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

Abstract 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, indicating that deterministic processes are structuring these assemblages. The turnover, and the environmental factors differed among watersheds with different deforestation histories. Besides being scale-dependent, turnover patterns are also likely dependent on land use dynamics and involve time-lags.

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Ecoregional, catchment, and reach-scale environmental factors shape functional-trait structure of stream fish assemblages

Hydrobiologia ◽

10.1007/s10750-015-2235-z ◽

2015 ◽

Vol 753 (1) ◽

pp. 265-283 ◽

Cited By ~ 22

Author(s):

Allison A. Pease ◽

Jason M. Taylor ◽

Kirk O. Winemiller ◽

Ryan S. King

Keyword(s):

Environmental Factors ◽

Fish Assemblages ◽

Functional Trait ◽

Stream Fish ◽

Trait Structure ◽

Stream Fish Assemblages

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Effects of different indices and pairwise methods on the longitudinal pattern of β diversity of stream fish assemblages

Ecology Of Freshwater Fish ◽

10.1111/eff.12627 ◽

2021 ◽

Author(s):

Dong Zhang ◽

Rundong Gao ◽

Jiayun He ◽

Ling Chu ◽

Yunzhi Yan

Keyword(s):

Fish Assemblages ◽

Stream Fish ◽

Β Diversity ◽

Longitudinal Pattern ◽

Stream Fish Assemblages

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Advances in Understanding Landscape Influences on Freshwater Habitats and Biological Assemblages

Advances in Understanding Landscape Influences on Freshwater Habitats and Biological Assemblages ◽

10.47886/9781934874561.ch17 ◽

2019 ◽

Keyword(s):

Land Use ◽

Fish Assemblage ◽

Fish Assemblages ◽

Urban Land ◽

Urban Land Use ◽

Stream Fish ◽

Landscape Variables ◽

Stream Fish Assemblages ◽

Anthropogenic Land Use ◽

Assemblage Metrics

<i>Abstract.</i>—Anthropogenic activities including urbanization, agriculture, and dams degrade stream habitats and are a dominant reason for global biodiversity declines in fluvial fish assemblages. Declining diversity trends have been well documented in many regions of the world; however, fishes vary regionally in response to anthropogenic land use, resulting from complex relationships between landscape variables and mechanisms controlling stream fish assemblages. To test for differences in regional fish response to anthropogenic land use, we conducted our study across five freshwater ecoregions in the temperate mesic portion of the United States and evaluated data characterizing stream fish assemblages from 10,522 locations across all study freshwater ecoregions. Fishes were summarized by metrics describing assemblage structure, trophic groupings of species, levels of tolerance to anthropogenic stressors, and life history characteristics, with seven metrics used for analyses. Natural and anthropogenic landscape variables were assessed across freshwater ecoregions, and we tested for regionally specific influences of percent catchment urbanization, percent catchment agriculture, and catchment densities of dams and stream-road crossings on stream fishes. We used cascade multivariate regression trees to quantify variance explained in fish metrics by these landscape variables after controlling for influences of natural landscape variables, including catchment area, catchment lithology, and elevation of study sites. Results indicated differences in dominant influences by freshwater ecoregion, as well as differences in the levels of anthropogenic land use influencing fishes within and across freshwater ecoregions. For example, urban land use was the most influential anthropogenic land use in both Appalachian Piedmont and Chesapeake Bay freshwater ecoregions, with fish assemblage metrics showing responses at 10% and 1% catchment urban land use, respectively. In contrast, dam density in the network catchment was the most influential anthropogenic variable on fish assemblage metrics in both the Laurentian Great Lakes and Middle Missouri freshwater ecoregions. Also, large amounts of agriculture in the catchment was the most influential anthropogenic land use on fish assemblage metrics in the Upper Mississippi freshwater ecoregion. Knowledge of regional differences in the top contributing anthropogenic landscape variables and the levels at which fish assemblages respond to these variables lends insight into mechanisms controlling stream fish assemblages by freshwater ecoregions and can aid in development of region-specific conservation strategies to prevent biodiversity loss from current and future anthropogenic land use.

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Role of environmental and spatial processes structuring fish assemblages in streams of the eastern Amazon

Marine and Freshwater Research ◽

10.1071/mf17103 ◽

2018 ◽

Vol 69 (2) ◽

pp. 243 ◽

Cited By ~ 5

Author(s):

N. L. Benone ◽

R. Ligeiro ◽

L. Juen ◽

L. F. A. Montag

Keyword(s):

Environmental Factors ◽

Environmental Variables ◽

Fish Assemblages ◽

Flood Plain ◽

Habitat Isolation ◽

Flood Plains ◽

Β Diversity ◽

Flood Period ◽

Stream Fish Assemblages ◽

Stream Biota

Considering the increasing importance of analysing spatial structure in ecological studies, the aims of the present study were to test whether fluvial distances and environmental factors are important drivers of the β-diversity of stream fish assemblages, and whether β-diversity is different in distinct hydrological periods. Specimens were sampled at 33 stream sites in the eastern Amazon. Eight environmental variables were measured at each site and fluvial distances between pairs of stream sites were determined. Environmental variables were the main factors structuring fish assemblages in both periods. However, fluvial distances were important only during the flood period. This can be related to the formation of extensive flood plains in this period, which increases connectivity between streams, breaking habitat isolation and increasing the regional signal for fish species. The higher correlation of β-diversity with environmental variables during the flood period may be related to decreased dispersal limitations and intermediate dispersal. Finally, β-diversity was higher during the flood period, highlighting the importance of the heterogeneity of the flood plain to stream biota. The results of the present study indicate that spatial and environmental factors play complementary roles in structuring fish assemblages in Amazon streams, and that β-diversity was affected by changes in the habitat connectivity experienced in different hydrological periods.

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