Cyanobacteria -: a neglected component of biodiversity:: patterns of species diversity in inland marshes of northern Belize (Central America)

Cyanobacterial mats, widely distributed in the inland alkaline marshes of northern Belize and other regions in the Caribbean, are not only important and functionally complex components of these habitats, but they are also significant reservoirs of biological diversity. Highly diverse and (relatively) isolated marshes have provided conditions suitable for cyanoprokaryotic organisms and conditioned the adaptation and stabilization of numerous specialized eco- and morphotypes. Species richness of cyanobacteria assemblages follows the conductivity gradient and is highest in the marshes of medium conductivity (c. 1000-2000 muS cm(-1)) and decreases at low (< 500 muS cm(-1)) and high (> 3000 muS cm(-1)) conductivities. This ecologically unique cyanobacterial microflora is very sensitive to nutrient enrichment, both directly and indirectly through shading by expanding macrophytes. Species richness of cyanobacterial assemblages decreases dramatically as a result of eutrophication. Similar cyanobacterial communities are widely distributed in limestone-based areas of Florida, Central America and Caribbean but none of them is currently under any legal protection status. The purpose of this paper is to bring attention to an ecologically important group of organisms that have traditionally not been considered in species diversity evaluations or conservation efforts.