While bird diversity in the Atlantic Forest can be considered well-known, how the communities have been affected by deforestation and habitat fragmentation is not. We studied birds in 10 forest ...fragments of distinct sizes (all originally within the Atlantic Forest) in southern Bahia. In 5,391 bird encounters, we found 251 species, with 46 endemics and eight considered globally vulnerable or endangered. We also compiled a list of the 380 species that should comprise the expected regional assemblage, and found that only 66% of these species were present in all the fragments combined. Only 9% of all observed species were found in all fragments. The largest fragment (700 ha) had the greatest number of endemic species (40), and seven threatened species. All fragments had some conservation-important species (some were found in one or a few fragments), but no fragment included them all. Fragments shared 10% of endemic species, but overall, the contingent of endemics was unique in each fragment. Finally, most functional traits of bird assemblages decreased with increasing fragment size. Neither species richness nor similarity correlated with fragment size or distance between fragments, and unknown, non-random factors probably influence the likelihood of species survival in each fragment. Thus, to ensure the persistence of threatened species, as well as maintain the most common species, conservation management decisions should include all fragments together because no single fragment is most representative of the local community.
Abstract Here we present a brief review on how the loss of fauna can cause a concomitant loss in plant diversity in the state of Espírito Santo, focusing on the context of current habitat loss and ...fragmentation and the importance of the mutualistic interactions between animals and plants. We discuss the main groups of fauna that are involved in pollination and seed dispersal, especially those that are found in the state of Espírito Santo. These ecological processes were selected due to their relevance for population dynamics and population genetics of plants. In Atlantic Forest, important pollinators include a variety of insects (especially bees), along with many species of birds and bats. Seed dispersers also include many taxonomic groups, from ants to large mammals. Each of these groups contribute in their own unique and complementary, rather than redundant, way. Habitat fragmentation causes a variety of problems for habitat integrity and the reduction of species diversity, and smaller fragments tend to support fewer species and smaller populations. As a consequence, pollinators and seed dispersers are lost or their activity is reduced, thereby reducing even further the reproductive success of the plants, leading to a vicious cycle of reduction of species diversity.
Resumo O presente trabalho apresenta uma breve revisão sobre como a perda de fauna pode causar a perda concomitante de diversidade vegetal no estado do Espírito Santo, considerando o cenário atual de perda e fragmentação de habitats e a importância das interações mutualísitcas entre animais e plantas. Foram considerados os principais grupos zoológicos envolvidos na polinização e na dispersão de sementes, especialmente aqueles com ocorrência no estado do Espírito Santo. Estes processos ecológicos foram selecionados devido à sua relevância na dinâmica e a genética populacional das plantas. Na Mata Atlântica, importantes polinizadores incluem uma variedade de insetos (especialmente abelhas), juntamente com muitas espécies de aves e morcegos. Os dispersores de sementes também abrangem muitos grupos taxonômicos, desde formigas até grandes mamíferos. Cada um desses grupos contribui de maneira única e complementar, mais do que de forma redundante. A fragmentação de habitats compromete a integridade do habitat e reduz a diversidade de espécies, ressaltando que fragmentos menores tendem a suportar menos espécies e menores populações. Como consequência, os polinizadores e os dispersores de sementes são perdidos ou sua atividade é reduzida, diminuindo ainda mais o sucesso reprodutivo das plantas, levando a um círculo vicioso de redução da diversidade de espécies.
Population dynamics are influenced by environmental variability and understanding the abundance and persistence of individuals and populations is a fundamental goal of population ecology. Thus, ...estimating demographic parameters to identify the factors important for population variability is required to understand temporal and spatial dynamics. The stream‐living diurnal frog Hylodes heyeri is endemic to the Atlantic Forest of Brazil in the states of Paraná, São Paulo and Santa Catarina. Here we use capture‐mark‐recapture methods to estimate survival rates and population size of this Brazilian Torrent Frog in Pico do Marumbi State Park, Paraná. We used CJS models for an open population to estimate apparent survival, capturability and population size in two streams. The number of captures during each session was positively correlated with the minimum weekly temperature. Despite that correlation, the most parsimonious model of survival and capturability was the constant model for both parameters, resulting in a monthly survival rate of 0.38 (95% CI = 0.30–0.46). Thus, only the abundance of the frog differed in the two streams (79 vs. 36), with the population size estimate of 187 individuals. Reproduction is seasonal in the Brazilian Torrent Frog and so the low monthly survival rate suggests that animals move over time rather than die, because 38% month−1 survival should result in <1% of the population remaining after 5 months. Thus, researchers must recognize that populations are labile and individuals often move or are washed downstream during heavy rainfall, generating apparently rapid local turnover that is unlikely to reflect true mortality.
In the northern hemisphere, bird counts have been fundamental in gathering data to understand population trends. Due to the seasonality of the northern hemisphere, counts take place during two ...clearly defined moments in time: the breeding season (resident birds) and winter (after migration). Depending on location, Neotropical birds may breed at any time of year, may or may not migrate, and those patterns are not necessarily synchronous among species. Also in contrast to the northern hemisphere, population trends and the impact of rapid urbanization and deforestation are unknown and unmonitored. Throughout one year, we used point counts to better understand temporal patterns of bird species richness and relative abundance in the state of São Paulo, southeastern Brazil, to examine how to implement similar bird counts in tropical America. We counted birds twice each day on 10 point transects (20 points day‑1), separated by 200 m, with a 100 m limited detection radius in a semideciduous tropical forest. Both species richness and bird abundance were greater in the morning, but accumulation curves suggest that longer-duration afternoon counts would reach the same total species as in morning counts. Species richness and bird abundance did not vary seasonally and unique species were counted every month; relatively few species (20%) were present in all months. Most (84%) known forest species in the area were encountered. We suggest that point counts can work here as they do in the northern hemisphere. We recommend that transects include at least 20 points and that the simplest timing of bird counts would also be seasonal, using timing of migration of austral migrants (and six months later) to coordinate counts. We propose that bird counts in Brazil, and elsewhere in Latin America, would provide data to help understand population trends, but would require greater effort than in temperate latitudes due to greater species richness and different dynamics of reproduction and migration. With collaboration among ornithologists and coordinated bird surveys, we may develop a technique for the tropics that would yield information for population trends and conservation of birds, similar to counts in temperate latitudes.
Theory predicts that, even within the same population, birds may vary their breeding investment with age. This may be due to an improvement in individual quality of old birds in body condition, ...foraging and in nesting experience. Birds commonly signal age and individual quality to potential mates and competitors through plumage colour. Young male and female breeders of Saffron Finches (Sicalis flaveola) have dull plumages that change to yellow with age. We asked whether older, yellow birds are in better condition and invest more in breeding than dull, younger birds. In southern Brazil, we monitored Saffron Finches breeding in nest-boxes over three breeding seasons. We found that yellow birds were in better condition: females had more furcular fat and males were heavier. Yellow parents bred earlier, had larger clutch sizes, shorter incubation periods, re-nested more and ultimately fledged twice as many offspring as dull parents. Egg mass, nestling mass and nest survival probability were similar between plumage colours. Female colour predicted clutch sizes and incubation periods better than male colour. Our results highlight the importance of accounting for female quality and reproductive investment decisions within the context of sexual selection.
Poorly known species may be cryptically endangered, especially when they inhabit fragmented and threatened habitats. Heart‐tongued frogs (genus Phyllodytes, family Hylidae, Lophyohylinae) comprise 17 ...species of poorly known frogs that have obligatory associations with tank bromeliads. The distributions of all species are restricted to a small, extremely fragmented, region of Atlantic Forest in eastern Brazil. We model climate and tank bromeliad distributions to better understand frog distribution limits. Using records from several sources for frogs and bromeliads with climate data from WorldClim, we modelled the distribution of Phyllodytes using maximum entropy. We compared climate and altitude within the distribution and nearby to test how climate may limit distribution. Climate together with bromeliad distributions provided the best model and predicted the smallest suitable area for Phyllodytes that was larger than that occupied, from the state of Paraíba in the north to Rio Grande do Sul in the south. Phyllodytes occurs in lower elevations that are warmer, wetter and less variable than the surrounding regions where it does not occur, and dispersal is apparently limited by the surrounding, inhospitable, region. Dispersal limitation and habitat fragmentation have relegated Phyllodytes to many very small habitat fragments. With many species in this genus being known from a single or few samples, this unfortunate combination of limitation and fragmentation suggests that some or all species of Phyllodytes may be threatened with extinction, especially if habitat fragmentation continues at its present pace in eastern Brazil.
Population structure and dynamics of the black-cheeked gnateater (Conopophaga melanops) were studied at Salto Morato Nature Reserve, in Paraná, southern Brazil, from October 2006 to September 2007. ...Territory size and population density, breeding season (timing and length), reproductive success and annual survival rates were estimated from sightings of 18 marked adult birds and the success of 18 nesting attempts. The black-cheeked gnateater is socially monogamous and territorial, with a breeding-season length of approximately 3 mo beginning in early October. Predation caused most nest failures, nest survival was 0.96 d−1 and apparent annual nesting success was 22%, resulting in annual productivity of 0.36 individuals per adult. Apparent adult annual survival was ~0.44 y−1. Seventy-five per cent of fledglings survived at least 2 mo after fledging. Two methods of estimating population growth rate suggest very different rates: r = −0.04 (~ stable), or λ varies between 0.475–0.616 (declining). Yet, low apparent adult survival suggests that territories are not permanent, perhaps abandoned after nest failure. We find that by estimating population growth, even in short-term studies, testable hypotheses can be generated that will allow better understanding of population dynamics.
We studied nesting in marked pairs of Star-throated Antwrens (Rhopias gularis) over 3 years to examine whether breeding traits in subtropical Brazil are more similar to temperate patterns of breeding ...than is typical of the patterns observed within the mostly tropical Thamnophilidae. This Antwren is socially monogamous and permanently territorial, as are all Thamnophilidae, and has a long incubation period (18 days) and shorter nestling period (13 days). Its breeding season is relatively short (<4 months) and nesting success high (36%) compared with those traits of tropical antbirds. Daily nest- survival rate (DSR) during incubation was fairly low and declined throughout the breeding season, whereas DSR was greater and constant during the nestling period. Thus, early nests were more successful and, after hatching, nestlings had a very high probability of fledging (up to 90%). Only males built nests, which can be reused, apparently reducing reproductive demand on females. Pairs did not re-nest in the same season after a successful nesting attempt. Average fecundity was 1.0 ± 0.3 fledglings female
−1
year
−1
, similar to that of tropical thamnophilids. We argue that the timing of breeding and reproductive effort are adjusted to reduce breeding costs in a subtropical climate, resulting in a unique combination of life-history traits for a bird of tropical origin.
Surprising genomic diversity in the Neotropical fish Synbranchus marmoratus (Teleostei: Synbranchidae): how many species? Torres, Rodrigo Augusto(Universidade Federal do Paraná Departamento de Zoologia Laboratório de Genômica Evolutiva e Ambiental); Roper, James Joseph(Universidade Tuiutí do Paraná Departamento de Biologia); Foresti, Fausto(Universidade Estadual Paulista Departamento de Morfologia Laboratório de Biologia e Genética de Peixes) ...
Neotropical Ichthyology,
06/2005, Letnik:
3, Številka:
2
Journal Article
Odprti dostop
Chromosomes and nuclear DNA content variation in the eel Synbranchus marmoratus were studied in seven samples taken from rio Paraguay and rio Paraná basins to examine whether karyotype and nuclear ...DNA content variations could offer useful information for the characterization of independent evolutionary lineages in the genus and construction of evolutionary and biogeographical hypotheses. The occurrence of different karyotypes was already described for this species; however, a new cytotype from rio Miranda was discovered. Nuclear DNA content showed a wide variation among samples and individuals, ranging from 5.2 to 9.1 pg of DNA/nuclei. An analysis of variance confirmed the occurrence of significant differences among samples. In a deeper series of analyses, a multimodality was found in the distribution of nuclear DNA content, in which several, more or less discrete units arose. Finally, combining karyotype formulae with nuclear DNA content, a complex relationship among the rivers sampled was found. Based on the available data, we suggest that several independent evolutionary lineages of Synbranchus marmoratus occur in the rivers sampled. Biogeographical hypotheses are proposed and discussed.
Os cromossomos e a variação de conteúdo de DNA nuclear foram estudados em sete amostras de Synbranchus marmoratus das bacias dos rios Paraguai e Paraná com o objetivo de avaliar se diferenças no cariótipo e no conteúdo de DNA nuclear poderiam fornecer informações para a caracterização de linhagens evolutivas independentes no gênero e para a elaboração de hipóteses evolutivas e biogeográficas. A ocorrência de diferentes cariótipos já foi descrita para essa espécie, entretanto, um novo citótipo foi encontrado no rio Miranda. O conteúdo de DNA nuclear mostrou uma ampla variação entre as amostras e indivíduos, com valores entre 5,2 a 9,1 pg de DNA/núcleo. Uma análise de variância confirmou a ocorrência de diferenças significativas entre as amostras. Em uma série de análises, um padrão multimodal foi encontrado na distribuição do conteúdo de DNA nuclear, pelo qual várias unidades, mais ou menos discretas, foram identificadas. Combinando a fórmula cariotípica com o conteúdo de DNA nuclear, uma relação complexa entre os rios foi observada. Com base nos dados disponíveis, sugerimos que existem várias linhagens evolutivas independentes de Synbranchus marmoratus nos rios amostrados. Hipóteses biogeográficas são propostas e discutidas.
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