Good timing: evaluating anuran activity and detectability patterns in the Brazilian Atlantic Forest

Abstract

ContextAnimal activity patterns throughout the day constitute an important dimension of their ecological niche, and may have ecological and evolutionary implications; for an organism to be active during the day or night period, a series of conditions requiring different anatomical, physiological and behavioural adaptations must be met. AimsTo study the anuran community in an area of Atlantic Forest in Brazil, to evaluate the species activity period as well as the diurnal and nocturnal detection probabilities of anurans, and to relate these activities to environmental variables such as air temperature, relative humidity and precipitation. MethodsThe anurans were sampled along 21 plot transects in the diurnal period and during a nocturnal period, with temperature and relative humidity measured in each plot. Species were considered predominantly diurnal or nocturnal if 35% or more individuals were recorded during one of these periods. Anuran detectability was estimated using single-season occupancy models, relating to environmental variables. Key resultsOf the individuals recorded, 12% were recorded during diurnal sampling and 88% were recorded during nocturnal sampling, with Ololygon agilis being the only species considered diurnal. The probability of detection was affected by only two variables (period and humidity). ConclusionsThe anuran community in the study area was essentially nocturnal, with only one species that could be considered diurnal. Additionally, detectability was higher at night, with humidity being the most important variable affecting species detection. ImplicationsSurveys can be planned under climatic conditions that positively influence the probabilities of detection to improve the effectiveness of monitoring species and/or anurans community.

Co-occurrence patterns and habitat selection of the mountain hare, European hare, and European rabbit in urban areas of Sweden

“…Moreover, detectability also differs between land cover types, accessibility, and depending on animal activity (Mair & Ruete 2016;Pereira-Ribeiro et al 2019). As most observations likely came from active lagomorphs, our results probably represent occurrence and habitat selection of active individuals and from areas that were easily accessible to observers.…”

“…For example, it is plausible that citizens rather recorded animal observations in their own gardens and in parks compared to city centers and industrial areas. Moreover, detectability also differs between land cover types, accessibility, and depending on animal activity (Mair & Ruete 2016; Pereira-Ribeiro et al . 2019).…”

Changes in the community structure of anurans in the Coastal plain forest, southeastern Brazil

“…Samplings were carried out in the daytime period (11:00 a.m.–5:30 p.m.) and at night (6:00–11:00 p.m.) to increase the possibility of sampling a higher range of anuran species with different activity periods. Majority of the Atlantic Forest anurans are nocturnal (Rocha et al, ), some are diurnal activity in the studied area (e.g., Ololygon agilis ; Pereira‐Ribeiro, Ferreguetti, Bergallo, & Rocha, ).…”

A three-year Herpetofauna survey from one of the largest remnants of the Atlantic Rainforest Biome (Reserva Natural Vale)

“…The rarefaction curve for frogs tended to stabilize, with an expected richness of about 40 species, a value quite similar to that species richness we recorded. Although some recent studies on frog communities in this reserve had provided a considerable number of frog species varying from 21 up to 24 species (Pereira- Ribeiro et al, 2019Ribeiro et al, , 2020a, they were designed for a shorter period and using particular sampling efforts and methods to study just one of the physiognomies of the reserve (i.e., the Coastal plain forest or Floresta de Tabuleiro) (Pereira- Ribeiro et al, 2020b), or to investigate some particular ecological parameters as the activity, occupancy, detectability and short-term rainfall effects on the frogs activity (Pereira- Ribeiro et al, 2019Ribeiro et al, , 2020a. Conversely, the present study based on a systematic method of sampling (in RAPELD Modules) covered all types of vegetation present in the area of the reserve and sampled continuously for about three years, which allowed to reach a better approximation of the actual frog species richness occurring in the reserve.…”

“…The VNR-SBR forest block has a remarkable richness of flora and fauna, harboring several species threatened, and its importance for the protection of the biodiversity of the Atlantic Forest has already been reinforced in several studies (see Rolim et al, 2016;Fraga et al, 2019). However, less attention has been paid to the herpetofauna community, although the number of studies has steadily increased in recent years (e.g., Pereira-Ribeiro et al, 2019;2020a, b). The herpetofauna knowledge scenario is even worse when we consider only the reptile group, with only two studies available covering this region's reptile community (Rocha, 1998;Bérnils et al, 2014).…”