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The complete genome sequence of Roseobacter denitrificans reveals a mixotrophic rather than photosynthetic metabolism 下载免费PDF全文
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George B. Chuyong David Kenfack Kyle E. Harms Duncan W. Thomas Richard Condit Liza S. Comita 《Plant Ecology》2011,212(8):1363-1374
Niche differentiation with respect to habitat has been hypothesized to shape patterns of diversity and species distributions
in plant communities. African forests have been reported to be relatively less diverse compared to highly diversed regions
of the Amazonian or Southeast Asian forests, and might be expected to have less niche differentiation. We examined patterns
of structural and floristic differences among five topographically defined habitats for 494 species with stems ≥1 cm dbh in
a 50-ha plot in Korup National Park, Cameroon. In addition, we tested for species–habitat associations for 272 species (with
more than 50 individuals in the plot) using Torus translation randomization tests. Tree density and basal area were lowest
in areas with negative convexity, which contained streams or were inundated during rainy periods and highest in moist well-drained
habitats. Species composition and diversity varied along the topographical gradient from low flat to ridge top habitats. The
low depression and low flat habitats were characterized by high diversity and similar species composition, relative to slopes,
high gullies and ridge tops. Sixty-three percent of the species evaluated showed significant positive associations with at
least one of the five habitat types. The majority of associations were with low depressions (75 species) and the fewest with
ridge tops (8 species). The large number of species–habitat associations and the pronounced contrast between low (valley)
and elevated (ridgetop) habitats in the Korup plot shows that niche differentiation with respect to edaphic variables (e.g.,
soil moisture, nutrients) contributes to local scale tree species distributions and to the maintenance of diversity in African
forests. 相似文献
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