Species Composition and Rhizophora Dominance in a Rehabilitated Mangrove Area at Panatao Port, Claver, Surigao del Norte, Philippines
Abstract
Quantifying community structure and species diversity in rehabilitated coastal ecosystems is essential for evaluating restoration success and supporting evidence-based coastal management. This study assessed mangrove species composition, relative abundance, dominance, and diversity at Panatao Port, Barangay Panatao, Claver, Surigao del Norte, Philippines, a rehabilitated coastal greenbelt adjacent to port infrastructure. Field sampling was conducted during low tide from March 15–17, 2025, using line transects and quadrat sampling across three permanent transects (T1–T3), comprising nine 10 m × 10 m plots with a total sampled area of 900 m². All true mangrove trees were identified and enumerated. Species richness (S), Simpson dominance (D), Shannon–Wiener diversity (H′), and Pielou’s evenness (J) were calculated using PAST software (v4.03). Only two true mangrove species were recorded, Rhizophora apiculata and Rhizophora mucronata, indicating low species richness. A total of 490 individuals were recorded, with R. apiculata strongly dominating the community (476 individuals; 97.14% relative abundance), whereas R. mucronata accounted for only 14 individuals (2.86%) and was absent from T2. Accordingly, Shannon–Wiener diversity was very low across the transects (T1: H′ = 0.1914; T2: H′ = 0.0000; T3: H′ = 0.1095; overall: H′ = 0.1297), accompanied by high Simpson dominance (D = 0.9445) and low overall evenness (J = 0.1872). Comparison with natural and rehabilitated mangrove forests in Surigao del Norte indicated that the Panatao Port stand exhibited a highly simplified community structure dominated by a single species, potentially reflecting historical species-selection bias during planting, localized intertidal conditions, and port-related disturbance. These findings highlight the need to shift coastal rehabilitation from single-species revegetation toward multi-species ecological mangrove restoration through targeted enrichment planting of suitable native species, including Avicennia marina and Sonneratia alba. This study provides baseline information for coastal resource management, long-term ecological monitoring, and future habitat enrichment at Panatao Port.