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Gabriel Brejão

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Nerissa Russell

Cornell University

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University of Gothenburg

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University of Cambridge

Yannis Hamilakis

Brown University

Field Museum

Leonardo García Sanjuán

Universidad de Sevilla

Hungarian Academy of Sciences

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Armando Marques-Guedes

UNL - New University of Lisbon

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Papers by Gabriel Brejão

Spatial non-stationarity in the distribution of fish species richness of tropical streams

Community Ecology, Nov 22, 2022

Transferability of Bioindicators Based on Fish Assemblages to Detect Human Impacts on Stream Ecosystems is Influenced by Spatial Distance and Environmental Differences

SSRN Electronic Journal

A Ecologia De Peixes De Riacho Sob a Perspectiva Da Ecologia De Paisagens

Oecologia Australis

Landscape ecology emphasizes the interaction between spatial patterns and ecological processes, i... more Landscape ecology emphasizes the interaction between spatial patterns and ecological processes, i.e., the consequences of spatial heterogeneity across various scales. It is an interdisciplinary science that seeks to understand the relationships between ecological patterns and processes considering different spatial and temporal scales. This understanding has been supported by the rapid development of a methodological framework, largely based on Geographic Information Systems (GIS). Thus, it has allowed understanding how ecological processes are affected by anthropogenic activities that trigger profound changes in ecosystems, such as habitat loss and fragmentation. Although commonly applied to studies in terrestrial ecosystems, there is a time lag in both theoretical development and methodological adaptation of landscape ecology applied to studies in streams, especially in Brazil. Methodological adaptations are necessary considering the particularities of aquatic environments in rela...

Habitat use, trophic, and occurrence patterns of Inpaichthys kerri and Hyphessobrycon vilmae (Pisces: Characidae) in Amazonian streams

Fish ecomorphology and diet can help us to understand species response to impacts and coexistence... more Fish ecomorphology and diet can help us to understand species response to impacts and coexistence patterns. Thus, we developed a comparative analysis of ecomorphology and diet of Inpaichthys kerri and Hyphessobrycon vilmae and tested for environmental variables that explain their abundance in headwater streams. We sampled streams from the Aripuanã River basin, Mato Grosso State, Brazil. We sampled environmental variables following a standardized protocol and used 30 and 80 individuals from each species to obtain ecomorphological attributes and feeding index, respectively. To identify environmental variables that influence species abundance, we developed generalized additive mixed models. Inpaichthys kerri presented broader and deeper caudal peduncles, more dorsal eyes, and larger fins, besides the lower consumption of aquatic insects, algae, and detritus when compared to H. vilmae. Inpaichthys kerri was more abundant in fast waters with little amounts of marginal grasses, conditions...

Characterization and assessment of aquatic environments in the Turvo/Grande basin

ABSTRACT The Turvo/Grande basin is located in the northwestern portion of the São Paulo State and... more ABSTRACT The Turvo/Grande basin is located in the northwestern portion of the São Paulo State and is composed by 64 municipalities, with a drainage area of 15.925 km2. Total human population accounts for 1,3 millions inhabitants, with 91% located in urban areas. This predominance of urban populations with the low availability of surface water, low rates of natural vegetation coverage, and soils with high potential to erosion can be cited as factors that threat the quality and quantity of aquatic resources of the basin. In this chapter, we described the main biotic and abiotic features of the Turvo/Grande basin and provided an evaluation on the present condition of streams, main rivers, and marginal lagoons, aiming to identify the major threats to the aquatic resources of the basin and provide suggestions to management. The main threat to small streams is physical habitat degradation, mostly derived from the lack of forest vegetation along the riparian buffer. For main rivers, metal contamination is of high concern, additionally to siltation, that is related to the lack of forest coverage in the basin. Knowledge on the marginal lagoons dynamics is still scarce, albeit preliminary efforts have revealed high biodiversity of fish and aquatic macrophytes, as also the existence of complex biotic interactions yet to be elucidated. Riparian forest recovery, soil conservation, control of metals and other contaminants, and floodplain protection must be of utmost interest to managers regarding aquatic resource conservation of such important river basin.

Você conhece a represa

A Represa Municipal de Sao Jose do Rio Preto, localizada no centro da cidade, e um ambiente aquat... more A Represa Municipal de Sao Jose do Rio Preto, localizada no centro da cidade, e um ambiente aquatico inserido na paisagem urbana e oferece varios servicos ecossistemicos, tais como fonte de agua para abastecimento e local de lazer. Os ambientes naturais urbanos tem sido pouco considerados em projetos de conservacao, uma vez que sao vistos apenas como equipamentos urbanos e nao como ecossistemas. Este projeto pretende levar a populacao que frequenta o parque da Represa informacoes sobre o ecossistema aquatico da Represa, com o intuito de desenvolver nas pessoas a consciencia da preservacao do ecossistema. Durante varios domingos, ao longo do ano, serao realizadas exposicoes no parque da represa, onde sao abordados varios aspectos ecologicos do ecossistema aquatico (p.ex.: a bacia hidrografica, as condicoes ambientais, a comunidade planctonica; a comunidade de peixes; as aves da represa e outros). As pessoas que participam do projeto estao distribuidas em todas as faixas etarias. Nos ...

Estradas, alagados antrópicos, peixes e a fragmentação de redes fluviais em uma paisagem agrícola do Nordeste do Pará

Badly planned roads crossing streams can generate small impoundments in channel segments upstream... more Badly planned roads crossing streams can generate small impoundments in channel segments upstream these crossings, turning lotic environments into lentic ones. The aim of this work was to study the diversity and functional structure of fish communities in anthropic impoundments in northeastern Pará state. These impoundments are formed due to roads construction on the riverine network, with large or small impacts on the hydrological connectivity, subject that is largely ignored for Neotropical lotic systems. Eighteen reaches were sampled in seven streams: six crossed by roads, and one not crossed by roads, used as a reference. Five streams are located in the cities of Igarapé-Açu and Marapanim in an agricultural landscape, and two in the city of São Francisco do Pará in a forest matrix. Five of six streams crossed by roads showed the formation of large impounded areas. In these locations three reaches were selected to sample fish: one upstream, one inside, and another one downstream ...

Taxonomic and functional turnover of Amazonian stream fish assemblages is determined by deforestation history and environmental variables at multiple scales

Neotropical Ichthyology, 2021

High rates of deforestation, either in the past or the present, affect many of the ecological pro... more High rates of deforestation, either in the past or the present, affect many of the ecological processes in streams. Integrating deforestation history and the current landscape structure enhances the evaluation of ecological effects of land-use change. This is especially true when contemporary landscape conditions are similar but the temporal path to those conditions differs. One approach that has shown promise for evaluating biodiversity responses over time and space is the β-diversity partitioning, which combines taxonomic and functional trait-based approaches. We tested hypotheses related to stream fish assemblages’ turnover in watersheds with different environmental conditions and deforestation histories. We sampled fish from 75 watersheds in the Machado River basin, Brazil, and environmental factors were quantified at multiple scales. Taxonomic turnover was higher than expected by chance, whereas functional turnover was lower than expected by the observed taxonomic turnover, ind...

Thresholds of freshwater biodiversity in response to riparian vegetation loss in the Neotropical region

Journal of Applied Ecology, 2020

When roads cross streams: fish assemblage responses to fluvial fragmentation in lowland Amazonian streams

Neotropical Ichthyology, 2020

Roads affect biodiversity by increasing mortality rates, habitat loss, and natural landscape frag... more Roads affect biodiversity by increasing mortality rates, habitat loss, and natural landscape fragmentation. Poorly installed culverts can impound streams, changing the environmental conditions, and affecting aquatic communities. We evaluated the effects of road crossings on the taxonomic composition and functional structure of fish assemblages in lowland eastern Amazonian streams, Brazil. We tested the hypothesis that the presence of road-derived impoundments affects assemblage taxonomic and functional composition and structure. Two predictions were addressed: (1) Species and functional group composition will differ in impounded reaches in relation to lotic reaches; (2) Assemblages in downstream lotic reaches will be richer in species and functional groups in relation to upstream lotic and impoundment reaches. We sampled five streams crossed by roads presenting impoundment formation, conducted by visual census (day, dusk, and night) in 200 m line transects. Assemblage composition fr...

Habitat use, trophic, and occurrence patterns of Inpaichthys kerri and Hyphessobrycon vilmae (Pisces: Characidae) in Amazonian streams

Neotropical Ichthyology, 2020

Fish ecomorphology and diet can help us to understand species response to impacts and coexistence... more Fish ecomorphology and diet can help us to understand species response to impacts and coexistence patterns. Thus, we developed a comparative analysis of ecomorphology and diet of Inpaichthys kerri and Hyphessobrycon vilmae and tested for environmental variables that explain their abundance in headwater streams. We sampled streams from the Aripuanã River basin, Mato Grosso State, Brazil. We sampled environmental variables following a standardized protocol and used 30 and 80 individuals from each species to obtain ecomorphological attributes and feeding index, respectively. To identify environmental variables that influence species abundance, we developed generalized additive mixed models. Inpaichthys kerri presented broader and deeper caudal peduncles, more dorsal eyes, and larger fins, besides the lower consumption of aquatic insects, algae, and detritus when compared to H. vilmae. Inpaichthys kerri was more abundant in fast waters with little amounts of marginal grasses, conditions...

Mining activity in Brazil and negligence in action

Perspectives in Ecology and Conservation, 2020

h i g h l i g h t s • A new disaster in Brazil involving the rupture of a tailings dam reopened t... more h i g h l i g h t s • A new disaster in Brazil involving the rupture of a tailings dam reopened the discussions about socio-environmental impact. • The absence of actions by the companies and the lack of a management plan can imperil the efforts for environmental recovery. • The slowdown of Brazilian environmental legislation can generate a future darker scenario.

Stream fish from recently deforested basins in the Meridional Amazon, Mato Grosso, Brazil

Biota Neotropica, 2020

The replacement of tropical forests to production systems is one of the leading causes of riverin... more The replacement of tropical forests to production systems is one of the leading causes of riverine ecosystem alterations. However, current assemblages' composition may also result from the time since these transformations have begun. Therefore, the knowledge of diversified historical scenarios can facilitate the accomplishment of actions that involve the aquatic environments recovery. In this study, an inventory of stream fish was carried out in basins whose deforestation was intensified in the last 20 years, to compose a baseline for ecological and taxonomic studies. The habitat, physical and chemical variables, and the fish assemblages from 60 streams in the northwest region of the state of Mato Grosso, in the Aripuanã and Juruena river basins, were sampled with standardized procedures. For a total of 130 species, a numerical predominance of small-sized Characidae and great rarity were registered, with 50 species represented by less than ten individuals and 19 singletons. Approximately 15% of the sampled taxa were identified only at the generic level, and for several taxa, more detailed taxonomic and molecular studies are required in order to achieve satisfactory identifications. None threatened species were so far reported. On the other hand, two specimens of non-native species were sampled. Although habitat quality is higher in forested streams, no differences in the species richness were registered when compared to the pasture with riparian forest streams or to more deforested streams. However, abundance was greater in these last two streams groups as a result of small-sized characins dominance.

How deforestation drives stream habitat changes and the functional structure of fish assemblages in different tropical regions

Aquatic Conservation: Marine and Freshwater Ecosystems, 2019

1. Deforestation can modify stream habitat and the functional structure of fish assemblages. The ... more 1. Deforestation can modify stream habitat and the functional structure of fish assemblages. The aims of this study were (a) to identify whether deforestation has a similar effect on local habitats from two biogeographically distinct river basins in a tropical region; (b) to identify how fish trait-habitat relationships were influ

A multiple hypothesis approach to explain species richness patterns in neotropical stream-dweller fish communities

PloS one, 2018

Several hypotheses are used to explain species richness patterns. Some of them (e.g. species-area... more Several hypotheses are used to explain species richness patterns. Some of them (e.g. species-area, species-energy, environment-energy, water-energy, terrestrial primary productivity, environmental spatial heterogeneity, and climatic heterogeneity) are known to explain species richness patterns of terrestrial organisms, especially when they are combined. For aquatic organisms, however, it is unclear if these hypotheses can be useful to explain for these purposes. Therefore, we used a selection model approach to assess the predictive capacity of such hypotheses, and to determine which of them (combined or not) would be the most appropriate to explain the fish species distribution in small Brazilian streams. We perform the Akaike's information criteria for models selections and the eigenvector analysis to control the special autocorrelation. The spatial structure was equal to 0.453, Moran's I, and require 11 spatial filters. All models were significant and had adjustments rangi...

Effects of agriculture and topography on tropical amphibian species and communities

Ecological applications : a publication of the Ecological Society of America, Jan 4, 2018

Habitat loss is the greatest threat to the persistence of forest-dependent amphibians, but it is ... more 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 diversity and endemism of amphibians, but little is known about the specific responses of many of these species to landscape features. In this paper, we quantify the response of amphibian species and communities to landscape-scale characteristics in streams within the fragmented Brazilian Atlantic Forest. We surveyed amphibian communities during a rainy season in 50 independent stream segments using Standardized Acoustic and Visual Transect Sampling (active) and Automated Acoustic Recorders (passive) methods. We developed a hierarchical multi-species occupancy model to quantify the influence of landscape-scale characteristics (forest cover, a...

Threshold responses of Amazonian stream fishes to timing and extent of deforestation

Conservation biology : the journal of the Society for Conservation Biology, Jan 6, 2017

Deforestation is a primary driver of biodiversity change through habitat loss and fragmentation. ... more Deforestation is a primary driver of biodiversity change through habitat loss and fragmentation. Stream biodiversity may not respond to deforestation in a simple linear relationship. Rather, threshold responses to extent and timing of deforestation may occur. Identification of critical deforestation thresholds is needed for effective conservation and management. We tested for threshold responses of fish species and functional groups to degree of watershed and riparian zone deforestation and time since impact in 75 streams in the western Brazilian Amazon. We used remote sensing to assess deforestation from 1984 to 2011. Fish assemblages were sampled with seines and dip nets in a standardized manner. Fish species (n = 84) were classified into 20 functional groups based on ecomorphological traits associated with habitat use, feeding, and locomotion. Threshold responses were quantified using threshold indicator taxa analysis. Negative threshold responses to deforestation were common and...

Shared or distinct responses between intermediate and satellite stream fish species in an altered Amazonian River?

Environmental Biology of Fishes, 2017

Environmental and spatial variables can distinctly influence the occupancy frequency distribution... more Environmental and spatial variables can distinctly influence the occupancy frequency distributions in stream fish. From a metacommunity context, we tested the following hypothesis, intermediate species are governed by dispersal and niche-based processes; in contrast, satellite species are governed by niche-based processes. To test this, we separately analyzed three data sets, the entire metacommunity, the intermediate species and the satellite species, using a forward selection of explanatory variables, and a partial Redundancy Distance Analysis. The fish and 31 variables of 52 stream reaches of a Brazilian river basin in the Western Amazon were collected during the dry period of 2012. The results for all of the data set revealed two different patterns: on one side, satellite species revealed that niche and dispersal-based processes were the most important; on the other side, for intermediate species and for all of the species set, only dispersal-based processes were the most important. For the data set including all of the species and the intermediate species, the variance was explained mainly by landscape scale variables. By contrast, the variance within the satellite species set was explained by local scale variables. Management efforts for intermediate species should be taking at larger scale, but they are usually less critical for the maintenance of aquatic biodiversity; on the other hand, management efforts for satellite species should be taken at smaller scale and based on specific biological and ecological information for the focal species.

The stream fish fauna from the rio Machado basin, Rondônia State, Brazil

Check List, 2013

The rio Machado (also known as Ji-Paraná) is a tributary of the rio Madeira in the Amazon basin. ... more The rio Machado (also known as Ji-Paraná) is a tributary of the rio Madeira in the Amazon basin. Currently, the rio Madeira contains the greatest fish species richness of the world, with approximately 1,000 species. The present study presents the fish inventory from streams of the rio Machado basin. In total, 75 stream reaches, 80 meter-length, randomly selected, were sampled in 2011 (August to October) and 2012 (June to July). Overall, 22,875 fish in eight orders, 32 families, 89 genera, and 140 species were collected. Richness estimators indicate that almost 90% of the expected richness was registered. The great majority of specimens (52.2%) was represented by small sized piabas such as Serrapinnus aff. notomelas, Moenkhausia collettii, Serrapinnus microdon, and Hemigrammus melanochrous. Of the total richness, 25 species were restricted to 9°00’ S and 10°00’ S; among them, 14 were exclusive to the lower portion of the basin, which exhibits the larger proportion of native vegetatio...

Florestas como promotoras de complementaridade funcional na ictiofauna da Amazônia Ocidental

O desmatamento e a degradação da vegetação natural acarretam perdas de biodiversidade, tanto de c... more O desmatamento e a degradação da vegetação natural acarretam perdas de biodiversidade, tanto de comunidades terrestres quanto aquáticas, podendo alterar os padrões de abundância e riqueza, bem como os padrões funcionais das comunidades. A estrutura funcional das comunidades é comumente medida através da variabilidade nos traços funcionais, que pode demonstrar padrões de complementaridade ou redundância. Atributos ecomorfólogicos podem ser utilizados como traços funcionais. Neste estudo, testamos a influência de variáveis ambientais (escala local e paisagem) e espacial (distância fluvial entre trechos) na estrutura funcional da comunidade de peixes de riachos Amazônicos em trechos inseridos em microbacias com diferentes graus de desmatamento. Foram amostrados 75 trechos de riachos da bacia do Rio Machado (Rondônia, Brasil) nos períodos de Agosto a Outubro de 2011 e de Junho a Julho de 2012. Foram realizadas medidas morfológicas em 137 espécies, das quais foram obtidos seis traços eco...

Spatial non-stationarity in the distribution of fish species richness of tropical streams

Community Ecology, Nov 22, 2022

Transferability of Bioindicators Based on Fish Assemblages to Detect Human Impacts on Stream Ecosystems is Influenced by Spatial Distance and Environmental Differences

SSRN Electronic Journal

A Ecologia De Peixes De Riacho Sob a Perspectiva Da Ecologia De Paisagens

Oecologia Australis

Landscape ecology emphasizes the interaction between spatial patterns and ecological processes, i... more Landscape ecology emphasizes the interaction between spatial patterns and ecological processes, i.e., the consequences of spatial heterogeneity across various scales. It is an interdisciplinary science that seeks to understand the relationships between ecological patterns and processes considering different spatial and temporal scales. This understanding has been supported by the rapid development of a methodological framework, largely based on Geographic Information Systems (GIS). Thus, it has allowed understanding how ecological processes are affected by anthropogenic activities that trigger profound changes in ecosystems, such as habitat loss and fragmentation. Although commonly applied to studies in terrestrial ecosystems, there is a time lag in both theoretical development and methodological adaptation of landscape ecology applied to studies in streams, especially in Brazil. Methodological adaptations are necessary considering the particularities of aquatic environments in rela...

Habitat use, trophic, and occurrence patterns of Inpaichthys kerri and Hyphessobrycon vilmae (Pisces: Characidae) in Amazonian streams

Fish ecomorphology and diet can help us to understand species response to impacts and coexistence... more Fish ecomorphology and diet can help us to understand species response to impacts and coexistence patterns. Thus, we developed a comparative analysis of ecomorphology and diet of Inpaichthys kerri and Hyphessobrycon vilmae and tested for environmental variables that explain their abundance in headwater streams. We sampled streams from the Aripuanã River basin, Mato Grosso State, Brazil. We sampled environmental variables following a standardized protocol and used 30 and 80 individuals from each species to obtain ecomorphological attributes and feeding index, respectively. To identify environmental variables that influence species abundance, we developed generalized additive mixed models. Inpaichthys kerri presented broader and deeper caudal peduncles, more dorsal eyes, and larger fins, besides the lower consumption of aquatic insects, algae, and detritus when compared to H. vilmae. Inpaichthys kerri was more abundant in fast waters with little amounts of marginal grasses, conditions...

Characterization and assessment of aquatic environments in the Turvo/Grande basin

ABSTRACT The Turvo/Grande basin is located in the northwestern portion of the São Paulo State and... more ABSTRACT The Turvo/Grande basin is located in the northwestern portion of the São Paulo State and is composed by 64 municipalities, with a drainage area of 15.925 km2. Total human population accounts for 1,3 millions inhabitants, with 91% located in urban areas. This predominance of urban populations with the low availability of surface water, low rates of natural vegetation coverage, and soils with high potential to erosion can be cited as factors that threat the quality and quantity of aquatic resources of the basin. In this chapter, we described the main biotic and abiotic features of the Turvo/Grande basin and provided an evaluation on the present condition of streams, main rivers, and marginal lagoons, aiming to identify the major threats to the aquatic resources of the basin and provide suggestions to management. The main threat to small streams is physical habitat degradation, mostly derived from the lack of forest vegetation along the riparian buffer. For main rivers, metal contamination is of high concern, additionally to siltation, that is related to the lack of forest coverage in the basin. Knowledge on the marginal lagoons dynamics is still scarce, albeit preliminary efforts have revealed high biodiversity of fish and aquatic macrophytes, as also the existence of complex biotic interactions yet to be elucidated. Riparian forest recovery, soil conservation, control of metals and other contaminants, and floodplain protection must be of utmost interest to managers regarding aquatic resource conservation of such important river basin.

Você conhece a represa

A Represa Municipal de Sao Jose do Rio Preto, localizada no centro da cidade, e um ambiente aquat... more A Represa Municipal de Sao Jose do Rio Preto, localizada no centro da cidade, e um ambiente aquatico inserido na paisagem urbana e oferece varios servicos ecossistemicos, tais como fonte de agua para abastecimento e local de lazer. Os ambientes naturais urbanos tem sido pouco considerados em projetos de conservacao, uma vez que sao vistos apenas como equipamentos urbanos e nao como ecossistemas. Este projeto pretende levar a populacao que frequenta o parque da Represa informacoes sobre o ecossistema aquatico da Represa, com o intuito de desenvolver nas pessoas a consciencia da preservacao do ecossistema. Durante varios domingos, ao longo do ano, serao realizadas exposicoes no parque da represa, onde sao abordados varios aspectos ecologicos do ecossistema aquatico (p.ex.: a bacia hidrografica, as condicoes ambientais, a comunidade planctonica; a comunidade de peixes; as aves da represa e outros). As pessoas que participam do projeto estao distribuidas em todas as faixas etarias. Nos ...

Estradas, alagados antrópicos, peixes e a fragmentação de redes fluviais em uma paisagem agrícola do Nordeste do Pará

Badly planned roads crossing streams can generate small impoundments in channel segments upstream... more Badly planned roads crossing streams can generate small impoundments in channel segments upstream these crossings, turning lotic environments into lentic ones. The aim of this work was to study the diversity and functional structure of fish communities in anthropic impoundments in northeastern Pará state. These impoundments are formed due to roads construction on the riverine network, with large or small impacts on the hydrological connectivity, subject that is largely ignored for Neotropical lotic systems. Eighteen reaches were sampled in seven streams: six crossed by roads, and one not crossed by roads, used as a reference. Five streams are located in the cities of Igarapé-Açu and Marapanim in an agricultural landscape, and two in the city of São Francisco do Pará in a forest matrix. Five of six streams crossed by roads showed the formation of large impounded areas. In these locations three reaches were selected to sample fish: one upstream, one inside, and another one downstream ...

Taxonomic and functional turnover of Amazonian stream fish assemblages is determined by deforestation history and environmental variables at multiple scales

Neotropical Ichthyology, 2021

High rates of deforestation, either in the past or the present, affect many of the ecological pro... more High rates of deforestation, either in the past or the present, affect many of the ecological processes in streams. Integrating deforestation history and the current landscape structure enhances the evaluation of ecological effects of land-use change. This is especially true when contemporary landscape conditions are similar but the temporal path to those conditions differs. One approach that has shown promise for evaluating biodiversity responses over time and space is the β-diversity partitioning, which combines taxonomic and functional trait-based approaches. We tested hypotheses related to stream fish assemblages’ turnover in watersheds with different environmental conditions and deforestation histories. We sampled fish from 75 watersheds in the Machado River basin, Brazil, and environmental factors were quantified at multiple scales. Taxonomic turnover was higher than expected by chance, whereas functional turnover was lower than expected by the observed taxonomic turnover, ind...

Thresholds of freshwater biodiversity in response to riparian vegetation loss in the Neotropical region

Journal of Applied Ecology, 2020

When roads cross streams: fish assemblage responses to fluvial fragmentation in lowland Amazonian streams

Neotropical Ichthyology, 2020

Roads affect biodiversity by increasing mortality rates, habitat loss, and natural landscape frag... more Roads affect biodiversity by increasing mortality rates, habitat loss, and natural landscape fragmentation. Poorly installed culverts can impound streams, changing the environmental conditions, and affecting aquatic communities. We evaluated the effects of road crossings on the taxonomic composition and functional structure of fish assemblages in lowland eastern Amazonian streams, Brazil. We tested the hypothesis that the presence of road-derived impoundments affects assemblage taxonomic and functional composition and structure. Two predictions were addressed: (1) Species and functional group composition will differ in impounded reaches in relation to lotic reaches; (2) Assemblages in downstream lotic reaches will be richer in species and functional groups in relation to upstream lotic and impoundment reaches. We sampled five streams crossed by roads presenting impoundment formation, conducted by visual census (day, dusk, and night) in 200 m line transects. Assemblage composition fr...

Habitat use, trophic, and occurrence patterns of Inpaichthys kerri and Hyphessobrycon vilmae (Pisces: Characidae) in Amazonian streams

Neotropical Ichthyology, 2020

Fish ecomorphology and diet can help us to understand species response to impacts and coexistence... more Fish ecomorphology and diet can help us to understand species response to impacts and coexistence patterns. Thus, we developed a comparative analysis of ecomorphology and diet of Inpaichthys kerri and Hyphessobrycon vilmae and tested for environmental variables that explain their abundance in headwater streams. We sampled streams from the Aripuanã River basin, Mato Grosso State, Brazil. We sampled environmental variables following a standardized protocol and used 30 and 80 individuals from each species to obtain ecomorphological attributes and feeding index, respectively. To identify environmental variables that influence species abundance, we developed generalized additive mixed models. Inpaichthys kerri presented broader and deeper caudal peduncles, more dorsal eyes, and larger fins, besides the lower consumption of aquatic insects, algae, and detritus when compared to H. vilmae. Inpaichthys kerri was more abundant in fast waters with little amounts of marginal grasses, conditions...

Mining activity in Brazil and negligence in action

Perspectives in Ecology and Conservation, 2020

h i g h l i g h t s • A new disaster in Brazil involving the rupture of a tailings dam reopened t... more h i g h l i g h t s • A new disaster in Brazil involving the rupture of a tailings dam reopened the discussions about socio-environmental impact. • The absence of actions by the companies and the lack of a management plan can imperil the efforts for environmental recovery. • The slowdown of Brazilian environmental legislation can generate a future darker scenario.

Stream fish from recently deforested basins in the Meridional Amazon, Mato Grosso, Brazil

Biota Neotropica, 2020

The replacement of tropical forests to production systems is one of the leading causes of riverin... more The replacement of tropical forests to production systems is one of the leading causes of riverine ecosystem alterations. However, current assemblages' composition may also result from the time since these transformations have begun. Therefore, the knowledge of diversified historical scenarios can facilitate the accomplishment of actions that involve the aquatic environments recovery. In this study, an inventory of stream fish was carried out in basins whose deforestation was intensified in the last 20 years, to compose a baseline for ecological and taxonomic studies. The habitat, physical and chemical variables, and the fish assemblages from 60 streams in the northwest region of the state of Mato Grosso, in the Aripuanã and Juruena river basins, were sampled with standardized procedures. For a total of 130 species, a numerical predominance of small-sized Characidae and great rarity were registered, with 50 species represented by less than ten individuals and 19 singletons. Approximately 15% of the sampled taxa were identified only at the generic level, and for several taxa, more detailed taxonomic and molecular studies are required in order to achieve satisfactory identifications. None threatened species were so far reported. On the other hand, two specimens of non-native species were sampled. Although habitat quality is higher in forested streams, no differences in the species richness were registered when compared to the pasture with riparian forest streams or to more deforested streams. However, abundance was greater in these last two streams groups as a result of small-sized characins dominance.

How deforestation drives stream habitat changes and the functional structure of fish assemblages in different tropical regions

Aquatic Conservation: Marine and Freshwater Ecosystems, 2019

1. Deforestation can modify stream habitat and the functional structure of fish assemblages. The ... more 1. Deforestation can modify stream habitat and the functional structure of fish assemblages. The aims of this study were (a) to identify whether deforestation has a similar effect on local habitats from two biogeographically distinct river basins in a tropical region; (b) to identify how fish trait-habitat relationships were influ

A multiple hypothesis approach to explain species richness patterns in neotropical stream-dweller fish communities

PloS one, 2018

Several hypotheses are used to explain species richness patterns. Some of them (e.g. species-area... more Several hypotheses are used to explain species richness patterns. Some of them (e.g. species-area, species-energy, environment-energy, water-energy, terrestrial primary productivity, environmental spatial heterogeneity, and climatic heterogeneity) are known to explain species richness patterns of terrestrial organisms, especially when they are combined. For aquatic organisms, however, it is unclear if these hypotheses can be useful to explain for these purposes. Therefore, we used a selection model approach to assess the predictive capacity of such hypotheses, and to determine which of them (combined or not) would be the most appropriate to explain the fish species distribution in small Brazilian streams. We perform the Akaike's information criteria for models selections and the eigenvector analysis to control the special autocorrelation. The spatial structure was equal to 0.453, Moran's I, and require 11 spatial filters. All models were significant and had adjustments rangi...

Effects of agriculture and topography on tropical amphibian species and communities

Ecological applications : a publication of the Ecological Society of America, Jan 4, 2018

Habitat loss is the greatest threat to the persistence of forest-dependent amphibians, but it is ... more 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 diversity and endemism of amphibians, but little is known about the specific responses of many of these species to landscape features. In this paper, we quantify the response of amphibian species and communities to landscape-scale characteristics in streams within the fragmented Brazilian Atlantic Forest. We surveyed amphibian communities during a rainy season in 50 independent stream segments using Standardized Acoustic and Visual Transect Sampling (active) and Automated Acoustic Recorders (passive) methods. We developed a hierarchical multi-species occupancy model to quantify the influence of landscape-scale characteristics (forest cover, a...

Threshold responses of Amazonian stream fishes to timing and extent of deforestation

Conservation biology : the journal of the Society for Conservation Biology, Jan 6, 2017

Deforestation is a primary driver of biodiversity change through habitat loss and fragmentation. ... more Deforestation is a primary driver of biodiversity change through habitat loss and fragmentation. Stream biodiversity may not respond to deforestation in a simple linear relationship. Rather, threshold responses to extent and timing of deforestation may occur. Identification of critical deforestation thresholds is needed for effective conservation and management. We tested for threshold responses of fish species and functional groups to degree of watershed and riparian zone deforestation and time since impact in 75 streams in the western Brazilian Amazon. We used remote sensing to assess deforestation from 1984 to 2011. Fish assemblages were sampled with seines and dip nets in a standardized manner. Fish species (n = 84) were classified into 20 functional groups based on ecomorphological traits associated with habitat use, feeding, and locomotion. Threshold responses were quantified using threshold indicator taxa analysis. Negative threshold responses to deforestation were common and...

Shared or distinct responses between intermediate and satellite stream fish species in an altered Amazonian River?

Environmental Biology of Fishes, 2017

Environmental and spatial variables can distinctly influence the occupancy frequency distribution... more Environmental and spatial variables can distinctly influence the occupancy frequency distributions in stream fish. From a metacommunity context, we tested the following hypothesis, intermediate species are governed by dispersal and niche-based processes; in contrast, satellite species are governed by niche-based processes. To test this, we separately analyzed three data sets, the entire metacommunity, the intermediate species and the satellite species, using a forward selection of explanatory variables, and a partial Redundancy Distance Analysis. The fish and 31 variables of 52 stream reaches of a Brazilian river basin in the Western Amazon were collected during the dry period of 2012. The results for all of the data set revealed two different patterns: on one side, satellite species revealed that niche and dispersal-based processes were the most important; on the other side, for intermediate species and for all of the species set, only dispersal-based processes were the most important. For the data set including all of the species and the intermediate species, the variance was explained mainly by landscape scale variables. By contrast, the variance within the satellite species set was explained by local scale variables. Management efforts for intermediate species should be taking at larger scale, but they are usually less critical for the maintenance of aquatic biodiversity; on the other hand, management efforts for satellite species should be taken at smaller scale and based on specific biological and ecological information for the focal species.

The stream fish fauna from the rio Machado basin, Rondônia State, Brazil

Check List, 2013

The rio Machado (also known as Ji-Paraná) is a tributary of the rio Madeira in the Amazon basin. ... more The rio Machado (also known as Ji-Paraná) is a tributary of the rio Madeira in the Amazon basin. Currently, the rio Madeira contains the greatest fish species richness of the world, with approximately 1,000 species. The present study presents the fish inventory from streams of the rio Machado basin. In total, 75 stream reaches, 80 meter-length, randomly selected, were sampled in 2011 (August to October) and 2012 (June to July). Overall, 22,875 fish in eight orders, 32 families, 89 genera, and 140 species were collected. Richness estimators indicate that almost 90% of the expected richness was registered. The great majority of specimens (52.2%) was represented by small sized piabas such as Serrapinnus aff. notomelas, Moenkhausia collettii, Serrapinnus microdon, and Hemigrammus melanochrous. Of the total richness, 25 species were restricted to 9°00’ S and 10°00’ S; among them, 14 were exclusive to the lower portion of the basin, which exhibits the larger proportion of native vegetatio...

Florestas como promotoras de complementaridade funcional na ictiofauna da Amazônia Ocidental

O desmatamento e a degradação da vegetação natural acarretam perdas de biodiversidade, tanto de c... more O desmatamento e a degradação da vegetação natural acarretam perdas de biodiversidade, tanto de comunidades terrestres quanto aquáticas, podendo alterar os padrões de abundância e riqueza, bem como os padrões funcionais das comunidades. A estrutura funcional das comunidades é comumente medida através da variabilidade nos traços funcionais, que pode demonstrar padrões de complementaridade ou redundância. Atributos ecomorfólogicos podem ser utilizados como traços funcionais. Neste estudo, testamos a influência de variáveis ambientais (escala local e paisagem) e espacial (distância fluvial entre trechos) na estrutura funcional da comunidade de peixes de riachos Amazônicos em trechos inseridos em microbacias com diferentes graus de desmatamento. Foram amostrados 75 trechos de riachos da bacia do Rio Machado (Rondônia, Brasil) nos períodos de Agosto a Outubro de 2011 e de Junho a Julho de 2012. Foram realizadas medidas morfológicas em 137 espécies, das quais foram obtidos seis traços eco...