Resumo
In studies of avian diversity, many different methods have been applied. Since methodological approaches may affect research results, the choice of a given methodology must be consistent with the scientific objectives. The aim of this study was to investigate how different methodologies with their intrinsic limitations help detect and monitor birds to evaluate how they complement each other in the survey of species. Three different assessment methods, mist nets, point counts, and autonomous acoustic recordings were used to serve this purpose in a study of different Pantanal habitats, such as savannas and forests. The point counts detected more species (126 species) than the two other methods autonomous acoustic recordings (113 species) and mist nets (79 species). We observed significant differences in the number of species detected by mist nets and the other two methods. Each survey method identified exclusive species. When comparing habitats, all three methods showed significant differences in bird species composition. Savannas were richer in bird species than forests, and replacement was the main driver responsible for the differences in beta diversity between the habitats. The three methodologies, when applied together, proved to be complementary in avian species detection.
Assuntos
Animais , Aves/classificação , BiodiversidadeResumo
Fire might occur under natural conditions in the Pantanal of Brazil; however, with climate change, severe periods of drought potentiated the devasting fires in 2020, resulting in substantial wildlife loss. Considering that mammal communities are strongly affected by fire and habitat alterations, the aim of this study was to evaluate possible differences in mammal diversity and the number of records before and one year after the fire in one region of the Pantanal of Mato Grosso, Brazil (Parque SESC Baía das Pedras - PSBP). The data collection was performed using camera trapping between 2015 and 2017 and 2021, together with visual field observations in PSBP. We observed that the mammal assemblage composition was similar before and one year after the fire. Four species were more or less frequent in burned areas than in unburned ones. Since the fire was controlled in this area, avoiding its total destruction, and the species that fled from the surrounding areas, which were completely burnt, might be using PSBP as a refuge while the vegetation recovers elsewhere. Therefore, the PSBP might have contributed to protecting mammal species after the fire and maintaining and conserving biodiversity on a regional scale in the Pantanal of Mato Grosso, Brazil.
Assuntos
Animais , Biodiversidade , Áreas Alagadas , Incêndios , Mamíferos/classificaçãoResumo
This study focuses on incubation parameters, egg morphometrics, and body mass development, hatching, and behavioral adaptations to heat stress within a colony of freshwater-breeding Black Skimmers (Rynchops niger) located in the private nature reserve of Serviço Social do Comércio (SESC) in the northern Pantanal, Mato Grosso, Brazil. Temperatures of nest, eggs, and surface substratum, as well as the development of embryos, were surveyed using thermal imaging, a method allowing digital recording from a distance and in a fraction of the time of traditional measuring techniques. The mean egg dimensions (n = 71) were 4.48 (± 0.13) × 3.27 (± 0.07) cm; the mean mass at hatching was 24.3 (± 1.9) g, with a significant decrease over incubation time. The mean surface temperature of eggs varied from 30.9â to 39.7â, while the sand surface temperature was 20â at 06:00 h, rising to 47.7â at 11:00 h. There was a significant increase (7%) in egg surface temperature throughout incubation. Incubation-bout durations (n = 2108) were correlated with the microclimatic conditions of the substratum, becoming shorter with increasing sand-surface temperature around midday. Egg hatching lasted one day, and siblings hatched no more than 24 h apart. The mean body mass on Day 1 after hatching was 16.8 (± 1.6) g (n = 6). Three days after hatching, chicks moved to new sand depressions provided by parents near the original nest, where they remained motionless or tried to hide under riparian vegetation. The single chick that fledged had a growth rate of K = 0.117 and a t10â90 value of 37.3 days. On Day 7, dorsal pintail feathers and primaries appeared, which were open on Day 15. After 14 days, the chick was able to regulate its body temperature, and no more feeding by parental birds during the daytime was observed. On Day 21, the immature plumage was fully developed. Fledging was completed on Day 27. Our study demonstrates that thermal imaging is a useful method of surveying egg and embryo development in the Black Skimmer, reducing nest disturbance and observation efforts.(AU)