First report of myxomycetes in the karst forest of Minalungao National Park, Nueva Ecija, Philippines with updates on the limestone-inhabiting myxomycetes of the Philippines

The karst forest landscape is a unique terrestrial ecosystem where myxomycetes have not been extensively studied. Herewith, we report the first formal listing and ecological assessment of myxomycetes on the limestone forest in Minalungao National Park, Nueva Ecija, Central Luzon, Philippines. The integrated field and moist chamber techniques gave a total of 318 identifiable fruiting bodies classified into 28 species and 14 genera, nine of which are recorded as rare, and five as abundant. Moist chambers with above-ground plant materials, i.e., aerial leaf litter and woody vines (78%) were more productive than the forest floor litter – twigs (72%) and ground leaf litter (63%). The species accumulation curve determined that 80% of the species were recovered from the area. We also determined the general taxonomic diversity (TDI = 2.07) and species diversity (HG = 4.86, HS = 0.91, FAI = 7.76, E = 0.37) of myxomycetes associated with the limestone forest habitat. However, among substrates, woody vines and twigs were the most “favored” substrates with the highest taxonomic and species diversity. Furthermore, Bray Curtis (BC) community analysis of myxomycete assemblages showed high similarities in species composition between similar types of microhabitats, i.e., between aerial and ground leaf litter and between woody vines and twigs. Our study provided baseline information on the composition of limestone-inhabiting myxomycetes and gives updates on the status of myxomycetes in limestone forests in the Philippines.