| Autor: |
Senay, Caroline, Macnaughton, Camille, Lanthier, Gabriel, Harvey-Lavoie, Simonne, Lapointe, Michel, Boisclair, Daniel |
| Předmět: |
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| Zdroj: |
Aquatic Sciences; Oct2015, Vol. 77 Issue 4, p709-721, 13p |
| Abstrakt: |
Modelling the spatial variability of species distribution is recognized as a significant ecological challenge due to the potentially large number of local and larger scale explanatory variables. Our objectives were (1) to estimate the relative importance of hydraulic, sediment size, biogenic (i.e., related to biotic processes), and physico-chemical features in within species distribution models of river fishes (WSDM); (2) to identify the environmental variables having the highest explanatory capacity in WSDM; and (3) to assess the effects of physiographic regions and river flow regulation on the relative importance of environmental features contributing to WSDM. Fish species biomass and environmental features were estimated in 989 sites (average surface area = 300 m) in 28 temperate rivers (15 unregulated rivers and 13 rivers regulated by a hydropower facility) distributed in six physiographic regions of Canada. The variance explained by WSDM ranged from 1 to 60 %. In decreasing order, environmental features contributing most to WSDM were: hydraulic, bed sediment size, biogenic, and physico-chemical. Water velocity, water depth, and sediment size were variables maximizing WSDM explanatory capacity and should be included in monitoring surveys and conservation programs to forecast the changes in species distribution following modifications of river environmental features. The explanatory capacity of WSDM significantly increased in a non-linear fashion following a square root relationship with total fish biomass. Physiographic regions and river flow regulation had no effect on the relative importance of environmental features included in the models. These observations suggested that similar processes might be shaping within-river variations of profiles of relative species biomass across physiographic regions, and in unregulated and regulated rivers. However, even when the proper environmental variables are identified, it may difficult to develop WSDM having an explanatory capacity larger than ~40 % when total fish biomass is <2 g/m. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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