Date of Award

Winter 2000

Project Type

Dissertation

Program or Major

Natural Resources

Degree Name

Doctor of Philosophy

First Advisor

Thomas Lee

Abstract

The composition, diversity, and phytogeographic affinities of the vascular flora of Bolivia's wetlands were examined and compared with wetland floras from the other Neotropical countries and the New World Temperate region. Forty-six wetlands distributed throughout Bolivia and ranging in elevation from 90 in to >4400 m were established as study sites. Regional and national wetland floras were compiled from field research, the literature, herbarium specimens, and available databases.

Two thousand and sixty species in 149 families and 666 genera were identified as associated with wetlands in Mesoamerica and tropical and subtropical South America. Of these, 1026 species in 126 families and 450 genera were noted for Bolivian wetlands. When considered both in terms of number of species per system and in comparisons of species-area curves, Bolivia's wetlands were found to be less diverse than wetlands of the New World Temperate region. At the macroregional level, both South and Central America were less diverse than the New World Temperate region. Thus, at both the system and regional scales, it appeared that phytodiversity in New World wetlands constituted an exception to the widely recognized latitudinal gradient in species richness. Additionally, phytodiversity in Neotropical wetlands was generally not well-correlated with diversity in terrestrial habitats.

A large portion of the Neotropical wetland species possessed very broad ranges, and few endemic species were noted relative to the Neotropical terrestrial habitats. Similarity Indices were generally unsatisfactory for analyzing floristic similarities at the system level. Both Detrended Correspondence Analysis (DCA) and Frequency Analysis produced more satisfactory results. Species that typically tended towards dominance in Bolivian wetlands most often were extremely widely distributed, precluding the identification of regional wetland associations based on dominant species. Nevertheless, ordination of the study sites by DCA generally grouped wetlands from within the same Bolivian region. At the macroregional level, an ordination by DCA ordered the countries of the Neotropics into three groups: (1) Bolivia, Brazil and Peru; (2) Colombia, The Guianas, and Venezuela; and, (3) all Central American countries. Two countries, Mexico and Ecuador, were not clearly associated with any group.

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