Beach and Mangrove Forest

Mangrove Forest

The mangrove forest of Apo Reef Island exhibits the old-growth form or type, having mature stands of mangrove species and mangrove associates with little to no regenerants on its understory. Mature trees of Rhizophora mucronata and Rhizophora apiculata dominated the mangrove forest. On the other hand, scattered trees of Sonneratia alba, Brugiera gymnorhiza, Xylocarpus granatum, Pemphis acidula and Ceriops zippeliana were also recorded in Apo Reef Island. Based on the Mangrove Assessment Survey in 2023, the overall mean dbh and tree height for the mangrove forest in Apo Island, Apo Reef Natural Park are 18.52 cm and 7.34m, respectively, with percent crown cover of 90. 03% (ARNP PAMO, 2023). Twelve monitoring stations in Apo Island, ARNP were surveyed (Figure 6). These stations were similar with those monitored last year. The monitoring team included personnel from the ARNP-PAMO and the Municipal Environment and Natural Resources Office (MENRO) of Sablayan.

The mangrove forest of Apo Reef Natural Park is generally in excellent condition following the criteria of Deguit et al. (2004). It qualifies in three of the four criteria namely, crown cover, mean height, disturbance level. The density of regenerants (1 individual/m2 or greater) is the sole criterion that was not reached. Nonetheless, this does not indicate that the mangrove forest in Apo Reef Natural Park is degraded.

Flowers and fruits of selected mangrove species in Apo Island and Binanggaan. A) Sonneratia alba, B) Avicennia marina, C) Pemphis acidula, D) Xylocarpus rumphii, E) Bruguiera cylindrica, F) Rhizophora apiculata, G) Rhizophora mucronata, and H) Rhizophora

beach forest

             For the beach forest, a total of 107 mature individuals were accounted for (REECS, 2017). Ipomoea pes-caprae (L.) R, Br. along with Heliotropium, Pandanus tectorius Parkinson ex Du Roi, Canavalia maritima (Aubl.) Thouars, and Crinum asiaticum L. were found in the accreting shorelines of Apo Reef Island. On the other hand, mixed species could be found on the landward portions of the island. Species from the beach vegetation has an average diameter at breast height (dbh) of 14.12 cm and an average height of 4.5 meters. Terminalia catappa L. has the largest dbh among the species recorded at the sampled beach vegetation. The diversity index analyzed using PAST software revealed a value of 2.53, which suggests that the beach vegetation of the island has a moderate species diversity. Pandanus tectorius has the greatest number of mature individuals (25 individuals) across the sampled plots, dominating the seaward portion of the island. This was followed by Talipariti tiliaceum, Terminalia catappa and Premna serratifolia with 16, 11 and 10 individuals respectively.

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