RESUMO
Mist nets are one of the most widely used techniques in the study of birds and bats worldwide. However, a number of risks are involved, including opportunistic predation. Given this potential cost, here we: (1) review the global literature to understand the factors that might contribute to predation risk for birds and bats captured in mist nets; (2) review existing guidelines for best practice use of mist nets; and (3) based on our reviews, recommend new guidelines for the use of mist nets to minimize the risk of opportunistic predation. Based on keyword in English, Spanish, Portuguese, and French, and using Google Scholar, Scopus, SciElo, and Web of Science, we found 48 articles reporting opportunistic predation. In the included articles, 178 predation events, involving 52 predator and 84 prey species, were reported. In most of the reports, the mist nets were placed at ground level, the bats and birds were preyed on from the shelf closest to the ground, the mist-net checks occurred at intervals of 1 h or 30 min and the most common predators were arboreal and scansorial species (primates and marsupials). Despite the occurrences of predation in 13 countries, guidelines for best practice mist-net use were found in only three, despite extensive searches and contact with key people in each country. Based on the existing guidelines and our results, we recommend that mist nets be fixed with the lowest shelf at least 50 cm above ground level and be checked at 15-min intervals; when predators are observed near mist nets, the nets either be constantly observed, closed, or relocated; suppressed the vegetation around the mist nets; captured animals be removed from the mist nets as soon as possible, and more than one researcher/technician should be in the field at all times.
RESUMO
Bats are the second-most diverse group of mammals in the world, and bat flies are their main parasites. However, significant knowledge gaps remain regarding these antagonistic interactions, especially since diverse factors such as seasonality and host sex can affect their network structures. Here, we explore the influence of such factors by comparing species richness and composition of bat flies on host bats, as well as specialization and modularity of bat-bat fly interaction networks between seasons and adult host sexes. We captured bats and collected their ectoparasitic flies at 10 sampling sites in the savannahs of Amapá State, northeastern region of the Brazilian Amazon. Despite female bats being more parasitized and recording greater bat fly species richness in the wet season, neither relationship was statistically significant. The pooled network could be divided into 15 compartments with 54 links, and all subnetworks comprised >12 compartments. The total number of links ranged from 27 to 48 (for the dry and wet seasons, respectively), and female and male subnetworks had 44 and 41 links, respectively. Connectance values were very low for the pooled network and for all subnetworks. Our results revealed higher bat fly species richness and abundance in the wet season, whereas specialization and modularity were higher in the dry season. Moreover, the subnetwork for female bats displayed higher specialization and modularity than the male subnetwork. Therefore, both seasonality and host sex contribute in different ways to bat-bat fly network structure. Future studies should consider these factors when evaluating bat-bat fly interaction networks.
RESUMO
Abstract: In recent years there has been an increase in research interest in remnants of Atlantic Forest above 500 m a.s.l., such as in the Serra da Mantiqueira, which is considered a priority area for conservation. The chiropterofauna of the Serra da Mantiqueira remains relatively under-studied, and here we present a list of bat species from the "Reserva Particular do Patrimônio Natural (RPPN) Cachoeira do Tombo", a private conservation unit located in an area of montane Atlantic Forest in the Serra da Mantiqueira. Bats were captured with mist nets along trails and near a diurnal roost. A total of 498 individuals of 19 bat species belonging to the families Phyllostomidae, Vespertilionidae and Molossidae were captured. Phyllostomidae were captured only along the trails, Molossidae were captured only in the diurnal roost and Vespertilionidae were captured in both. The species accumulation curves did not show stabilizing trends. However, 80% of the expected richness was sampled and the species richness of bats found is similar to other studies previously carried out in the region. In contrast to other inventories carried out in the Atlantic Forest, Desmodus rotundus was the species most frequently captured along the trails. A large number of individuals of Molossus aztecus sheltering in man-made structures were caught, constituting an unusual event. Additionally, here we report cohabitation of this species with Molossus molossus for the first time. Our results show that this area, which appears on the map of environmental conflicts for the state of Minas Gerais, has a rich chiropterofauna and also further corroborate the importance of using mist-nets at roosts to increase the probability of capturing the richness and abundance of insectivorous bats present in the area.
Resumo: Nos últimos anos houve um aumento no interesse em pesquisas em remanescentes de Floresta Atlântica acima de 500 m de altitude, como na Serra da Mantiqueira, a qual é considerada área prioritária para a conservação. A fauna de quirópteros na Serra da Mantiqueira ainda permanece relativamente pouco estudada, e aqui nós apresentamos uma lista de espécies de morcegos da Reserva Particular do Patrimônio Natural (RPPN) Cachoeira do Tombo, uma unidade de conservação privada localizada em área de Floresta Atlântica Montana na Serra da Mantiqueira. Os morcegos foram capturados com redes de neblina ao longo de trilhas e junto de um abrigo diurno. Um total de 498 indivíduos de 19 espécies de morcegos pertencentes às famílias Phyllostomidae, Vespertilionidae e Molossidae foram capturados. Phyllostomidae foram capturados somente em trilhas, Molossidae no abrigo diurno e Vespertilionidae em ambos. As curvas de acumulação de espécies não mostraram tendência de estabilização. No entanto, 80% da riqueza esperada foi amostrada e a riqueza de espécies encontrada foi similar a outros estudos previamente conduzidos na região. Diferente de outros inventários realizados na Mata Atlântica, Desmodus rotundus foi a espécie mais frequentemente capturada ao longo das trilhas. Um grande número de indivíduos de Molossus aztecus foi encontrado se abrigando em abrigo artificial, o que constitui um evento pouco usual. Adicionalmente, a coabitação dessa espécie com Molossus molossus é reportada aqui pela primeira vez. Os resultados mostram que essa área, que está inserida no mapa de conflitos ambientais do estado de Minas Gerais, possui uma rica chiropterofauna e corrobora a importância de usar redes de neblina em abrigos para aumentar a probabilidade de capturar a riqueza e abundância de morcegos insetívoros presentes na área.
