ISSN:
1573-5117
Keywords:
Benthic
;
macroalgae
;
macrophytes
;
niche pre-emption
;
riparian shading
;
stream
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The seasonal distribution and abundance of benthic macrophytes were characterized from second- and third-order segments of a stream flowing over granite flatrock in the southeastern United States. Eighteen genera were identified over two annual cycles including macroalgae (60% of the total), angiosperms (30%), and bryophytes (10%). Light availability as affected by riparian shading was a major factor influencing community structure. Based on strong agreement among two-way indicator species analysis, detrended correspondence analysis and cluster analysis, we identified four communities characteristic of distinct light regimes and seasons. In shaded sites the red alga Lemanea australis was dominant during cool seasons, and the aquatic moss Fontinalis sp. was dominant during warm seasons. By contrast, in open sites L. australis and the angiosperm Podostemum ceratophyllum were co-dominant during cool seasons, and P. ceratophyllum was also dominant in warm seasons. The prolific macrophyte communities followed a pattern of broad seasonal maxima for dominant species along with rapid fluctuations in ephemerals. The community dynamics suggest that competitive interactions control space partitioning among macrophytes on the granite flatrock.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00016155
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