Cited by 180Fish biology, ecology, and behaviorFish Ecology and Management StudiesFreshwater macroinvertebrate diversity and ecology

The DOI matches its Crossref record; 36 of the 36 references it cites were found in a registry or an index; none of the 39 sources its claims cite is checked for support yet.

Effects of deforestation on fish community structure in Ecuadorian Amazon streams

Open access
Bojsen, B. H., Barriga, R.·2002·Freshwater Biology

Abstract

SUMMARY 1. There is little information on the impacts of deforestation on the fish fauna in neotropical streams, and on parameters influencing species diversity and community structure of fish. We analysed these aspects in 12 stream sites in the Ecuadorian Amazon. The stream sites represented a large gradient in canopy cover and were located in an area of fragmented forest. While some streams had been deforested, they had not suffered gross degradation of the habitat. 2. The species richness of stream fish was not related to deforestation. Local fish diversity (Fisher's Alpha) was positively related to the surface area of stream pools (m 2). Beta diversity was higher among forested than deforested sites, indicating greater heterogeneity in species composition among forested than deforested sites. The percentage of rare species was positively correlated with canopy cover. 3. Total fish density increased with deforestation, and the fish community changed from dominance by omnivorous and insectivorous Characiformes at forested sites to dominance of periphyton‐feeding loricariids at deforested sites. 4. Multidimensional statistical analysis of fish community structure showed that six environmental variables (the area of stream bottom covered by leaves, relative pool area, particulate organic matter, mean depth, conductivity and suspended solids) were related to the ordination axes. The presence of leaves, which was strongly correlated to canopy cover, was the variable most closely related to fish community structure, while relative pool area was the second strongest variable. Thus, fish community structure was strongly affected by deforestation.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

In 12 Ecuadorian Amazon stream sites spanning a canopy-cover gradient, deforestation did not reduce fish species richness but increased total fish density and shifted biomass dominance toward periphyton-feeding loricariids. Fish community structure was most strongly related to leaf cover on the stream bottom, followed by relative pool area.

Key findings

  • Species richness was not related to deforestation: 42 species were caught in deforested sites versus 35 in forested sites, with mean species richness 20 versus 15 and mean Fisher’s Alpha 3.34 versus 2.92, neither significantly different.
  • Beta diversity was higher among forested than deforested sites (Whittaker’s Beta 1.31 versus 1.12; Routledge’s Beta 0.52 versus 0.22), and the percentage of rare species was positively correlated with canopy cover (r = 0.62*).
  • Total fish density increased with deforestation, while total biomass was not significantly related to canopy cover (P = 0.08); Loricariidae made up 29% of biomass in deforested sites versus 5% in forested sites.
  • Correspondence analysis linked fish community structure most strongly to leaf cover on the stream bottom (axis 1 correlation 0.90*), with relative pool area, mean depth, conductivity, and suspended solids also related to axis 2.

Methods

  • The study sampled 12 sites in nine headwater streams (orders 1–3) in the upper Rio Napo catchment, Ecuadorian Amazon; six sites were forested (canopy cover >50%) and six deforested (canopy cover <50%), with canopy cover ranging from 6 to 82%.
  • Fish were sampled in 1999 during wet and dry seasons using push seine, gill net, and minnow traps; density and biomass estimates included active and gill-net fishing, while trap catches were excluded from quantitative estimates and used only for species richness.
  • Analyses included Fisher’s Alpha diversity, beta diversity indices, PCA on 27 environmental variables, DCA/CA ordination of fish assemblage data, and Spearman/Pearson correlations with habitat variables.

Limitations

  • The paper states that fish abundance data are semiquantitative because none of the sampling techniques used are truly quantitative, and trap catches were excluded from density and biomass estimates.
  • The authors note that distinguishing stream-size effects from deforestation effects is difficult, and that their study area involved small-scale forest fragmentation rather than clear cutting with gross habitat degradation.
  • The paper states it did not demonstrate increased periphyton productivity with declining canopy cover, only higher periphyton biomass and likely light availability; evident limitations include the small sample of six sites per category and the correlational, single-timeframe design.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1046/j.1365-2427.2002.00956.x

Cites

36 of 36 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Verification

Claims the paper makes

70 Own result · 39 Own interpretation · 16 No full text of the sources · 13 No basis given · 6 Own method · 5 Sources not found · 4 Not checked yet

Show all 104 claims

  • It may state two separate claims as one. 26
  • Probably not a substantial claim. 28
49 of 49
  • The paper relies on this without support.

    Periphyton-feeding fish are common in Neotropical streams.

    “Because periphyton-feeding fish are common in Neotropical streams, we hypothesised that the increased dominance of periphyton-feeding fishes would be a consequence of deforestation.”
  • The paper relies on this without support.

    Little information is available on the influence of small-scale deforestation (fragmentation of forest by subsistence farmers) on stream fish communities in the Amazon and elsewhere.

    “Little information is available on the influence of small-scale deforestation (fragmentation of forest by subsistence farmers) on stream fish communities in the Amazon and elsewhere.”
  • The paper relies on this without support.

    The deforested streams had not suffered gross degradation of the habitat.

    “While some streams had been deforested, they had not suffered gross degradation of the habitat.”
  • The paper relies on this without support.

    It is possible to identify four major pool habitats (edge, bottom, surface and middle), while riffles have only the bottom and edge habitat.

    “It is possible to identify four major pool habitats (edge, bottom, surface and middle), while riffles have only the bottom and edge habitat.”
  • The authors state this as an assumption.

    The positive relationship between total fish biomass and relative pool area reflects space limitation.

    “Although total fish biomass was positively related to relative pool area, but not to absolute pool area, we assume that this relationship reflects space limitation.”
  • The paper relies on this without support.

    There are large differences in the body size of tropical stream fish and small individuals often dominate the fauna.

    “There are large differences in the body size of tropical stream fish and small individuals often dominate the fauna.”
  • The paper relies on this without support.

    Several fish species use fallen leaves for feeding and shelter.

    “Finally, several species use fallen leaves for feeding and shelter, making them an important structural and functional parameter.”
  • The paper relies on this without support.

    Opposing patterns (positive and negative effects of deforestation) have been found for species richness.

    “The same opposing patterns were found for species richness.”
  • The paper relies on this without support.

    Pools are a heterogeneous habitat, with low current velocity and often rich in allochthonous food resources, which are favoured by many fish species.

    “As already discussed, pools are a heterogeneous habitat, with low current velocity and often rich in allochthonous food resources, which are favoured by many fish species.”
9 of 9

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

4 of 4

Citations

Cites

Show all 35 references

Research works printed but not linked: 1

  1. Castro R.M.C., 1997, The fish fauna from a small forest stream of the upper Paraná River basin, southeastern Brazil, Ichthyological Exploration of Freshwaters, 7, 337

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Metadata

Authors
Bojsen, B. H., & Barriga, R.
Affiliations
  • University of Copenhagen (DK)
  • National Polytechnic School (EC)
Corresponding author
Bojsen, B. H.
Venue
Freshwater Biology
Publisher
Wiley
Published
2002-10-25
Volume
47
Issue
11
Pages
2246-2260
ISSN
  • 0046-5070 (ISSN-L)
  • 1365-2427
OpenAlex
W2109533734
Cited by
180
References
35
Citations by year
2026: 2 · 2025: 10 · 2024: 7 · 2023: 7 · 2022: 13 · 2021: 16 · 2020: 10 · 2019: 11 · 2018: 13 · 2017: 13 · 2016: 9 · 2015: 13 · 2014: 5 · 2013: 8 · 2012: 5
FWCI
1.56
Type
journal article
Language
en
Open access
Locations
  • Freshwater Biology (publishedVersion)
  • Research at the University of Copenhagen (University of Copenhagen) (submittedVersion)
Funders
  • Udenrigsministeriet
  • Rådet for Udviklingsforskning
  • Danish International Development Agency
Topics
  • Physical Sciences › Environmental Science › Nature and Landscape Conservation › Fish biology, ecology, and behavior
  • Physical Sciences › Environmental Science › Nature and Landscape Conservation › Fish Ecology and Management Studies
  • Physical Sciences › Environmental Science › Ecology › Freshwater macroinvertebrate diversity and ecology
Keywords
deforestation, fish community structure, Amazonian streams, canopy cover, beta diversity, species richness, fish density, Characiformes, Loricariidae, leaf cover, stream pools, habitat heterogeneity, forest fragmentation, Neotropical streams

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