Barbastella barbastellus (Schreber, 1774) en minas del Norte de Portugal: ¿un caso de “swarming”?

Abstract

Abstract:This study investigated the visitation of an underground site by bats during the "swarming" season (September and October) of 2009, 2011 and 2012, in a mine located in the Northeast Portugal (Vila Cova mine, 850 m a.s.l.). A total of 79 bats were captured, representing 12 of the 25 bat species identified in Portugal Continental. The Western Barbastelle (Barbastella barbastellus) was the most predominant species, with 31,6% of the captures. Although the relative low number of specimens captured, the species composition and their conservation status were significant due to the presence of Critical Endangered species (Rhinolophus euryale and Myotis blythii), Vulnerable species (Rhinolophus ferrumequinun, Rhinolophus hipposideros, Myotis myotis, Myotis escalerai and Miniopterus schreibersii) and species with Data Deficient (Barbastella barbastellus and Plecotus auritus). Considering that a just 5 hours sampling effort was conducted, the peak of the nocturnal activity was 3-4 hours after sunset, with statistically significant differences between males and females in the third hour after sunset (P=0,002). In total, 75,9% of the specimens captured were males, representing a sex ratio of 3♂♂:1♀♀. In the specific case of B. barbastellus the ratio was of 2:1. The peak of captures between males and females was different along time, with females arriving later to the mine. This behavior was also verified to B. barbastellus. The differences regarding Body Condition Index (BCI) between sexes in B. barbastellus were statistically different, with females presenting higher BCI than males (P=0,015). Undoubtedly, the conservation value of "swarming" sites is of special concern for bats management strategies, especially when used by species such as B. barbastellus, characterized by high level of philopatry within their populations.Keywords: Barbastella barbastellus, bats, conservation, Portugal, "swarming".Resumen: Este trabajo investiga la visita a un refugio subterráneo por los quirópteros en la época de "swarming" (septiembre y octubre) de 2009, 2011 y 2012, en una mina localizada en el Norte de Portugal (Mina de Vila Cova, 850 m.s.n.m). Fueron capturados un total de 79 quirópteros, representando 12 de las 25 especies existentes en Portugal Continental. El murciélago de bosque (Barbastella barbastellus) fue la especie predominante con el 31,6% de las capturas. A pesar del número relativamente bajo de individuos capturados, la composición de las especies y sus estatus de conservación son significativos, incluyendo especies En Peligro Crítico (Rhinolophus euryale y Myotis blythii), Vulnerables (Rhinolophus ferrumequinun, Rhinolophus hipposideros, Myotis myotis, Myotis escalerai y Miniopterus schreibersii) y especies con Información Insuficiente (B. barbastellus y Plecotus auritus). Teniendo en cuenta que se estudiaron 5 horas, el pico de actividad fue observado entre las 3 y las 4 horas después del ocaso, con diferencias estadísticamente significativas entre machos y hembras en la tercera hora después del ocaso (P=0,002)....