Fungal diversity associated with Avicennia marina under contrasting mangrove conditions in North Sumatra

Abstract

Mangrove ecosystems function as important coastal habitats and natural sinks for pollutants, including heavy metals. Fungi play a key role in organic matter decomposition and nutrient cycling, but their diversity is sensitive to environmental stress. This study evaluated fungal diversity associated with Avicennia marina in two contrasting mangrove ecosystems in North Sumatra, the polluted Belawan Sicanang and the relatively undisturbed Pulau Sembilan. Fungi were isolated from roots, bark, and sediment using serial dilution and identified based on morphological characteristics. Diversity was analyzed using the Shannon index. The results showed lower fungal diversity in the polluted site (H’ = 0.996) compared to the control site (H’ = 1.012). Fungal communities in both sites were dominated by Aspergillus sp., indicating high tolerance to environmental stress. Reduced diversity in the polluted ecosystem suggests environmental filtering. These findings highlight the potential of fungal communities as bio indicators of mangrove ecosystem health.