The effects of land use at different spatial scales on instream features in agricultural streams

Molina, Mariana C.; Roa‐Fuentes, Camilo A.; Zeni, Jaquelini O.; Casatti, Lílian

doi:10.1016/j.limno.2017.06.001

Cited by 48 publications

(26 citation statements)

References 45 publications

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“…We quantified land cover variables for the entire drainage network upstream of the sampling site (hereafter "total catchment") and within a 30-m buffer extending 300 m upstream and downstream from the sampling site (hereafter "immediate catchment"; see Supporting Information Figure S1) to capture potential landscape influences on stream fish assemblages (Frimpong et al, 2005;Molina, Roa-Fuentes, . Buffer zones at the immediate catchment scale are comparable to the way riparian buffers are measured according to Brazilian law.…”

Section: Environmental Variablesmentioning

confidence: 99%

Land cover, riparian zones and instream habitat influence stream fish assemblages in the eastern Amazon

Montag

Winemiller

Keppeler

et al. 2018

Ecology of Freshwater Fish

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The Amazon rainforest has experienced rapid land-use changes over the last few decades, including extensive deforestation that can affect riparian habitats and streams. The aim of this study was to assess responses of stream fish assemblages to deforestation and land cover change in the eastern Amazon. We expected that percentage of forest in the catchment is correlated with local habitat complexity, which in turn determines fish assemblage composition and structure. We sampled 71 streams in areas with different land uses and tested for relationships between stream fish assemblages and local habitat and landscape variables while controlling for the effect of inter site distance. Fish assemblage composition and structure were correlated with forest coverage, but local habitat variables explained more of the variation in both assemblage composition and structure than landscape variables.Inter site distance contributed to variance explained by local habitat and landscape variables, and the percentage of variance explained by the unique contribution of local habitat was approximately equivalent to the shared variance explained by all three factors in the model. In these streams of the eastern Amazon, fish assemblages were most strongly influenced by features of instream and riparian habitats, yet indirect effects of deforestation on fish assemblage composition and structure were observed even though intact riparian zones were present at most sites. Long-term monitoring of the hydrographic basin, instream habitat and aquatic fauna is needed to test for potential legacy effects and time lags, as well as assess species responses to continuing deforestation and land-use changes in the Amazon. Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for PROCAD/ CAPES funding (project no 88881.068425/2014-01), the graduate scholarship for TOB and senior internship scholarship for LFAM to conduct research at Texas A&M University (process 88881.119097/2016-1). The manuscript was improved during the review process by addressing the thoughtful comments from Philip Kaufmann and an anonymous reviewer.

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Section: Environmental Variablesmentioning

confidence: 99%

Land cover, riparian zones and instream habitat influence stream fish assemblages in the eastern Amazon

Montag

Winemiller

Keppeler

et al. 2018

Ecology of Freshwater Fish

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“…Changes in stream habitat caused by deforestation have been observed in several studies (Allan & Castillo, ; Leitão et al, ; Molina et al, ; Scott & Helfman, ), but most of these studies were developed at smaller scales and without a biogeographical comparative approach, such as the one applied in this study. Native forest plays a vital role in physical channel heterogeneity by supplying large wood, branches, litter and roots to aquatic systems (Allan, ; Jackson et al, ).…”

Section: Discussionmentioning

confidence: 96%

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

Zeni

Pérez‐Mayorga

Roa‐Fuentes

et al. 2019

Aquatic Conservation

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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 influenced by deforestation; and (c) to compare functional redundancy patterns in these basins. Environmental and biological variables were obtained for 160 stream reaches, 85 located in the Alto Paraná River basin and 75 in the Machado River basin. Traits were associated with body size, habitat preference, food items and foraging period. Linear models were constructed to verify the environmental convergence of habitats across streams from the Alto Paraná and the Machado basins. An RLQ and a fourth‐corner analysis were conducted to investigate how deforestation affected habitat variables and trait–habitat relationships. The nearest relative index (NRI) was used as a functional redundancy measure. Deforestation led to a similar habitat gradient from streams with a higher proportion of coarse roots in more forested catchments to streams with streamside grasses, bare soil and unconsolidated substrate in more deforested catchments; however, a general pattern of fish trait–habitat relationships was not identified across basins. Functional redundancy was associated with a long history of habitat loss in the Alto Paraná streams, whereas functional complementarity was related to more recent and less intense habitat loss in Machado streams. We believe that differences in regional species pools and historical processes between the basins influenced the fish functional responses to deforestation. Nevertheless, the results highlighted the importance of stream habitat heterogeneity and the presence of preserved forest fragments in a region to prevent the loss of unique traits. Decision‐makers should therefore maintain large forest fragments and restore riparian forests to preserve stream habitat and the functional structure of fish assemblages.

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“…Forested riparian zones could feasibly buffer stream habitats to changes in drainage basin land use (and thus cause a lack of relationship between instream and drainage basin attributes), but almost all of the study sites lacked intact riparian forest. Furthermore, a recent study from the same region (Molina et al, 2017) found that forested riparian zones had no effect on instream habitat and suggested that riparian zones were not sufficient to buffer streams from changes in land use in the drainage basin. That being said, we detected evidence of a time lag or legacy effect, thus the effects of rapid conversion of the landscape for biofuel production on instream habitat and biodiversity are presumably not yet fully evident.…”

Section: Magnitude Of Change In Drainage Basin Land Use Was Not Corrementioning

confidence: 99%

“…Cumulative land-use changes for the study area over the past century result in less than 4% of native forest remaining in small and isolated fragments (Nalon, Mattos, & Franco, 2008). Moreover, streams from this area have insignificant amount of riparian forest, because most of the area has been used by livestock grazing (Molina, Roa-Fuentes, Zeni, & Casatti, 2017). Consequently, most of the streams show high physical degradation and relatively homogenous fish assemblages (Casatti et al, 2006(Casatti et al, , 2015.…”

Section: Study Areamentioning

confidence: 99%

Effects of pasture conversion to sugarcane for biofuel production on stream fish assemblages in tropical agroecosystems

2017

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One of the main causes of biodiversity loss in aquatic ecosystems is instream habitat change associated with land‐use change in the drainage basin. Biofuel crop production is an increasingly important driver of land‐use change in existing agricultural drainage basins. Conceptually, biofuels such as sugarcane (Saccharum spp.: Poaceea) can provide a sustainable alternative to fossil fuels, but little is known about the consequences of biofuel crop production for biodiversity. Thus, our aim was to investigate if and how the degree of further environmental changes at regional and local scales can influence taxonomic and functional structure of fish assemblages in agroecosystem streams. We quantified drainage basin land use, instream and riparian habitat, and fish assemblages in 38 agroecosystem streams in Brazil with drainage basins experiencing rapid expansion of sugarcane production, and calculated degree of environmental change and corresponding response in taxonomic and functional structure of stream fish assemblages. Procrustes and redundancy analyses tested for correlation between land use and instream habitat and environmental factors correlated with fish assemblage structure, respectively. Previous studies demonstrated relationships between land‐use change, instream habitat change and taxonomic and functional structure of stream fish assemblages. Therefore, we used regression to test the hypothesis that degree of environmental change is positively correlated with magnitude of change in taxonomic and functional structure of fish assemblages. Primary gradients of environmental change included conversion of pasture to sugarcane and reduction of stream width, depth and volume. Although drainage basin and instream attributes were not correlated within a year, we detected a legacy effect of land use on instream habitat. The degree of environmental change was not significantly correlated with taxonomic or functional changes in stream fish assemblages in most cases. However, abundances of resistant taxa increased, whereas nektonic functional groups decreased, and the biological response also presented evidence of a legacy effect. Our findings demonstrate that instream habitat and aquatic biodiversity in streams with agricultural drainage basins undergoing rapid conversion to biofuel production likely will not experience the full magnitude of responses in the short term. Therefore, repeated sampling of sufficient duration to account for legacy effects or time lags is needed to test for effects of biofuel expansion on biodiversity, and similarly to assess whether management practices such as riparian zone preservation can benefit biodiversity in agroecosystems.

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The effects of land use at different spatial scales on instream features in agricultural streams

Cited by 48 publications

References 45 publications

Land cover, riparian zones and instream habitat influence stream fish assemblages in the eastern Amazon

Land cover, riparian zones and instream habitat influence stream fish assemblages in the eastern Amazon

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

Effects of pasture conversion to sugarcane for biofuel production on stream fish assemblages in tropical agroecosystems

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