Reptiles are highly susceptible to climate change, responding negatively to thermal and rainfall alterations mainly in relation to their reproductive processes. Based on that, we evaluated the effects of climate change on climatically suitable areas for the occurrence of snakes in the Atlantic Forest hotspot, considering the responses of distinct reproductive groups (oviparous and viviparous). We assessed the species richness and turnover patterns affected by climate change and projected the threat status of each snake species at the end of the century. We also evaluated the effectiveness of the protected areas in safeguarding the species by estimating the mean percentage overlap between snake species distribution and protected areas (PAs) network and by assessing whether such areas will gain or lose species under climate change. Our results showed greater species richness in the eastern-central portion of the Atlantic Forest at present. In general, we evidenced a drastic range contraction of the snake species under climate change. Temporal turnover tends to be high in the western and north-eastern edges of the biome, particularly for oviparous species. Our predictions indicate that 73.6% of oviparous species and 67.6% of viviparous species could lose at least half of their original range by 2080. We also found that existing protected areas of the Atlantic Forest Hotspot have a very limited capacity to safeguard snakes at the current time, maintaining the precarious protection in the future, with the majority of them predicted to lose species at the end of this century. Although oviparous and viviparous snakes have been designated to be dramatically impacted, our study suggests a greater fragility of the former in the face of climate change. We advocated that the creation of new protected areas and/or the redesign of the existing network to harbour regions that maximize the snake species occupancy in the face of future warming scenarios are crucial measures for the conservation of this group.
Aim: This study uses the abundance of fish eggs and larvae to evaluate the importance of the main channel of the Paraná River and the adjacent areas of the floodplain, in the last dam-free stretch in the Brazilian territory, for the spawning and development of fish of different reproductive guilds, in order to obtain subsidies to assist in the management and conservation policies of this area, focusing on the maintenance of dam-free areas. Methods: Data were taken quarterly from August 2013 to May 2015, in 25 sites, grouped into three biotopes: main channel, tributaries and lagoons. Possible spatial variations in fish spawning and development as well as composition and structure of larvae were evaluated. Results: Higher densities of eggs were found in tributaries (Paracaí and Amambai rivers) and greater densities of larvae were observed in lagoons (Saraiva). Significant differences in composition and structure of larvae were detected only between sampling stations. As for taxonomic composition, 29 taxa were recorded, mostly non-migratory. However, long-distance migratory were also widely distributed, such as Brycon orbignyanus, Pseudoplatystoma corruscans, Prochilodus lineatus, Piaractus mesopotamicus and Rhaphiodon vulpinus, as well as invasive species Platanichthys platana and Hemiodus orthonops. In turn, Salminus brasiliensis presented low occurrence. Conclusions: This study evidenced that different species spawn in the region, mainly in tributaries, and their eggs and larvae are transported to the main channel of the Paraná River and adjacent lagoons, to complete their early development. The capture of larvae of important migratory species suggests that this environment still exhibits suitable conditions for their reproduction, mainly due to the presence of dam-free tributaries. Also, they emphasize the importance of the integrity of these environments for the maintenance of the regional fish fauna, and it is extremely important the monitoring of reproduction of the most endangered species, as well as of invasive species.
Freshwater fish reproduce annually in environments that provide favourable conditions for spawning and larval survival and growth. Thus, the aims of this study were to use long-term larval density data to evaluate the temporal distribution of the dourado Salminus brasiliensis, its habitat use for larval development and the effects of environmental variables on reproduction. S. brasiliensis larvae were mainly recorded in October and January in the Ivinheima River, and higher densities of larvae, primarily in the preflexion and flexion stages, were captured in the river and backwater biotopes. Water level, dissolved oxygen and temperature were the primary variables affecting the density of larvae, and this species can migrate over 200km to reproduce in the Ivinheima River and its tributaries. Therefore, S. brasiliensis is reproducing annually, indicating favourable local conditions for migration and spawning, and exhibits differential use of biotopes for reproduction, including rivers and backwaters (spawning) and lagoons (refuge and growth). Therefore, considering that the dourado is a key species for conservation, ensuring its reproductive success means maintaining a balanced ecological structure.
http://dx.doi.org/10.5007/2175-7925.2016v29n2p33A distribuição e abundância das espécies de peixes de riacho podem ser influenciadas por características ambientais relacionadas ao meio aquático e às suas margens. O objetivo do presente trabalho foi inventariar a fauna de peixes dos riachos da Cruz, Taquaruçu e Taquaruçu II, localizados na bacia do rio Paranapanema, analisando parâmetros de diversidade da ictiofauna e associando-os com variáveis abióticas. Foram coletados 4.956 exemplares, distribuídos em 27 espécies, com predominância de Characiformes e Siluriformes. A largura, a profundidade e a floresta ripária foram as variáveis ambientais que melhor explicaram a diversidade de espécies encontrada no riacho Taquaruçu II, enquanto a dominância de espécies nos riachos da Cruz e Taquaruçu pode refletir os impactos antrópicos presentes nestes ambientes, como alto grau de erosão das margens. A maior similaridade da ictiofauna entre os riachos da Cruz e Taquaruçu pode estar relacionada com suas conectividades hidrológicas. A condutividade elétrica e a largura dos riachos foram as variáveis abióticas que mais se correlacionaram com a abundância e diversidade de espécies nos riachos amostrados. Os resultados do presente estudo demonstram a importância da conservação dos ecossistemas aquáticos para a manutenção da diversidade de peixes, além de alertar para o efeito de impactos antropogênicos sobre a ictiofauna.
The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large‐scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications.
RESUMO:Espécies não nativas causam danos imprevisíveis sobre os ecossistemas e são consideradas pela IUCN como a segunda maior causa mundial de perda de biodiversidade. Os ecossistemas aquáticos são particularmente vulneráveis a esse impacto e muitas pesquisas mostram que essas espécies não nativas podem alterar a composição das comunidades nativas. A proposta deste estudo é apresentar as principais causas de introduções de espécies em ecossistemas aquáticos e possíveis medidas de prevenção e controle de espécies invasoras. Em ambientes aquáticos destacam-se como causas de introduções: destruição de barreiras geográficas como construções de reservatórios e canais de transposição de rios; criação e melhoria dos estoques naturais, devido à falta de planejamento na construção e manutenção dos locais de criação; aquariofilia e ornamentação de paisagens. Além disso, o turismo através da pesca esportiva, o controle biológico na tentativa de exterminar outra espécie já introduzida, a fauna associada a qual é transportada junto com a água, substratos ou hospedeiros e água de lastro principalmente proveniente de navios mercantis, também contribuem para as introduções de espécies. Medidas de controle de espécies não nativas são escassas e a identificação de vetores, monitoramento, políticas públicas e estudos são algumas estratégias que podem ajudar a diminuir os impactos ambientais causados por espécies não nativas em ecossistemas aquáticos. A divulgação e orientação sobre os impactos ambientais causados por espécies não nativas direcionadas para a população leiga e científica faz-se necessário, sendo a Internet uma ferramenta imprescindível e prioritária no combate a espécies não nativas.
The objective of this study was to evaluate the influence of a dam on the ecological parameters of the fish assemblages of a stream of second order of the upper Paraná River basin, southern Brazil. Samplings of abiotic data and ichthyofauna occurred quarterly between September 2012 and June 2013. Were collected 3,128 individuals in six orders, eight families and 13 species. The Cluster analysis (Jaccard) based on species composition indicated the separation of the sampling units into two groups, demonstrating the dissimilarity between upstream and downstream units. The artificial dam was characterized as a discontinuity factor for diversity patterns and ecological processes related to biota. Thus, this study has indications that the creation of dams can significantly affect the richness and abundance of fish species of small lotic systems, as streams, by modifying their environments.
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