Beta diversity can provide insights into the processes that regulate communities subjected to frequent disturbances, such as flood pulses, which control biodiversity in floodplains. However, little is known about which processes structure beta diversity of amphibians in floodplains. Here, we tested the influence of flood pulses on the richness, composition, and beta diversity of amphibians in Amazonian floodplain environments. We also evaluated indicator species for each environment. We established linear transects in three environments: low várzea, high várzea, and macrophyte rafts. Species richness decreased and beta diversity increased according to the susceptibility of habitats to flood pulses. Indicator species differed among environments according to forest succession promoted by the flood pulse. The decrease in species richness between high and low várzea is due to non‐random extinctions. The higher rates of species turnover between várzeas and macrophyte rafts are driven by the colonization of species adapted to open areas. Our results highlight that the maintenance of complex environments is needed to protect biodiversity in floodplains.

Despite the historical knowledge on amphibians of the Purus River basin, basic information on assemblages is fragmented, with gaps in knowledge existing at various scales, which limits conservation strategies. This study provides information on the composition, richness and abundance of the amphibian fauna in varzea environments and floating meadows of the oxbow lakes of the Middle Purus River between the Boca do Acre and Pauiní municipalities, Amazonas, Brazil. We sampled six oxbow lakes using forty-seven 200-meter transects, distributed among the ''floating meadows,'' ''high varzea'' and ''low varzea,'' from April to January 2014. We recorded 59 species, with the family Hylidae being predominant. This amphibian fauna represents approximately 19% of the species known for the Amazon, 28% for Amazonas State and 45% of the species recorded so far in the Purus River, increasing the richness of the basin to 132 species. Eight species were considered rare, and 29 are endemic to the Amazon. This study adds to the knowledge on the amphibian species of the Amazonian lowlands, including the expansion of known distributions, as well as increases the knowledge of several species that are locally rare, endemic and/or that are data deficient regarding distribution and ecology. Keywords: Amazon, floodplain, flood pulse, diversity, conservation. Resumo: Apesar do histó rico conhecimento sobre anfíbios ao longo da bacia do rio Purus, informac¸õ es bá sicas sobre as taxocenoses encontram-se fragmentadas, formando lacunas no conhecimento do grupo em diversas escalas e restringindo estratégias de conservac¸ã o. Este estudo apresenta a composic¸ão, a riqueza e a abundâ ncia da fauna de anfíbios em ambientes de vá rzea e bancos de macró fitas de lagos de meandro do médio Rio Purus, entre os municípios de Boca do Acre e Pauiní, Amazonas, Brasil. Conduzimos amostragens em seis lagos de meandro, através de 47 transectos de 200 metros, distribuídos entre os ambientes ''banco de macró fitas'', ''vá rzea alta'' e ''vá rzea baixa'', entre abril de 2013 e janeiro de 2014. Registramos 59 espécies, com predomínio de espécies da família Hylidae. Essa fauna de anfíbios representa aproximadamente 19% das espécies conhecidas para a Amazô nia, 28% para o estado do Amazonas e 45% do registrado até o momento para o rio Purus, elevando a riqueza da bacia para 132 espécies. Oito espécies foram consideradas raras e 29 sã o endêmicas da Amazô nia. Este estudo contribui para o conhecimento das espécies de anfíbios das terras baixas na Amazô nia, incluindo a ampliac¸ão da distribuic¸ã o e aumento do conhecimento sobre diversas espécies localmente raras, endêmicas e/ou com deficiência de dados sobre distribuic¸ã o e ecologia. Palavras-chave: Amazônia, planície de inundac¸ão, pulso de inundac¸ão, diversidade, conservac¸ão.

ABSTRACT. Local diversity and infl uence of seasonality on amphibians and reptiles assemblages in the Reserva Extrativista Chico Mendes, Acre, Brazil. Despite the high richness of amphibians and reptiles known for the southwestern portion of the Brazilian Amazon, the knowledge of these is punctual and few studies have evaluated the temporal variations in the occurrence and abundance of species. The goals of this study were to present the amphibians and reptiles assemblages in a locality of the Chico Mendes Extractive Reserve, verify which climate variables infl uence the temporal fl uctuations in richness and abundance, and identify the main species of the amphibians and reptiles infl uenced by them. The study area is located in the Seringal Etelvi region, southwestern portion of the Reserve, municipality of Brasiléia, state of Acre. Data collection took place between October 2011 and September 2012, for 48 sampling days, using the methods of searches limited by time and pitfall traps. There were recorded 978 specimens of 31 amphibians and 54 reptiles. Higher richness and abundance of amphibians occurred during the rainy season, with the monthly abundance positively associated with the mean temperature. Only the abundance of reptiles was higher during the rainy period. However, both richness and abundance were positively associated with mean temperature. Four amphibians, Allobates gr. marchesianus, Hamptophryne boliviana (Parker, 1927), Boana geographica (Spix, 1824) and Rhinella marina (Linnaeus, 1758), and two reptiles, Kentropyx pelviceps Cope, 1868 and Norops fuscoauratus (D'Orbigny, 1837), had their monthly abundances positively associated with the mean temperature. The lizard Dactyloa punctata (Daudin, 1802) had the monthly abundance associated with precipitation. It was possible to verify the increase of richness and abundance of amphibians and reptiles during periods when the availability of resources is favorable for many species. Species can react diff erently to climatic variations, whereas others are sensitive to fl uctuations, others seem answer easily or not reduce their abundances in periods theoretically unfavorable.KEYWORDS. Richness, abundance, Southwestern Amazonia, seasonality, temporal variation.RESUMO. Apesar da elevada riqueza de anfíbios e répteis conhecida para a porção Sul-Ocidental da Amazônia brasileira, o conhecimento sobre estes é pontual e poucos estudos avaliaram as variações temporais na ocorrência e abundância das espécies. Os objetivos deste estudo foram descrever as taxocenoses de anfíbios e répteis em uma localidade da Reserva Extrativista Chico Mendes, verifi car quais variáveis climáticas infl uenciam as fl utuações temporais na riqueza e abundância e identifi car as principais espécies de anfíbios e répteis infl uenciadas por elas. A área de estudo está localizada na região do Seringal Etelvi, porção sudoeste da Reserva, município de Brasiléia, estado do Acre. A coleta de dados ocorreu entre outubro de 2011 e setembro de 2012, num total de 48 dias de amostragem, com os mét...

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