Relative importance of local and landscape variables on fish assemblages in streams of Brazilian savanna

2019 ◽  
Vol 26 (2) ◽  
pp. 119-130 ◽  
Author(s):  
Hugo de Oliveira Barbosa ◽  
Pedro Paulino Borges ◽  
Renato Bolson Dala-Corte ◽  
Patrick Thomaz de Aquino Martins ◽  
Fabrício Barreto Teresa
Keyword(s):  
Fish Assemblages ◽  
Brazilian Savanna ◽  
Relative Importance ◽  
Landscape Variables

Advances in Understanding Landscape Influences on Freshwater Habitats and Biological Assemblages

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.

Fish assemblages in coastal lagoons in land-uplift succession: The relative importance of local and regional environmental gradients

2009 ◽  
Vol 81 (2) ◽  
pp. 247-256 ◽  
Author(s):  
Martin Snickars ◽  
Alfred Sandström ◽  
Antti Lappalainen ◽  
Johanna Mattila ◽  
Kajsa Rosqvist ◽  
...  
Keyword(s):  
Fish Assemblages ◽  
Environmental Gradients ◽  
Coastal Lagoons ◽  
Relative Importance ◽  
Land Uplift

The relative importance of local versus landscape variables on site occupancy in bats of the Brazilian Cerrado

2016 ◽  
Vol 32 (4) ◽  
pp. 745-762 ◽  
Author(s):  
Poliana Mendes ◽  
Kimberly A. With ◽  
Luciana Signorelli ◽  
Paulo De Marco
Keyword(s):  
Site Occupancy ◽  
Relative Importance ◽  
Brazilian Cerrado ◽  
Landscape Variables

Landscape Influences on Stream Habitats and Biological Assemblages

2006 ◽  
Keyword(s):  
Fish Assemblage ◽  
Human Disturbance ◽  
Agricultural Land ◽  
Fish Assemblages ◽  
Spatial Scales ◽  
Relative Importance ◽  
Land Uses ◽  
Catchment Scale ◽  
Assemblage Composition ◽  
Local Factors

<em>Abstract.</em>—We analyzed data from 287 streams in Wisconsin and northern Michigan to evaluate the relative effects of human disturbance levels on the influence of catchment, network riparian, reach riparian, and instream variables on fish assemblages. The streams were divided into high, medium, and low human disturbance groups based on catchment and network riparian urban and agricultural land uses. We used canonical correspondence analyses to evaluate relations among variables at the four spatial scales and fish assemblage composition, abundance, and presence/absence and to partition the relative importance of spatial scales. Catchment and network riparian land uses were among the dominant variables correlated with fish for high disturbance catchments but not for low disturbance catchments. The variations in fish assemblage composition, abundance, and presence/absence explained by catchment factors were substantially higher for high than for low disturbance catchments, although the variations explained by network riparian factors and reach riparian land uses were similar among disturbance levels. In contrast, the variations in fish variables explained by instream factors and the interaction of the four spatial scale environmental factors were considerably lower for high disturbance than for low disturbance catchments. We concluded that in largely undisturbed catchments, fish assemblages were predominantly influenced by local factors, but as disturbance increased in catchments and riparian areas, the relative importance of local factors declined and that of catchment increased. Hence, instream and riparian habitat improvements would be most effective in catchments that are largely undisturbed and catchment scale land-use management would be more effective for improving stream quality in degraded catchments.

scholarly journals Landscape scale terrestrial factors are also vital in shaping Odonata diversity of watercourses

2019 ◽  
Author(s):  
H. Beáta Nagy ◽  
Zoltán László ◽  
Flóra Szabó ◽  
Lilla Szőcs ◽  
György Dévai ◽  
...  
Keyword(s):  
Patch Size ◽  
Landscape Scale ◽  
Farm Management ◽  
Relative Importance ◽  
Population Abundance ◽  
Forest Patch ◽  
Terrestrial Environment ◽  
Landscape Variables ◽  
Insect Populations ◽  
Landscape Scales

ABSTRACTHabitat loss and fragmentation causes decline of insect populations. Odonata (both dragonflies and damselflies) are especially threatened, because they are notably influenced by both aquatic and terrestrial environment. We explored the relative importance of local and landscape variables for Odonata assemblages (species richness, assemblage composition, population abundance) revealing differences in the sensitivity of Zygoptera and Anisoptera on the selected variables. Our study took two years and was placed along 11 lowland watercourses. We sampled the specimens using 500 m long transects from May to September. Landscape variables (length of watercourses, forest patch proportion, and farmland patch size) were calculated at three scales to better account for fragmentation. Our findings show that local variables influence damselflies, but dragonflies are more sensitive to landscape variables. Damselfly’s diversity decreased with the increasing macrovegetation cover, while dragonfly’s diversity decreased with the increasing degree of land use intensification, but increased with the length of watercourses. Our findings, both on local and landscape scales demonstrated the importance of terrestrial environment on Odonata. Based on our findings we stress the importance of partial watercourse clearing, and maintenance of traditional farm management based on small parcel farming near watercourses to maintain diverse and healthy Odonata assemblages.

Seasonal Variation in Trophic Diversity and Relative Importance of Basal Resources Supporting Tropical River Fish Assemblages in Chiapas, Mexico

2020 ◽  
Vol 149 (6) ◽  
pp. 753-769
Author(s):  
Allison A. Pease ◽  
Miriam Soria‐Barreto ◽  
Alfonso A. González‐Díaz ◽  
Rocío Rodiles‐Hernández
Keyword(s):  
Seasonal Variation ◽  
Fish Assemblages ◽  
Relative Importance ◽  
Tropical River ◽  
Trophic Diversity ◽  
Basal Resources ◽  
River Fish
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