Myxomycete ecology along an elevation gradient on Cocos Island, Costa Rica

The marine biota of Cocos Island is well known; however, the terrestrial biota is poorly understood. In an effort to document the myxomycetes of the island and to determine their ecological distribution along an elevation gradient, a survey was carried out in 2005. Forty-one species were recorded, mostly from moist chamber cultures prepared with samples of various types of substrate material collected from a series of selected study sites. The assemblage of species on Cocos Island was found to be more similar to that reported from previous studies in Puerto Rico than those obtained from other investigations carried out in continental Costa Rica. This suggests that the very isolation provided by the ocean may influence the biotic interactions and ecological factors involved in determining the distribution patterns and dispersal potential of myxomycetes in the various microhabitats in which these organisms occur. Decreasing diversity with increasing elevation and the role of certain microenvironmental factors in maintaining myxomycete assemblages in particular microhabitats is also discussed. The data generated in this study also contributes to the body of knowledge required to evaluate some of the biogeographical and ecological hypotheses currently under discussion within the scientific community.