Dispersal, Environment, and Floristic Variation of Western Amazonian Forests

• Published in: Science (American Association for the Advancement of Science) 2003-01, Vol.299 (5604), p.241-244
• Main Authors: Tuomisto, Hanna, Ruokolainen, Kalle, Yli-Halla, Markku
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Biodiversity; Biological and medical sciences; Botany; Colombia; Determinism; Ecosystem; Ecuador; Edaphic factors; Environment; Environmental aspects; Environmental conservation; Environmental Influences; Ferns - classification; Ferns - growth & development; Flowers & plants; Forest soils; Fundamental and applied biological sciences. Psychology; Geographic regions; Geography; Individualized Instruction; Mantels; Melastomataceae - classification; Melastomataceae - growth & development; Organic Chemistry; Peru; Plant ecology; Plant genetics; Plants; Rainforests; Sampling; Seasons; Soil; Species; Sustainable agriculture; Synecology; Terrestrial ecosystems; Topography; Trees; Tropical rain forests
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1078037

The distribution of plant species, the species compositions of different sites, and the factors that affect them in tropical rain forests are not well understood. The main hypotheses are that species composition is either (i) uniform over large areas, (ii) random but spatially autocorrelated because of dispersal limitation, or (iii) patchy and environmentally determined. Here we test these hypotheses, using a large data set from western Amazonia. The uniformity hypothesis gains no support, but the other hypotheses do. Environmental determinism explains a larger proportion of the variation in floristic differences between sites than does dispersal limitation; together, these processes explain 70 to 75% of the variation. Consequently, it is important that management planning for conservation and resource use take into account both habitat heterogeneity and biogeographic differences.