# Evaluating Litter Yield and Decomposition for Re-Vegetated Mangroves in a Subtropical Mudflat
## 1 Introduction  
Mangrove wetlands play an important role in the provision of ecosystem services [1; 2; 3]. Rapid coastal development in the past few decades has led to a large-scale destruction of mangroves around the world [4], with its adverse impact on coastal ecosystems becoming more and more evident [5; 6]. To halt further ecological degradation in tropical and subtropical estuarine areas, re-vegetation of mangroves is thought to be an effective measure in addition to mangrove wetland conservation [7; 8; 9]. However, replanting mangrove trees in tidal zones is more challenging and usually involves larger capital and labor inputs, as compared to re-vegetation of terrestrial lands.  
The economic viability of a mangrove re-vegetation project needs to be carefully evaluated based on a sound cost-benefit analysis. Carbon credit is among the major benefits from restoration of mangrove wetlands [10]. While carbon being stored in the living parts of mangrove trees is important, carbon storage in mangrove soils plays an even more important role in carbon sequestration [11; 12]. Due to anaerobic conditions encountered in tidal zones, decomposition of mangrove litters is relatively slow [13; 14]. Therefore, mangrove soils/sediments tend to contain more organic carbon as compared to many terrestrial forest soils [15; 16].  
The potential of mangroves to contribute to tidal soil/sediment carbon credit is determined by the difference between carbon input and carbon output [17]. Litter production of mangroves is the primary source of organic carbon input in mangrove wetlands while decomposition of mangrove litters and the associated release of carbon-containing gases is the major pathway through which soil carbon is lost. Therefore, there is a need to understand the litter yield of mangroves and the decomposition of litter in the mangrove soils in order to evaluate the capacity of replanted mangrove trees to sequester atmospheric carbon dioxide (CO\({}_{2}\)) and store the captured carbon in the tidal soils/sediments.  
Due to varying physiographic conditions and the difference in mangrove species, the yield of mangrove litter could vary markedly from location to location, with a range of 170-5384 g/m\({}^{2}\)[18]. Similarly, the decomposition rate of mangrove litter is also highly variable and depends on environmental conditions such as temperature, salinity, and redox potential [14]. While there has been increasing research done to examine mangrove litter yield and in-soil decomposition, many efforts have been focused on natural mangroves in tropical and subtropical climatic zones [19; 20; 21; 22] with insufficient work being done for replanted mangroves.  
Barren tidal mudflats are widespread on the subtropical South China coast [23] and can be potentially used for planting mangroves. The objective of this study was to examine the litter yield and decomposition for mangrove species that are suitable for being grown on the South China coast in order to obtain useful information that can be used for evaluating the potential contribution of mangrove re-vegetation to soil carbon sequestration in the South China coastal areas.