Present address: Consejo Transitorio de Administracion Regional – Loreto, Av. A. Quiñones Km. 2, Iquitos, Peru
Floristic patterns along a 43-km long transect in an Amazonian rain forest
Article first published online: 19 SEP 2003
Journal of Ecology
Volume 91, Issue 5, pages 743–756, October 2003
How to Cite
Tuomisto, H., Ruokolainen, K., Aguilar, M. and Sarmiento, A. (2003), Floristic patterns along a 43-km long transect in an Amazonian rain forest. Journal of Ecology, 91: 743–756. doi: 10.1046/j.1365-2745.2003.00802.x
- Issue published online: 19 SEP 2003
- Article first published online: 19 SEP 2003
- Received 11 December 2002 revision accepted 13 May 2003
- beta diversity;
- chronological clustering.;
- floristic composition;
- Mantel test;
- random walk model;
- satellite imagery;
- tropical rain forest
- 1The 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.
- 2We 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.
- 3The 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.
- 4Floristic 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.
- 5Spatially 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.
- 6Our 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.