Marcelo Menin

Topographic and edaphic effects on the distribution of terrestrially reproducing anurans in Central Amazonia : mesoscale spatial patterns

Many studies suggest that edaphic variables are major determinants of frog distributions. However, leaf-litter depth and soil characteristics are influenced by distance from streams, so the apparent relationship between edaphic characteristics and species distributions could be an artefact of the dependence of species on free water for reproduction. Therefore, we investigated the effect of edaphic variables on the mesoscale distribution of frog species not dependent on free water for reproduction. We evaluated the effects of soil texture, pH, slope, number of trees and leaf-litter volume on the distribution of nine terrestrially reproducing anuran species in the Reserva Ducke, a 100-km 2 terra firme forest preserve in central Amazonia. Diurnal and nocturnal assemblages of anuran species were sampled in 72 plots systematically distributed across the reserve. We sampled the diurnal anuran assemblage by visual encounter in 250 x 1-m plots and the nocturnal assemblage in 250 x 20-m plots using both auditory and visual surveys. The majority of terrestrially breeding anuran species were influenced by topographic and/or edaphic variables, such as slope, soil clay content and pH. However, responses to environmental predictors differed among species. Most species occurred throughout all environmental gradients and relationships with soil characteristics were subtle, indicating that these species occur in the majority of habitats in Reserva Ducke. The results of this study indicate that terrestrially breeding frogs are habitat generalists that show little mesoscale beta diversity associated with habitat variation.

Temporal variation in the abundance and number of species of frogs in 10,000 ha of a forest in central amazonia, Brazil

Abstract In this study we sampled diurnal and nocturnal anuran assemblages in 10,000 ha of tropical forest. We provide data on composition and variation in the occurrence and abundance of these species during two rainy seasons. Our study took place at Reserva Florestal Adolpho Ducke, Manaus, Amazonas state, Brazil. We analysed the anuran assemblage for three diurnal samples and five nocturnal samples from November/2002 to May/2004. Data were collected in 72 plots systematically distributed over a 64 km2 grid. Diurnal anuran assemblage surveys were conducted by visual encounter. We sampled the nocturnal anuran assemblage using standardized methods – simultaneous visual encounter surveys and auditory sampling. We detected 30 species of anurans, belonging to seven families using all methods and periods. A total of 6,030 individuals belonging to eight species and four families were recorded in diurnal samples and 25 species (16,050 individuals), belonging to six families were recorded in nocturnal samples. The number of nocturnal species varied from 18 in the beginning of the second rainy season to 22 in the middle of the rainy season. Fourteen species were found in the five sampling periods. The species with high abundance that were widely distributed in the study area were those with reproductive specializations such as direct development, development in terrestrial nests, or development in bromeliads with parental care. This study showed the viability of the system of surveys and the methods used for sampling anuran assemblages in a tropical forest. They were also adequate for estimating the richness and abundance of species. However, systematically distributed plots, such as those used in this study, mostly reveal terrestrially breeding frogs. The aquatic-breeding frogs were found mainly in riparian zones and were rare in zones distant from water bodies. There were a low number of plots around water bodies (25%) which, consequently, reduced the record of aquatic-breeding individuals.

Species richness, relative abundance, and habitat of reproduction of terrestrial frogs in the Triângulo Mineiro region, Cerrado biome, southeastern Brazil

Based on field observations and pitfall sampling, we determined the species richness, relative abundance, and reproductive habitat of terrestrial frogs in three municipalities in the Triângulo Mineiro region, south Cerrado biome, in southeastern Brazil. We found thirty-two species of terrestrial frogs, belonging to the families Brachycephalidae, Bufonidae, Cycloramphidae, Dendrobatidae, Leiuperidae, Leptodactylidae and Microhylidae. Most of the species were found in open areas and reproduced in human-generated environments, such as artificial lakes (10 species) and ponds (14 species). Dominance was high, with Physalaemus cuvieri Fitzinger, 1826 (Leiuperidae) representing 48% of sampled frogs. A larger number of individuals was captured in the wet season, when most of the species were reproducing. Compared to other areas of Cerrado biome, the Triângulo Mineiro sites presented a larger number of species, which may be attributed to the larger sampled area and greater sampling effort, lower altitude and presence of human generated habitats. The richness of terrestrial frogs was also larger than that in some forested localities in southeastern Brazil, indicating that the number of species cannot be explained only by precipitation and type of vegetation cover. The greater abundance of individuals during the wet season may be related to a greater movement of adults to breeding sites and to juvenile recruitment/dispersion. The heterogeneity of environments in the Cerrado biome, including its several isolated highlands, contributes to its high (local and regional) diversity of frogs.

Composition and Abundance of Anurans in Riparian and Non-Riparian Areas in A Forest in Central Amazonia, Brazil

ABSTRACT. We determined the anurofauna composition and variation in a terra-firme forest surveyed during one rainy season. The study was carried out in the Fazenda Experimental of the Universidade Federal do Amazonas, Manaus, Amazonas, Brazil. Between November 2008 and May 2009, three samples were taken at night in 41 plots distributed across a 24 km2 grid. Twenty one plots were located away from water bodies (non-riparian plots) and the remaining 20 plots were located alongside the water bodies (riparian plots). Sampling was performed using standardized sampling methods: visual and auditory surveys performed simultaneously. A total of 6,677 individuals belonging to 33 species and nine families (Aromobatidae, Bufonidae, Centrolenidae, Ceratophryidae, Hylidae, Leptodactylidae, Microhylidae, Pipidae and Strabomantidae) were recorded. The number of species ranged from 23 species at the beginning of the rainy season to 26 species at the end of the season. Twenty-four species were detected in non-riparian plots, whereas 28 species were recorded in riparian plots. Fifteen species were recorded throughout the three sampling periods. The most abundant and widely distributed species in the study area were those with reproductive specializations. Differences in species richness and abundance between riparian and non-riparian plots were observed during sampling periods: in general, in the riparian plots the number of species and number of individuals were higher than those recorded in the non-riparian plots. These differences were related to the presence of species recorded exclusively in riparian plots, corresponding to species dependent on water bodies for reproduction. Differences in species composition between our study site and other nearby areas in central Amazonia may reflect local characteristics, such as variation in topography and presence of specific sites for anuran reproduction.

Diversidade de anfíbios e répteis Squamata na região do baixo rio Purus, Amazônia Central, Brasil

A regiao do baixo rio Purus na Amazonia Central - Brasil representa uma area de relevante interesse para conservacao de anfibios e repteis. No entanto, ha pouca informacao disponivel sobre estes grupos taxonomicos para areas de florestas de terra firme e florestas de varzea, principais paisagens nesta regiao. Nesse estudo, realizamos uma amostragem ampla em esforco e area, em dois periodos: 2004-2005 e 2009-2010. Utilizamos tecnicas complementares eficientes na amostragem da herpetofauna em florestas tropicais: procura ativa limitada por tempo (PLT), armadilhas de interceptacao e queda (AIQ) e armadilhas de interceptacao com funis duplos (AIF). Foram registradas 160 especies, sendo 75 de anfibios (73 anuros e dois gimnofionos) e 85 de repteis (34 lagartos e 51 serpentes). O registro do anuro Dendropsophus allenorum foi o primeiro para o Brasil. Comparando a eficiencia dos metodos de coleta, a busca ativa por coletores capacitados (PLT) foi o metodo mais eficaz na amostragem da herpetofauna; seguido das AIQ, eficientes na captacao de anuros terricolas e lagartos de serrapilheira nas florestas de terra firme. Nao utilizamos AIQ nas areas de varzea por estas terem solos hidricamente saturados. As AIF, apesar de menos eficientes na amostragem de anuros e lagartos, foram eficazes na captura serpentes e facilmente adaptaveis aos solos hidromorficos das varzeas. Uma maior riqueza de especies e familias foi encontrada nas florestas de terra firme. As florestas de varzea tiveram uma marcante ausencia de familias fossoriais e de serrapilheira. No entanto, nas florestas de varzea encontramos um maior numero de especies de anuros arboricolas (Hylidae) e de lagartos heliotermicos maiores (Teiidae). Entretanto, avaliando separadamente cada periodo de amostragem, a riqueza de especies da herpetofauna torna-se similar entre os diferentes tipos de paisagens florestais, tendendo ser maior nas florestas de terra firme. Apesar de similares em numero especies, as florestas de terra firme e de varzea foram diferentes quanto ao conjunto das especies. A diversidade complementar de anfibios e repteis Squamata entre florestas de terra firme e de varzea (diversidade beta-β), paisagens de maior abrangencia local, possivelmente representa a maior contribuicao para a diversidade regional da herpetofauna no baixo rio Purus (diversidade Gama-γ).

Reproductive aspects of Leptodactytus hylaedactylus (Anura: Leptodactylidae), a member of the Leptodactylus marmoratus species group, with a description of tadpoles and calls

In this paper we describe some aspects of the reproductive biology of Leptodactylus hylaedactylus from open areas of Central Amazonia, Brazil. We describe the calling site, reproductive season, daily pattern of calling activity, chamber structure, vocalizations and tadpole morphology. Males of Leptodactylus hylaedactylus called amidst grasses and bushes in open and urban areas, throughout the year, and a greater number of males were heard in the period from 16:00 to 20:00 h. The eggs are deposited in underground chambers, which are spherical or elliptical. Larval development occurs inside the chambers. Two types of vocalizations were detected, the advertisement and the territorial call. The advertisement call of the species studied herein differs from other calls described for L. hylaedactylus from other localities of Brazil, but is very similar to that described from Peru. Tadpole morphology is similar to that described from individuals in French Guiana.

Distribution of frogs in riparian areas of an urban forest fragment in Central Amazonia

This study aimed to evaluate how environmental variables (width of valley, stream size, forest edge distance, and leaf-litter depth) affect the abundance and richness of species of frog species in riparian areas of an urban forest fragment in Central Amazonia. The study was conducted at the campus of the Universidade Federal do Amazonas, Manaus, Brazil, between May 2008 and April 2009, when three nocturnal and diurnal samples were taken from ten plots. A total of 17 species belonging to seven families were registered. The number of species recorded per plot varied from seven to 14. We detected a relationship between the edge distance and richness: the plots with lower richness were located near the fragment border. The variables had no significant effect on abundance of each species.

Karyotypic diversity in seven Amazonian anurans in the genus Hypsiboas (family Hylidae)

BackgroundHypsiboas species have been divided into seven groups using morphological and genetic characters, but for most of the species, there is no cytogenetic information available. A cytogenetic analysis using conventional staining, C-banding, silver staining, and fluorescence in situ hybridization (FISH) with telomeric sequence probes were used to investigate the karyotype of seven Amazon species of the genus Hypsiboas belonging to the following intrageneric groups: H. punctatus (H. cinerascens), H. semilineatus (H. boans, H. geographicus, and H. wavrini), and H. albopunctatus (H. lanciformis, H. multifasciatus, and H. raniceps). The aim was to differentiate between the karyotypes and use the chromosomal markers to distinguish between the Hypsiboas groups. The data were compared with a previous phylogenetic proposal for these anurans. In addition, H. lanciformis, H. boans, and H. wavrini are described here for the first time, and we characterize the diploid numbers for H. cinerascens, H. geographicus, H. multifasciatus, and H. raniceps.ResultsThe diploid number for all of the species analyzed was 24, with the exception of Hypsiboas lanciformis, which had 2n = 22 chromosomes. The constitutive heterochromatin distribution, nucleolar organizer region locations, and interstitial telomeric sites differed between the species. A hypothesis that the heterochromatic patterns are evolving is proposed, with the divergence of the groups probably involving events such as an increase in the heterochromatin in the species of the H. semilineatus group. The FISH conducted with the telomeric probes detected sites in the terminal regions of all of the chromosomes of all species. Interstitial telomeric sites were detected in three species belonging to the H. semilineatus group: H. boans, H. geographicus, and H. wavrini.ConclusionThe results of this study reinforce the complexity previously observed within the genus Hypsiboas and in the different groups that compose this taxon. More studies are needed focusing on this group and covering larger sampling areas, especially in the Brazilian Amazon, to improve our understanding of this fascinating and complex group.

Functional necrophilia: a profitable anuran reproductive strategy?

Explosive breeding is a common reproductive strategy, especially in anurans. In some cases of explosive breeding in anurans, intense aggressive interactions occur among males attempting to gain access to females, and for terrestrial species that mate in water, females may die by drowning during long mating struggles. Such occurrences are obviously detrimental to females, and may also cause a decrease in the reproductive success of males through depletion of energy without obtaining access to a live female. However, the males of the small Amazonian frog Rhinella proboscidea can promote the ejection of oocytes from the abdominal cavities of dead females and fertilize them. This behaviour can minimize losses to both partners during explosive reproduction events. The existence of such a “functional necrophile strategy” shows that there may be possible selection in favour of stronger and more persistent males in explosive breeders.

POPULATION STRUCTURE AND REPRODUCTIVE PATTERN OF PRISTIMANTIS AFF. FENESTRATUS (ANURA: STRABOMANTIDAE) IN TWO NON-FLOODED FORESTS OF CENTRAL AMAZONIA, BRAZIL

ABSTRACT. Pristimantis aff. fenestratus is a common species in non-flooded forests of central Amazonia, Brazil. Herein, we show the reproductive pattern and data on population structure of this species from two sites, using standardized sample methods (visual and auditory surveys), during three rainy seasons. The higher number of males in calling activity was detected in the beginning of the rainy season. However, sporadic male calls were also heard in the dry season. Females were significantly larger than males, and males captured at the end of the rainy season were larger than those captured in other periods. Females with eggs visible through the abdominal wall were found in all samplings at one site, but a larger number of juveniles were found at the end of the rainy season. The size of juveniles was variable and the smallest individuals were found at the end of the rainy season. According to nocturnal visual surveys males were significantly more abundant than females (1.9:1 adult sex ratio). According to data collected on gravid female occurrence, juvenile number variation, and presence of calling males, we suggest that P. aff. fenestratus reproduces during the rainy season showing marked seasonality.