High primary productivity under submerged soil raises the net ecosystem productivity of a secondary mangrove forest in eastern Thailand

Abstract

The distribution of mangrove forests is limited to the coastal zones of tropical and subtropical regions, and their total area is far smaller than that of upland forests (Spalding et al. 2010). Mangrove forests often show unique patterns of biomass allocation and carbon dynamics because they are periodically submerged by tides (Komiyama et al. 2008). Therefore, the contribution of mangrove forests to the global carbon fixation process should be carefully evaluated even though their distribution area is limited.

Net Ecosystem Productivity Studies in Mangrove Forests

“…The NEP estimations obtained by the eddy covariance technique in subtropical regions (Barr et al, 2006;Barr et al, 2010;Barr et al, 2012) were similar to those estimated for tropical regions by the summation method (Poungparn et al, 2012). This may imply a possibility of under-estimation via the summation method in comparison to the eddy covariance technique, as Poungparn et al (2012) did not include root litter in their estimation.…”

“…(Alongi, 2011). Although Poungparn et al (2012) and Alongi (2011) estimated NEP in mangrove forests in Thailand, the NEP estimated by Alongi (2011) was higher due to including algal GPP in the NPP.…”

“…According to the NEP estimation of a secondary mangrove forest, Poungparn et al (2012) estimated NEP using a common formula NEP = GPP -(AR+HR) = NPP -HR, where HR represents heterotrophic respiration ( growth increment and litter-fall production to NPP while excluding the amount grazed by herbivores. Although Clark et al (2001) suggested that not accounting for leaf herbivores may result in an under-estimation of NPP, the rate of grazing by herbivores in mangrove forests could be low due to a high tannin content in the mangrove trees (Komiyama et al, 2008).…”

“…Apart from Poungparn et al (2012), the NEP estimations reported by Alongi (2011) and Burford et al (2008) were obtained by balancing GPP and R total (Table 1). Alongi (2011) factored algal GPP levels into carbon input while factoring water respiration (gained by algal respiration) into carbon output.…”

“…This may imply a possibility of under-estimation via the summation method in comparison to the eddy covariance technique, as Poungparn et al (2012) did not include root litter in their estimation. Similarly, in Kira and Shidei (1967) the summation method counted the total biomass increment of forests and included solely the aboveground production processes (due to the difficulties in investigating the belowground dynamics).…”