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101.
Variations of tree species composition and community structure and their relationship with environmental variables are described for five sites of the Atlantic rain forest in Picinguaba, southeastern Brazil, distributed along an elevation gradient sampled by plots located at the altitudes of 2, 100, 300, 600 and 1000 m a.s.l. Sampled trees with DBH ≥ 5 cm were identified to species level and their diameter and height were measured. Environmental variables obtained for each plot included 11 topsoil variables and altitude. The residuals of all linear models were tested for spatial structure and multivariate analyses were performed to seek for relationships between the overall species’ abundances and selected environmental variables. Although both forest physiognomy and species’ abundances did change with altitude, this was clearly sharp only from the coastal plain (2 m) to 100 m, and from 600 m to the summit (1000 m). The three mid-slope sites (100, 300 and 600 m) were rather undifferentiated, though they were richer in species and had taller canopy trees. The altitude and the edaphic variables silt, clay, pH and total exchangeable bases (TEB) presented significant correlations with the variations in species’ abundances, while only pH and TEB were significantly correlated with species richness. The present study demonstrates for the first time that the composition and structure of Atlantic Forest can change accompanying the soil and altitude variations over short distances. 相似文献
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Intermediary disturbance increases tree diversity in riverine forest of southern Brazil 总被引:1,自引:0,他引:1
Jean Carlos Budke João André Jarenkow Ary Teixeira de Oliveira-Filho 《Biodiversity and Conservation》2010,19(8):2371-2387
Floods are frequently associated with disturbance in structuring riverine forests and they lead to environmental heterogeneity
over space and time. We evaluated the distribution of tree species, ecological groups, species richness and diversity from
the point bar to the slope of a riverside forest in southern Brazil (Lat. 30°01′S, Long. 52°47′W) to analyze the effects of
flooding on soil properties and forest structure. A plot of 50 × 200 m divided in five contiguous transects of 10 × 200 m
parallel to the river was installed, where we measured all the individual trees with pbh ≥ 15 cm. A detailed topographical
and soil survey was carried out across the plot and indicated significant differences in organic matter and most mineral nutrients
through the topographical gradient. The 1,229 surveyed individuals belonged to 72 species and 35 families. We used Partial
CCA and Species Indicator Analysis to observe the spatial distribution of species. Both analyses showed that species distribution
was strongly related to the flooding gradient, soil properties and also by space and pure spatial structuring of species and
environmental variables (spatial autocorrelation), although a large part of variation remains unexplained. The ecological
groups of forest stratification, plant dispersal and requirements for germination indicated slight differences among frequently,
occasional and non-flooded transects. Species richness and diversity were higher at intermediate elevations and were associated
to the increased spatial–temporal environmental heterogeneity. Across the plot, the direct influence of flooding on tree species
distribution created a vegetation zonation that is determined by predicted ecological traits. 相似文献