Tadeu Siqueira

University of Canterbury | UC · School of Biological Sciences

Aquatic insects comprise 64% of freshwater animal diversity and are widely used as bioindicators to assess water quality impairment and freshwater ecosystem health, as well as to test ecological hypotheses. Despite their importance, a comprehensive, global database of aquatic insect occurrences for mapping freshwater biodiversity in macroecological...

Eutrophication is a key threat to aquatic biodiversity around the world, but especially in the Cerrado biome that has undergone intensive land use conversion and fertilizer use. In this study, we investigated how water conditions and different taxonomic and functional indicators of phytoplankton communities responded to eutrophication over time and...

Environmental and spatial heterogeneity affects the distribution of aquatic insects, determining or influencing the variation in local species composition. Dragonflies and damselflies (Odonata) have different strategies for oviposition site selection that depend on environmental conditions. However, Land Use and Land Cover (LULC) can reduce the ava...

Local communities and individual species jointly contribute to the overall beta diversity in metacommunities. However, it is mostly unknown whether the local contribution (LCBD) and the species contribution (SCBD) to beta diversity can be predicted by local and regional environmental characteristics and by species traits and taxonomic relatedness,...

The temporal stability of ecological properties increases with spatial scale and levels of biological organization, but how does it propagate across trophic levels? We compiled 35 metacommunity time-series datasets spanning basal resources (e.g., phytoplankton) to top predators (e.g., piscivorous fish) from 384 freshwater sites across three contine...

Small communities are predicted to be strongly influenced by stochastic demographic events and, thus, less affected by environmental selection than large communities. However, this prediction has only been tested with computer simulations, simplified controlled experiments, and limited observational data. Using multicontinental data on riverine fis...

Food web responses to environmental change are not straightforward to understand as they occur through an intricate arrangement of direct and indirect effects. Although previous investigations have advanced knowledge on freshwater food web structure, we must better understand the intricate relationships between the main drivers of environmental cha...

Host age is known to influence the risk of parasite infection, but there is very little experimental evidence on whether parasites show preference towards potential hosts of a specific age. To investigate how host age affects host choice by parasites, we used the Nile tilapia (Oreochromis niloticus) as a fish parasite model and manipulated its gill...

River managers strive to use the best available science to sustain biodiversity and ecosystem function. To achieve this goal requires consideration of processes at different scales. Metacommunity theory describes how multiple species from different communities potentially interact with local‐scale environmental drivers to influence population dynam...

• Biodiversity is structured in space and time, yet our understanding about the temporal variation of biological communities is still limited. Recent work suggests that temporal β diversity should be lowest in unpredictable systems with low seasonality, as expected for tropical ecosystems. However, this hypothesis remains largely unexplored. • Here...

Acoustic signaling is key in mediating mate‐choice, which directly impacts individual fitness. Because background noise and habitat structure can impair signal transmission, the acoustic space of mixed‐species assemblages has long been hypothesized to reflect selective pressures against signal interference and degradation. However, other potential...

Aim Evaluating how groups of organisms vary in dispersal capability and how environmental, spatial and temporal signals vary across multiple scales is critical to elucidating metacommunity theory. We examined whether the relative contributions of environmental, spatial and hydrological factors have different effects on organismal groups with differ...

Previous studies have found mixed results regarding the relationship between beta diversity and latitude. In addition, by influencing local environmental heterogeneity, land use may modify spatial taxonomic and functional variability among communities causing biotic differentiation or homogenization. We tested 1) whether taxonomic and functional be...

1. Temporal scale in animal communities is often associated with seasonality, despite the large variation in species activity during a diel cycle. A gap thus remains in understanding the dynamics of short-term activity in animal communities. 2. Here we assessed calling activity of tropical anurans and addressed how species composition varied during...

Traits define how organisms interact with their surrounding environment and with other organisms. Thus, trait composition of biological communities is expected to change predictably along environmental gradients. Because organisms’ traits, but not taxonomic identity, determine their fitness, trait-environment relationships should provide a better w...

1. Evidence indicating that ecological communities show delayed responses to environmental change has raised the need to better understand the effects of landscape history on biodiversity. 2. We investigated how freshwater biodiversity is related to both recent and past land use change in tropical river catchments. More specifically, we analyzed th...

1. Protecting riparian vegetation around streams is vital in reducing the detrimental effects of environmental change on freshwater ecosystems and in maintaining aquatic biodiversity. Thus, identifying ecological thresholds is useful for defining regulatory limits and for guiding the management of riparian zones towards the conservation of freshwat...

Ecologists studying emerging wildlife diseases need to confront the realism of imperfect pathogen detection across heterogeneous habitats to aid in conservation decisions. For example, spatial risk assessments of amphibian disease caused by Batrachochytrium dendrobatidis (Bd) has largely ignored imperfect pathogen detection across sampling sites. B...

Ecological uniqueness is one aspect of beta (β) diversity that shows the relative contribution of sites (local contribution to beta diversity – LCBD) and taxa (species contribution to beta diversity – SCBD) in the formation of a unique environment in terms of species composition, and may be directly related to habitat quality. Our objective was to...

Ecological drift can override the effects of deterministic niche selection on small populations and drive the assembly of some ecological communities. We tested this hypothesis with a unique dataset sampled identically in 200 streams in two regions (tropical Brazil and boreal Finland) that differ in macroinvertebrate community size by five‐fold. Nu...

For several decades, ecologists have been trying to explain how species abundance distributions (SAD) emerge within communities. Niche models predict that species habitat requirements and life-history traits determine SADs. Here, based on predictions from a well-known niche-based SAD (Sugihara's model), we tested whether abundant species are ecolog...

Reliable biological assessments are essential to answer ecological and management questions but require well-designed studies and representative sample sizes. However, large sampling effort is rarely possible, because it demands large financial resources and time, restricting the number of sites sampled, the duration of the study and the sampling e...

The complexity of ecological systems is a major challenge for practitioners and decision-makers who work to avoid, mitigate and manage environmental change. Here, we illustrate how metaecology – the study of spatial interdependencies among ecological systems through fluxes of organisms, energy, and matter – can enhance understanding and improve man...

Some local communities contribute more to beta diversity than others, which has been known as compositional uniqueness or local contribution to beta diversity. Compositional uniqueness should correlate positively with environmental uniqueness and site isolation. We evaluated compositional uniqueness (total and in terms of species replacement and ne...

Tropical forests hold some of the world's most diverse communities of plants. Many populations of large‐bodied herbivores are threatened in these systems, yet their ecological functions and contribution towards the maintenance of high levels of plant diversity are poorly known. The impact of these herbivores on plant communities through antagonisti...

The increasing worldwide interest on the conservation of tropical forests reflects the conversion of over 50% of their area into agricultural lands and other uses. Understanding the distribution of remaining biodiversity across agricultural landscapes is an essential task to guide future conservation strategies. To understand the long-term effects...

Ecological drift can override or interact with the effects of deterministic niche selection on small populations to drive the assembly of small communities. We tested the hypothesis that small communities are more dissimilar among each other because of ecological drift than large communities, which are mainly structured by niche selection. We used...

A coordinated distributed experiment, replicated across multiple labs and multiple taxa, reveals that both resources and predators govern dispersal between habitats, affecting local and regional stability of biological communities.

The complexity of ecological systems is a major challenge for practitioners and decision-makers who work to avoid, mitigate and manage environmental change. Here, we illustrate how metaecology - the study of spatial interdependencies among ecological systems through fluxes of organisms, energy, and matter - can enhance understanding and improve man...

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 clima...

Habitat loss is the greatest threat to the persistence of forest‐dependent amphibians, but it is not the only factor influencing species occurrences. The composition of the surrounding matrix, structure of stream networks, and topography are also important landscape characteristics influencing amphibian distributions. Tropical forests have high div...

Aim: We analysed beta-diversity patterns of various biological groups simultaneously, from the perspective of site ecological uniqueness. We also investigated whether ecological uniqueness variation could be explained by variations in environmental conditions and spatial variables. Data: Central Amazonia. Methods: We estimated the total beta divers...

The role of niche differences and competition is invoked when one finds coexisting species to be more dissimilar in trait composition than expected at random in community assembly studies. This approach has been questioned as competition has been hypothesized to either lead to communities assembled by similar or dissimilar species, depending on whe...

The regional occupancy and local abundance of species are thought to be strongly correlated to their body size, niche breadth and niche position. The strength of the relationships among these variables can also differ between different organismal groups. Here, we analyzed data on stream diatoms and insects from a high-latitude drainage basin to inv...

Metacommunity models predict that species richness and composition patterns in communities are determined predominantly by environmental selection and dispersal, with speciation and drift playing a lesser role. In the tropics, our understanding about these processes comes almost purely from empirical data; there is lack of formal confrontation betw...

Decisions about biodiversity conservation depend on how different taxonomic groups respond to human influenced environmental change. Here, we ask whether richness and composition of terrestrial (frugivorous butterflies and dung beetles) and aquatic insects (Plecoptera, Trichoptera, Ephemeroptera, Odonata and Coleoptera) change in a congruent manner...

Latin America embodies countries of special interest for ecological studies, given that areas with great value for biodiversity are located within their territories. This highlights the importance of an evaluation of ecological research in the Latin America region. We assessed the scientific participation of Latin American researchers in ecological...

Periphytic algae are important components of aquatic ecosystems. However, the factors driving periphyton species richness variation remain largely unexplored. Here, we used data from a subtropical floodplain (Upper Paraná River floodplain, Brazil) to quantify the influence of environmental variables (total suspended matter, temperature, conductivit...

Periphytic algal species within groups formed based on attachment strategies and size. (DOCX)

Sub-basins, geographic coordinates and hydrology of the sampling environments in the Upper Paraná river floodplain. (DOCX)

Description of the best models. (DOCX)

List of references used to identify zooplankton species. (DOCX)

A positive relationship between occupancy and abundance of species has been widely described for various groups of organisms. Also, it has been observed to occur on different scales, ranging from broad biogeographic regions to small areas within a drainage basin. The influence of body size on species distribution can also differ between different o...

Large continuous rainforests are the main hope for sustaining the population of large-bodied vertebrates that cannot cope with fragmentation or unsustainable hunting. The Brazilian Atlantic forest is considered a biodiversity hotspot and although highly fragmented, it still contains large forest patches that may be important for the conservation of...

Studies on phylogenetic community ecology usually infer habitat filtering when communities are phylogenetically clustered or competitive exclusion when communities are overdispersed. This logic is based on strong competition and niche similarity among closely related species—a less common phenomenon than previously expected. Dragonflies and damself...

We simulated metacommunities in a hypothetical riverine network to investigate whether and how connectivity affects the species richness of groups with different dispersal abilities under different niche- and dispersal-assembly rules. The simulated network was represented by a graph in which the nodes represented habitat patches, each with a partic...

We investigated (1) the variation of both species composition and species relative abundances of aquatic beetles associated with submerged woody debris in a transitional region between Cerrado (Brazilian savannah) and Atlantic Forest biomes; and (2) which assembling processes are more associated with the observed patterns, species sorting or mass e...

1. Deconstructing biological communities by grouping species according to their commonness or rarity might improve our understanding about the processes driving variation in biological communities. Such an approach considers differences among organisms and emergent ecological patterns. 2. In this study, we addressed the relative role of spatial and...

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...

Inter-specific competition is considered one of the main selective pressures affecting species distribution and coexistence. Different species vary in the way they forage in order to minimize encounters with their competitors and with their predators. However, it is still poorly known whether and how native species change their foraging behavior in...

AimThe 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 exam...

Appropriate sampling effort is crucial for ecologists. Procrustes analysis can be used to tackle this question by quantifying the match between subsamples and the complete dataset. We used stream macroinvertebrates to show how sampling design can be optimized by reducing the number of subsamples and increasing the number of sites. Definir esforço a...

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 Bra...

1. Metacommunity ecology addresses the situation where sets of local communities are connected by the dispersal of a number of potentially interacting species. Aquatic systems (e.g. lentic versus lotic versus marine) differ from each other in connectivity and environmental heterogeneity, suggesting that metacommunity organisation also differs betwe...

Several factors decrease plant survival throughout their lifecycles. Among them, seed dispersal limitation may play a major role by resulting in highly aggregated (contagious) seed and seedling distributions entailing increased mortality. The arrival of seeds, furthermore, may not match suitable environments for seed survival and, consequently, for...

The hypotheses that beta diversity should increase with decreasing latitude and increase with spatial extent of a region have rarely been tested based on a comparative analysis of multiple datasets, and no such study has focused on stream insects. We first assessed how well variability in beta diversity of stream insect metacommunities is predicted...

The hypotheses that beta diversity should increase with decreasing latitude and increase with spatial extent of a region have rarely been tested based on a comparative analysis of multiple datasets, and no such study has focused on stream insects. We first assessed how well variability in beta diversity of stream insect metacommunities is predicted...

The hypotheses that beta diversity should increase with decreasing latitude and increase with spatial extent of a region have rarely been tested based on a comparative analysis of multiple datasets, and no such study has focused on stream insects. We first assessed how well variability in beta diversity of stream insect metacommunities is predicted...