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131.
132.
Effects of hydrological variation on the aquatic plant community in a floodplain palustrine wetland of southern Brazil 总被引:1,自引:0,他引:1
This study analyzed macrophyte richness, biomass, and composition under flooding of brief duration (less than 3 days) and
drawdown events over an annual cycle in a floodplain palustrine wetland in the south of Brazil. The study was carried out
to test the hypothesis that floods of brief and very brief duration are not long enough to compromise the richness and the
biomass of aquatic macrophytes and that the alternation between wet and drawdown phases may cause variations in the macrophyte
richness and composition. A total of 26 aquatic macrophyte species were observed from April 2003 to May 2004: 13 species were
observed during the wet phase, and 24 during the drawdown phase. The mean richness was higher during the drawdown phase than
during the wet phase, however, the mean biomass was similar in both phases. Although macrophyte richness was not modified
after the three flooding events, mean biomass was modified after two events. The number of macrophyte species of which the
biomass was modified after the first flooding event increased with subsequent floods. These results illustrate the importance
of the dynamics between brief floods and drawdown events to the aquatic plant community in floodplain wetlands in southern
Brazil. 相似文献
133.
134.
F. R. SCARANO FLS H. M. DUARTE G. RÔÇAS S. M. B. BARRETO E. F. AMADO F. REINERT T. WENDT A. MANTOVANI H. R. P. LIMA C. F. BARROS 《Botanical journal of the Linnean Society. Linnean Society of London》2002,140(4):391-401
The clonal tank-bromeliad Aechmea bromeliifolia (Rudge) Baker was found in four different habitats in a restinga (vegetation mosaic on sandy coastal plains), of south-eastern Brazil. These habitats (swamp forest, dry forest, dry shrubland and herbaceous marsh) lie within a few hundred metres of each other along a gradient extending inland from the coast, and differ markedly in terms of light and flood regime. We compared ramet morphology, leaf anatomy and physiology, and population parameters to examine the amplitude of trait variation of this widespread species in the studied restinga. This integrated approach allowed us to examine which variation conferred acclimation and which was merely a stress symptom. A . bromeliifolia showed site-specific differences in abundance, distribution, rosette size and shape, leaf anatomical arrangement and photochemical efficiency (potential quantum yield; F v / F m ) during the day. Most of the variation found seemed to be related to the interaction of light and flooding. The lowest number and size of ramets at the exposed, dry shrubland was matched by a marked leaf photoinhibition, which suggested poor acclimation to local levels of light intensity and limited water supply. In the other habitats, the morpho-physiological parameters measured suggested adequate foraging behaviour and site acclimation. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society, 2002, 140 , 391-401. 相似文献