Differential success in sampling of Atlantic Forest amphibians among different periods of the day

Abstract

In general, anurans tend to be nocturnal, though diurnal activity is characteristic of some groups. Studies show that frog activity may be inferred based on the number of individuals collected at different periods of the day, during large-scale field surveys. We investigated the best period of the day to conduct amphibian sampling in nine Atlantic Rainforest areas in southeastern Brazil, based on intensive field surveys. At each locality we employed similar sampling effort during diurnal, crepuscular and nocturnal searches (totaling 704.5 sampling hours). We pooled data from all localities for each period and estimated the proportion of frogs of each species active at each period based on the total number of individuals and on the number of species found during all surveys for that period. We recorded a total of 817 individual frogs from 69 species. Species richness was highest at night (median = 12 species), intermediate at dusk (median = 8), and lowest during the day (median = 4). The percentage of the total number of individual frogs found (pooled species) was highest during the night (ca. 53%) and lowest during the day (ca. 14%). Analyzing each species separately, the number of individuals recorded was consistently higher at dusk and night for most species. Our study evidences a trend for nocturnal activity for most Atlantic Rainforest frogs, with few species having primarily diurnal habits. Those results may favor future studies and conservation efforts for amphibian species.Keywords: activity pattern, amphibian, anuran assemblages, southeastern Brazil, tropical forest. Sucesso diferenciado na amostragem de anfíbios da Mata Atlântica entre diferentes períodos do dia ResumoEm geral, anuros tendem a ser noturnos, apesar de a atividade diurna ser característica de alguns grupos. Estudos mostram que a atividade de anuros pode ser inferida com base no número de indivíduos coletados em diferentes períodos do dia durante pesquisas de campo de larga escala. Nós avaliamos qual o melhor período do dia para conduzir amostragens de anfíbios em nove áreas da Mata Atlântica no sudeste do Brasil, com base em amostragens de campo intensivas. Em cada localidade nós empregamos esforço de amostragem similar durante amostragens diurnas, crepusculares e noturnas (totalizando 704,5 horas de amostragem). Nós agrupamos dados de todas as localidades para cada período e estimamos a proporção de anuros de cada espécie ativa em cada período com base no número total de indivíduos e no número de espécies encontradas durante todas as buscas naquele período. Nós registramos um total de 817 indivíduos pertencentes a 69 espécies. A riqueza de espécies foi maior à noite (mediana = 12 espécies), intermediária ao crepúsculo (mediana = 8) e menor durante o dia (mediana = 4). A porcentagem do número total de indivíduos encontrados (todas as espécies agrupadas) foi maior durante a noite (ca. 53%) e menor durante o período diurno (ca. 14%). Analisando cada espécie separadamente, o número de indivíduos registrados foi consistentemente maior...

A continental assessment of diurnality in frog calling behaviour

“…We leveraged a continental-scale citizen science dataset to highlight a surprisingly high rate of diurnal calling behaviour across Australian frogs, despite a generally assumed pattern of nocturnality in frogs in general (Duellman & Trueb 1994;Rich & Longcore 2006, pg. 197;Rocha et al 2015), and Australian frogs specifically (Commonwealth of Australia 2010). We found that most Australian frog species, 140 of the 196 species available in the dataset (including the introduced Cane Toad Rhinella marina), showed at least some evidence of diurnal calling, with at least one record of them calling during the day.…”

“…Other texts state that 'most species of adult anurans are completely or partly nocturnal' (Rich & Longcore 2006, pg. 197); that 'in many species of anuran amphibians (frogs and toads), adults are normally active only at night' (Duellman & Trueb 1994); and 'in general, anurans tend to be nocturnal' (Rocha et al 2015). Quantification of such behaviour has been historically limited, given a lack of available data and the relative cost of collecting detailed behaviour data.…”

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, ).…”

Primer registro de miasis (diptera: sarcophagidae) en anuros de leptodactylidae (amphibia)

“…Occurrence of apparently uncommon parasitosis, like the presently observed, may indicate the reduction of fitness of population to resist to stressing agents that may indicate a risk for this group. Even having L. latrans a predominantly nocturnal activity, not coincident to the diurnal one of Sarcophagidae flies, females of this frog present a very strong parental care for their tadpoles (RODRIGUES et al, 2011;Rocha et al, 2015), which can expose them to larviposition at any moment of the day. In the literature, three genera (Sarcophaga, Sarcodexia e Lepidodexia) of Sarcophagidae have been reported as causing myiasis in amphibians, all of them including diurnal flies (ROY and DASGUPTA, 1977;HAGMAN et al, 2005).…”