity of deciduous woods, the intense use of exotic plantations, and the extremely large foraging radius suggest that the studied area is a suboptimal landscape for the species.
Acta Chiropterologica, 2003
In a previous study on habitat use by Rhinolophus euryale in an Atlantic area (Northern Iberian Peninsula), this bat species foraged exclusively in woodland, including both native deciduous woodland and exotic plantations. As the study was carried out in a landscape that was profoundly altered by industrial forestry, we predicted that in a better preserved landscape this species would select smaller feeding areas located at closer distances from the roost, according to the optimal foraging theory, and would use almost exclusively the preferred habitat, i.e., native deciduous woodland. To test these hypotheses, we radiotracked 14 R. euryale from the largest known breeding colony of northern Iberian Peninsula and determined their habitat selection, spatial foraging pattern, and hunting behaviour. Our predictions on habitat selection, as well as on the foraging site size and on commuting range were confirmed. Rhinolophus euryale used almost exclusively native deciduous woodland, and hedgerows were positively selected. We suggest that the richness of tree species in hedgerows provides a high prey availability sustained in time and space. Our findings show that habitat disturbance constitutes a major cause of decline for R. euryale in the study area.
Urban Ecosystems, 2020
Urban areas are increasing globally causing fragmentation and loss of habitats for many forest dwelling species. At the same time new habitats are created, which may be exploited by species with a broad ecological tolerance. Bats form the largest mammal group living in cities in Central Europe. Species diversity might be higher in some cities compared to rural areas. Yet, habitatspecialists struggle with rapid landscape change and urban development. The Bechstein's bat Myotis bechsteinii is dependent on old growth deciduous forests that supply tree cavities to roost in. The use of small home ranges requires high prey abundance around roosts. Despite their habitat specialization we identified two Bechstein's maternity colonies within the metropolitan area of Frankfurt/Main (Germany). The colonies numbered 25 and 31 adult females respectively. We radio tracked individuals from both colonies (n = 14) and compared their habitat use to that of females (n = 79) of 11 colonies from rural woodlands. We identified a total of 29 roosts used by the two maternity colonies during summer. Roost choice of the urban forest colonies was similar to the rural forest colonies with a preference for oak trees with woodpecker holes. The distances between roosts were similar between urban and rural colonies. Habitat selection was strongly towards old forest patches. We emphasize the importance of the persistence of old forest islands within urban areas to support remaining bat colonies with a network of bat areas, similar to the important bird areas (IBAs). Specialized species that fail to adapt to the rapid changes may survive within the urban environment relying on old forest patches.
Bat ecology and conservation in semiarid Mediterranean landscapes
This doctoral thesis is composed by four articles that have been published in international journals, attempts to resolve questions related with the biology, ecology and conservation of bats in semiarid Mediterranean landscapes (SE Spain). The research effort focused on fundamental aspects of bat biology that is take into consideration in preliminary studies in areas for which little information exists and where conservation measures need to be applied. The first article is a biometrical study of the wing measurements of Myotis myotis. The aims were: 1) to ascertain whether sexual size dimorphism (SSD) applies to wing measurements and to determine which of these measurements are more discriminant, 2) to check whether there are differences between paired and single males inside the swarming roosts, and 3) to discuss the ecological implications of SSD in this species. Our results confirmed SSD in M. myotis, where females are significantly bigger than males. The forearm and third finge...
Journal of Zoology, 2007
We recorded bat activity on Zakynthos island (Greece) to test the hypotheses that (1) olive (Olea europea) groves and native woodlands provide comparable foraging habitat for insectivorous bats, (2) lower foraging activity occurs in olive groves treated with insecticide chemicals. We acoustically sampled bat activity (passes per minute) in four wooded habitats (organic and non-organic olive groves, oak woodland (Quercus ilex and Quercus coccifera) and pine (Pinus halepensis) woodland from June to August 2005. Habitat type did not affect overall bat activity. A single application of insecticide chemicals annually did not affect activity over traditional olive groves. Habitat use on the island differed in several ways from that reported in studies at mainland sites. Most strikingly, pine woodland supported higher bat activity than expected relative to other habitat types, and we recorded unexpectedly high levels of M. capaccinii activity in woodland habitats. We suggest that traditional olive groves buffer some bat species from the effects of deforestation. Conservation plans for Mediterranean bats should consider the biodiversity value of these groves along with the need to conserve small woodland patches. Finally, understanding island-specific patterns of habitat use is essential to bat conservation on small offshore islands.