Influence of Hydrological and Meteorological Factors on the Diversity of Phallus Species in the Srepok River Basin, Vietnam

Abstract

Moisture-dependent environments of the tropical river basins influence macrofungal fruit body production at the canopy level, on decomposing substrates, and through the availability of water and climate. The Phallus morphotypes documented at Chu Yang Sin National Park in the upper Srepok River Basin, Viet Nam, were analysed with regard to their regional occurrence and environmental data. For 12 main field specimens, sample code was recorded, coordinates, habitat description, morphotype and visible morphological traits and developmental stage. Only exploratory distribution mapping was done for 18 secondary georeferenced records found on GBIF/iNaturalist for a total of 30 occurrence records. Primary specimens included egg and semi-mature and mature stages, which occurred primarily in the moist forest floor, shaded slope, thick litter, humus rich soil, rotting wood and decomposing organic matter. Rainfall, vegetation condition, thermal environment and soil-water availability were given landscape-scale context by open environmental datasets, such as CHIRPS data for rainfall, MODIS land surface temperature, MODIS NDVI/EVI, and SMAP soil moisture, and ERA5 Land variables. Due to the lack of molecular identification and measurements of microclimate at the plot level, the results are considered as tentative associations to the field environment rather than evidence of cause and effect. The framework is useful in planning for future monitoring of fungal biodiversity in the tropical river-basin ecosystems.