ISSN:
1573-5117
Keywords:
fluvial macrophytes
;
anthropogenic factors
;
Portugal
;
Mediterranean rivers
;
canonical correspondence analysis
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract River plants were studied at 119 sites from a southern Iberian river basin. A site length of 50-100 m was found to be adequate for characterising local plant richness in these rivers. Average number of river plant species per site was 48 (range 21-76). Species richness showed a maximum at mid-course, with considerable variation in the upper course and a decreasing trend towards the floodplain. Sixteen environmental variables were initially considered to explain the biological variability. Nine, retained by the forward selection procedure, were significant predictors of the species distribution. Canonical correspondence analysis was used to directly relate plant species composition to these environmental variables. Altitude, conductivity, river width, pH, percentage of hard substrates and fine particulate organic matter on the river bed, average rainfall and temperature, and human-related disturbance were significantly related to the species distribution. Species positioned at the axes extremes could be arranged into species groups related to different geographical areas of the river system.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1003837802366
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