Recolonization of mollusc assemblages in mangrove plantations damaged by Typhoon Chan-hom in the Philippines

• Main Authors: Salmo, Severino G, III, Tibbetts, Ian R, Duke, Norman C
• Format: text
• Published: Archīum Ateneo 2019
• Subjects: Mangrove Restoration; Mollusc assemblages; Disturbance; Typhoon; Habitat recovery; Ecology and Evolutionary Biology; Environmental Sciences
• Online Access: https://archium.ateneo.edu/es-faculty-pubs/31; https://archium.ateneo.edu/cgi/viewcontent.cgi?article=1030&context=es-faculty-pubs
• Institution: Ateneo De Manila University

We investigated the effects of a catastrophic typhoon on mollusc assemblages of damaged mangrove plantations of different ages. Molluscs were sampled from infaunal, epifaunal and arboreal assemblages of mangrove stands in Lingayen Gulf, northwest Philippines, and compared with assemblages of un-impacted areas. Prior to the occurrence of the typhoon, there were clear shifts in the species diversity (H’) and composition of mollusc assemblages with stand age of mangrove forests. This was observed in species composition through the succession in dominance from pioneer to seral or putative climax species, and assemblage type (as arboreal, epifaunal and infaunal). However, severe damage to vegetation structure and sediment properties (associated with a reduction in tree density and canopy cover resulting in increased temperatures and exposure) following the typhoon resulted in an alteration of trajectory patterns in the damaged stands. There were shifts in species composition and dominant species from having mature mangrove-associated species (pre-typhoon) to an abrupt return in dominance of pioneer species (post-typhoon). The damage was more evident in older stands than in intermediate-aged stands. Furthermore, the reduced presence of molluscs (and also probably their activities, i.e. burrowing) may have contributed to the delayed recovery of mangroves. The prospects for recovery of the system to pre-typhoon levels are therefore uncertain where the re-establishment of seral or edaphic mollusc assemblages appears to be related to the recovery of vegetation and sediment conditions.