Environment-driven changes in diversity of riparian plant communities along a mountain river.

The study of changes in species richness and composition along rivers has focused on large spatial scales. It has been ignored that in different sections of the river (high mountain area, middle zone, and mouth of the river) the specific environmental conditions can generate different longitudinal patterns of the species richness and composition. In this study, we determine whether species richness and composition of the riparian plant communities change along a mountain river and whether these changes are related to environmental variables. We expect an increase in species richness and turnover along the river, that the upstream communities would be a subset of the downstream communities, and that such would be related to edaphic and hydrologic conditions. To test this, we sampled three strata of the riparian vegetation (upper: individuals with <1 cm of ND, middle: individuals with >1 cm of ND, low: individuals with >1 m tall) in a set of 15 sites that we place along a mountain river. Additionally, we recorded topographic, hydrological, morphological, and soil variables. We performed correlation analyzes to determine whether changes in species richness and turnover were related to increased distance to the origin of the river. Also, we obtained the nestedness and evaluated the importance of environmental variables with GLM, LASSO regression, and CCA. With the increase in distance, the species richness decreases in the upper stratum, but not in the middle and the low stratum (although the highest values were observed near the origin of the river), the turnover increase in all strata and the upstream communities were not a subset of the downstream communities. The changes in species richness and composition were related to topographic (altitude), hydrological (flow), and edaphic (conductivity and pH) variables. Our results indicate that at small spatial scales the patterns of richness and composition differ from what has been found at larger spatial scales and that these patterns are associated with environmental changes in the strong altitude gradients of mountain rivers.

[Optimal design of sample size for estimating species richness of fishes in Dianshan Lake, China]. / æ·€å±±æ¹–é±¼ç±»ç”Ÿç‰©å¤šæ ·æ€§è°ƒæŸ¥æ ·æœ¬é‡çš„ä¼˜åŒ–è®¾è®¡.

Sample size plays a significant role in determining accuracy and precision for estimates of fish population dynamics or fish communities. A fisheries survey that estimated the fish community in Dianshan Lake was conducted as a case study to determine the necessary sample size for such estimates. Monthly surveys of 24 survey stations in Dianshan Lake were conducted from July, 2010 to June, 2011, resulting in the collection of 45 fish species from 14 families. A resampling technique was used to estimate the optimal survey times and number of survey stations for a Dianshan Lake fishery survey. Results showed a negative relationship between the number of stations per survey and survey times per year. To maintain a 90% fixed percentage of fish species detection and 95% fixed probability of detection within the fishery survey, the required sample sizes were 19 and 21 stations per survey and 12 and 11 survey times per year, correspondingly. The Shannon diversity index increased with the number of stations before reaching equilibrium, therefore, the optimal survey stations for estimating fish biodiversity of the Dianshan Lake fishery was determined to be 21 stations. This study provided a framework for determining the optimal sampling effort in similar studies at other locations.

Composition, abundance and aspects of temporal variation in the distribution of Anopheles species in an area of Eastern Amazonia

Introduction The diverse and complex environmental conditions of the Amazon Basin favor the breeding and development of Anopheles species. This study aimed to describe the composition, abundance and temporal frequency of Anopheles species and to correlate these factors with precipitation, temperature and relative humidity. Methods The study was conducted in the District of Coração, State of Amapá, Brazil. Samples were collected monthly during three consecutive nights, from 6:00 PM to 10:00 PM, from December 2010 to November 2011. In addition, four 12-hour collections (i.e., 6:00 PM to 6:00 AM) were performed during this period. Results A total of 1,230 Anopheles specimens were collected. In the monthly collections, Anopheles darlingi was the predominant species, followed by An. braziliensis and An. albitarsis s.l., whereas An. darlingi, An. peryassui and An. braziliensis were the most frequent species collected in the 12-hour collections. The greatest number of anophelines was collected in September (the dry season). The highest frequency of anophelines was observed for An. darlingi during September, when there were the least rainfalls of the year, along with lower relative humidity and higher temperatures. There was little variation in the abundance of this species in other months, with the exception of slight increases in February, July and August. Conclusions The major malaria vectors, An. darlingi and An. albitarsis s.l. (likely An. marajoara), were the most abundant species collected in the study area. Consequently, prevention and control measures should be taken to prevent malaria outbreaks in the District of Coração. .

A new golden frog species of the genus Diasporus (Amphibia, Eleutherodactylidae) from the Cordillera Central, western Panama.

We describe the frog species Diasporus citrinobapheussp. n. from the Cordillera Central of western Panama. The new species differs from all other species in its genus in coloration, disk cover and disk pad shape, skin texture, advertisement call, and size. It is most similar to Diasporus tigrillo, from which it differs in dorsal skin texture, relative tibia length, number of vomerine teeth, ventral coloration, dorsal markings, and relative tympanum size, and to Diasporus gularis, from which it can be distinguished by the lack of membranes between the toes, adult size, posterior thigh coloration, and position of the choanae. We provide data on morpho- logy, vocalization, and distribution of the new species, as well as brief information on its natural history.

Bat assemblage in savanna remnants of Sonora, central-western Brazil / Comunidade de morcegos em remanescentes de savana em Sonora, centro-oeste do Brasil

The Cerrado (savanna) is a wide Neotropical formation, but the knowledge on the occurrence and distribution of bat species for this phytogeographic region is scarce, especially in the western portion. Here we address what are the bat species and their relative abundances in a western Cerrado site, municipality of Sonora, Mato Grosso do Sul, Brazil. Bats were mist-netted in eight non consecutive months over the course of two years. Sampled bats (n = 507) belonged to 18 species. The estimator Jackknife 1 estimated 22 species, and diversity (H') was 1.6. Richness and diversity of bats in Sonora were slightly higher than in the southern Cerrado, and similar to or lower than in the central Cerrado. Frugivorous species predominated, as expected, however richness and abundance of nectarivorous were unexpectedly high. Carollia perspicillata was the dominant species. The endemic bat Lonchophylla dekeyseri was highly abundant in Sonora, which enhances the importance of conserving the savanna remnants in this region.

O Cerrado (savana) é uma ampla formação neotropical, porém o conhecimento sobre a ocorrência e distribuição de espécies de morcegos é escasso para esta região fitogeográfica, principalmente na porção oeste. Estudamos aqui quais são as espécies de morcegos e suas abundâncias relativas em uma localidade da porção oeste do Cerrado, no município de Sonora, Mato Grosso do Sul, Brasil. Morcegos foram capturados em redes-de-neblina em oito meses não consecutivos ao longo de dois anos. Os morcegos amostrados (n = 507) pertenceram a 18 espécies. O estimador Jackknife 1 estimou 22 espécies, e a diversidade (H') foi 1,6. A riqueza e a diversidade de morcegos em Sonora foram pouco maiores que na porção sul do Cerrado, e semelhantes ou menores que no Cerrado central. Espécies frugívoras predominaram, como esperado, porém a riqueza e abundância de nectarívoras foram inesperadamente altas. Carollia perspicillata foi a espécie dominante. O morcego endêmico Lonchophylla dekeyseri foi muito abundante em Sonora, fato que aumenta a importância de conservar os remanescentes de savana dessa região.

Ictiofauna do Ribeirão Limoeiro, Bacia do Rio Cachoeira, BA / Ichthyofauna of the Ribeirão Limoeiro, Cachoeira River Basin, BA

Os riachos da Bacia do Leste caracterizam-se por serem pequenos, pouco complexos e com ictiofauna endêmica decorrente do isolamento geográfico. Neste contexto, foi realizado um estudo da distribuição das espécies e estrutura da comunidade de peixes do Ribeirão Limoeiro, BA ao longo de um gradiente espacial no período de um ano, utilizando-se a pesca elétrica como método de coleta. Foram coletadas 21 espécies totalizando 2264 indivíduos em quatro pontos: dois próximos da cabeceira (P1A e P1M), um no médio curso (P2) e outro próximo à sua foz (P3). Characiformes e Siluriformes foram as ordens mais representativas dentre as quatro registradas. Algumas espécies ocorreram exclusivamente na cabeceira (Astyanax sp. e Trichomycterus cf. bahianus) e outras próximo da foz (Leporinus sp. e Callichthys callichthys). Por outro lado, Characidium zebra, Parotocinclus cf. cristatus, Poecilia vivipara, Astyanax sp.1, Rhamdia sp. e Poecilia reticulata ocorreram em todos os pontos amostrados. Foi coletada uma espécie com "status" de vulnerável (Nematocharax venustus) e duas exóticas (Tilapia rendalli e Poecilia reticulata). Quanto à estrutura da comunidade, os valores dos índices de riqueza de "Margalef" e de diversidade de "Shannon" foram significativamente maiores no ponto P3, por outro lado, este ponto apresentou valores significativamente menores do índice de dominância de "Berger-Parker". O ponto com vegetação ripária preservada (P1M) apresentou menor valor médio da temperatura da água e os pontos de cabeceira (P1A e P1M) apresentaram os maiores valores médios de oxigênio dissolvido e velocidade superficial. Condutividade, largura e profundidade médias aumentaram da cabeceira para a foz. Vários resultados encontrados estão de acordo com a literatura atual que trata de ecologia de comunidades de peixes de riachos neotropicais.

The streams of the Eastern Basin are characterized by being small, somewhat complex and endemic fish fauna due to geographical isolation. In this context, a study of species distribution and community structure of stream fish Limoeiro, BA along a spatial gradient in one year, using electrofishing as the collection method. Twenty one fish species were collected totalizing 2264 specimens in four points: two points near the head (P1A and P1M), one in the middle course (P2) and another near the mouth (P3). Characiformes and Siluriformes were the orders more important among the four registered. Some species occurred exclusively at the head (Astyanax sp. and Trichomycterus cf. bahianus) and other near the mouth (Leporinus sp. and Callichthys callichthys). On the other hand, Characidium zebra, Parotocinclus cf. cristatus, Poecilia vivipara, Astyanax sp.1, Rhamdia sp. and Poecilia reticulata occurred all sampling points. Was collected one specie the "status" of vulnerable (Nematocharax venustus) and two exotics (Tilapia rendalli and Poecilia reticulata). About the community structure, the values of the index of richness of "Margalef" and of the index of diversity of "Shannon" were greater in this point P3, then this point were significantly lower value of "Berger-Parker" dominance index. The point with riparian vegetation preserved (P1M) showed a lower average water temperature and the points near the head (P1A and P1M) showed the highest values of dissolved oxygen and surface velocity. Conductivity, width and depth of the medium increased toward the mouth. Several results are in accordance with the current literature dealing with community ecology of neotropical stream fish.