Добірка наукової літератури з теми "Amphibiens – Amazonie"

ABSTRACT Amazonia harbors the largest and most diverse tropical forest in the world, but knowledge about the species diversity of the region is still far from ideal. Given this low level of faunal and floral knowledge, we present an annotated list of the species of amphibians and reptiles found in Floresta Nacional do Pau-Rosa (FNPR), along the Rio Paraconi, municipality of Maués, state of Amazonas, Brazil. Herpetofauna of the FNPR was sampled with pitfall traps, active search and occasional encounters from February 18 to March 28, 2009. A total of 270 specimens were collected, representing 39 species of amphibians and 24 species of reptiles. At least seven of the species collected at FNPR represented, at the time, unnamed taxa (four of which have now been named). The number of taxa collected and the high number of unnamed taxa highlight the importance of this area in terms of biodiversity and as a priority for conservation. We also discuss about the amphibian diversity in Amazonia.

Amphibians are probably the most vulnerable group to climate change and climate-change associate diseases. This ongoing biodiversity crisis makes it thus imperative to improve the taxonomy of anurans in biodiverse but understudied areas such as Amazonia. In this study, we applied robust integrative taxonomic methods combining genetic (mitochondrial 16S, 12S and COI genes), morphological and environmental data to delimit species of the genusAmazophrynella(Anura: Bufonidae) sampled from throughout their pan-Amazonian distribution. Our study confirms the hypothesis that the species diversity of the genus is grossly underestimated. Our analyses suggest the existence of eighteen linages of which seven are nominal species, three Deep Conspecific Lineages, one Unconfirmed Candidate Species, three Uncategorized Lineages, and four Confirmed Candidate Species and described herein. We also propose a phylogenetic hypothesis for the genus and discuss its implications for historical biogeography of this Amazonian group.

This study presents a list of anurans and lizards of a Central Amazonian terra-firme rainforest site at Rio Preto da Eva, Amazonas, Brazil sampled for 38 days from December 2003 to February 2004. The study area is located close to highway AM-010 (Manaus-Itacoatiara), where deforestation represents the main threat to the local biota. Using two complementary sampling methods, active search and pitfall traps with drift fence, we recorded 23 anuran species in 12 genera and six families and 20 lizard species in 16 genera and seven families. Relative to other sites in Central Amazon, our study site presented a similar number of species of lizards but fewer amphibians.

Abstract In the Miocene (23–5 Ma), a large wetland known as the Pebas System characterized western Amazonia. During the Middle Miocene Climatic Optimum (c. 17–15 Ma), this system reached its maximum extent and was episodically connected to the Caribbean Sea, while receiving sediment input from the Andes in the west, and the craton (continental core) in the east. Towards the late Miocene (c. 10 Ma) the wetland transitioned into a fluvial-dominated system. In biogeographic models, the Pebas System is often considered in two contexts: one describing the system as a cradle of speciation for aquatic or semi-aquatic taxa such as reptiles, molluscs and ostracods, and the other describing the system as a barrier for dispersal and gene flow for amphibians and terrestrial taxa such as plants, insects and mammals. Here we highlight a third scenario in which the Pebas System is a permeable biogeographical system. This model is inspired by the geological record of the mid-Miocene wetland, which indicates that sediment deposition was cyclic and controlled by orbital forcing and sea-level change, with environmental conditions repeatedly altered. This dynamic landscape favoured biotic exchange at the interface of (1) aquatic and terrestrial, (2) brackish and freshwater and (3) eutrophic to oligotrophic conditions. In addition, the intermittent connections between western Amazonia and the Caribbean Sea, the Andes and eastern Amazonia favoured two-way migrations. Therefore, biotic exchange and adaptation was probably the norm, not the exception, in the Pebas System. The myriad of environmental conditions contributed to the Miocene Amazonian wetland system being one of the most species-rich systems in geological history.

We present a checklist for reptiles and amphibians of the Reserva Extrativista do Rio Gregório, at the upper Juruá River basin, in the southwest Brazilian Amazonia. Using time-constrained searches, pitfall traps, vocalization, and accidental sightings, we recorded 84 species: 46 amphibians and 38 reptiles. Although analyses suggest still higher diversity, considering the short sampling time, relatively high species richness was documented, which reveals the relevance of this region for conservation. Species richness did not differ between upland and floodplain habitats. Species compositions were significant different between these habitat categories for amphibians and snakes, but not for lizards, suggesting some habitat preferences. Additionally, we found threatened and vulnerable species. We did not assess impacts of human activities on natural populations in RESEX do Rio Gregório, but since resident people have directly used natural resources (e.g. consuming turtles and modifying natural habitats), we recommend monitoring biodiversity to avoid negative impacts.

In this study we present a list of amphibians and reptiles from the Reserva Biológica do Tapirapé (REBIOTA), an area in the Amazonian rainforest in Pará State, Brazil. We sampled the area for 21 days, in both dry and rainy seasons, using pitfall traps and active searching methods. Our efforts resulted in the discovery of 35 species of amphibians and 27 species of reptiles. This study provides the first list of amphibians and adds eigh new species of reptiles for the Carajás region.

A species list of amphibians from Santa Isabel do Rio Negro in Brazilian Amazonia is provided. Collections were made from March–April 2012 along each of two 3-km trails with the following sampling methods: (1) pitfall traps with drift fences; (2) visual and auditory surveys; and (3) chance encounters. The trail at Daraá is north of the Rio Negro, whereas the other in Ayuanã is south of the river. Forty species of anurans and one salamander species representing 20 genera and nine families were recorded. The species composition was compared with those of 16 other studies conducted in the Guiana, Imeri, and Jaú areas of endemism, where species richness varies from 21–63, and similarity indices range from 23–100%. The anuran fauna at our sites resembles that of Flota Faro in eastern Amazonia more than it does that of the nearest site in the Departamento del Guainía of Colombia. The index of similarity is extremely variable between sites of the same and distinct areas of endemism. This pattern also was observed in the cluster analysis. As expected, geographically close areas have similar faunal compositions. However, the anuran fauna of Parque Nacional do Jaú (Jaú area of endemism) resembles that of Manaus (Guiana area of endemism) more closely than it does that of the Ayuanã River, which belongs to the same area of endemism as Parque Nacional do Jaú. The limits of the areas of endemism are better defined by the presence / absence of other terrestrial vertebrates, such as birds and mammals, than by the assemblage of amphibians and squamate reptiles.

ABSTRACT Amphibians are excellent bioindicators because they are sensitive to chemical pollution and can indicate ecosystem changes due to the presence of or exposure to chemical compounds. Here we report evidence of the impact of herbicides, including glyphosate, on amphibians in a locality in the central Brazilian Amazon and compare it with data from other biomes in Brazil. We observed malformations in three species of Leptodactylus and local extinctions of Scinax ruber and Rhinella marina from reproductive sites close to an area where herbicides had been applied. The observations in the Amazon are similar to reports from Brazil’s Atlantic forest on morphological anomalies and mortality in amphibians exposed to herbicides. We warn of the threat of expanding crops for the production of biofuels in the Amazon due to their cultivation being associated with agrochemicals, including glyphosate, posing a threat to the biodiversity of the Amazon biome.

Absctract Eustrongylides spp. nematodes have birds as final hosts and uses other vertebrates as intermediate/paratenic host (fish, amphibians and reptiles) and have zoonotic potential. In amphibians, the larvae may be located in the subcutaneous tissues, liver and mesentery, between the muscle fibres, especially in the lower limbs. Rhinella marina, which is widely observed in Brazil, has exhibited complex diversity in its helminth fauna, reflecting the unique habitat of the Amazon biome. For the first time, this study describes the morphological aspects of third-stage larvae of Eustrongylides sp. in Rhinella marina from Santa Cruz do Ararí, Marajó Archipelago, Eastern Amazonia, using light and scanning electron microscopy.

We present the first species amphibian list for municipality of Coari, state of Amazonas, Brazil. The list was drawn up as a result of data obtained from specimens deposited in the Herpetological Collection of the Museu Paraense Emílio Goeldi and inventories conducted in the Urucu Petrol Base, in 2003-2004 and 2007-2009. Sampling methods included pitfall traps with drift fences and time constrained searches. We considered the data collected by other researchers, incidental encounters and records of dead individual on the road. Fifty four species were recorded. Rhinella gr. margaritifera (n= 68), Adenomera gr. marmorata (n= 59), and Osteocephalus leprieurii (n= 20) were the most collected, while ten species were less collected. Compared with other studies in eastern Amazonia, the region of Urucu presented a large number of anurans. Nonetheless, it ́s not possible to confirm this because the data collected were not standardized among studies. However, further studies by, increasing the sampling effort, could prove this area to be richer in anurans than that observed so far.

Avec une surface de plus de six millions de kilomètres carrés, l'Amazonie abrite la plus grande forêt tropicale humide au monde, ainsi qu'une grande partie de la diversité terrestre. Cependant, les origines spatiales et temporelles de cette diversité demeurent mal comprises et nécessitent d'être plus étudiées pour identifier les causes de cette impressionnante diversification. Les amphibiens sont un groupe taxonomique particulièrement adapté à l'étude de la biogéographie historique en Amazonie car ils ont diversifié de manière importante dans la région et présentent d'importante variations d'utilisation de l'habitat ainsi que de capacités de dispersion entre groupes. Nous avons d'abord reconstruit l'histoire biogéographique du genre Allobates qui se rencontre principalement dans des forêts de terra-firme et pour lequel l'Amazonie de l'Ouest a joué un rôle important de source de diversification il y a entre 14 et 10 Millions d'années. Ce patron spatio-temporel coïncide avec une période marquée par la présence d'un système de méga-marécage qui recouvrait la plupart de l'Amazonie de l'Ouest il y a entre 23 et 10 Millions d'années. La décharge progressive de ce système marécageux a été suivie par une expansion des forêts de terra-firme en Amazonie de l'Ouest, une disponibilité en habitat favorable qui a probablement contribué à la diversification d'Allobates. Nos résultats suggèrent également que les rivières de l'Ouest Amazonien ont pu promouvoir la diversification au cours des 10 derniers Millions d'années en agissant comme une barrière semi-perméable à la dispersion, permettant la spéciation par dispersion suivie d'isolation géographique. Dans un second temps, nous avons reconstruit l'histoire biogéographique du groupe Pristimantis conspicillatus qui a diversifié de manière continue au cours du temps. Ce groupe présente un patron spatial de diversification particulier, avec quatre clades anciens ayant diversifié dans différentes aires simultanément, avec relativement peu d'évènements de dispersion comparé à Allobates. Ces importantes différences suggèrent que les espèces d'amphibiens ont des capacités de dispersion très variables qui sont probablement liées à leurs traits d'histoire de vie. Pour finir, nous avons comparé les histoires biogéographiques de six clades d'amphibiens partageant des temps d'origines comparables et qui sont représentatifs de la diversité Amazonienne en termes de taxonomie, de traits d'histoire de vie, d'utilisation de l'habitat et de type de reproduction. L'Amazonie de l'Ouest a été identifiée comme la principale source de diversification pour les amphibiens Amazonien, bien qu'elle ne se soit comportée comme tel qu'à partir d'il y a 10 Millions d'années pour les groupes présentant de l'adaptabilité dans la disponibilité de l'habitat ; et seulement entre il y a 10 et 5 Millions d'années pour les groupes conservatifs dans la disponibilité de l'habitat. Cela suggère que les groupes conservatifs dans la disponibilité de l'habitat remplissent la niche écologique plus rapidement que les espèces présentant de l'adaptativité, ce qui se traduit par des phases de diversification plus courtes. Nos résultats suggèrent également que les rivières agissent comme des barrières à la dispersion uniquement pour les groupes conservatifs dans l'utilisation de l'habitat. Nous tenons à souligner que ces résultats doivent être considérés avec prudence car ils ont été obtenus en étudiant une petite fraction de la diversité Amazonienne, ils apportent néanmoins de nouveaux éléments l'influence du conservatisme de niche sur les trajectoires évolutives en Amazonie, ce qui permettra peut-être d'inciter un plus grand effort de recherche sur cette thématique
With more than six million square kilometers, Amazonia hosts the largest tract of lowland tropical rainforest in the world and a large portion of the global terrestrial diversity. However, the temporal and spatial origins of this diversity remain poorly understood and need to be better comprehended to identify the processes responsible for this tremendous diversification. Amphibians are a particularly adequate group for investigating patterns of biogeographical history within Amazonia because they extensively diversified within the region and present important disparities in habitat use and dispersal abilities across groups. We first investigated the historical biogeography of the terra-firme genus Allobates and identified western Amazonia as an important source of diversification between 14 and 10 million years ago (Mya). This spatio-temporal pattern was coinciding with the existence of the Pebas system, a mega-wetland system that occupied most of western Amazonia during this period, that was unsuitable for terra-firme species. The Pebas system discharge was likely followed by an extension of terra-firme forests that likely fostered Allobates diversification. Our results also suggested that western Amazonia rivers might have subsequently (after 10 Mya) promoted diversification, by acting as semi-permeable barriers allowing speciation by dispersal and isolation. Secondly, we investigated the biogeographical history of the Pristimantis conspicillatus group which, instead, presented a continuous diversification throughout Neogene. This group displays a striking spatial pattern of diversification with four ancient clades that have diversified concomitantly in distinct areas in Amazonia and the Atlantic Forest, with much fewer dispersal events between areas than in Allobates. These differences suggest that amphibian species display differences in dispersal abilities that can be related to their life history traits. Finally, we compared the biogeographic histories of six frog clades, including the two aforementioned ones, that share comparable crown ages and span the Amazonian frog diversity in terms of life history traits, taxonomy, habitat use and reproduction modes. We identified western Amazonia as the principal source of diversification for Amazonian amphibians, although it acted as such only after 10 Mya for the groups that have adapted to various types of habitats; and only between 10 and 5 Mya for the ecologically conservative groups. This suggest that species with lower habitat availability reach niche filling more rapidly than ecologically adaptive species, resulting in shorter diversification phases. Our results also suggest that riverine barrier effect seems to have affected solely conservative groups particularly when the river course is stable over time. While these results were obtained by considering only a fraction of Amazonian diversity, they provide interesting insights on the influence of niche conservatism upon Amazonian evolutive trajectories, which will hopefully foster further and more ample research in this direction

Le Plateau des Guyanes a été géologiquement stable au cours de l'ère Cénozoïque, exempt de l'influence de l'orogénèse des Andes et de la mise en place du bassin de l'Amazone. Cette région est-elle biogéographiquement homogène au sein de l'Amazonie ? Quelles sont les modalités spatio-temporelles de diversification au sein de cette région ? Afin de répondre à ces questions, j'ai exploré sa biorégionalisation sur la base de la distribution des amphibiens anoures. Cette approche a permis de définir trois biorégions dans l'est du Plateau des Guyanes, et de révéler une forte sous-estimation de l'endémisme. Ensuite, j'ai étudié les patrons de diversification au sein du genre endémique Anomaloglossus. Ce volet a permis de dévoiler l'existence de spéciation cryptique au sein du genre, avec un patron biogéographique composé de quatre zones de diversification au sein du Plateau des Guyanes et une origine du genre dans les tepuis
The Guiana Shield has been geologically stable during the Cenozoic era, exempt of the influence of the uplift of the Andes and the setting up of the Amazon basin. Is this region biogeographically homogeneous within Amazonia? What are the spatio-temporal diversification modalities within this region? To answer these questions, I explored bioregionalisation within Amazonia and the Guiana Shield based on the dis- tribution of anuran amphibians. This approach enabled to define three bioregions in the eastern Guiana Shield and to reveal a high underestimation of endemism. Then, I studied the diversification patterns within the endemic frog genus Anomaloglossus. This part en- abled to reveal cryptic speciation within the genus, and a biogeographic pattern composed of four areas of diversification in the Guiana Shield, with an origin of the genus in the western highlands (tepuis)

Global biodiversity is currently facing the sixth mass extinction, with extinction rates at least 100 times higher than background levels. The Amazon Basin has the richest amphibian fauna in South America, but there remain significant gaps in our knowledge of the drivers of diversity in this region and how amphibian assemblages are responding to environmental change. Surveys were conducted in the Pacaya-Samiria National Reserve (PSNR) in Amazonian Peru, with a view to (1) comparing assemblage structure on floating meadows and adjacent terrestrial habitats; (2) determining the predictors of diversity in these habitats; and (3) exploring the effects of disturbance and seasonal flooding on diversity measures. Eighty-one species of amphibians have been recorded in these habitats since 1996 representing 11 families and three orders. In 2012-2013 22 anuran species used the floating meadow habitat, of which 10 were floating meadow specialists. These specialists were predominantly hylids which breed on floating meadows all the year round. Floating meadows therefore host an assemblage of species which is different to that found in adjacent terrestrial areas which are subject to seasonal flooding. Floating meadows enhance the amphibian diversity of the region, and rafts of vegetation that break away and disperse frogs downstream may explain the wide distribution of hylids within the Amazon Basin. Fourteen different reproductive modes were represented within the 54 anuran species observed. The number of reproductive modes present was influenced by localised disturbance and seasonal flooding. Diversity increased in the low water period, with hylids breeding in temporary pools. When the forest is inundated most species disperse away from the flood waters. Disturbance, habitat change, emerging diseases and climate change would likely lead to changes in species composition and assemblage structure rather than wholescale extinctions. However, further studies are needed to evaluate long-term consequences of synergistic environmental change.

Biological diversity is threatened worldwide and it is a priority to generate more information that can be used both for understanding ecological processes and determining conservation strategies. For my dissertation, I focused on amphibian diversity patterns in lowland rainforests of southwestern Amazonia to evaluate the importance of habitat heterogeneity in the region. My main purpose was to test the hypothesis that amphibian communities in different forest types differ in species richness, composition, and abundance. I used standardized visual encounter surveys to quantify the species composition and abundance of amphibians at four sites, each containing four forest types (floodplain, terra firme, bamboo, and palm swamp). I used leaf-litter plots to evaluate the effect of soil and leaf-litter characteristics on species richness and abundance of leaf-litter frogs. I intensively sampled at one site and then sampled three other sites (distance among sites varied 3.5-105 km) to evaluate whether the patterns observed at one site were similar elsewhere. I also updated the information on threatened and potentially threatened amphibians in Peru and my study region. I found that no species appears to have experienced population declines in southeastern Peru, suggesting that the region still contains the original species pool. My results support the hypothesis that amphibian communities differ across forest types and that patterns observed at the local scale (one site) are similar at the regional scale (four sites). My data also indicate that there is no correlation between species composition and geographic distance among sites. Instead, an important proportion of the gamma diversity is represented by habitat-related beta diversity. My leaf-litter plot data showed that part of the variation in the leaf-litter community structure is explained by soil and litter characteristics. I found that soil total phosphorus and, to a lesser extent, humidity, leaf-litter mass, and pH is linked to species presence/absence and abundance. My study provides the first standardized, quantitative comparison of amphibian community structure across four major forest types in southwestern Amazonia and highlights the fact that forest types are complementary and necessary for maintaining high species richness in the region.

It is interesting to note in Swettenham’s account that the Malays were already practicing conservation methods for the river terrapins in the nineteenth century. By protecting the beaches from poachers and leaving the third laying to hatch, they maintained moderate recruitment to offset the egg harvest. Similar conservation measures existed on the Amazon River in the nineteenth century to protect the heavily exploited giant South American river turtle, including the protection of females and leaving a third of the eggs laid on the beaches to hatch (Goeldi, 1906 in Parsons, 1962; see also a brief history of exploitation patterns of this species in chapter 5, this volume.). Unfortunately, conservation actions such as these have been the exception rather than the rule in human interactions with river turtles. As emphasized in earlier chapters, populations of most riverine turtle species have seriously declined from nineteenth century levels, but unlike the general declines reported for amphibians, most of the causes are obvious. The burgeoning commercial exploitation for food, traditional medicines, and pets, expanding populations of traditional and introduced predators, and extensive habitat destruction exemplified by such practices as sand mining, damming, channelizing, and pollution of flowing waterways have been key factors. We know far better how we reached this state of decline than how we can reverse the trend. Since the early beginnings of river turtle conservation chronicled by Swettenham and Goeldi, a variety of conservation techniques have been tried world-wide. As there are few proven methods, most actions have been based on what seemed logical or was simply cloned from the methods being used in sea turtle conservation programs. The latter may not have been the best approach for as Pritchard warned in a 1980 paper (Pritchard, 1980b) “sea turtle conservation remains without a theoretical framework, and almost all techniques that have been used remain unproven and riddled with paradox.” Conservation methodology is generally divisible into two divergent approaches, one emphasizing in-situ (on site) techniques and the other ex-situ (off site) techniques. The former aim at protecting animals and their habitat while minimizing intrusion into the life history of the target species.