Abstract
Community-managed mangrove forests need monitoring indicators that can separate canopy-forming woody regeneration from general vegetation cover. This study characterised woody stand structure, woody regeneration, and associated ground flora in a community-managed Avicennia-dominated mangrove in Bogak Besar, North Sumatra, Indonesia. Vegetation was surveyed from February to April 2023 using 20 nested plots within an approximately 4-ha sampled mangrove block located inside a broader approximately 12-ha community-managed mangrove area. Woody trees, saplings, and seedlings were analysed separately from associated ground flora, although woody seedlings and ground flora were recorded in the same smallest subplot. For woody taxa, density, frequency, dominance, and importance value index were used to describe stand structure and regeneration, while diameter- and height-class distributions were used to assess horizontal and vertical structure. Associated ground flora was analysed as a separate lower-layer floristic assemblage. A total of 19 taxa were recorded, comprising seven true mangrove taxa and 12 associated taxa. The woody stand was strongly dominated by Avicennia alba, followed by A. marina var. rumphiana and A. marina, whereas woody saplings and seedlings were dominated by the A. marina complex. Tree diameters showed an inverse-J distribution, consistent with continued ingrowth into the measured tree-size threshold, but the narrow diameter range and concentration of stems in low to intermediate height classes indicate a young-to-intermediate rather than structurally mature stand. Associated ground flora was compositionally distinct from woody regeneration and reflected lower-layer habitat heterogeneity rather than stand developmental stage. By separating woody regeneration from associated ground-layer vegetation, this study provides a site-specific diagnostic baseline for monitoring whether community-managed mangroves are developing as canopy-forming forests rather than merely increasing in vegetation cover.