Mangrove forest structure and productivity in the Fly River estuary, Papua New Guinea

Abstract

Abstract. In April, July and August 1989 and February 1990, the delta region of the Fly River was surveyed to establish the aerial extent of mangrove forests, their species composition, tree densities and basal areas, and potential net primary production. Mangrove forests cover 87 400 ha, mainly on islands within the delta. Twentynine mangrove plant species were recorded, but there were only three major forest types in the delta. Rhizophora apiculata-Bruguiera parviflora forests (hereafter Rhizophora-Bruguiera forests) predominated in regions where river water salinities were > 10%o. These forests covered 31 500 ha and had mean total tree densities and basal areas of 2027 stems ha-1 and 21 m 2 h a -l , respectively. Forests of the palm Nypafruticans (hereafter Nypa forests) covered 38 400 ha, mainly in regions where river salinities were ~ 1 to 10%o, and had mean total densities and basal areas of 4431 stems ha -1 and 38 m 2 ha -l, respectively. Forests dominated by Avicennia marina and/or Sonneratia lanceolata (hereafter Avicennia-Sonneratia forests) predominated on accreting banks of sediment and covered 17 500 ha. In very low-salinity (< 1%0) regions there are large monospecific stands of S. lanceolata. Mean total densities and basal areas for AvicenniaSonneratia forests were 7036 stems ha-1 and 22 m 2 ha-l, respectively. Mean net primary productivity (kg C ha-1 d -x) was estimated to be 26.7, 27.1 and 19.0 for Rhizophora-Bruguiera, Nypa and Avicennia-Sonneratia forests, respectively. Total daily net primary production by all mangrove forests was estimated at 22•4 t carbon. Using assumptions based on work in tropical Australia, it was estimated that ~ 678 t carbon (or 31% of primary production) were exported daily from mangrove forests to the waters of the delta.

The Guideline Development for Sustainable Livelihood Indicators of Village Marginal Mangrove Forest in the Satun Province, Thailand

“…The perception of productivity in mangrove forests is similar to Robertson et al, (1991) report to productivity increasing variance form rate of natural resource. However, in the dimension of villagers' concentration with primary productivity only, it does not cover to biomass carbon absorption issue (Amarasinghe & Balasubramaniam, 1992).…”

Pristine Mangrove Community in Wondama Gulf, West Papua, Indonesia

“…Some studies found the similar distribution of Nypa, such as Bunt et al (1982); Hamilton and Murphy (1988); Robertson et al (1991), Ukpong et al (1991) and Theerawitaya et al (2014). Ukpong et al (1991) represented that Nypa distribution had a significant and negative correlation to salinity.…”

“…Ukpong et al (1991) represented that Nypa distribution had a significant and negative correlation to salinity. Robertson et al (1991) found that N. fruticans was growth in 1-10 ppt salinity range.…”

Recent Change in the Extent of Mangroves in the Northern Gulf of Papua, Papua New Guinea

“…The mangroves of the Gulf of Papua are considered to be important nursery areas for fish and prawns (Birkeland 1985;Robertson and Duke 1987;Robertson et al 1991Robertson et al , 1998. They support a characteristic fish fauna in addition to forming a marginal habitat for both marine and riverine species.…”