Fine-scale habitat selection of Chilean dolphins was studied between January and April 2002 through shore-based theodolite tracking in order to investigate the environmental and behavioural determinants of habitat use, and to evaluate the interactions between this species and aquaculture activities in Yaldad Bay, southern Chile. During 293.5 h of effort, movement and habitat selection patterns of dolphins exhibited a significantly concentrated use of only 21% of the entire study area. Correspondence analysis showed that shallow waters (5–10 m), proximity to coast and rivers were the most significant environmental parameters determining fine-scale dolphin distribution patterns, with foraging the most frequently observed activity. Aquaculture activities in the area were observed to affect dolphin habitat use patterns by restricting space available for biologically important dolphin behaviours.

The density of Brazilian tapirs (Tapirus terrestris) was studied in the northeastern part of the Pantanal wetlands of Brazil using two simultaneous and independent methods: (1) systematic camera trapping combined with capture–recapture analysis, with camera traps spaced 1 km apart and distributed over 54 km2; and (2) line‐transect sampling using an array of 12 linear transects, from 3.8 to 7.2 km long, covering the principal open and forest habitat types across the entire 1063 km2 SESC Pantanal Reserve. The two methods yielded conservative density estimates of 0.58 ± 0.11 tapirs/km2 (camera trapping) and 0.55 (95% CI 0.30–1.01) tapirs/km2 (line transects). The study suggests that certain Pantanal habitats and sites can sustain relatively high population densities of tapirs when these animals are protected from hunting. Further testing of the camera‐trapping methodology as applied to tapirs is required, particularly focusing on extending the survey period. As it represents a relatively rapid method for estimating population density, in comparison to line‐transect surveys, and as it generates information simultaneously on multiple species that are conservation priorities, we recommend that camera‐trapping surveys be applied more widely across a variety of Pantanal habitats and land‐use categories in order to confirm the value of the vast 140,000 km2 wilderness region for this vulnerable species.

The Brazilian Cerrado is a global biodiversity hotspot with notoriously high rates of native vegetation suppression and wildfires over the past three decades. As a result, climate change can already be detected at both local and regional scales. In this study, we used three different approaches based on independent datasets to investigate possible changes in the daytime and nighttime temperature and air humidity between the peak of the dry season and the beginning of the rainy season in the Brazilian Cerrado. Additionally, we evaluated the tendency of dew point depression, considering it as a proxy to assess impacts on biodiversity. Monthly increases of 2.2−4.0℃ in the maximum temperatures and 2.4−2.8℃ in the minimum temperatures between 1961 and 2019 were recorded, supported by all analyzed datasets which included direct observations, remote sensing, and modeling data. The warming raised the vapor pressure deficit, and although we recorded an upward trend in absolute humidity, relative humidity has reduced by ~15%. If these tendencies are maintained, gradual air warming will make nightly cooling insufficient to reach the dew point in the early hours of the night. Therefore, it will progressively reduce both the amount and duration of nocturnal dewfall, which is the main source of water for numerous plants and animal species of the Brazilian Cerrado during the dry season. Through several examples, we hypothesize that these climate changes can have a high impact on biodiversity and potentially cause ecosystems to collapse. We emphasize that the effects of temperature and humidity on Cerrado ecosystems cannot be neglected and should be further explored from a land use perspective.

We evaluated the effects of climate seasonality from a thermal and water availability perspective on the activity patterns and resource use of Pecari tajacu and Tayassu pecari during wet and dry seasons in the northeastern Brazilian Pantanal. We used camera traps and temperature sensors to record species activity patterns in relation to temperature, established five habitat categories based on flooding intensity and local vegetation characteristics, assessed the activity patterns of each species in dry and wet periods and in artificial water bodies using circular statistical metrics, and calculated niche amplitude and overlap on three axes (temperature, time, and habitat) in both periods. Peccaries shared a strong resemblance in resource use and in their responses to seasonal variations in the tested gradients. The activity patterns of both species exhibited a significant correlation with air temperature on all the evaluated measures, and both species strongly reduced their activity when the air temperature exceeded 35 °C. High temperatures associated with low water availability were most likely responsible for the changes in species activity patterns, which resulted in an increased temporal overlap in habitat use throughout the dry season. However, the peccaries avoided intensively flooded habitats; therefore, the habitat gradient overlap was greater during the wet period. Our results show that an increase in niche overlap on the environmental gradient as a result of climatic seasonality may be partially compensated by a reduction in other niche dimensions. In this case, temporal partitioning appears to be an important, viable mechanism to reduce competition by potentially competing species.

ResumoEstudos sobre biodiversidade permitem avaliações ecossistêmicas e monitoramentos de impactos e mudanças ambientais. A diversidade parasitária pode refletir o processo coevolutivo entre parasitos e hospedeiros, e mudanças ambientais que permitem a perda, ganho ou a manutenção das espécies nesse processo. O presente trabalho utilizou espécies/morfotipos de ovos de helmintos encontrados em fezes de sete mamíferos silvestres (os grupos Dasypodidae e grandes felinos, e as espécies: Tamandua tetradactyla, Cebus apella, Alouatta caraya, Cerdocyon thous, Pecari tajacu) e dois domésticos (Canis familiaris e Sus scrofa), que cohabitam o Parque Nacional Serra da Capivara (PNSC) e seu entorno, para analisar a diversidade dos helmintos intestinais desses mamíferos. Neste trabalho, utilizou-se achados da fauna helmintológica de mamíferos silvestres e domésticos, para avaliar um possível fluxo de helmintos entre estes dois grupos hospedeiros usando Unweighted Pair Group Method with Arithmetic Mean (UPGMA) dos hospedeiros com base na composição de suas faunas helmintológicas. Os resultados indicam que a região do PNSC, ainda mantém condições ambientais que ainda propiciam a manutenção da composição da fauna de helmintos de mamíferos silvestres, diferente da encontrada nos animais domésticos.Palavras-chave: Helmintos, diversidade, Caatinga, Parque Nacional Serra da Capivara, mamíferos. AbstractBiodiversity studies allow ecosystem assessment and monitoring of environmental changes and impacts. Parasite diversity could reflect the host/ parasite coevolutionary process and the environment changes that permit the loss, gain or maintenance of species. This survey used species/morphotypes of helminths eggs found in feces from seven wild mammal species (the groups Dasypodidae and Large Cats, and Tamandua tetradactyla, Cebus apella, Alouatta caraya, Cerdocyon thous, Pecari tajacu) and from two domestic species (Canis familiaris and Sus scrofa), which occur within the Serra da Capivara National Park (PNSC) and surrounding areas in order to analise the diversity of mammal intestinal helminths. This work used the helminthological fauna findings of wild and domestic mammals, to consider a possible helminth flux between these two host groups using Unweighted Pair Group Method with Arithmetic Mean (UPGMA) of the hosts based on helminthological fauna composition. The results indicate that the region of the PNSC still maintains environmental conditions that still keep wild mammal helminthological fauna composition different from the one found for domestic mammals.