Species composition and density estimates of the anurofauna of a site within the northernmost large Atlantic Forest remnant (Parque Estadual do Desengano) in the state of Rio de Janeiro, Brazil

Abstract

We present data on species composition, relative abundance and estimated densities for leaf-litter anuran amphibians from an Atlantic Forest area within the Parque Estadual do Desengano, in the state of Rio de Janeiro, Brazil, based on results of a short-term survey carried out during the winter at altitudes of 1000-1500 m. Three sampling methods were used: plot sampling, visual encounter surveys (VES; performed during the day, at the twilight, and at night), and pitfall traps. We recorded 13 species, with the direct-developer Ischnocnema parva (Girard, 1853) being the most abundant. Most frogs (ca. 90% of all individuals) sampled by VES were captured during the crepuscular and nocturnal periods. The estimated density of the local leaf-litter frog assemblage based on plot sampling was 13.2 ind.100 m-2, which is one of the highest values currently reported for Atlantic Rainforest areas. This is the first study analyzing the anuran fauna of the Parque Estadual do Desengano and adds to the knowledge of the fauna of the northern region of the state of Rio de Janeiro, which is still poorly studied.

Anuran species composition and density estimates from an Atlantic Forest area within the APA Serra da Mantiqueira, Rio de Janeiro state, Brazil

“…The estimated overall density of the local leaf litter frog assemblage was high (18.1 ind/100 m 2 ) when compared to those found for most other sites sampled (also with large quadrats) within the Atlantic Forest in southeastern and southern Brazil (1.4-13.2 ind/100 m 2 ; Giaretta et al 1997, Rocha et al 2001, 2013, Almeida-Gomes et al 2008, Santos-Pereira et al 2011, Siqueira et al 2011a, Oliveira et al 2013. Exceptions are two localities in the municipality of Cachoeiras de Macacu, state of Rio de Janeiro, that yielded comparable (17.1 ind/100 m 2 ; Siqueira et al 2009) or higher estimates (24.6 ind/100 m 2 ; Siqueira et al 2014).…”

“…Indeed, this small direct-developing anuran numerically dominated the anuran assemblage at the studied site in the APA Serra da Mantiqueira (as also evidenced by the VES methodology). Several other plotsampling studies in Atlantic Forest areas have also evidenced a clear dominance of species with direct development of terrestrial eggs in the local leaf-litter frog assemblages (e.g., Giaretta et al 1997, Rocha et al 2001, 2013, Almeida-Gomes et al 2008, Siqueira et al 2009, 2011a, and this has also been observed in Amazonian (e.g., Rodriguez 1992, Gascon 1996 and Central American forest areas (e.g., Scott 1976, Toft 1981, Liebermann 1986, Fauth et al 1989, Hofer & Bersier 2001. Direct-developing anurans may be more widely distributed within the forest due to their independence of water bodies for reproduction (Haddad & Prado 2005), though other factors such as rates of dehydration/rehydration (Dabés et al 2012) and a generalist diet (Alves-dos- Santos et al 2021) may also play a role.…”

“…Cumulative and rarefaction curves using data from VES method indicated that sampling effort was almost enough to obtain a representative sample of the local anuran fauna, with a tendency toward stabilization, despite plot methodology falling short of reaching the asymptote. Plot sampling is useful for sampling anurans typical of forest floor leaf litter in Atlantic Forest areas (Giaretta et al 1997, Rocha et al 2001, 2013, Siqueira et al 2009, 2011a and, despite our effort being not enough using this method, members of that guild of anurans were also recorded by VES, adding four leaf litter species to our list that were not recorded in plots (e.g., Ischnocnema juipoca, Paratelmatobius mantiqueira, Odontophrynus americanus and Proceratophrys boiei). Moreover, our additional effort with non-standardized samplings in 2010 and 2011, added two additional species that live in the forest floor (Brachycephalus rotenbergae and Physalaemus cuvieri), besides five more anuran taxa with arboreal or semi-aquatic habits (Boana pardalis, Dendropsophus minutus, Leptodactylus latrans, Phantasmarana lutzae and Phasmahyla cochranae).…”

“…Recent surveys have provided lists of amphibian species, mostly preliminary, for some high montane Atlantic Forest areas (i.e., above 1,000 m) in southeast Brazil (Cruz et al 2009, Siqueira et al 2011a,b, Garey et al 2014, Folly et al 2016, Lima et al 2021). These habitats are known for their high rates of endemism of anurans, particularly in portions of the Serra do Mar (Siqueira et al 2011b, Carvalho-e-Silva et al 2020 and Serra da Mantiqueira regions (Neves et al 2018.…”

The amphibians of the state of Rio de Janeiro, Brazil: an updated and commented list

“…Thus, the state of Rio de Janeiro, in spite of its relatively small territorial extension, contains approximately 19% of the amphibian species known to occur in Brazil and nearly 40% of the Atlantic Forest amphibian species. Nevertheless, the list reported herein for Rio de Janeiro is likely still far from exhaustive, judging by the numerous recent reports of undescribed species from throughout the state, including members of genera such as Brachycephalus (Siqueira et al, 2011a(Siqueira et al, , b, 2013, Ischnocnema (Siqueira et al, 2011b;Gehara et al, 2013), Euparkerella (Fusinatto et al, 2013), Adenomera (Fouquet et al, 2014), Fritziana (Siqueira et al, 2011b;Castroviejo-Fisher et al, 2015), Aplastodiscus (Berneck et al, 2016), and Scinax (Bittencourt- . This indicates that the current amphibian richness recorded for the state is still an underestimate, and is likely to increase in the years to come following the intensification of taxonomic studies and of local herpetofaunal surveys.…”