Journal ArticleDOI
Floristic patterns along a 43-km long transect in an Amazonian rain forest
TLDR
In this paper, the authors studied the floristic variation of two phylogenetically distant plant groups along a continuous 43-km long line transect that crossed tierra firme rain forest in northern Peru.Abstract:
Summary
1
The floristic variation in Amazonian lowland forests is poorly understood, especially in the large areas of non-inundated (tierra firme) rain forest. Species composition may be either unpredictable as abundances fluctuate in a random walk, more-or-less uniform, or it may correspond to environmental heterogeneity.
2
We tested the three hypotheses by studying the floristic variation of two phylogenetically distant plant groups along a continuous 43-km long line transect that crossed tierra firme rain forest in northern Peru.
3
The observed floristic patterns were compared to patterns in the spectral reflectance characteristics of the forest as recorded in a Landsat TM satellite image. The topography of the transect was measured in the field, and surface soil samples were collected to document edaphic conditions. The two plant groups, pteridophytes and the Melastomataceae, were assessed in 2-m wide and 500-m long sampling units.
4
Floristic similarity (Jaccard index) between sampling units ranged from 0.01 to 0.71 (mean = 0.27), showing that some units were almost completely dissimilar while others were very alike.
5
Spatially constrained clustering produced very similar subdivisions of the transect when based separately on satellite image data, pteriophytes, and Melastomataceae, and the subdivisions were also related to topography and soil characteristics. Mantel tests showed that floristic similarity patterns of the two plant groups were highly correlated with each other and with similarities in reflectance patterns of the satellite image, and somewhat less correlated with geographical distance.
6
Our results lend no support to the uniformity hypothesis, but they partially support the random walk model, and are consistent with the hypothesis that species segregate edaphically at the landscape scale within the uniform-looking forest.read more
Citations
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Journal ArticleDOI
Associations between species and groups of sites: indices and statistical inference
TL;DR: This work presents permutation tests to assess the statistical significance of species-site group associations and bootstrap methods for obtaining confidence intervals, which includes several new indices.
Journal ArticleDOI
Analyzing beta diversity: partitioning the spatial variation of community composition data
TL;DR: In this article, the authors compare two statistical methods, namely, canonical ordination and variation partitioning on distance matrices (Mantel approach), to test the origin and maintenance of community diversity among sites.
Journal ArticleDOI
Improving indicator species analysis by combining groups of sites
TL;DR: This paper suggests improving indicator species analysis by considering all possible combinations of groups of sites and selecting the combination for which the species can be best used as indicator.
Journal ArticleDOI
Community ecology in the age of multivariate multiscale spatial analysis
Stéphane Dray,Raphaël Pélissier,Raphaël Pélissier,Pierre Couteron,Marie-Josée Fortin,Pierre Legendre,Pedro R. Peres-Neto,Edwige Bellier,Roger Bivand,F. G. Blanchet,M. De Caceres,Anne-Béatrice Dufour,Einar Heegaard,Thibaut Jombart,Thibaut Jombart,François Munoz,Jari Oksanen,Jean Thioulouse,Helene H. Wagner +18 more
TL;DR: In this paper, the authors suggest that ecological studies would benefit from the combined use of the classical statistical models of community composition data, such as constrained or unconstrained multivariate analyses of site-by-species abundance tables, with rapidly emerging and diversifying methods of spatial pattern analysis.
Journal ArticleDOI
Tree species distributions and local habitat variation in the Amazon: large forest plot in eastern Ecuador
Renato Valencia,Robin B. Foster,Gorky Villa,Richard Condit,Richard Condit,Jens-Christian Svenning,Consuelo Hernandez,Katya Romoleroux,Elizabeth Losos,Elizabeth Losos,Else Magård,Henrik Balslev +11 more
TL;DR: In this article, the authors mapped and identified all trees ≥ 10 mm in diameter in 25 ha of lowland wet forest in Amazonian Ecuador, and found 1104 morphospecies among 152 353 individuals.
References
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Journal ArticleDOI
Species assemblages and indicator species:the need for a flexible asymmetrical approach
Marc Dufrêne,Pierre Legendre +1 more
TL;DR: A new and simple method to find indicator species and species assemblages characterizing groups of sites, and a new way to present species-site tables, accounting for the hierarchical relationships among species, is proposed.
Book
The Unified Neutral Theory of Biodiversity and Biogeography
TL;DR: A study of the issue indicates that it is not a serious problem for neutral theory, and there is sometimes a difference between some of the simulation-based results of Hubbell and the analytical results of Volkov et al. (2003).
Journal ArticleDOI
Partialling out the spatial component of ecological variation
TL;DR: In this paper, a method is proposed to partition the variation of species abundance data into independent components: pure spatial, pure environmental, spatial component of environmental influence, and undetermined.