Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Multi-scale assessment of human-induced changes to Amazonian instream habitats
AU - Gontijo Leal, Cecilia
AU - Pompeu, Paulo Santos
AU - Gardner, Toby Alan
AU - Leitao, Rafael
AU - Hughes, Robert
AU - Kaufmann, Phil
AU - Zuanon, Jansen
AU - de Paula, Felipe R.
AU - de Barros Ferraz, Silvio Frosini
AU - Thomson, James R.
AU - Mac Nally, Ralph
AU - Ferreira, Joice
AU - Barlow, Bernard Josiah
PY - 2016/10/31
Y1 - 2016/10/31
N2 - ContextLand use change and forest degradation have myriad effects on tropical ecosystems. Yet their consequences for low-order streams remain very poorly understood, including in the world´s largest freshwater basin, the Amazon.ObjectivesDetermine the degree to which physical and chemical characteristics of the instream habitat of low-order Amazonian streams change in response to past local- and catchment-level anthropogenic disturbances.MethodsTo do so, we collected field instream habitat (i.e., physical habitat and water quality) and landscape data from 99 stream sites in two eastern Brazilian Amazon regions. We used random forest regression trees to assess the relative importance of different predictor variables in determining changes in instream habitat response variables.ResultsMultiple drivers, operating at multiple spatial scales, were important in determining changes in the physical habitat and water quality of the sites. Although we found few similarities in modelled relationships between the two regions, we observed non-linear responses of specific instream characteristics to landscape change; for example 20 % of catchment deforestation resulted in consistently warmer streams.ConclusionsOur results highlight the importance of local riparian and catchment-scale forest cover in shaping instream physical environments, but also underscore the importance of other land use changes and activities, such as road crossings and upstream agriculture intensification. In contrast to the property-scale focus of the Brazilian Forest code, which governs environmental regulations on private land, our results reinforce the importance of catchment-wide management strategies to protect stream ecosystem integrity.
AB - ContextLand use change and forest degradation have myriad effects on tropical ecosystems. Yet their consequences for low-order streams remain very poorly understood, including in the world´s largest freshwater basin, the Amazon.ObjectivesDetermine the degree to which physical and chemical characteristics of the instream habitat of low-order Amazonian streams change in response to past local- and catchment-level anthropogenic disturbances.MethodsTo do so, we collected field instream habitat (i.e., physical habitat and water quality) and landscape data from 99 stream sites in two eastern Brazilian Amazon regions. We used random forest regression trees to assess the relative importance of different predictor variables in determining changes in instream habitat response variables.ResultsMultiple drivers, operating at multiple spatial scales, were important in determining changes in the physical habitat and water quality of the sites. Although we found few similarities in modelled relationships between the two regions, we observed non-linear responses of specific instream characteristics to landscape change; for example 20 % of catchment deforestation resulted in consistently warmer streams.ConclusionsOur results highlight the importance of local riparian and catchment-scale forest cover in shaping instream physical environments, but also underscore the importance of other land use changes and activities, such as road crossings and upstream agriculture intensification. In contrast to the property-scale focus of the Brazilian Forest code, which governs environmental regulations on private land, our results reinforce the importance of catchment-wide management strategies to protect stream ecosystem integrity.
KW - Anthropogenic impacts
KW - Physical and chemical habitat
KW - Random forest models
KW - Watershed management
KW - Deforestation
KW - Land use change
KW - Freshwater
KW - Amazon basin
KW - Tropical forest
U2 - 10.1007/s10980-016-0358-x
DO - 10.1007/s10980-016-0358-x
M3 - Journal article
VL - 31
SP - 1725
EP - 1745
JO - Landscape Ecology
JF - Landscape Ecology
SN - 0921-2973
IS - 8
ER -