Biogeographical assessment of myxomycete assemblages from Neotropical and Asian Palaeotropical forests

Abstract

Aim Lowland/highland and Neotropical/Asian Palaeotropical assemblages of myxomycetes were compared to test the null hypothesis that neither species diversity nor species composition differs between the two ecoregions. This can be expected if myxomycetes behave as ubiquists and are capable of unlimited long distance dispersal. Location Four pairs (lowland/highland) of comprehensive regional surveys encompassing c. 7500 specimens were compared; these represented Neotropical (Yasuni/Maquipucuna in Ecuador; Guanacaste/Monteverde in Costa Rica) and Asian Palaeotropical forests (Cat Tien/Bi Dup Nui Ba in Vietnam; Chiang Mai in Thailand/South Luzon in the Philippines). Methods Each survey was carried out in an area characterized by relatively homogenous vegetation consisting of natural or near-natural forests, and incorporated both field collecting and the use of moist chamber cultures, and all observed fructifications were recorded. Analyses of diversity (i.e. richness) and community composition were carried out with EstimateS and R. Results Between 400 and 2500 records per survey were obtained. Species accumulation curves indicated moderate to nearly exhaustive completeness (70– 94% of expected species richness recorded). Multivariate analyses suggest that geographical separation (Neotropic versus Palaeotropic) explained the observed differences in composition of myxomycete assemblages better than habitat differences (lowland versus highland forests). Main Conclusion Both geographically restricted morphospecies and differences in myxomycete assemblages provide evidence that myxomycetes are not ubiquists but tend to follow the moderate endemicity hypothesis of protist biogeography