Macrofungal taxa and diversity for monitoring of productivity and sustainability of Bombongan-Lewin Subwatershed in Laguna, Philippines

Abstract

Macroscopic fungi (Basidiomycetes and Ascomycetes) are equally important organisms with other lifeforms. They sustain the watershed ecosystem’s productivity through nutrient cycling and decomposition, carbon storage, and plant symbiosis. However, there is a paucity of information and limited appreciation of fungal resources as an integral component of watersheds. This paper examined species composition and macrofungal diversity for monitoring the productivity and sustainability of the Bombongan-Lewin Subwatershed (BLW). With the help of stakeholders, a 2–ha permanent biodiversity monitoring plot was established and subdivided into 50 subplots measuring 20 x 20 m each. The fungal habitat was categorized across vegetation types and land use, while soil at the rhizosphere layer was collected for physicochemical analysis. Macroscopic fungi were sampled during wet months for morpho-anatomical characterization using a classical approach for identification. Population dynamics were determined, including substrates, density, biomass, importance values, diversity index, and structured community survey. The fungal habitats were generally classified as natural forest and agroforestry plantations where soil pH is strong to moderately acidic (pH 3.4 – 4.7). The total macrofungal taxa recorded were 163 species from 56 genera and 35 families. Fruiting bodies mainly inhabit secondary growth forests where litter was abundant with relatively higher soil phosphorus (7%) and potassium (40–50%). Functional values were represented by taxa of wood decomposers, mycorrhizas, and food sources. Fungal habitats showed very high to moderate Shannon diversity (H’= 4.11–2.48) with a significant difference at 5% level (F6,234 = 0.27, Fc = 9.94) using Scheffe’s pairwise comparison. Fungal biomass (r = 0.83–0.86, p < 0.05) and habitat area (r = 0.88–0.91, p < 0.05) have strong positive correlations with species richness, abundance, and diversity, indicating their ecological importance. Knowledge sharing and appreciation of fungal values for continued regular biodiversity monitoring and conservation are important to sustain watershed functions.