PARENT SESSION
Poster Session 4: Marine Ecology
Monday, August 8, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Study on the regeneration and growth of Kandelia candel seedlings at Mangrove Wetland of Zhangjiang Estuary in Fujian.
Zhang, Yihui1, 2, Wang, Wenqing1, 2, Lin, Peng1, 2, 1 School of Life Sciences, Xiamen University, Xiamen, China2 Research Center for Wetlands and Ecological Engineering, Xiamen University, Xiamen, China
ABSTRACT- To evaluate Kandelia candel's persistence in the intertidal and to develop a better understanding of factors influencing its regeneration, we conducted a field experiment in Zhangjiang Estuary in Fujian. Fates of propagules and growth of seedlings were monitored for 12 months. Surveys showed that the rates of propagule rootage varied spatially. The lowest rates were occurring in sampling sites under Avicennia marina forest(69.7%). But the rates were high under K. candel forest(90.0%), canopy gap at the edge of mangrove forest(89.3%), and bare tidal flat outside the mangrove forest(82.7%). After 1 year, the survival rates of seedlings under K. candel forest, A. marina forest, canopy gap, and bare tidal flat were 54.7%, 13.7%, 76.0%, and 34.7%, respectively. The surviving seedlings in canopy gap and bare tidal flat grew much better in terms of height, stem diameter, leaf number, leaf area, and biomass than did under A. marina forest and K. candel forest. Correlate analyses showed that sediment texture, pH, salinity, organic matter, total N, and total P among sites had no relationship with K. candel seedling's performance into significant differences in terms of establishment and early growth. On the contrary, interspecies competition, propagule predation by insect and crab, and the received light of seedling had significant effect on the seedling survival and growth. At the early growth stage, the compact root system of A. marina prevented K. candel from rootage so that the propagules tended to be driven away by tidal current under A. marina forest. The rates of insect and crab predation were higher under canopies than in canopy gap and bare tidal flat. Long-term survival of seedlings and their development into saplings depend on light availability. Only those seedlings in canopy gap and bare tidal flat established more successfully. Our results also indicated that the rapid growth of Spartina alterniflora reduced the regeneration of K. candel. Served as competitive plant to K. candel in the mid intertidal zone, S. alterniflora may be having a large impact on the mangroves composition of our study forests. A need to search for ways to protect this reserve area of mangrove wetland is necessary.
Key words: mangroves, Kandelia candel, regeneration, growth