RESUMO

ABSTRACT Congeneric species have similarities in phenotypic and ecological traits. The sympatry of congeneric species constitutes an opportunity for studies on coexistence. Two bird species of Mimidae, the native Tropical mockingbird, Mimus gilvus Oberholser, 1919, and the restinga invader Chalk-browed mockingbird, Mimus saturninus (Lichtenstein, 1823), currently occur in sympatry across the sandy-coastal ecosystem (restinga) of Espírito Santo state, Southeastern Brazil. We studied the spatial distribution of Tropical mockingbird and Chalk-browed mockingbird to understand the degree of competition across a preserved and urban gradient. We sampled 1,451 sampling units across a preserved and urban landscape in a coastal area of southeastern Brazil. The best-fitting model for abundance (Punctual Abundance Index) included urbanization index, distance from the coast, and distance from the closest protected area, which explained 63% and 97% of the abundance of Tropical mockingbird and Chalk-browed mockingbird, respectively. The species exhibited a segregated spatial pattern at small scale, indicating that both species are avoiding one another. Chalk-browed mockingbird showed ecological plasticity in modified environments, whereas Tropical mockingbird was more sensitive to urbanization. We suggested that the coexistence of these species is associated with resource partitioning. Monitoring Tropical mockingbird populations may be a proxy for the assessment of habitat quality and restoration success in the highly threatened restinga ecosystem.

RESUMO

Human activities result in the formation of a mosaic of forest patches within a non-habitat matrix. The response of the local biodiversity to changes in land-use may occur at different scales. It is important to evaluate the effects of the attributes of both the patches and the surrounding landscape on the occupancy of forest patches by animal populations. Here, we assessed the predictive potential of local (basal area, tree density), patch (size, shape) and landscape scale (total area of forest, number of patches, matrix permeability, patch proximity) variables on the occupancy of forest patches by the syntopic primates Alouatta caraya, Sapajus libidinosus and Callithrix penicillata in the city of Goiânia in the Cerrado region of central Brazil. We used playback to survey primate populations in 22 focal patches and assessed the landscape within a 1000 m buffer zone around each site. In A. caraya, occupancy was influenced by the shape of the focal patches, the amount of forest and fragmentation level of the landscape. Focal patch size and the permeability of the matrix were the principal determinants of the occupancy of S. libidinosus. None of the predictors influenced patch occupancy in C. penicillata, and the structure of the vegetation did not influence occupancy in any of the species. The preservation of as many forest patches as possible, both large and small, as well as gallery forests, and the enhancement of matrix permeability will be essential for the long-term conservation of the syntopic primates of the Cerrado of central Brazil.

Assuntos

RESUMO

Human activities result in the formation of a mosaic of forest patches within a non-habitat matrix. The response of the local biodiversity to changes in land-use may occur at different scales. It is important to evaluate the effects of the attributes of both the patches and the surrounding landscape on the occupancy of forest patches by animal populations. Here, we assessed the predictive potential of local (basal area, tree density), patch (size, shape) and landscape scale (total area of forest, number of patches, matrix permeability, patch proximity) variables on the occupancy of forest patches by the syntopic primates Alouatta caraya, Sapajus libidinosus and Callithrix penicillata in the city of Goiânia in the Cerrado region of central Brazil. We used playback to survey primate populations in 22 focal patches and assessed the landscape within a 1000 m buffer zone around each site. In A. caraya, occupancy was influenced by the shape of the focal patches, the amount of forest and fragmentation level of the landscape. Focal patch size and the permeability of the matrix were the principal determinants of the occupancy of S. libidinosus. None of the predictors influenced patch occupancy in C. penicillata, and the structure of the vegetation did not influence occupancy in any of the species. The preservation of as many forest patches as possible, both large and small, as well as gallery forests, and the enhancement of matrix permeability will be essential for the long-term conservation of the syntopic primates of the Cerrado of central Brazil.(AU)

Assuntos

RESUMO

Mountains of the Brazilian Atlantic Forest can act as islands of cold and wet climate, leading to the isolation and speciation of species with low dispersal capacity, such as the toadlet species of the genus Brachycephalus. This genus is composed primarily by diurnal species, with miniaturized body sizes (<2.5 cm), inhabiting microhabitats in the leaf litter of montane forests. Still, little is known about the geographical distribution, altitudinal range, and ecological limits of most Brachycephalus species. In this study, we review the available data on the geographical and altitudinal distribution of Brachycephalus based on occurrence records compiled from literature and museums, both for the genus as a whole and separately for the three recently proposed groups of species (ephippium, didactylus, and pernix). The final ensemble dataset comprised 333 records, 120 localities, 28 described species, and six undescribed ones. Species were recorded in six relief units, the richest of which being the Serra do Mar, with 30 species. When the Serra do Mar is subdivided into three subunits, Northern, Central and Southern Serra do Mar, the number of species increase from north to the south, with records of six, nine, and 16 species, respectively. We were able to estimate the extent of occurrence of nearly half of the described species, and the resulting estimates indicate that many of them show remarkably small ranges, some of which less than 50 ha. Brachycephalus species are present from sea level to roughly 1,900 m a.s.l., with the highest richness being found between 751 and 1,000 m a.s.l. (21 spp.). The species with the broadest altitudinal range were B. didactylus (1,075 m) and Brachycephalus sp. 1 (1,035 m), both in the didactylus group, and B. ephippium (1,050 m), of the ephippium group. The broadest altitudinal amplitude for species of the pernix group was recorded for B. brunneus (535 m). The lowest altitudinal records for the pernix group were at 845 m a.s.l. in the state of Paraná and at 455 m a.s.l. in the state of Santa Catarina. The altitudinal occurrence in the pernixspecies group seems to decrease southward. Syntopy between species is also reviewed.

RESUMO

In this study we analyzed diet composition, niche breadth and overlap of the two leaf-litter frogs Ischnocnema henselii and Adenomera marmorata. Frogs were collected in an Atlantic Rainforest area in the Reserva Natural Salto Morato, in Paraná State, Southern Brazil, using plots of 16 m2 established on forest floor. Ischnocnema henselii consumed 18 different types of prey and the diet of this species was composed predominantly by Hymenoptera (Formicidae) (15.4%), Araneae (13.83%), Orthoptera (6.15%) and Opiliones (6.15%), whereas Adenomera marmorata consumed 15 different types of prey and its diet was composed mainly by Hymenoptera (Formicidae) (45.7%), Acari (31.8%) and Blattodea (14.8%). The niche breadth of I. henselii was BA = 0.43 and that of A. marmorata was BA = 0.19. The diet of the two sympatric species of leaf-litter frogs was basically composed by arthropods and the trophic niche overlap among them did not differ from expected at random. The differences in prey consumption should potentially facilitate the coexistence of two sympatric frogs on the forest floor. Possibly, this difference of prey consumption partly reflects differences in jaw width, species-specific body size of the two species and the period of activity of these two species.

Neste estudo analisamos a composição da dieta e a amplitude e sobreposição do nicho trófico dos anuros de folhiço Ischnocnema henselii e Adenomera marmorata. Os anuros foram coletados em uma área de Mata Atlântica na Reserva Natural Salto Morato, no Estado do Paraná, Sul do Brasil, utilizando o método de parcelas de 16 m2 estabelecidas no chão da floresta. Ischnocnema henselii consumiu 18 diferentes tipos de presa e a dieta desta espécie foi composta predominantemente por Hymenoptera (Formicidae) (15,4%), Araneae (13,83%), Orthoptera (6,15%) e Opiliones (6,15%), enquanto Adenomera marmorata consumiu 15 diferentes tipos de presas e sua dieta foi composta principalmente por Hymenoptera (Formicidae) (45,7%), Acari (31,8%) e Blattodea (14,8%). A amplitude de nicho de I. henselii foi BA = 0,43 e de A.marmorata foi BA = 0,19. A dieta das duas espécies de anuros simpátricos do folhiço por nós estudadas foi composta basicamente de artrópodes e a sobreposição de nicho trófico entre elas não diferiu do esperado para ocorrer ao acaso. As diferenças no consumo de presas potencialmente devem facilitar a coexistência desses dois anuros simpátricos no chão da floresta. Possivelmente, esta diferença no consumo de presas em parte reflete diferenças na largura da mandíbula, no tamanho do corpo e no período de atividade dessas duas espécies.

Assuntos

RESUMO

In this study we analyzed diet composition, niche breadth and overlap of the two leaf-litter frogs Ischnocnema henselii and Adenomera marmorata. Frogs were collected in an Atlantic Rainforest area in the Reserva Natural Salto Morato, in Paraná State, Southern Brazil, using plots of 16 m2 established on forest floor. Ischnocnema henselii consumed 18 different types of prey and the diet of this species was composed predominantly by Hymenoptera (Formicidae) (15.4%), Araneae (13.83%), Orthoptera (6.15%) and Opiliones (6.15%), whereas Adenomera marmorata consumed 15 different types of prey and its diet was composed mainly by Hymenoptera (Formicidae) (45.7%), Acari (31.8%) and Blattodea (14.8%). The niche breadth of I. henselii was BA = 0.43 and that of A. marmorata was BA = 0.19. The diet of the two sympatric species of leaf-litter frogs was basically composed by arthropods and the trophic niche overlap among them did not differ from expected at random. The differences in prey consumption should potentially facilitate the coexistence of two sympatric frogs on the forest floor. Possibly, this difference of prey consumption partly reflects differences in jaw width, species-specific body size of the two species and the period of activity of these two species.(AU)

Neste estudo analisamos a composição da dieta e a amplitude e sobreposição do nicho trófico dos anuros de folhiço Ischnocnema henselii e Adenomera marmorata. Os anuros foram coletados em uma área de Mata Atlântica na Reserva Natural Salto Morato, no Estado do Paraná, Sul do Brasil, utilizando o método de parcelas de 16 m2 estabelecidas no chão da floresta. Ischnocnema henselii consumiu 18 diferentes tipos de presa e a dieta desta espécie foi composta predominantemente por Hymenoptera (Formicidae) (15,4%), Araneae (13,83%), Orthoptera (6,15%) e Opiliones (6,15%), enquanto Adenomera marmorata consumiu 15 diferentes tipos de presas e sua dieta foi composta principalmente por Hymenoptera (Formicidae) (45,7%), Acari (31,8%) e Blattodea (14,8%). A amplitude de nicho de I. henselii foi BA = 0,43 e de A.marmorata foi BA = 0,19. A dieta das duas espécies de anuros simpátricos do folhiço por nós estudadas foi composta basicamente de artrópodes e a sobreposição de nicho trófico entre elas não diferiu do esperado para ocorrer ao acaso. As diferenças no consumo de presas potencialmente devem facilitar a coexistência desses dois anuros simpátricos no chão da floresta. Possivelmente, esta diferença no consumo de presas em parte reflete diferenças na largura da mandíbula, no tamanho do corpo e no período de atividade dessas duas espécies.(AU)

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RESUMO

Foram analisadas a morfologia, topografia e morfometria dos lobos tímicos em 20 aves da linhagem Paraíso Pedrês. As aves tiveram seus lobos tímicos dissecados, medidos com paquímetro (comprimento x largura x espessura) e analisados quanto suas topografias e morfologias individuais. Os lobos tímicos apresentaram-se localizados dorsolaterais ao pescoço, desde a clavícula até seu terço cranial (65%), com números médios de 5,40 e 5,53 lobos para antímero direito e esquerdo, respectivamente. E médias de 1,19 cm de comprimento, 0,49 cm de largura e 0,20 cm de espessura para os lobos cervicais do antímero esquerdo e média de 1,30 x 0,59 x 0,26 cm para os contra laterais. As correlações foram de média intensidade, indicaram que quanto maiores, mais largos e mais espessos, os lobos foram mais numerosos e, preferencialmente ocuparam a posição dorso-lateral ao plexo vasculoneural e pescoço.(AU)

We analyzed the morphology, topography and morphology of thymic lobes in 20 birds of Paraíso Pedrês lineage. The birds had their thymic lobes dissected, measured using a caliper rule(length x width x thickness) and analyzed for their individual morphologies and topographies. The thymic lobes were located dorsolateral to the neck, from the clavicle to the third cranial (65%), with an average of 5.40 and 5.53 lobes for right and left antimere, respectively. And averaging of 1.19 cm lenght, 0.49 cm width and 0.20 cm thickness for cervical lobes of the left antimere and average of 1.30 x 0.59 x 0.26 cm to the contralateral. The correlations were of medium intensity, indicated that when it's the larger, wider and thicker, the lobes were more numerous and preferentially occupied the dorsolateral position to the vasculo-neural plexus and neck.(AU)

Assuntos

RESUMO

We analyzed the diet and microhabitat use for two Hylodinae anurans (Cycloramphidae), Hylodes phyllodes Heyer & Cocroft, 1986 and Crossodactylus gaudichaudii Duméril & Bibron, 1841, living in sympatry at an Atlantic Rainforest area of Ilha Grande, in southeastern Brazil. The two species live syntopically at some rocky streams. The two species differed strongly in microhabitat use. Hylodes phyllodes occurred mainly on rocks, whereas C. gaudichaudii was observed mostly on the water. Regarding diet, coleopterans, hymenopterans (ants), and larvae were the most important prey item consumed by both species. Data suggest that microhabitat use appears to be an important parameter differentiating these frogs with respect to general resource utilization.

Nós analisamos a dieta e o uso do microhabitat em duas espécies de anuros da subfamília Hylodinae (Cycloramphidae), Hylodes phyllodes Heyer & Cocroft, 1986 e Crossodactylus gaudichaudii Duméril & Bibron, 1841, que vivem em simpatria em uma área de Mata Atlântica na Ilha Grande, na região sudeste do Brasil. As duas espécies vivem sintopicamente em alguns riachos pedregosos. As duas espécies diferiram fortemente no uso do microhabitat. Hylodes phyllodes ocorreu principalmente sobre pedras, enquanto C. gaudichaudii foi observado na maioria das vezes dentro d'água. Com relação à dieta, coleópteros, himenópteros (formigas), e larvas foram as presas mais consumidas por ambas as espécies. Os dados sugerem que o uso do microhabitat parece ser um importante parâmetro diferenciando esses anuros com respeito a utilização de recursos.

RESUMO

We analyzed the diet and microhabitat use for two Hylodinae anurans (Cycloramphidae), Hylodes phyllodes Heyer & Cocroft, 1986 and Crossodactylus gaudichaudii Duméril & Bibron, 1841, living in sympatry at an Atlantic Rainforest area of Ilha Grande, in southeastern Brazil. The two species live syntopically at some rocky streams. The two species differed strongly in microhabitat use. Hylodes phyllodes occurred mainly on rocks, whereas C. gaudichaudii was observed mostly on the water. Regarding diet, coleopterans, hymenopterans (ants), and larvae were the most important prey item consumed by both species. Data suggest that microhabitat use appears to be an important parameter differentiating these frogs with respect to general resource utilization.

Nós analisamos a dieta e o uso do microhabitat em duas espécies de anuros da subfamília Hylodinae (Cycloramphidae), Hylodes phyllodes Heyer & Cocroft, 1986 e Crossodactylus gaudichaudii Duméril & Bibron, 1841, que vivem em simpatria em uma área de Mata Atlântica na Ilha Grande, na região sudeste do Brasil. As duas espécies vivem sintopicamente em alguns riachos pedregosos. As duas espécies diferiram fortemente no uso do microhabitat. Hylodes phyllodes ocorreu principalmente sobre pedras, enquanto C. gaudichaudii foi observado na maioria das vezes dentro d'água. Com relação à dieta, coleópteros, himenópteros (formigas), e larvas foram as presas mais consumidas por ambas as espécies. Os dados sugerem que o uso do microhabitat parece ser um importante parâmetro diferenciando esses anuros com respeito a utilização de recursos.