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Variation in fish community composition along an Iberian river basin from low to high discharge: relative contributions of environmental and temporal variables
Author(s) -
Godinho F. N.,
Ferreira M. T.,
Santos J. M.
Publication year - 2000
Publication title -
ecology of freshwater fish
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 55
eISSN - 1600-0633
pISSN - 0906-6691
DOI - 10.1034/j.1600-0633.2000.90104.x
Subject(s) - tributary , sampling (signal processing) , environmental science , environment variable , brackish water , hydrology (agriculture) , altitude (triangle) , ecology , discharge , streams , drainage basin , structural basin , spatial variability , geography , salinity , physical geography , biology , statistics , mathematics , geology , cartography , computer network , paleontology , geometry , geotechnical engineering , filter (signal processing) , computer science , computer vision
– Factors associated with the spatial and temporal variation of the lower Guadiana basin (southern Iberia) fish community were determined using data from 20 sites sampled during the summer of 1994 (dry year following a period of low discharge, total discharge from 1992 to 1994=1.45×10 9 m 3 ) and again during the summer of 1996 (wet year following a period of higher discharge, total discharge from January 1995 to August 1996=6.18×10 9 m 3 ). From the 17 explanatory variables initially considered six were retained for analysis by a forward selection procedure: maximum depth, altitude, channel width, substrate coarseness, SALT (a dummy variable identifying sampling locations belonging to tributaries that discharge to the brackish Guadiana) and YEAR (a dummy variable identifying the sampling year). Further, we partitioned the total variability in the Guadiana fish community into that accounted uniquely by selected environmental variables (34.9%), uniquely by sampling year (4.1%), by both sampling year and environmental variables (0.3%), and unexplained (60.7%). NOTE