NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics

Xenarthrans – anteaters, sloths, and armadillos – have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with 24 domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, ten anteaters, and six sloths. Our dataset includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data-paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the south of the USA, Mexico, and Caribbean countries at the northern portion of the Neotropics, to its austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n=5,941), and Cyclopes sp. has the fewest (n=240). The armadillo species with the most data is Dasypus novemcinctus (n=11,588), and the least recorded for Calyptophractus retusus (n=33). With regards to sloth species, Bradypus variegatus has the most records (n=962), and Bradypus pygmaeus has the fewest (n=12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other datasets of Neotropical Series which will become available very soon (i.e. Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans dataset

Coletar morcegos por seis ou doze horas a cada noite?

Pesquisadores brasileiros de morcegos concentram a atividade de coleta com redes de neblina na primeira metade da noite, onde é descrito que ocorre a maior parte da atividade das espécies a serem coletadas. Para avaliar os resultados quanto ao total capturado e a riqueza de espécies em parte da noite, analisamos o horário de captura em inventário realizado no sudeste do Brasil. A amostragem total compreendeu 570 capturas e 25 espécies de três diferentes famílias. Das 18 espécies em que foi possível calcular a média do horário de capturas, apenas duas espécies insetívoras aéreas apresentaram valores anteriores às 21:00 h. Notou-se grande similaridade quanto a abundância das espécies, tanto na primeira metade da noite quanto na segunda metade. A riqueza e o total capturado resultaram em elevada similaridade entre a amostragem observada do pôr-do-sol às 00:00 e das 00:01 h ao amanhecer. A realização de coletas durante toda a noite pode resultar em maior riqueza e deve ser o método escolhido para um inventário.<br>Brazilian researchers of bats concentrate the sampling activity with mist nets in the first half of the night, when it is described that concentrates most of the activity of the species. To evaluate the results of the total captured and species richness during the night, we analyzed the time of capture in inventories developed in southeastern Brazil. The total sampling comprised 570 captures and 25 species of three different families. Of the 18 species in that was possible to calculate the average of time of capture, only two insectivore species showed values previous to 21:00 h. We noticed high similarity in the abundance of the species between the first and the second half of the night. The all night sampling can result in larger richness and should be the chosen methods for inventory

Do bigger bats need more time to forage?

We test the hypothesis is that bats using the same area and at the same time would be using similar preys, but they would have different foraging times due to specific differences in biomass. A total of 730 captures was analyzed 13 species of Vespertilionidae and Molossidae bats netted over a small dam in southeastern Brazil from 1993 and 1999. The relationship between the average time of captures and the biomass of the species of Vespertilinidae and Molossidae most frequent (captures > 4) was positive and significant (r = 0.83, p = 0.022, N = 7). Two lines are discussed to answer the longer foraging time for bigger bats: 1) larger insectivorous bats don't consume proportionally larger preys and 2) larger insects are less available