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Biodiversity monitoring studies in Brazil are scarce, especially those related to ant communities in the Northeast region. In view of this lack, two distinct areas of a fragment of urban vegetation, close to the Parque Estadual Botânico do Ceará, were evaluated to verify the hypothesis that the communities have distinctions of richness, diversity, dissimilarity and equitability of species. The first collection area was formed by a Mata de Tabuleiro and the second by herbaceous vegetation. A total of 50 collection points, per environment, were distributed along five transects. At each point, three collection methods were used (pitfall trapping, honey baits and sardine baits). A total of 37 species from 24 genera and seven subfamilies were identified. The richness of the environments was similar, despite a clear difference in the composition and heterogeneity of the communities. The heterogeneity of the herbaceous vegetation area was influenced by temperature. The indices of diversity and equitability of the communities revealed low biodiversity and uniformity in the distribution of the relative abundance of the species. Three species showed high relative abundance: Paratrechina longicornis (85.39%), Solenopsis saevissima (63.05%) and Pheidole biconstricta (18.95%). A low proportion of generalist (8.1%), rare (35.1%) and specialist species (Mata de Tabuleiro: 27% and Herbaceous: 29.7%) was observed, indicating the occurrence of a strong environmental imbalance in the regions. Los estudios de monitoreo de la biodiversidad en Brasil son escasos, especialmente los relacionados con las comunidades de hormigas en la región Nordeste. Ante esta carencia, dos áreas distintas de un fragmento de vegetación urbana, cerca del Parque Estadual Botânico do Ceará, fueron evaluadas para verificar la hipótesis de que las comunidades tienen distinciones de riqueza, diversidad, disimilitud y equidad de especies. La primera zona de recolección estuvo formada por una Mata de Tabuleiro y la segunda por una vegetación herbácea. Se distribuyeron un total de 50 puntos de recolección, por ambiente, a lo largo de cinco transectos. En cada punto se utilizaron tres métodos de recolección (trampas pitfall, cebos de miel y cebos de sardina). Se identificaron un total de 37 especies de 24 géneros y siete subfamilias. La riqueza de los ambientes fue similar, a pesar de una clara diferencia en la composición y heterogeneidad de las comunidades. La heterogeneidad del área de vegetación herbácea estuvo influenciada por la temperatura. Los índices de diversidad y equidad de las comunidades revelaron baja biodiversidad y uniformidad en la distribución de la abundancia relativa de las especies. Tres especies mostraron abundancia relativa alta: Paratrechina longicornis (85,39%), Solenopsis saevissima (63,05%) y Pheidole biconstricta (18,95%). Se observó una baja proporción de especies generalistas (8,1%), raras (35,1%) y especialistas (Mata de Tabuleiro: 27% y Herbácea: 29,7%), lo que indica la ocurrencia de un fuerte desequilibrio ambiental en las regiones. Estudos de monitoramento da biodiversidade no Brasil são escassos, em especial aqueles relacionados às comunidades de formigas da região Nordeste. Tendo em vista essa carência, duas áreas distintas de um fragmento de vegetação urbana, próximas ao Parque Estadual Botânico do Ceará, foram avaliadas para verificar a hipótese de que as comunidades possuem distinções de riqueza, diversidade, dissimilaridade e equitabilidade de espécies. A primeira área de coleta era formada por uma Mata de Tabuleiro e a segunda por uma vegetação herbácea. Um total de 50 pontos de coleta, por ambiente, foram distribuídos ao longo de cinco transectos. Em cada ponto foram utilizados três métodos de coleta (pitfall trapping, iscas de mel e iscas de sardinha). Um total de 37 espécies de 24 gêneros e sete subfamílias foram identificados. A riqueza dos ambientes se mostrou similar, apesar de uma nítida diferença na composição e na heterogeneidade das comunidades. A heterogeneidade da área de vegetação herbácea foi influenciada pela temperatura. Os índices de diversidade e equitabilidade das comunidades revelaram baixa biodiversidade e uniformidade na distribuição da abundância relativa das espécies. Três espécies apresentaram alta abundância relativa: Paratrechina longicornis (85,39%), Solenopsis saevissima (63,05%) e Pheidole biconstricta (18,95%). Foi observada uma baixa proporção de espécies generalistas (8,1%), raras (35,1%) e especialistas (Mata de Tabuleiro: 27% e Herbácea: 29,7%), indicando a ocorrência de um forte desequilíbrio ambiental nas regiões.

The present study was conceptualized to study the muraenid species (moray eels) occurring around the volcanic archipelagos of the Azores, Madeira, Selvagens, Canary and Cabo Verde islands (eastern-central Atlantic). The biogeographic patterns of these species were analysed and compared. We then hypothesized that this fish family is an ideal group for testing at small-scale the coherency of Macaronesia and its direct biogeographic units: i.e. the Azores, Webbnesia and Cabo Verde, as proposed in recent scientific literature. Additionally, this paper provides for the first time separate fishery statistics for this group in the region that were analysed to contrast the biogeographic results., Este trabajo fue ideado para estudiar las especies de Muraenidae (morenas) presentes en aguas de los archipiélagos volcánicos de Azores, Madeira, Salvajes, Canarias y Cabo Verde (Atlántico centro-oriental), cuyos patrones biogeográficos fueron analizados y comparados. La hipótesis de partida fue que esta familia ictiológica es un grupo ideal para verificar, a pequeña escala, la coherencia de la Macaronesia y sus unidades biogeográficas directamente relacionadas -i.e. Azores, Webbnesia y Cabo Verde- propuestas en la literatura reciente. Además, este estudio proporciona, por primera vez, estadísticas pesqueras separadas de este grupo en la región que fueron analizadas para contrastar los resultados biogeográficos.

We studied the species composition of frogs in two phytophysiognomies within Pampa biome (grassland and forest) of a Ramsar site in southern Brazil to assess the distribution of species and dissimilarities in community composition on a small spatial scale. We tested the hypothesis that the vegetation structure and the types of land cover present in each physiognomy influence species distribution and the compositional dissimilarity patterns between locations. We sampled individuals using pitfall traps and active search in the areas around the traps. We evaluated the existence of these differences by using permutational multivariate analysis of variance and multivariate dispersion. We found that the compositional dissimilarity was higher between the sampling sites from different phytophysiognomies than within the same phytophysiognomy. Also, the difference in anuran species composition between the sampling sites within the forest was considerably high. These differences were mainly due to the type of land cover present in each sampled site. Based on our results, we could assume that the phytophysiognomies evaluated here offer quite different colonization opportunities for anurans, especially those related to microhabitat characteristics, such as microclimate variables. Still, the presence of different types of land cover seems to be a decisive factor for the maintenance of some anuran species, since these can serve as an important source for obtaining food resources, in addition to facilitating the dispersion of individuals within and between locals, serve as sites for the regulation of physiological functions and also refuges against predators.

Whereas the anthropogenic impact on marine biodiversity is undebated, the quantification and prediction of this change are not trivial. Simple traditional measures of biodiversity (e.g. richness, diversity indices) do not capture the magnitude and direction of changes in species or functional composition. In this paper, we apply recently developed methods for measuring biodiversity turnover to time-series data of four broad taxonomic groups from two coastal regions: the southern North Sea (Germany) and the South African coast. Both areas share geomorphological features and ecosystem types, allowing for a critical assessment of the most informative metrics of biodiversity change across organism groups. We found little evidence for directional trends in univariate metrics of diversity for either the effective number of taxa or the amount of richness change. However, turnover in composition was high (on average nearly 30% of identities when addressing presence or absence of species) and even higher when taking the relative dominance of species into account. This turnover accumulated over time at similar rates across regions and organism groups. We conclude that biodiversity metrics responsive to turnover provide a more accurate reflection of community change relative to conventional metrics (absolute richness or relative abundance) and are spatially broadly applicable. This article is part of the theme issue ‘Integrative research perspectives on marine conservation’.

Anthropogenic activities strongly influence river habitat conditions and surrounding landscape patterns. A major challenge is to understand how these changes impact microbial community composition and structure. Here, a comprehensive analysis combining physicochemical characteristics in sediment with sequencing targeting the V4 region of the 16S rRNA gene was conducted to test the hypothesis that diverse habitat conditions induce dissimilarity of microbial community composition and structure in a regulated urban river. The results suggested that observed species richness and Shannon&ndash, Wiener diversity had a decreasing variation along the land use intensified gradient, while beta diversity also revealed significant separation of microbial community structure between headwaters and urban reaches. Total nitrogen (TN), total phosphorus (TP), oxidation&ndash, reduction potential (ORP) and total organic carbon (TOC) in sediment were the dominant factors in structuring bacterial and archaeal community assemblages. Further analysis in dominant fecal-associated bacteria indicated that elevated nutrient concentrations may significantly (p &lt, 0.05) increase the relative abundance of Clostridium and Acinetobacter in sediment. The findings highlight the pivotal roles of alpha diversity and fecal-associated bacteria in understanding the dynamics of microbial communities in a regulated urban river ecosystem.

Multidimensional analysis of traits are now common in ecology and evolution and are based on trait spaces in which each dimension summarizes the observed trait combination (a morphospace or an ecospace). Observations of interest will typically occupy a subset of this space, and researchers will calculate one or more measures to quantify how organisms inhabit that space. In macroevolution and ecology, these measures called disparity or dissimilarity metrics are generalized as space occupancy measures. Researchers use these measures to investigate how space occupancy changes through time, in relation to other groups of organisms, or in response to global environmental changes. However, the mathematical and biological meaning of most space occupancy measures is vague with the majority of widely used measures lacking formal description. Here, we propose a broad classification of space occupancy measures into three categories that capture changes in size, density, or position. We study the behavior of 25 measures to changes in trait space size, density, and position on simulated and empirical datasets. We find that no measure describes all of trait space aspects but that some are better at capturing certain aspects. Our results confirm the three broad categories (size, density, and position) and allow us to relate changes in any of these categories to biological phenomena. Because the choice of space occupancy measures is specific to the data and question, we introduced https://tguillerme.shinyapps.io/moms/moms, a tool to both visualize and capture changes in space occupancy for any measurement. https://tguillerme.shinyapps.io/moms/moms is designed to help workers choose the right space occupancy measures, given the properties of their trait space and their biological question. By providing guidelines and common vocabulary for space occupancy analysis, we hope to help bridging the gap in multidimensional research between ecology and evolution., Different measurements of multidimensional space occupancy can give different results and are affected by the multidimensional space properties and biological question. This paper provides a guideline of what different measurements are capturing and in which context they can be useful for answering biological questions.

Netherlands Organisation for Scientific Research (NWO), Grant/Award Number: 019.171LW.023; German Research Foundation; German Research Foundation DFG, Grant/Award Number: 264740629; FONDECYT, Grant/Award Number: 11150835; CONICYT-PAI, Grant/Award Number: 82130046; 7th European Community Framework Programme, Grant/Award Number: FORECOFUN-SSA PIEF-GA-2010–274798; European Research Council Synergy, Grant/Award Number: ERC-SyG-2013-610028; Austrian Science Foundation, Grant/Award Number: I2086-B16; Czech Science Foundation, Centre of Excellence PLADIAS, Grant/Award Number: 14-15414S and RVO 67985939; EXPRO, Grant/Award Number: 19-28807X; VEGA, Grant/Award Number: 0051/1, van der Sande, M.T., Bruelheide, H., Dawson, W., Dengler, J., Essl, F., Field, R., Haider, S., van Kleunen, M., Kreft, H., Pagel, J., Pergl, J., Purschke, O., Pyšek, P., Weigelt, P., Winter, M., Attorre, F., Aubin, I., Bergmeier, E., Chytrý, M., Dainese, M., De Sanctis, M., Fagundez, J., Golub, V., Guerin, G.R., Gutiérrez, A.G., Jandt, U., Jansen, F., Jiménez-Alfaro, B., Kattge, J., Kearsley, E., Klotz, S., Kramer, K., Moretti, M., Niinemets, Ü., Peet, R.K., Penuelas, J., Petřík, P., Reich, P.B., Sandel, B., Schmidt, M., Sibikova, M., Violle, C., Whitfeld, T.J.S., Wohlgemuth, T., Knight, T.M.

We investigated the role of present (Recent) and historical (Pleistocene, i.e., Wurmian Last Glacial Maximum) eco-geographical variables on the richness and diversity of non-marine molluscs in the Tuscan Archipelago, as well as inter-island faunal dissimilarity and relationships with source pools (Sardinia and Corsica, Tuscany). The association between species richness and present and historical eco-geographical variables were assessed with Spearman’s rank correlation test, while faunal dissimilarity both between islands and with their source pools was analyzed through beta-diversity partitioning (Sorensen index and its nestedness and turnover component) with UPGMA clustering tested with a multiscale bootstrap procedure. Non-metric multidimensional scaling in RGB color space was also used. Multiple regressions on distance matrices were then applied to explain assemblage composition between islands. Analyses were performed on all species and on all species except aliens. The overall framework showed the combined effects of current eco-geographical and paleogeographical imprints on non-marine malacofauna in the Tuscan Archipelago. However, excluding aliens, differences in species spatial turnover showed a clear correlation with Pleistocene inter-island distances, evidence of stronger historical biogeographical relationships between islands. This may indicate that widespread native species established their distribution during the Pleistocene, while alien species spread into the Tuscan Archipelago through stochastic and human-mediated dispersion events in recent times. Interestingly, Giglio’s relationships do not agree with the most accepted paleogeographical model, suggesting that this island might have been connected to the Tuscan mainland during the Wurmian Last Glacial Maximum. An in-depth revision of the paleogeographic framework of the northern Tyrrhenian is therefore called for.

We investigated the relationships between exotic freshwater fish invasions, environmental factors and ecofunctional diversity (i.e. the combination of ecological traits in communities) in streams. We used data from 335 stream sites, belonging to 105 watersheds and 3 basins in Italy, to test whether the exotic species invasion was dominated by species with generalist traits and whether the environment-ecofunctional trait relationships of exotic and native species would differ from each other. We also tested the hypothesis that ecofunctional uniqueness patterns between exotic and native species would be substantially different. We found that generalist traits were widespread in nearly all areas where exotic species occurred, but not all generalist traits were equally abundant in exotic communities. Only temperature tolerant, low oxygen tolerant and eurytopic traits were typically more dominant in exotic communities than native ones, suggesting that not all generalist traits are equally important in the invasion process and that more complex mechanisms of trait selection could take place. Environment-ecofunctional trait relationships of exotic and native species partly differed both in direction and magnitude, suggesting that invasion dynamics could decouple the linkage between environment and biotic communities, but also that this decoupling might decrease at later invasion stages (i.e. > 30 years after major invasions). Finally, site and trait ecofunctional uniqueness differed between exotic and native species. Exotic species ecofunctional diversity hotspots were located in human-disturbed areas, suggesting that human disturbance might play a strong role in invasion patterns. We advocate for a wider use of ecofunctional approaches in conservation studies in the future, as they could be a key to understand complex ecological processes such as exotic invasions.

Aim The aim of this study was to determine the diversity of Trichoptera in subtropical streams and the effects of environmental variables and geographical position on alpha and beta diversity in natural and rural streams. Methods We collected Trichoptera with a Surber sampler in 12 small order subtropical streams (six streams with apparent absence of anthropic disturbance and six streams with rural activity in their drainage areas) and measured limnological variables. We evaluated the effects of environmental variability and geographical distance on the dissimilarity of the assemblage and calculated the contribution of alpha and beta diversity for each stream. Results We collected a total of 1,264 Trichoptera larvae distributed in 17 genera and 11 families. The genera Phylloicus and Smicridea were found in almost all streams. We observed a positive effect of environmental variability on biological variability but not of geographical distance. The environmental variability was basically generated by the influence of higher concentrations of dissolved organic carbon and nutrients. We observed the greatest contribution of the alpha diversity of the Trichoptera assemblages in natural streams and of beta diversity in the rural streams. Conclusions Our results demonstrate that the variability of Trichoptera is affected by environmental characteristics, but not by geographical position. Resumo: Objetivo O objetivo desse estudo foi determinar a diversidade de Trichoptera em riachos e o efeito das variáveis ambientais e posição geográfica na diversidade alfa e beta em riachos naturais e rurais. Métodos Coletamos larvas de Trichoptera com um amostrador Surber em 12 riachos subtropicais de pequena ordem (seis riachos com ausência aparente de distúrbios antrópicos e seis riachos com atividades rurais na área de drenagem) e quantificamos as variáveis limnológicas. Avaliamos os efeitos da variabilidade ambiental na dissimilaridade das assembleias e calculamos a contribuição da diversidade alfa e beta nos riachos. Resultados Coletamos um total de 1264 larvas de Trichoptera distribuidas em 17 gêneros e 11 famílias. Os gêneros Phylloicus e Smicridea foram encontramos em praticamente todos os riachos. Observamos um efeito positivo da variabilidade ambiental na variabilidade biológica, mas não da posição geográfica. A variabilidade ambiental foi gerada basicamente pela influência de maiores concentrações de carbono orgânico dissolvido e nutrientes. Observamos maior contribuição da diversidade alfa nas assembleias de Trichoptera nos riachos naturais, e da diversidade beta nos riachos rurais. Conclusões Nossos resultados demonstram que a variabilidade de Trichoptera é afetada por características ambientais, e não pela posição geográfica.

Understory vegetation hosts high biodiversity and plays a critical role in the ecosystem processes of boreal forests. However, the drivers of understory plant diversity in this high-latitude ecosystem remain uncertain. To investigate the influences of forest type and latitude on understory beta diversity at different scales, we quantified the species composition of Vaccinium uliginosum Linnaeus communities under broadleaf and coniferous forests at two latitudes at the quadrat (2 &times, 2 m) and plot (10 &times, 10 m) scales in the Greater Xing&rsquo, an Mountains, NE China. At the quadrat scale, species alpha diversity of V. uliginosum communities was higher in broadleaf forests than that in coniferous forests at both latitudes. The differences in species beta diversity (the S&oslash, rensen&rsquo, s dissimilarity) in two forest types depended on the latitude: beta diversity in broadleaf forests was higher than that in coniferous forests at the higher latitude, while beta diversity in coniferous forests was higher at the lower latitude. At the plot scale, alpha and beta diversity of V. uliginosum communities decreased from broadleaf forests to coniferous forests at the higher latitude, and they did not show significant differences between forest types at the lower latitude. These results indicate the interactive effects of forest type and latitude on beta diversity of understory vegetation. Moreover, the influences of forest type and latitude on species alpha and beta diversity were different across the two spatial scales, suggesting that the assembly mechanisms underlying species diversity may be different at different scales. Understanding the maintenance of understory vegetation diversity will benefit the conservation and management of boreal forests.

Bacterial and fungal communities in biofilms are important components in driving biogeochemical processes in stream ecosystems. Previous studies have well documented the patterns of bacterial alpha diversity in stream biofilms in glacier-fed streams, where, however, beta diversity of the microbial communities has received much less attention especially considering both bacterial and fungal communities. A focus on beta diversity can provide insights into the mechanisms driving community changes associated to large environmental fluctuations and disturbances, such as in glacier-fed streams. Moreover, modularity of co-occurrence networks can reveal more ecological and evolutionary properties of microbial communities beyond taxonomic groups. Here, integrating beta diversity and co-occurrence approach, we explored the network topology and modularity of the bacterial and fungal communities with consideration of environmental variation in glacier-fed streams in Central Asia. Combining results from hydrological modeling and normalized difference of vegetation index, this study highlighted that hydrological variables and vegetation status are major variables determining the environmental heterogeneity of glacier-fed streams. Bacterial communities formed a more complex and connected network, while the fungal communities formed a more clustered network. Moreover, the strong interrelations among the taxonomic dissimilarities of bacterial community and modules suggest they had common processes in driving diversity and taxonomic compositions across the heterogeneous environment. In contrast, fungal community and modules generally showed distinct driving processes to each other. Moreover, bacterial and fungal communities also had different driving processes. Furthermore, the variation of bacterial community and modules were strongly correlated with hydrological properties and vegetation status but not with nutrients, while fungal community and modules (except one module) were not associated with environmental variation. Our results suggest that bacterial and fungal communities had distinct mechanisms in structuring microbial networks, and environmental variation had strong influences on bacterial communities but not on fungal communities. The fungal communities have unique assembly mechanisms and physiological properties which might lead to their insensitive responses to environmental variations compared to bacterial communities. Overall, beyond alpha diversity in previous studies, these results add our knowledge that bacterial and fungal communities have contrasting assembly mechanisms and respond differently to environmental variation in glacier-fed streams.

Resumen En Costa Rica, el bosque seco tropical se encuentra restringido al Pacifico Norte del país, siendo uno de los pocos remanentes de bosque seco mesoamericano existente. Este bosque presenta notables variaciones en las condiciones climáticas a lo largo del año, especialmente en términos de precipitación. Esta variación hace necesario que la fauna que aquí habita deba de adaptarse en función de la disponibilidad de alimento. Analizamos la variación del ensamblaje de murciélagos y la composición de gremios tróficos en un agro paisaje de bosque seco. Describimos como la presencia y abundancia de diferentes especies y gremios de murciélagos en el sitio está relacionada con la variación en el patrón de lluvias, afectando distintivamente a nectarívoros, frugívoros, insectívoros o hematófagos. Proponemos que las especies que conforman el ensamble de murciélagos en el sitio, probablemente realizan movimientos locales periódicos, utilizando el área de estudio solo temporalmente. Destacamos que dado el probable movimiento de especies durante el año, es necesario mantener elementos naturales, como parches de bosque y humedales, dentro de los agro paisajes como una estrategia de conservación de la biodiversidad a nivel regional. Abstract In Costa Rica, the tropical dry forest is restricted into the North Pacific, being one of the few remnants of the Mesoamerican dry forest. This forest presents remarkable climatic variation throughout the year, especially in precipitation. This variation makes it necessary for the animals that live here to adapt according mainly to food availability. We analyze a bat assemblage in terms of its species richness and guild composition in an agro dry forest landscape. We describe how the presence, abundance and guilds of different bat species varies through time and closely relates to rainfall pattern, distinctly affecting nectarivorous, frugivorous, insectivorous or hematophagous. We propose that the species that make up the assemblage of bats at this site probably make local movements periodically, using the area only temporarily. We emphasize that, given the movement of species during the year, the maintenance of natural elements such as forest patches and wetlands within ago-landscapes is mandatory in order to achieve a regional conservation strategies.

We thank the University of St Andrews Bioinformatics Unit (Wellcome Trust ISSF grant 105621/Z/14/Z). L.H.A.was supported by Fundação para a Ciência e Tecnologia, Portugal (POPH/FSE SFRH/BD/90469/2012), A.E.M. by the ERC BioTIME (250189) and BioCHANGE (727440), and B.J.M. by USDA Hatch grant to MAFES #1011538 and NSF ABI grant #1660000. The BioTIME database was funded by ERC AdG BioTIME (250189) and ERC PoC BioCHANGE (727440). β‐diversity (variation in community composition) is a fundamental component of biodiversity, with implications for macroecology, community ecology and conservation. However, its scaling properties are poorly understood. Here, we systematically assessed the spatial scaling of β‐diversity using 12 empirical large‐scale datasets including different taxonomic groups, by examining two conceptual types of β‐diversity and explicitly considering the turnover and nestedness components. We found highly consistent patterns across datasets. Multiple‐site β‐diversity (i.e. variation across multiple sites) scaling curves were remarkably consistent, with β‐diversity decreasing with sampled area according to a power law. For pairwise dissimilarities, the rates of increase of dissimilarity with geographic distance remained largely constant across scales, while grain size (or scale level) had a stronger effect on overall dissimilarity. In both analyses, turnover was the main contributor to β‐diversity, following total β‐diversity patterns closely, while the nestedness component was largely insensitive to scale changes. Our results highlight the importance of integrating both inter‐ and intraspecific aggregation patterns across spatial scales, which underpin substantial differences in community structure from local to regional scales. Postprint

Tropical high-altitude lakes are vital freshwater ecosystems for the functioning and dynamics of tropical high-altitude wetlands called páramos, found at over 3300 m above sea level. They play a major role in the hydrogeological cycle and provide important hydrological services such as water storage, and yet they are understudied. Describing the patterns and processes of community composition in these lakes is required to better understand the consequences of their degradation by human activities. In this study we tested the geographical and environmental components of distance–decay relationships in the phytoplankton structure across 24 tropical high-altitude lakes from Southern Ecuador. Phytoplankton composition at the phyla level showed high among-lake variation in the tropical high-altitude lakes from Tres Lagunas. We found no links, however, between the geographic distance and phytoplankton composition. On the contrary, we observed some environmentally related patterns of community structure like redox potential, altitude, water temperature, and total phosphorus. The absence of support for the distance–decay relationship observed here can result from a conjunction of local niche-based effects and dispersal limitations. Phytoplankton community composition in the Tres Lagunas system or any other ecosystem may be jointly regulated by niche-based and neutral forces that still need to be explored. Despite not proving a mechanistic explanation for the observed patterns of community structure, we hope our findings provide understanding of these vulnerable and vital ecosystems. More studies in tropical high-altitude lakes are urgently required.

In floodplain communities, beta diversity is influenced by different factors; however, environmental heterogeneity and floods are believed to be particularly influential. The influence of environmental heterogeneity and floods on beta diversity may vary among guilds that present different ecological traits. This study evaluated the correlation between the environmental heterogeneity and flood periods and the beta diversity of trophic and reproductive guilds of fish assemblages. Sampling was conducted quarterly between 2000 and 2012 in the upper Paraná River floodplain. The environmental heterogeneity and period (i.e., dry or flood) were associated with the beta diversity of each guild based on the results of generalized least squares linear models. Only guilds with parental care were influenced by the interaction between environmental heterogeneity and period. The beta diversity of the other guilds presented no relationship between environmental heterogeneity and period. It is likely that species with parental care presented less dispersal capacity, which increased the dissimilarity among assemblages. The higher dispersion rates of the other guilds may be responsible for the lack of relationship between the beta diversity and the environmental heterogeneity and period. In sum, these results suggest that reproductive guilds influence how environmental heterogeneity and floods affect beta diversity variation. RESUMO A diversidade beta é influenciada por diferentes fatores em comunidades de planícies de inundação; contudo, acredita-se que a heterogeneidade ambiental e inundações sejam particularmente influentes. A influência da heterogeneidade ambiental e inundações na diversidade beta podem variar entre guildas que apresentam diferentes características ecológicas. Este estudo avaliou a correlação entre heterogeneidade ambiental, os períodos de inundação e a diversidade beta de guildas tróficas e reprodutivas de peixes. A amostragem foi realizada trimestralmente entre 2000 e 2012 na planície de inundação do Alto rio Paraná. Heterogeneidade ambiental e o período (i.e., seca ou cheia) foram associados à diversidade beta de cada guilda por modelos lineares de quadrados mínimos generalizados. Somente guildas com cuidados parentais foram influenciadas pela interação entre heterogeneidade ambiental e período. A diversidade beta das outras guildas não apresentou relação com heterogeneidade ambiental e período. É provável que espécies com cuidados parentais apresentem menor capacidade de dispersão, o que aumenta a diferença entre as assembleias. As maiores taxas de dispersão de outras guildas podem ser responsáveis pela ausência de relação entre a diversidade beta e heterogeneidade ambiental e o período. Em suma, os resultados sugerem que as guildas reprodutivas influenciam a forma como a heterogeneidade ambiental e as inundações afetam a variação da diversidade beta.

Central Andean Highlands represent a singular environment characterized by various extreme conditions. Among them, peatbogs are exceptional marshy habitats scattered throughout this arid and harsh area. In an effort to understand the patterns of beta diversity, we sampled the benthic macroinvertebrates of thirteen peatbogs and related the biological distance with ecological distance using the GDM (Generalized Dissimilarity Modelling) approach. Variables analyzed were altitude, geographical distance, physical and chemical parameters of the water. A coefficient based on the ordering properties of count data, from the perspective of both sites and taxa, was used to measure the compositional similarity between samples. The most frequent taxa were: Hyallela, Simuliidae, Andesiops, Austrelmis, Podonominae, Protallagma, Trichocorixa, Orthocladiinae and Glossiphonidae. The highest altitudinal record ever for leeches is reported here. Altitude and conductivity contributed greatly to the single ecological predictor of beta diversity. Sampling points can be classified first by altitude (cutoff sets at 4200 m), which can be considered a surrogate of a regional factor (distinction between Puna and High Andean ecoregions) and then by conductivity (cutoff sets at 135 µS cm-1), which can be considered a proxy of a local factor (distinction between hyperfresh and more mineralized habitats). These results suggest a system of ecological filters acting on them. Fil: Nieto Peñalver, María Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucuman. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; Argentina Fil: Dos Santos, Daniel Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucuman. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; Argentina Fil: Izquierdo, Andrea Elisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucuman. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; Argentina Fil: Rodríguez, José S. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucuman. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; Argentina Fil: Grau, Hector Ricardo. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; Argentina

The spatial structure and underlying assembly mechanisms of bacterial communities have been studied widely across aquatic systems, focusing primarily on isolated sites, such as different lakes, ponds and streams. Here, our main aim was to determine the underlying mechanisms for bacterial biofilm assembly within a large, highly connected lake system in Northern Finland using associative methods based on taxonomic and phylogenetic alpha-and beta-diversity and a large number of abiotic and biotic variables. Furthermore, null model approaches were used to quantify the relative importance of different community assembly processes. We found that spatial variation in bacterial communities within the lake was structured by different assembly processes, including stochasticity, species sorting and potentially even dispersal limitation. Species sorting by abiotic environmental conditions explained more of the taxonomic and particularly phylogenetic turnover in community composition compared with that by biotic variables. Finally, we observed clear differences in alpha diversity (species richness and phylogenetic diversity), which were to a stronger extent determined by abiotic compared with biotic factors, but also by dispersal effects. In summary, our study shows that the biodiversity of bacterial biofilm communities within a lake ecosystem is driven by within-habitat gradients in abiotic conditions and by stochastic and deterministic dispersal processes.

Aim: Refugia under past climates have been important in structuring current patterns in diversity, while refugia under anthropogenic climate change will likely be important in retaining this diversity and shaping new patterns. However, few studies have examined the congruence of past, present and future refugia, or the spatiotemporal connectivity of these refugia. Our aim was to test the extent of overlap of refugia under Last Glacial Maximum (LGM), present (2015) and likely future climates (2100), for Tasmania's palaeoendemic flora. We then aimed to identify areas of high spatiotemporal refugia connectivity, as priority areas for conservation and management. Location: Tasmania, Australia. Methods: We developed and applied a new community-level approach to identifying refugia, based on generalized dissimilarity modelling of compositional turnover and a set of reference sites with known biodiversity value. Using these projections of palaeoendemic plant refugia for past, present and future climates, we developed and applied a second approach to quantify the level of connectivity of these refugia over space and time. Results: Although there was large overlap (85%) between current and future climates in the distribution of the highest value palaeoendemic refugia, the small congruence of these areas with refugia at the LGM resulted in only a small area ( c. km 2 ) of persistent high value refugia over all three time periods. Despite this, our spatiotemporal analysis identified several areas of high connectivity in refugial environments for Tasmania's palaeoendemic flora over time. Main conclusions: The community-level approaches we demonstrate here to quantify refugia and their spatiotemporal connectivity have the potential to advance our understanding of biodiversity dynamics, particularly for taxonomic groups that are species-rich, poorly studied or comprised of many rare species, where species-level approaches are less suitable.

Mediterranean streams are mostly characterised by intermittent flow regime, with droughts in summer followed by floods in autumn. During droughts, the creation of lentic habitats (i.e. lentification process) and isolated pools in the riverbeds (i.e. fragmentation process) represents a strong selective pressure on biotic communities, which might be intensified by human-induced water scarcity. In the highly heterogeneous habitat patches created by these processes, species sorting may be driven by stochastic mechanisms, as well as by environmental filtering. In this work, we investigated the spatial and temporal patterns in the assemblage of diatom communities during water scarcity periods in Mediterranean streams. Five oligotrophic streams, which were similar in terms of physical and chemical parameters, were sampled in the Ligurian Alps (NW Italy). Data were collected during moderate flow in April 2014 and then at least monthly during water scarcity, from June to September 2014, in: (1) lentic sites, where the water flow became slower but was permanent all year around, (2) fragmented sites, where the riverbed stretch dried out creating isolated pools. For each sampling site, we collected six benthic diatom samples from different microhabitats. We examined which type of factors, i.e. spatial or environmental, better explained the temporal and spatial variation in diatom communities. We then calculated the turnover and nestedness components of dissimilarity by comparing samples collected during moderate flow with samples obtained during a period of water scarcity. We further investigated if the idiosyncrasy of diatom species, i.e. a measure of their discrepancy from a nested pattern, could be explained by the ecological niche width of species and/or by species traits. Our results showed a contribution of both environmental and spatial factors in determining species composition during water scarcity, with the overall trends in community structure being driven by species turnover. The percentage of idiosyncratic species (those departing from the nested pattern) increased with increasing water scarcity, but showed no differences in terms of species traits. According to our results, species turnover, with replacement of sensitive species by tolerant species, seemed to be the dominating process in diatom benthic communities during water scarcity in the streams under investigation. A better evaluation of species autecology could improve the evaluation of water quality in Mediterranean streams.

Questions Plant communities of road verges adjoining arable fields are often managed for conservation purposes. How do the diversity and composition of plant communities differ within and between berms, embankments and field margins? What is the influence of management practices on the diversity and composition of plant communities within and between these elements? Considering species frequently occurring in these three elements (hereafter generalist species), do road–field management practices influence their abundance in field margins? Location Central-western France. Methods Three adjacent elements located between district roads and winter cereal fields – i.e. berm, embankment and field margin – were sampled in 40 road–field boundaries situated in an agricultural area. Management practices on each element were characterized (i.e. mowing frequency and/or mowing period, inputs of herbicide and nitrogen fertilizers). We compared species diversity and taxonomic composition within and between elements. We tested the influence of management practices on (i) species richness and species evenness in each element, (ii) abundance-based compositional dissimilarity between pairs of elements using a model averaging procedure, and (iii) abundance of generalist species in field margins using generalized Cochran-Mantel-Haenszel tests. Results Compositional dissimilarity between elements was mainly due to changes of dominant species. An early mowing of the berm increased berm species richness, while late mowing increased species richness of adjacent elements. An increase in embankment mowing frequency decreased species evenness in the embankment while input of herbicide on the embankment decreased the substitution rate between embankment and field margin. Finally, late mowing of the berm and one cut of the embankment both increased abundance of some generalist weeds in field margins. Conclusions In our agricultural landscape, mowing berms once in early summer is appropriate to promote plant species richness, while late mowing may potentially conflict with integrated weed management in adjacent arable fields. We suggest that programmes managing road verges should take into account the effects on plant assemblages within road verge elements and adjacent arable fields, as well as the potential increase in weed risk.

cited By 22; International audience; Aim: To propose a unified framework for quantifying taxon (Tβ), phylogenetic (Pβ) and functional (Fβ) beta diversity via pairwise comparisons of communities, which allows these types of beta diversity to be partitioned into ecologically meaningful additive components. Location: Global, with case studies in Europe and the Azores archipelago. Methods: Using trees as a common representation for taxon, phylogenetic and functional diversity, we partition total beta diversity (βtotal) into its replacement (turnover, βrepl) and richness difference (βrich) components according to which part of a global tree was shared by or unique to communities that were being compared. We demonstrate the application of this framework using artificial and empirical examples (mammals in Europe and epigean arthropods in the Azores). Results: Our empirical examples show that comparing Pβ and Fβ with the most commonly used Tβ revealed previously hidden patterns of beta diversity. More importantly, we demonstrate that partitioning Pβtotal and Fβtotal into their respective βrepl and βrich components facilitates the detection of more complex patterns than using the overall coefficients alone, further elucidating the different forces operating in community assembly. Main conclusions: The methods presented here allow the integration and full comparison of Tβ, Pβ and Fβ. They provide a tool for effectively disentangling the replacement (turnover) and richness difference components of the different biodiversity facets within the same methodological framework. © 2013 John Wiley & Sons Ltd.

1. Non-random species loss and gain in local communities change the compositional heterogeneity between communities over time, which is traditionally quantified with dissimilarity-based approaches. Yet, dissimilarities summarize the multivariate species data into a univariate index and obscure the species-level patterns of change, which are central to understand the causes and consequences of the community changes. 2. Here, we propose a model-based approach that looks for species-level effects of time period and construct a multiple-site metric as a sum across species to test the consistency of the individual species responses. Species fall into different response types, showing how they influence the changes in community heterogeneity. 3. In a comparison with other multiple-sitemetrics, we illustrate the properties of our method and the differences and similarities with other approaches. For instance, ourmetric estimates the total variation in a community data set based on species-level contributions, not the compositional dissimilarities between particular sites. Similar to some other approaches, we can distinguish between heterogeneity derived from turnover or richness differences. 4. Our approach was applied to a set of 23 forest understorey resurvey studies spread across Europe. We show the species gains and lossesmay as well decrease or increase levels of community heterogeneity. Although species occurrences and communities have not changed in a consistent way along continental-scale environmental gradients such as climatic conditions, several species shifted in a similar way across the different data sets. 5. Testing the significance of shifts in species prevalence over time to infer corresponding changes in the compositional heterogeneity among sites provides a very intuitive tool for community resurvey studies. The main strengths of our framework are the explicit consideration of the relative roles of species gains and losses and the straightforward generalization to different sets of hypotheses related to community changes. Key-words: biodiversity, community composition, biotic homogenization, binomial deviance, dissimilarity, beta diversity,multivariate analysis,meta-analysis, forest understorey

Questions: Does the magnitude of grazing-induced changes in species composition vary with habitat productivity? How does the sign and magnitude of grazing effects on species richness and beta-diversity change with increasing productivity? Do major life forms exhibit consistent responses to grazing along productivity gradients? Location: Steppes and grasslands of southern South America in Argentina and Uruguay. Methods: We evaluated grazing effects on plant composition, species richness, beta-diversity and life-form abundances along a ten-fold, regional productivity gradient and within subregions of contrasting productivity, using a common sampling protocol for 23 paired grazed vs ungrazed plots. The annual integral of the normalized difference vegetation index was used as a surrogate for above-ground net primary productivity. Results: Compositional dissimilarity between grazed and ungrazed plots, as well as grazing-induced differences in plant richness and beta-diversity all increased with habitat productivity. Grazing decreased species richness in low-productive steppes but enhanced the richness of high-productive grasslands. On average, grazing reduced beta-diversity in high-productive sites but not in low-productive sites. Dominant species were more strongly suppressed by grazing towards productive grasslands. Grazing generally decreased shrub species cover, whereas graminoid and forb cover did not consistently change with grazing through the productivity gradient. Conclusions: Our results indicate that the overall grazing effects on vegetation structure increased along a regional productivity gradient. Yet the sign of grazing impacts on species richness and beta-diversity shifted with habitat productivity, in agreement with models of herbivore-mediated co-existence and species colonization in productive systems. Further, we found that narrowing the spatial extent of analysis to the subregion generally obscured grazing–productivity relationships. Biodiversity conservation programmes should carefully weigh the varied impacts of livestock grazing across productivity gradients Fil: Lezama, Felipe. Universidad de la República. Facultad de Agronom ía. Unidad de Sistemas Ambientales; Uruguay Fil: Baeza, Santiago. Universidad de la República. Facultad de Agronom ía. Unidad de Sistemas Ambientales; Uruguay Fil: Altesor, Alice. Universidad de la República. Facultad de Ciencias. Instituto de Ecolog ía y Ciencias Ambientales; Uruguay Fil: Cesa, Ariela. Instituto Nacional de Tecnología Agropecuaria; Argentina Fil: Chaneton, Enrique Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina. Universidad de Buenos Aires. Facultad de Agronomia; Argentina Fil: Paruelo, José. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Métodos Cuantitativos y Sistemas de Información; Argentina

Aim The delineation of regions is a critical procedure in biogeography, but there is still no consensus about the best approach. Traditionally, a compositional dissimilarity index and a clustering algorithm are used to partition locations into regions. However, the choice of index and algorithm may have a profound impact on the final result, particularly when locations display different levels of species richness and when they are nested within each other. Our objective was to estimate the influence of species nestedness among locations on the delineation of biogeographical regions. Location As a case study, we used coral reef fishes (families Chaetodontidae, Pomacentridae and Labridae) from the Indo-Pacific, where a large richness gradient extends, often as a series of nested assemblages, from the species-rich Indo-Australian Archipelago (Coral Triangle) to species-poor peripheral locations. Methods We used the turnover and nestedness components of the Sorensen and Jaccard dissimilarity indices to estimate the effect of nestedness on the delineation of biogeographical regions. In addition, we compared the results with those obtained using a parsimony analysis of endemicity (PAE). Results Low Mantel correlation values revealed that the PAE method assembled locations in a very different way than methods based on dissimilarity indices for Indo-Pacific coral reef fishes. We also found that nestedness mattered when delineating biogeographical units because, for both the Sorensen and the Jaccard indices, reef fish assemblages were grouped differently depending on whether we used the turnover component of each index or the complete index, including the nestedness component. The turnover component ignored variation in species richness attributable to differences in habitat area between locations, and permitted a delineation based solely on species replacement. Main conclusions We demonstrate that the choice of the component used to measure dissimilarity between species assemblages is critical, because it may strongly influence regional delineations, at least for Indo-Pacific coral reef fishes. We conclude that the two components of the dissimilarity indices can reveal complementary insights into the role that history may have played in shaping extant patterns of biodiversity.

The assemblage of marine invertebrates associated with floating macroalgal rafts may potentially be structured by ecological interactions and the characteristics of the rafts themselves. Alternatively, the assemblages might reflect a random process of colonization and loss from fragments, such that there is no systematic variation in assemblage structure with raft type. Analyses of 51 rafts collected from Irish coastal waters found no evidence for consistent patterns in the occurrence of species with raft size or algal composition. The observed patterns could not be distinguished from the predictions of a model with random allocation of individuals to rafts. Invertebrate species richness increased with raft size, but a multivariate test showed that this pattern was not associated with consistent changes in the identities of species found. Macroinvertebrate species assemblages were not significantly structured by the different species of algae in the raft. In contrast, the environmental variables at the point of raft collection, along with location data, were associated with variation in the species composition of rafts. The absence of any systematic structure related to raft size or composition in the sampled rafts suggests that, for the region studied, processes of raft break-up and coalescence obscure any potential effects of ecological interactions on individual rafts. The location-related variation in rafting invertebrate populations may reflect spatial variation in source populations or environmental factors that alter species compositions independently of raft type.

The relationship between biodiversity and biogeochemical processes gained much interest in light of the rapidly decreasing biodiversity worldwide. In this article, we discuss the current status, challenges and prospects of functional concepts to plant litter diversity and microbial decomposer diversity. We also evaluate whether these concepts permit a better understanding of how biodiversity is linked to litter decomposition as a key ecosystem process influencing carbon and nutrient cycles. Based on a literature survey, we show that plant litter and microbial diversity matters for decomposition, but that considering numbers of taxonomic units appears overall as little relevant and less useful than functional diversity. However, despite easily available functional litter traits and the well-established theoretical framework for functional litter diversity, the impact of functional litter diversity on decomposition is not yet well enough explored. Defining functional diversity of microorganisms remains one of the biggest challenges for functional approaches to microbial diversity. Recent developments in microarray and metagenomics technology offer promising possibilities in the assessment of the functional structure of microbial communities. This might allow significant progress in measuring functional microbial diversity and ultimately in our ability to predict consequences of biodiversity loss in the decomposer system for biogeochemical processes.

Functional diversity is at the heart of current research in the field of conservation biology. Most of the indices that measure diversity depend on variables that have various statistical types (e.g. circular, fuzzy, ordinal) and that go through a matrix of distances among species. We show how to compute such distances from a generalization of Gower's distance, which is dedicated to the treatment of mixed data. We prove Gower's distance can be extended to include new types of data. The impact of this generalization is illustrated on a real data set containing 80 plant species and 13 various traits. Gower's distance allows an efficient treatment of missing data and the inclusion of variable weights. An evaluation of the real contribution of each variable to the mixed distance is proposed. We conclude that such a generalized index will be crucial for analyzing functional diversity at small and large scales.

Foi realizado um estudo morfométrico com Platyscytus decempunctatus (Carvalho 1945) coletados durante as estações seca e úmida no município de Viçosa, MG e em 23 municípios distribuídos pelos estados de Minas Gerais e Rio de Janeiro. Foram utilizados 30 machos e 30 fêmeas por estação no estudo de Viçosa e insetos adicionais (20 machos e 20 fêmeas) de cada um dos 23 municípios amostrados. Foram analisadas 27 características morfológicas a fim de verificar a influência sazonal e diferenças no dimorfismo sexual em indivíduos de Viçosa e diferenças entre as populações amostradas. As fêmeas de P. decempunctatus coletadas em Viçosa foram maiores que os machos na maioria das características avaliadas em ambas as estação (seca e úmida). Os machos apresentaram somente duas características corporais maiores que as fêmeas. Diferenças morfométricas interpopulacionais em P. decempunctatus se correlacionaram à distância geográfica entre os locais de coleta. A morphometry study was carried out with Platyscytus decempunctatus (Carvalho 1945) collected during the dry and wet seasons in Viçosa county, state of Minas Gerais, Brazil and in other 23 counties from the states of Minas Gerais and Rio de Janeiro in Brazil. A total of 30 males and 30 females were collected in Viçosa at each season and additional insects (20 males and 20 females) were collected at each county surveyed. The analysis with 27 morphological traits was carried out to verify the seasonal influence, differences between sexes and among populations in specimens from Viçosa. The females of P. decempunctatus collected in Viçosa were larger than the males in most of the traits evaluated in both seasons (dry and wet). The males showed only two body traits larger than the females. Interpopulational morphometry differences of P. decempunctatus were significantly correlated with geographic distance among sampling sites.