Abstract Damming is one of the main causes global decline in freshwater biodiversity. Yet, many hydroelectric dams are being built (or planned) Neotropics, where high species diversity and lack basic ecological knowledge provide a major obstacle to understanding effects this environmental change, which has been mostly described from perspective taxonomic change. However, approach does not account for biological function. Trait‐based analysis provides an alternative bioassessment. We assessed...

The earth's major mountain ranges provide opportunities to assess the effects of altitude and land use on stream fauna, but many basic patterns are still undescribed. Macroinvertebrates were therefore sampled from rifle marginal habitats 45 streams in three regions Ecuadorian Andes. Assemblage structure richness assessed relation habitat character, water chemistry catchment use. Land varied humid montane forest Western Eastern Cordillera transition Paramo Central Valley. However, c. 30 %...

Abstract We employed the trophic upsurge hypothesis as an analytical framework to describe response of Neotropical fish communities terrestrial inundation associated with river damming. Data were collected for impact assessment Peixe Angical Dam, Tocantins River, Brazil. Monthly surveys conducted at nine sites (seven upstream, two downstream) from 15 months before 20 after dam closure and a follow‐up survey 60–83 closure. Fish responses differed in timing magnitude across sites. In new...

Natural ecological variability and analytical design can bias the derived value of a biotic index through variable influence indicator body-size, abundance, richness, ascribed tolerance scores. Descriptive statistics highlight this risk for 26 aquatic systems; detailed analysis is provided contrasting weighted-average indices applying example BMWP, which has best supporting data. Differences in body size between taxa from respective classes common feature some it represents trend ranging...

The construction of salmon redds represents a localized but intense disturbance to benthic substrate and associated flora fauna. Pink (Oncorhynchus gorbuscha) have fixed 2-y life cycle. Thus, their spawning run in Wolf Point Creek, 1st-order coastal stream southeast Alaska, alternates between high-density (odd years) low-density (even returns. During July August 1996 1998, counts returning fish were low (<2000 fish) with little evidence streambed by redd construction, whereas 1997, >10,000...

Dams are considered one of the most important threats to freshwater ecosystems. To date, assessments impact riverine impoundments based primarily on taxonomic approaches where little can be inferred about functional ecological change. We assessed damming in a cold region river fish community Alberta, Canada, by integrating and trait-based over time (before, during first 5 years, after years dam construction), considering longitudinal habitat environmental change created reservoir formation...

Abstract Neotropical freshwaters host some of the most biodiverse ecosystems in world and are among threatened by habitat alterations. The high number species lack basic ecological knowledge provide a major obstacle to understanding effects environmental change. We assessed impact dam closure on fish communities neotropical river applying simple descriptions community organizations: abundance distribution biomass comparison curves. Fish data were collected using gillnets during three...

Habitat manipulation for migratory fish is typically aimed at fulfilling particular life-cycle stages and rarely acknowledges the wider role of these in lotic ecosystems. Recent research, indicating importance salmon carcasses stream ecosystems Pacific Northwest has highlighted their potential contribution restoring degraded rivers. Previous research emphasised in-stream habitat features such as pools debris dams carcass retention mature river systems but other habitats not been well...

The predicted increase in wildfires associated with climate change poses a risk to freshwater biodiversity that may be exacerbated by river regulation. We studied the effects of wildfire and management on fish assemblages Atlantic-Mediterranean streams northern Portugal. Employing chronosquence survey covering an 18-year gradient impact-recovery from major fire events (ca. 100% catchment burnt), we assessed ecological response respect time since wildfire, interpreting context species traits...

Weighting family-level trait descriptions by taxon frequencies improved the accuracy of macroinvertebrate traits defined at both individual and community level compared with derived from proportionate inclusion all taxa. Applying a priori data on (i) national rarity (rarity model) (ii) frequency occurrence reference sites (quality model), deviation family was measured in relation to nonweighted null model. Overall, quality model more divergent than model, reflecting respective specific...

Streams formed in Glacier Bay, southeast Alaska, following glacial recession rapidly support populations of spawning salmon. Using both observational and experimental approaches, we examined the importance pink salmon ( Oncorhynchus gorbuscha ) carcasses for benthic macroinvertebrate communities, approximately 10 years after first colonized Wolf Point Creek, a first-order, lake-fed stream. Macroinvertebrate abundance on naturally accumulating stream channel was low, dominated by chironomids...

Summary Heino et al . ( ) identified the weak explanatory power of abundance data as an important limitation macroinvertebrate trait analysis. This may be artefact analytical design. The widespread practice combining logarithmically transformed with frequencies, log(x + 1)*(trait frequency), represents a nonlinear weighting opposed to expression abundances per se Because addition logarithmic is equivalent multiplication on arithmetic scale, summing these abundance‐weighted frequencies...

Abstract The increasing risk of wildfire has focused attention on the timescale impact and recovery river ecosystems methods for their bioassessment. An 18‐year pseudo time‐series was exploited to document patterns in benthic macroinvertebrate evaluate efficacy alternative metrics assess fire damage. Macroinvertebrates were surveyed by kick‐sampling data collected habitats. Details catchments collated as a GIS database. Macroinvertebrate richness abundance recovered rapidly, marked phase...