Floristic composition across a climatic gradient in a neotropical lowland forest
Article first published online: 24 FEB 2009
2001 IAVS - the International Association of Vegetation Science
Journal of Vegetation Science
Volume 12, Issue 4, pages 553–566, August 2001
How to Cite
Pyke, C. R., Condit, R., Aguilar, S. and Lao, S. (2001), Floristic composition across a climatic gradient in a neotropical lowland forest. Journal of Vegetation Science, 12: 553–566. doi: 10.2307/3237007
- Issue published online: 24 FEB 2009
- Article first published online: 24 FEB 2009
- Received 29 June 2000; Revision received 22 February 2001; Final revision received 13 April 2001; Accepted 11 May 2001.
- Gradient analysis;
- Life zone;
- Spatial analysis;
- Tropical lowland forest
Abstract. This study deals with the floristic composition of lowland tropical forest in the watershed of the Panama Canal. The floristic composition of large trees in 54 forest plots was analysed with respect to environmental factors, including precipitation, geologic parent material, stand age, topography, and soils. The plots contain 824 species of trees with a diameter at breast height ≥10 cm and represent a regional flora with exceptional β-diversity. Plot data indicate that the Panamanian forest is strongly spatially structured at the landscape scale with floristic similarity decreasing rapidly as a function of inter-plot geographic distance, especially for distances <5 km. The ordinations and patterns of endemism across the study area indicate broad floristic associations well correlated with Holdridge life zones. The results indicate the positive aspects of life zone classification at regional scales, while simultaneously highlighting its inadequacy for finer scales of analysis and resource management. Multivariate gradient analysis techniques (Non-metric Multidimensional Distance Scaling and Detrended Correspondence Analysis) show clear patterns of floristic variability correlated with regional precipitation trends, surficial geology, and local soil attributes. Geologic and edaphic conditions, such as acidic soils or excessively drained limestone substrates, appear to override the effects of precipitation and modify forest composition. We conclude that the Panamanian forest shows clear patterns of spatial organization along environmental gradients, predominantly precipitation. The rapid decline in floristic similarity with distance between stands also suggests a role for dispersal limitation and stochastic events.