Aim The drivers of phylogenetic beta diversity include both local processes (e.g. environmental filtering) and regional processes (e.g. dispersal limitation). The role of environmental filtering can be investigated more directly by analysing community-environment associations, but dispersal limitation is one of the most challenging processes to examine. We investigated the role of traits related to dispersal -flight capacity, body size and voltinism -as drivers of phylogenetic distance decay relationships in Neotropical stream insect communities.Location Headwater streams spread over 600 km in south-eastern Brazil.Methods We compiled a data set of aquatic insect communities inhabiting streams across the State of São Paulo (Brazil). Then, we investigated environmental and spatial signals on phylobetadiversity patterns of aquatic insects using Mantel tests, multiple regressions on distance matrices and variation partitioning. We employed null models to investigate whether phylogenetic distance decay differed from pure compositional distance decay. We deconstructed the data set based on dispersal-related traits; we then ran distance decay analyses for these subsets separately.Results Geographical distance, rather than environmental distance, better explained the patterns of phylobetadiversity. We found that the phylogenetic decay relationship differed from the relationship expected for the null models only for univoltine, large-bodied genera with a high-flight capacity.Main conclusions Dispersal limitation, rather than species sorting, was the main driver for phylogenetic beta diversity in the metacommunity that we studied. We suggest that life-history strategies and mainly voltinism drive the distance decay of similarity in the insect communities examined. We additionally discuss the role of dispersal events over time to explain differences in distance decay patterns among tropical and other regions.

Habitat modification can homogenize biological communities. Beta diversity analyses provide key information for understanding biotic homogenization, especially given recent conceptual and methodological advances. Here, we investigated if landscape modification was associated with taxonomic homogenization in 32 stream insect communities from the Brazilian Atlantic Forest. We investigated: (1) if the way we defined landscape affected our estimates of beta diversity; (2) to what extent changes in species composition versus relative abundance caused the observed homogenization; and (3) if environmental heterogeneity among modified habitats influenced homogenization. We detected taxonomic homogenization caused by landscape modification only when we used refined landscape categorizations and abundance‐based diversity measures. For forested streams, changes in relative abundance rather than absolute taxonomic composition increased the biological variation. Forested streams were generally more heterogeneous, with a variable set of abundant genera; by contrast, non‐forested streams were more homogeneous, with the same set of genera being more or less abundant. We suggest that landscape modification by agriculture, pasture, and silviculture reduces beta diversity by limiting the colonization of potential species, and, ultimately, causing taxonomic homogenization. Studies investigating biotic homogenization should include multiple dissimilarity measures representing changes in relative species abundance and community composition.

2020. Community size can affect the signals of ecological drift and niche selection on biodiversity. Ecology 101(6):

The idea behind multimetric indices is to integrate information from several metrics to provide a general classification of water bodies without losing the particularities of each individual metric. Historically, multimetric indices use information on richness, taxon sensitivity, and taxonomic diversity. Recently, functional and phylogenetic diversity proved to capture different dimensions of biodiversity. Here we asked if these new metrics provide complementary information to classical metrics and should be included in multimetric indices. We used an index construction protocol based on statistical filters to test candidate metrics for range, sensitivity, and redundancy. We used macroinvertebrate data from streams located in a Savanna region of Brazil, encompassing a gradient of impact, to test our ideas. Of 41 candidate metrics, functional dispersion of functional diversity, mean nearest neighbor distance of phylogenetic diversity, and four classical metrics passed the filter selection composing the final multimetric index. Our results indicated that functional and phylogenetic diversity metrics indeed responded to environmental impact and complemented the information provided by classical metrics. We suggest that future indices should consider including new metrics of functional and phylogenetic diversity to properly monitor multiple dimensions of biodiversity.

Oviposition site selection by aquatic insects is usually influenced by both aquatic and terrestrial cues. Landscape changes (e.g. native vegetation loss) can affect the level of the reproductive success in aquatic insects, changing local species composition and richness. We investigate whether forest cover loss around streams influences the number of species with exophytic (species which lay eggs directly on the water surface), endophytic (species which lay their eggs directly into plant tissue), or epiphytic (species which lay eggs on the exposed surface of rocks, leaves, trunks or other substrates protruding from the stream surface) oviposition behaviour in dragonfly assemblages. We sampled adult dragonflies in 116 streams in a Neotropical savanna region in Brazil. The relationship between species richness for each behavioural category, and the proportion of forest cover around the streams, was tested using regression analysis. We collected 2413 dragonfly (Anisoptera and Zygoptera) individuals, belonging to 8 families, 30 genera, and 63 species. Of these, 25 species were classified as exophytic, 28 as epiphytic, and 10 as endophytic. Our results show that the number of species with exophytic or epiphytic behaviour was strongly related to riparian forest loss. Forest loss changes the habitat, and here, specifically changes site suitability for oviposition. We highlight the importance of using behavioural traits as a bioindicator tool for the assessment of anthropogenic impacts on tropical forest.

The assumption that traits and phylogenies can be used as proxies of species niche has faced criticisms. Evidence suggested that phylogenic relatedness is a weak proxy of trait similarity. Moreover, different processes can select different traits, giving opposing signals in null model analyses. To circumvent these criticisms, we separated traits of stream insects based on the concept of α and β niches, which should give clues about assembling pressures expected to act independently of each other. We investigated the congruence between the phylogenetic structure and trait structure of communities using all available traits and all possible combinations of traits (4095 combinations). To account for hierarchical assembling processes, we analyzed patterns on two spatial scales with three pools of genera. Beta niche traits selected a priori – i.e., traits related to environmental variation (e.g., respiration type) – were consistently clustered on the smaller scale, suggesting environmental filtering, while α niche traits – i.e., traits related to resource use (e.g., trophic position) – did not display the expected overdispersion, suggesting a weak role of competition. Using all traits together provided random patterns and the analysis of all possible combinations of traits provided scenarios ranging from strong clustering to overdispersion. Communities were phylogenetically overdispersed, a pattern previously interpreted as phylogenetic limiting similarity. However, our results likely reflect the co‐occurrence of ancient clades due to the stability of stream habitats along the evolutionary scale. We advise ecologists to avoid using combinations of all available traits but rather carefully traits based on the objective under consideration. Both trait and phylogenetic approaches should be kept in the ecologist toolbox, but phylogenetic distances should not be used as proxies of traits differences. Although the phylogenetic structure revealed processes operating at the evolutionary scale, only specific traits explained local processes operating in our communities.

Aim: Biological diversity typically varies between climatically different regions, and regions closer to the equator often support higher numbers of taxa than those closer to the poles. However, these trends have been assessed for a few organism groups, and the existing studies have rarely been based on extensive identical surveys in different climatic regions. Location:We conducted standardized surveys of wadeable streams in a boreal (western Finland) and a subtropical (south-eastern Brazil) region, sampling insects identically from 100 streams in each region and measuring the same environmental variables in both regions.Taxon: Aquatic insects. Methods:Comparisons were made at the scales of local stream sites, drainage basins and entire regions. We standardized the spatial extent of the study areas by resampling regional richness based on subsets of sites with similar extents. We examined differences in genus richness and assemblage abundance patterns between the regions using graphical and statistical modelling approaches. Results:We found that while genus accumulation and rank-abundance curves were relatively similar at the regional scale between Finland and Brazil, regional genus richness was higher in the latter but regional abundance much higher in the former region. These regional patterns for richness and abundance were reproduced by basin and local genus richness that were higher in Brazil than in Finland, and assemblage abundance that was much higher in Finland than in Brazil. The magnitude of the difference in genus richness between Brazil and Finland tended to increase from local through basin to regional scales. Main conclusions:Our findings suggest that factors related to evolutionary diversification might explain differences in genus richness between these two

*AB1abstract *AB2The use of phylogenetic tools and studies has strongly increased in the last two decades especially in conservation biology and community ecology. Phylogenetic trees have been essential to understand the processes of community or network assembly, to identify centers of diversification, and to help protect Earth's evolutionary heritage. Despite two decades of research and syntheses, there are still many discussions on how phylogenetic diversity (PD) methods should be effectively applied to those fields. In particular, conservation approaches based on PD have become similar to these used in community ecology. Thus, the main benefit of using PD calculations in conservation biology may have been ignored or misinterpreted. Our goal is to discuss and provide guidelines to the use of PD in biodiversity conservation so that its benefits are not hidden or lost in the approaches employed. We also aim that benefits and uses are better recognized and more easily understood by researchers or practitioners who would like to include PD in their studies and conservation planning. *S1Introduction