Comparative diversity and heavy metal biosorption of myxomycetes from forest patches on ultramafic and volcanic soils

Ultramafic and volcanic soils are exploited for industrial activities such as mining due to their high metal content, thus it is important that species in these areas are documented before irreversible environmental damage sets in. In this study, aerial and ground leaf litter, dead vines and twigs from six forest patches on volcanic and ultramafic soils in the provinces of Bataan, Pangasinan and Zambales in the Philippines were cultured in moist chambers (MC) and assessed for myxomycete diversity. From the 77% positive MC for myxomycetes, a total of 40 species from 14 genera were identified. Despite the higher heavy metal content, forest patches on ultramafic soils had greater species diversity as compared to volcanic soils. In this study, 10 species were abundant in both forest patches, namely Arcyria cinerea, Diachea leucopodia, Diderma effusum, D. hemisphaericum, Didymium ochroideum, Perichaena chrysosperma, P. corticalis, P. depressa, P. dictyonema and Physarum melleum. Selected myxomycetes tested for Cr and Mn content had equal or higher heavy metal levels than that of their leaf substrate. The study hypothesised that the presence of Mn⁷⁺ in fruiting bodies of myxomycetes was due to the phagocytosis of food bacteria inhabiting the substrates on the forest soil laden with heavy metal.