The placement of boulders in streams enhances aquatic habitat by increasing the heterogeneity of flow conditions. Practical design must ensure the stability of individual boulders, requiring calculation of their incipient movement conditions. The stability of a boulder on a cobble bed is shown experimentally to depend on its size, the bed material size, the degree of embedment of the boulder, the slope of the bed and the flow velocity and depth. An equation is derived through a pivoting analysis for predicting the relationship between the critical ambient depth-averaged velocity and the critical flow depth; this, together with a resistance equation, can be used to predict the flow conditions for boulder stability. The equation is used to develop a simpler form for unsubmerged spherical boulders and cobbles. The stability equation is tested against the experimental data, using an experimentally determined drag coefficient relationship.

Resumo A porção noroeste da ecorregião Floresta Atlântica do Alto Paraná é uma das mais alteradas e fragmentadas da Mata Atlântica, da qual pouco se sabe sobre a avifauna local. Nosso objetivo foi descrever a diversidade e composição da avifauna aquática, bem como analisar os padrões de similaridade quanto a distribuição temporal e espacial destas aves nesta ecorregião. Utilizamos a transecção linear para amostragem em seis áreas úmidas (corpos d’água lênticos e lóticos), nos períodos de seca e chuva entre 2012 e 2013. Registramos 52 espécies de aves aquáticas e as riquezas das áreas mostraram-se distintas, pois apenas Cairina moschata (Linnaeus, 1758), Tigrisoma lineatum (Boddaert, 1783), Rosthramus sociabilis (Vieillot, 1817), Aramus guarauna (Linnaeus, 1766), Vanellus chilensis (Molina, 1782), Jacana jacana (Linnaeus, 1766), and Arundinicola leucocephala (Linnaeus, 1764) foram comuns às seis áreas, o que indica seleção de habitat. Quando analisada a composição das aves nos dois períodos aliada à distribuição espacial, encontramos dissimilaridades temporais acentuadas entre os ambientes com características lóticas (rio e aterro) e lênticas (lagoas). Isto mostra que, além das diferentes épocas sazonais, é necessário analisar separadamente os diferentes tipos de áreas úmidas. Por fim, apesar da extensão pequena e baixa riqueza total, a área amostrada abrigou 1/3 das aves aquáticas de água doce para o estado de São Paulo, cinco espécies migratórias e 11 novas espécies para o noroeste do estado. A heterogeneidade de ambientes aquáticos locais, forte seleção de habitat aliada à sazonalidade e ausência de outros locais úmidos em seu entorno, explicam a diversidade e distribuição destas aves estreitamente relacionadas aos corpos d’água desta desconhecida ecorregião da Mata Atlântica.

Abstract The northwestern portion of the Upper Paraná Atlantic Forest ecoregion is one of the most disturbed and fragmented areas in the Atlantic Forest, and little is known about the local avifauna. In this study, we have described the composition and diversity of the aquatic avifauna of this region and analyzed the patterns of similarity with respect to the seasonal as well as spatial distribution. We used the line transect sampling technique in six distinct humid areas (including lentic and lotic water bodies) during the dry and rainy seasons of 2012 and 2013. A total of 52 species of waterfowl were recorded. The species richness of the studied areas was surprisingly distinct; only seven waterfowl species, namely Cairina moschata (Linnaeus, 1758), Tigrisoma lineatum (Boddaert, 1783), Rosthramus sociabilis (Vieillot, 1817), Aramus guarauna (Linnaeus, 1766), Vanellus chilensis (Molina, 1782), Jacana jacana (Linnaeus, 1766), and Arundinicola leucocephala (Linnaeus, 1764), were common to these six studied areas. This indicated that the other bird species that were observed might be habitat selective. Moreover, the analysis of the composition of birds in the two seasons (dry and rainy) combined with their spatial distributions showed significant dissimilarities between the areas with lotic (river and constructed wetland) and lentic (lagoons) characteristics. Nevertheless, despite the small extent and low total richness of the entire study area, it was found to be home to 1/3 of all freshwater aquatic birds documented in the state of São Paulo, with the record of 5 migratory species and 11 new species added to the northwest of the state. The heterogeneity of local aquatic environments, habitat selection combined with seasonality, and the absence of other humid locations in the surroundings can explain the diversity and distribution of these birds in the water bodies of this uninvestigated Atlantic Forest ecoregion.

Abstract Similarly to other animal communities, the diversity of subterranean aquatic fauna is influenced by several factors and processes, such as habitat fragmentation, dispersion, environmental heterogeneity, and physical and chemical water characteristics. Here, we studied cave aquatic communities of the Alto Ribeira hydrographic basin, regarding troglobitic and non-troglobitic species, located in a single karst area to evaluate the influence of sub-basins in fauna differentiation. We investigated how abiotic variables (flow, electrical conductivity, temperature, pH, and substrate) influence the fauna composition and the contribution of beta diversity components (nestedness and turnover) in explaining communities’ dissimilarities. Fauna composition differed between sub-basins, as most species did not co-occur in different caves. Caves with higher flow and substrate diversity were the richest. In addition, each cave community was influenced by a unique set of abiotic variables. Dissimilarity among caves was mainly explained by turnover, and our findings suggest the restricted species distribution could be due to ecological (e.g., limited dispersion capacity, tolerance to abiotic variables), hydrogeological (e.g., dispersion barriers, isolation of sub-basins), and historical (e.g., colonization, paleoclimatic events) factors and processes. Therefore, different elements are responsible for determining the composition of cave aquatic communities in different sub-basins, reflecting the variability within a single karst area. processes fragmentation heterogeneity characteristics Here basin nontroglobitic non subbasins sub basins differentiation flow, (flow conductivity temperature pH nestedness turnover dissimilarities subbasins, basins, cooccur co occur richest addition e.g., eg e g (e.g. capacity variables, , variables) barriers sub-basins) colonization events Therefore e.g. (e.g e.g

Caves are ecosystems and natural heritage sites with magnificent biological diversity, from microorganisms to animals, despite their selective environment for development and survival. Until now, studies on cave microbiomes have included taxonomic classification through metagenomics analysis, demonstrating microbiological heterogeneity mainly composed of prokaryotic organisms or bacteria species. The generally oligotrophic environment, with limited energy input and dark zone, is the main feature differentiating the cave microorganisms from the other microbiomes and resulting in a unique habitat, which has unexplored regard to biology and chemical diversity. Multi-omics integration is a key strategy for scanning and integrating the macro and micromolecular universe, providing a better comprehension of processes and answers of the microbiome in natural cavities. Here, we highlight the strategies employed to study the cave microbiome, from the microbial genomes to their ability to secondary metabolites production, and also the multi-omics integration to explore the chemical and biological diversity in caves. animals survival now analysis species zone habitat Multiomics Multi omics universe cavities Here production multiomics multi caves

Abstract Aim To understand the distribution of fish species and their use of habitat, a range of environmental variables were evaluated as predictors of fish assemblage composition and richness in tropical semiarid aquatic systems. Methods We surveyed the species composition of fish assemblages in semiarid aquatic systems and established their degree of association with the structure of the aquatic habitat. Sites consisted of stream reaches with surface water flow, isolated temporary pools, and man-made reservoirs. Fish sampling was conducted on four occasions during the wet (April and June 2006) and dry seasons (September and December 2006). The correlation between richness and abundance with the habitat structure was evaluated using stepwise multiple regression. Patterns of variation in fish assemblage composition across sites were evaluated using Nonmetric Multidimensional Scaling, and the Indicator Species Analysis was used to determine which species were significant indicators of sites. To establish multivariate correlations and test the hypothesis of local fish composition being associated with the environmental variables we used a Canonical Correspondence Analysis. Results Morphometric variables, stream reach width, stream length and elevation explained 75.6% of the variation in fish richness. Macrophyte cover and overhanging vegetation added to the predictive power of the model equation, where the final model explained 86.9% of the variation in fish richness. Canonical Correspondence Analysis showed a significant relationship between fish composition data and site morphology (altitude, bank slope and littoral depth). Among the water quality, habitat composition and substrate variables, temperature, sand, and gravel showed higher correlation with the CCA axes. Conclusions These results indicated that fish communities assume different structures and compositions across different habitat types following the environmental heterogeneity in dryland aquatic systems. flow pools manmade man made reservoirs April 2006 September 2006. . regression Scaling width 756 75 6 75.6 equation 869 86 9 86.9 altitude, altitude (altitude depth. depth depth) quality temperature sand axes 200 7 75. 8 86. 20 2

Resumo Objetivo Para entender a distribuição das espécies de peixes e seu uso do habitat, uma série de variáveis ambientais foi avaliada como preditoras da composição e riqueza de assembleias de peixes em sistemas aquáticos semiáridos tropicais. Métodos Nós avaliamos a composição de espécies de peixes em sistemas aquáticos semiáridos e estabelecemos seu grau de associação com a estrutura do habitat aquático. Os locais amostrados consistiram em trechos de riachos temporários com fluxo de água superficial, poças temporárias isoladas e reservatórios artificiais. A amostragem de peixes foi realizada em quatro ocasiões durante as estações úmida (abril e junho de 2006) e seca (setembro e dezembro de 2006). A correlação entre riqueza e abundância com a estrutura do habitat foi avaliada utilizando regressão múltipla. Os padrões de variação na composição da comunidade de peixes entre os locais foram avaliados utilizando Escalonamento Multidimensional Não-Métrico, e a Análise de Espécies Indicadoras foi utilizada para determinar quais espécies eram indicadoras significativas dos locais. Para estabelecer correlações multivariadas e testar a hipótese de que a composição local de peixes está associada às variáveis ambientais, utilizamos uma Análise de Correspondência Canônica. Resultados A regressão múltipla mostrou que as variáveis morfométricas, largura do trecho do riacho, comprimento do riacho e elevação explicaram 75,6% da variação na riqueza de peixes. A cobertura de macrófitas e a vegetação marginal adicionaram ao poder preditivo do modelo da equação, onde o modelo final explicou 86,9% da variação na riqueza de peixes. A Análise de Correspondência Canônica mostrou uma relação significativa entre os dados de composição de peixes e a morfologia dos locais amostrados (altitude, inclinação da margem e profundidade litorânea). Dentre as variáveis de qualidade da água, composição do habitat e substrato, a temperatura, areia e cascalho apresentaram maior correlação com os eixos da CCA. Conclusões Esses resultados indicaram que as comunidades de peixes assumiram diferentes estruturas e composições nos diferentes tipos de habitat de acordo com a heterogeneidade ambiental em sistemas aquáticos de regiões secas. tropicais aquático superficial artificiais abril 2006 setembro 2006. . NãoMétrico, NãoMétrico Não Métrico, Métrico Não-Métrico morfométricas 756 75 6 75,6 equação 869 86 9 86,9 altitude, altitude (altitude litorânea. litorânea litorânea) substrato temperatura CCA secas 200 7 75, 8 86, 20 2

Abstract One of the major paradigms in ecology is the understanding of processes and patterns related to the structure of biological communities. Reef ecosystems, with their high productivity, habitat heterogeneity, and fish diversity provide a model for studying these processes. We sampled four sites three times during the season associated with the California Current and two times associated with the North Equatorial Current using video-transects on the coast of Zihuatanejo, Guerrero, Mexico to determine the relationship between the habitat characteristics and the structure of the fish assemblage. We recorded a total of 26 families and 54 species and estimated fish richness and abundance. In addition to measuring local water variables such as temperature (°C), salinity (PPT), pH and dissolved oxygen (O2%), we determined habitat heterogeneity by processing photographs of the substrate and calculated rugosity using the tape chain. Oxygen and temperature were the variables associated to sea water conditions that differentiated the sampled sites. The fish community structure presented high correlations with temperature, salinity, and dissolved oxygen, followed by the heterogeneity components such as rugosity and substrate diversity. Our results showed that seasonal changes in water conditions and physical components in the coast of Zihuatanejo promotes changes in the fish community. communities ecosystems productivity videotransects video transects Guerrero assemblage 2 5 abundance °C, C °C , (°C) PPT, PPT (PPT) O2%, O2 O O2% (O2%) chain (°C (PPT (O2% (O2 (O

Resumen Uno de los principales paradigmas en ecología es el entendimiento de procesos y patrones relacionados con la estructura de las comunidades biológicas. Los ecosistemas de arrecifes, con su alta productividad, heterogeneidad de hábitat y diversidad de peces, proporcionan un modelo para estudiar estos procesos. Muestreamos cuatro sitios tres veces durante la temporada asociada a la Corriente de California y dos veces asociada a la Corriente Ecuatorial Norte utilizando video-transectos en la costa de Zihuatanejo, Guerrero, México para determinar la relación entre las características del hábitat y la estructura de la comunidad de peces. Registramos un total de 26 familias y 54 especies, y estimamos la riqueza y abundancia de peces. Además de medir variables locales del agua como temperatura (°C), salinidad (PPT), pH y oxígeno disuelto (O2%), determinamos la heterogeneidad del hábitat procesando fotografías del sustrato y calculamos la rugosidad usando una cadena. El oxígeno y la temperatura fueron las variables asociadas a las condiciones del agua de mar que diferenciaron los sitios muestreados. La estructura de la comunidad de peces presentó altas correlaciones con la temperatura, salinidad y oxígeno disuelto, seguido por los componentes de la heterogeneidad como rugosidad y diversidad del sustrato. Nuestros resultados mostraron que los cambios estacionales en las condiciones del agua y los componentes físicos en la costa de Zihuatanejo promueven cambios en la estructura de la comunidad de peces. biológicas arrecifes productividad videotransectos video transectos Guerrero 2 5 especies °C, C °C , (°C) PPT, PPT (PPT) O2%, O2 O O2% (O2%) cadena muestreados (°C (PPT (O2% (O2 (O

Resumen Introducción y objetivos : El aumento de plantas invasoras en ecosistemas de altura amenaza la conservación de la biodiversidad y de los servicios ecosistémicos en áreas protegidas de montaña. En este trabajo evaluamos si una leñosa exótica, Cotoneaster franchetii Bois, responde a la heterogeneidad ambiental de manera similar a la leñosa nativa dominante, Polylepis australis Bitter, o si puede ocupar una mayor variedad de hábitats dado el carácter generalista que se espera de ella. M&M : Registramos la ocurrencia y cobertura de ambas especies en 120 parcelas entre los 1200 y los 2200 msnm, dentro y en inmediaciones del Parque Nacional Quebrada del Condorito y la Reserva Hídrica Pampa de Achala (Córdoba, Argentina). Comparamos su distribución en relación con la vegetación y la topografía. Resultados : Cada especie dominó en altitudes diferentes pero, a escala local, ambas fueron más frecuentes en valles y laderas sur, con menor cobertura de pajonal y mayor cobertura rocosa y pendiente. Al contrario que la nativa, la cobertura de C. franchetii no se vio afectada por las características topográficas ni de la vegetación circundante. Conclusiones : La elevada ocurrencia de C. franchetii y la ausencia de restricciones para aumentar su cobertura una vez establecida sugieren un elevado potencial invasor. Su expansión representa un riesgo directo para P. australis por preferir hábitats similares. Al igual que en la expansión altitudinal, una elevada tolerancia ambiental promovería la invasión por leñosas hacia la vegetación natural en montañas.

Summary Background and aims : Invasive plants succeeding at high-elevation ecosystems threaten biodiversity and ecosystem services conservation in mountain protected areas. In this study we assessed whether an exotic woody species, Cotoneaster franchetii Bois, responds to mountain environmental heterogeneity in a similar way to the dominant coexisting native woody species, Polylepis australis Bitter, or if it instead occupies a greater variety of habitats aided by the wide environmental tolerance expected for mountain invaders. M&M : We recorded C. franchetii and P australis occurrence and cover in 120 square plots between 1200 and 2200 masl, inside and surrounding “Quebrada del Condorito” National Park and “Pampa de Achala” natural reserve (Córdoba, Argentina). We compared both species' distribution and its relationship with vegetation and topograpy. Results : Each species dominated at different elevations. However, at local scale, both species were more frequent in plots placed at valleys and south-facing steep slopes, with less cover of tussock grassland and more rock cover. Contrary to the native species, C. franchetii cover was unaffected by vegetation and topographic characteristics. Conclusions : High occurrence and no restrictions for increasing cover once established suggest a high spread potential of C. franchetii in these mountains. Polylepis australis is seemingly at risk since both species share habitat preferences. Wide environmental tolerance would not only trigger upward expansion of invasive species in mountains but also towards natural vegetation.

Abstract Teredinids are bivalves mollusks considered the most abundant of invertebrates group of marine wood borers performing an important role in the mangrove environment. This study aimed to characterize the Teredinidae species from the Acaraú River estuary in Ceará and analyse the relationship between the mangrove plant structure and the distribution of Teredinidae, according to gradients estuaries: vertical (flooding) and horizontal (salinity). The collection of mangrove logs with Teredinidae happened in three places within the estuary (inner, median, and upper); in each area, three transects were traced in which three plots were lined off, and a total of 40 logs were collected. Teredinidae species were found and identified: Nausitora fusticula; Neoteredo reynei; Teredo turnerae; Teredo cf. bartschi; Bankia bipennata; Bankia gouldi; Lirodus massa and Lyrodus cf. bipartitus. The Lyrodus cf. bipartitus, Bankia gouldi, and Teredo cf. bartschi species were registered for the first time in Ceará. The distribution and species richness of Teredinidae were directly related to the vertical gradient (flooding) and heterogeneity of the mangrove forest habitat. The data presented here are essential for comprehending the mechanisms responsible for the distribution patterns of the Teredinidae species in the mangrove, contributing to biodiversity conservation in Ceará coastal zones. environment estuaries flooding (flooding salinity. salinity . (salinity) inner, inner (inner median upper upper) area off 4 collected identified fusticula reynei turnerae cf bipennata gouldi bipartitus habitat zones (salinity

Resumo Os teredinídeos são moluscos bivalves considerados o grupo de invertebrados mais abundante de organismos perfuradores de madeira marinha, desempenhando importante papel ecológico nos ambientes de manguezais. O objetivo do estudo foi realizar a caracterização das espécies de Teredinidae do estuário do Rio Acaraú, Ceará e analisar a relação da estrutura vegetal do bosque de mangue com a distribuição dos teredinídeos de acordo com os gradientes estuarinos: vertical (inundação) e horizontal (salinidade). A coleta dos troncos de mangue com teredinídeos aconteceu em três pontos do estuário (interior, médio e superior). Em cada ponto foram traçados três transectos nos quais, foram demarcadas três parcelas das quais foram coletados o total de 40 troncos. Foram encontradas e identificadas 8 espécies de Teredinidae: Nausitora fusticula; Neoteredo reynei; Teredo turnerae; Teredo cf. bartschi; Bankia bipennata; Bankia gouldi; Lirodus massa e Lyrodus cf. bipartitus. As espécies Lyrodus cf. bipartitus, Bankia gouldi e Teredo cf. bartschi, foram registradas pela primeira vez no estado. A distribuição e riqueza de espécies de Teredinidae estiveram diretamente relacionadas com o gradiente vertical (inundação) e heterogeneidade de hábitat do bosque de mangue. Os dados aqui apresentados serão importantes para compreensão dos mecanismos responsáveis pelos padrões de distribuição das espécies de Teredinidae nos bosques de mangues, contribuindo para a conservação da biodiversidade em zonas costeiras do Ceará. marinha manguezais Acaraú estuarinos inundação (inundação salinidade. salinidade . (salinidade) interior, interior (interior superior. superior superior) 4 fusticula reynei turnerae cf bartschi bipennata bipartitus estado mangues (salinidade

Abstract In xeric environments, such as Caatinga Biome, habitat characteristics such as phytophysiognomy type and presence of water bodies can represent higher resource availability. In this context, the present study investigated the effect of phytophysiognomies and presence of water bodies in the abundance and community structure of medium and large mammal species (MLM) in the Serra de Santa Catarina, Paraíba, Brazil. To evaluate these variables we conduct an effort of 373 camera-trap days, between August 2012 and November 2014. We recorded 12 MLM species, distributed in six orders and 11 families. From those, Kerodon rupestris is the only one listed in the Brazilian List of Threatened Fauna. Regarding the habitat, the Mann-Whitney showed a significant higher frequency to the Shrubby habitat and the ANOSIM showed no shifts in the community structure between Arboreal and Shrubby. Concerning the presence of water bodies, both the Mann-Whitney and the ANOSIM showed significant higher frequency to the habitat with water presence. We observed that both phytophysiognomy and water bodies are important variables which affect mainly the abundance of mammalian species from semiarid environments. Nonetheless, whereas the forest remnants get smaller the existence of water bodies becomes a preponderant factor to the MLM species and its community structure. environments Biome availability context (MLM Catarina Paraíba Brazil 37 cameratrap camera trap days 201 2014 1 families those Fauna MannWhitney Mann Whitney Nonetheless 3 20 2

BACKGROUND: Much of the Grassland Biome in South Africa is prone to shrub encroachment, leading to loss of ecosystem services, habitat heterogeneity and species diversity. Burrowing mammals are an important component of grasslands as these animals create microhabitats for other taxa, including smaller mammal species, birds, reptiles and invertebrates. However, our understanding of how shrub encroachment affects burrowing mammals is poor OBJECTIVES: Here we assessed the relationship between burrow abundance and bankrupt bush, Seriphium plumosum, encroachment as well as burrowing mammal diversity in bankrupt bush encroached and non-encroached grasslands METHOD: Shrub density, medium and large mammal burrow abundance and density were measured in 24 encroached and 24 non-encroached areas randomly selected in the Telperion Nature Reserve, Mpumalanga, South Africa. In addition, burrowing mammal diversity was assessed using camera traps in a subset of six encroached and six non-encroached areas RESULTS: Our results show that the abundance and density of medium and large burrows were significantly lower in encroached areas than in non-encroached areas (p = 0.011 and p < 0.001, respectively). The relationship between burrow abundance and bankrupt bush encroachment was negative (rho = -0.456, p = 0.001). However, burrowing mammal diversity had no significant difference between encroached and non-encroached areas CONCLUSION: Our data, therefore, suggest that with increasing bankrupt bush encroachment and a decreased abundance in burrowing mammal ecosystem services, a negative effect will occur on burrowing mammal communities, leading to the reduction in species-specific habitat heterogeneity and possibly animal biodiversity

Resumen La degradación de los ecosistemas en los Andes, una de las regiones con mayor biodiversidad del mundo, es atribuida principalmente a la deforestación y la fragmentación. La implementación de áreas protegidas (AP) es una estrategia de conservación efectiva para mitigar los efectos de la transformación del paisaje sobre la biodiversidad. En la Cordillera Occidental de Colombia, en Antioquia, se estableció recientemente el Corredor del Oso de Anteojos (COA, ~4169 km2), como una estrategia para la conservación de la biodiversidad. En este estudio, a partir de información derivada de sensores remotos y bases de datos, localizamos las áreas con mayor biodiversidad en este corredor, y analizamos si estás áreas están siendo protegidas. Los resultados indican que la deforestación (162.37 km2) y la fragmentación (> 90 %) en el COA durante los últimos 19 años se concentran en las áreas más biodiversas, al interior y por fuera de las AP. Si bien las AP alcanzan 30% del área total del COA, las áreas de mayor biodiversidad están representadas en menos de un 17%. Estos resultados indican el riesgo de pérdida de biodiversidad y la creciente necesidad de fortalecer las AP y delimitar nuevas áreas biodiversas.

Abstract The degradation of ecosystems in the Andes, one of the most biodiverse regions in the world, is caused by deforestation and forest fragmentation. The implementation of protected areas (PA) is an effective conservation strategy to mitigate the effects of landscape transformation on biodiversity. In the western mountain range of Colombia, in Antioquia, the Spectacled Bear Corridor (COA, ~ 4169 km2) was recently established. We describe the state of forest conservation in the COA and analyze whether areas of high biodiversity are being protected or not, using information obtained from remote sensors and large databases. The results indicate that deforestation (162.37 km2) and fragmentation (> 90%) in the COA during the last 19 years are concentrated in the areas of greatest biodiversity, and occur both inside and outsidePA. Although protected areas reach 30% of the total area of the COA, the areas with the greatest biodiversity represent less than 17%. These results indicate the risk of biodiversity loss and the growing need to strengthen PA and to delimit new biodiverse areas.

Abstract Ecological and life history traits have been used to understand the basic ecology of fishes. This study aimed to examine the existence of plasticity in life history traits of populations of Hollandichthys multifasciatus in ten blackwater streams. This is an inseminating Characidae, endemic to the Atlantic coastal drainages of Brazil. Different aspects of the life-history of the species, such as mean length, sex ratio, absolute and relative fecundity, gonadosomatic index, condition factor, length-weight relationship and the growth parameter (b) of 185 specimens were studied during the period of low precipitation (June-September). Fish samples were obtained along a 100 m stretch of each stream, and some habitat variables recorded. ANOVA and Kruskal-Wallis tests indicated a similarity in most of the analyzed traits, with exception of the mean length of immatures, Gonadosomatic Index of mature males and condition factor of immatures and mature adults. Also, slope tests of the length-weight relationship were significantly different for immatures. The observed differences were attributed to heterogeneity in food availability and/or other site-specific factors, which may influence growth and/or breeding aspects among the studied localities. The approach used herein may improve understanding of trait plasticity under natural conditions, helping to understand fish-community responses to anthropogenic changes.

RESUMO Neste estudo, por meio de uma avaliação rápida, investigamos diferenças na riqueza, abundância, composição de espécies e diversidade beta de abelhas Euglossini em áreas preservadas e áreas alteradas por populações ribeirinhas na Floresta Nacional de Caxiuanã (norte da Amazônia). Nossas hipóteses foram: i) a riqueza de espécies, diversidade, abundância e composição das abelhas Euglossini diferem entre as áreas preservadas e alteradas, uma vez que muitas espécies são intolerantes a pequenos distúrbios antrópicos; e ii) áreas alteradas por populações ribeirinhas apresentam maiores valores de diversidade beta (dissimilaridade de espécies entre locais) do que áreas preservadas, devido às mudanças locais no habitat e aumento da heterogeneidade entre locais. Amostramos duas áreas (preservadas e alteradas) e, em cada área, foram amostrados quatro transectos com iscas odoríferas. Nós utilizamos testes t de Student, para avaliar diferenças de riqueza, abundância e índice de diversidade de Shannon-Wiener. Também avaliamos as diferenças na composição e as diferenças na diversidade beta entre as áreas. Foram coletados 102 espécimes, em 18 espécies e três gêneros, 63 deles (61,8%) em áreas preservadas e 39 (38,2%) em áreas alteradas. Euglossa liopoda (Dressler, 1982) foi a mais abundante nas áreas alteradas e Euglossa imperialis (Cockerell, 1922) nas áreas preservadas. A riqueza foi 2,5 vezes maior nos transectos de áreas preservadas, e a composição de espécies também diferiu entre as áreas amostradas. Em contraste, a abundância de espécies não foi diferente entre os transectos das duas áreas. Apesar de nosso esforço amostral reduzido, nossos resultados demonstram que a riqueza, composição e diversidade beta das abelhas Euglossini podem potencialmente ser afetadas por mudanças locais no habitat causadas por atividades de pequena escala fornecidas por grupos tradicionais da Amazônia. Esses resultados indicam a urgência por estudos mais extensos no sentido de investigar as relações aqui estudadas.

ABSTRACT In this study, through a rapid assessment, we evaluated differences in richness, abundance, species composition and beta diversity of Euglossini bees in preserved areas and areas altered by riverine human populations in the Caxiuanã National Forest (northern Amazon). Our hypotheses were: i) the species richness, diversity, abundance and composition of Euglossini bees differ between the preserved and altered areas because many species are intolerant to small anthropic disturbances; and ii) areas altered by riverine populations have higher values of beta diversity (species dissimilarity between sites) than preserved areas, due to local changes in habitat and increased heterogeneity between sites. We sampled two areas (preserved and altered) and, in each area, four transects were sampled with odorous baits. We used a Student’s t test to evaluate differences in richness, abundance, and Shannon-Wiener diversity index. We also evaluated differences in composition and differences in beta diversity between areas. We collected 102 specimens, identified in 18 species and three genera, 63 individuals (61.8% of the total) in preserved areas and 39 individuals (38.2%) in altered areas. Euglossa liopoda (Dressler, 1982) was the most abundant in altered areas and Euglossa imperialis (Cockerell, 1922) the most abundant in preserved areas. Species richness was 2.5 times greater in the transects of preserved areas, and species composition also differed between the sampled areas. In contrast, species abundance did not differ between transects of both areas. Despite our small sample size, this study demonstrated that the richness, composition and beta diversity of Euglossini bees can be potentially affected by local changes in habitat caused by small-scale activities provided by traditional Amazonian groups. Our results indicate the urgency for more comprehensive studies aimed to investigate these relationships.

Resumen Las hormigas son sensibles a cambios ambientales y la estructura de la comunidad puede ser moldeada por la heterogeneidad ambiental y las interacciones interespecíficas. Probamos 2 hipótesis: (1) la estructura de la vegetación afecta negativamente la diversidad de hormigas en hábitats simplificados y (2) las interacciones interespecíficas dan forma a las comunidades de hormigas. Colectamos hormigas en arbustos de 16 unidades de muestreo de 100 m2 utilizando paraguas entomológicos y bateo en un área en regeneración de Cerrado, Brasil. La riqueza, abundancia y altura promedio de plantas se utilizaron como medida de heterogeneidad ambiental. Muestreamos 457 hormigas de 17 especies. Observamos una mayor riqueza de especies en parcelas con mayor abundancia de plantas y menor altura, y una relación negativa entre la abundancia y la altura de plantas. Corroboramos que la estructura de la vegetación afecta negativamente la diversidad de hormigas en hábitats simplificados. Los valores observados del índice de coexistencia difirieron de lo esperado en matrices simuladas, sugiriendo que la competencia moldea la comunidad de hormigas en hábitats simplificados. Destacamos la importancia de conservar árboles pequeños en hábitats menos complejos, porque representan elementos clave que albergan una gran diversidad.

Abstract Ant species are highly sensitive to environmental changes, and ant community structure can be shaped by environmental heterogeneity and interspecific interactions. We tested 2 hypotheses: (1) vegetation structure negatively affecting ant diversity in simplified habitats and (2) interspecific interactions shaping ant communities. We collected ants on shrubs distributed in 16 sampling units of 100 m2 using the entomological umbrella and beating technique in a regenerating Cerrado area of Brazil. The richness, abundance and average height of the plants were used as a measure of environmental heterogeneity. A total of 457 ants belonging to 17 species were sampled. We observed higher ant species richness in plots with greater plant abundance and lower plant height. We observed a negative relationship between ant abundance and plant height per plot. These results corroborate that vegetation structure negatively affects ant diversity in simplified habitats. The observed values of co-occurrence index differed from the expected values of simulated matrices, suggesting that competition shaping ant community in simplified habitats. We highlight the importance of conserving small trees, especially in structurally less complex habitats, because they represent key elements that harbor high ant species diversity.

Resumen Aplicamos un enfoque de dominios ambientales para identificar las características ambientalmente heterogéneas que definen una matriz del paisaje. Construimos capas ambientales a 3 escalas, nacional, regional y local, para considerar las diferentes escalas que pueden tener distintos estudios. Utilizamos una clasificación numérica jerárquica para datos espaciales y una clasificación multivariada. Con base en los dominios obtenidos, construimos mapas de heterogeneidad ambiental y determinamos las variables asociadas para cada escala. Probamos específicamente la idoneidad de nuestro enfoque para definir estrategias de muestreo para estudios de genética del paisaje, usando como especie focal al roedor Heteromys pictus. Así, de los dominios obtenidos en la escala local seleccionamos sitios de muestreo que incluyeran la más amplia heterogeneidad del hábitat, los cuales corroboramos en campo. La matriz del paisaje que generamos fue utilizada con datos genéticos previamente obtenidos para H. pictus. Nuestro protocolo nos permitió identificar variables significativamente asociadas con la dispersión (flujo génico) de los individuos en su hábitat natural. Demostramos así su pertinencia para definir eficientemente localidades de muestreo (matriz del paisaje) que abarquen la mayor heterogeneidad ambiental, en paisajes explorados e inexplorados, e identificar de forma rápida localidades y sus características ambientales en sitios con poca información previa.

Abstract We apply an environmental domains approach to identify environmentally heterogeneous characteristics defining a landscape matrix. We built environmental layers for national, regional, and local scales, considering the different scales studies can have. We used a numerical classification of explicit spatial layers and performed a multivariate classification. Based on the domains obtained, we mapped the landscape’s climatic heterogeneity and identified a comprehensive set of environmental variables that defined the landscape matrix at each scale. We specifically tested our approach for its suitability to define a sampling strategy for a landscape genetics study, using as focal species the rodent Heteromys pictus. Namely, from the domains obtained at the local scale, we selected sampling localities that comprised the broadest habitat heterogeneity, which we corroborated in the field. The landscape matrix thus generated was used with genetic data previously obtained for H. pictus. Our approach allowed identification of environmental variables significantly associated with dispersal (gene flow) of H. pictus individuals in their natural habitat. We demonstrate its adequacy to efficiently determine sampling localities -or landscape sites- that encompass the highest environmental heterogeneity, in explored and unexplored landscapes, enabling rapid identification of localities and their environmental characteristics where in situ information is scarce.