An updated ecological assessment of floral and faunal communities of mangrove habitats in Tolo Harbour and Channel, Hong Kong

Abstract

Mangrove forests are coastal habitats of ecological and socio-economic importance, and those in Hong Kong have been found to support high species diversity. Located in northeastern Hong Kong, the mangroves in the Tolo Harbour and Channel (the Tolo area), like many mangrove communities in Hong Kong, have suffered from considerable threat due to rapid coastal development. To provide up-to-date ecological information on the species composition and diversity of major mangrove stands in the Tolo area and advise conservation priorities, surveys were conducted to investigate spatial and temporal variations in species composition of epibenthic and arboreal organisms and to quantify tree diversity in mangrove stands covering inner to outer Tolo areas. A total of 127 species/taxa were recorded in the Tolo area of which 51 were gastropods and 34 were crustaceans. Species richness was higher in the inner Tolo area associated with larger mangrove stands than the outer Tolo area. Mangrove tree communities varied spatially whereas epibenthic and arboreal communities varied both spatially and seasonally. Outer Tolo mangroves had more crab species than inner Tolo area, whereas mangrove stands in Plover Cove and inner Tolo Channel areas were richer in species and had taller mangrove trees as well as presence of endemic species. Priority should be given to conserve mangrove stands in Plover Cove and inner Tolo Channel areas in order to conserve the ecological value of the Tolo area. The present dataset could serve as a baseline for future environmental monitoring and management programmes on the mangrove habitats in the Tolo area.