ISSN:
1573-5117
Keywords:
phosphate
;
modelling
;
eutrophication
;
aquatic plants
;
rivers
;
irrigation channels
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract A series of models was developed using functionally-derived variables (mainly based on morphological attributes of freshwater macrophytes) to predict the trophic status of river and associated channel systems. The models were compared with an existing species-assemblage based procedure for predicting British river trophic conditions (the Macrophyte Trophic Ranking scheme, MTR). We compared sites in cooler temperate conditions (in Scotland) and warmer, sub-tropical conditions (in Egypt). In total, we made measurements of 13 traits from 〉600 individual plant specimens of 33 species growing at 42 sites (divided into independent input and test site datasets). N status (as annual mean concentration in water of total oxidised nitrogen, TON) was only very poorly predicted by this approach. However, P (as annual mean concentration in water of soluble reactive phosphate, SRP) was better predicted: both by a model based on MTR (r = −0.585, p〈0.001), and by models using functional attributes of the macrophyte vegetation. River Trophic Status Indicator (RTSI) models based on ranked plant functional group relationship to river water P concentrations (RTSIFG), or field-measured trait sets of the plants (RTSITR) could also individually explain up to about 34% of the variation in P, both for the total dataset and for subsets from Egypt or Scotland alone or for high v. low-flow sites. Combining both types of RTSI measure produced the most powerful predictive model (r = 0.72, p〈0.001), explaining just over half the variability in P.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1003833419359
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