Lessons from A Degradation of Planted Kandelia obovata Mangrove Forest in the Pearl River Estuary, China

Abstract

Kandelia obovata (L.) Druce and Sonneratia caseolaris (L.) Engl. are two dominant mangrove species in the subtropical coastlines of the Pearl River Estuary, China. The main aim of this study was to investigate the specific causes of K. obovata mortality versus S. caseolaris vitality on the west coast of Bao’an, Shenzhen, China and to propose sustainable management strategies for mangrove protection and future ecological planting restoration. Results showed that although both mangroves possessed simple and unstable community structures, S. caseolaris had a more tenacious vitality than the native species K. obovata, indicating that the former possesses stronger adaptability under adversity conditions. Moreover, the salinity of the seawater collection point 5 from the K. obovata plot was found to be lower than that of seawater collection point 1–3 from the S. caseolaris sample plots, indicating that no hydrologic connectivity existed in the K. obovata plots. In addition, the location of the drain outlet (seawater collection point 8) might be another potential risk factor for the dead of near K. obovata forests, implying that they were badly affected by poor oxygen and serious inorganic pollution, such as ammonium nitrogen, total phosphorus, and other inorganic substances. Depending on local circumstances, we should consider strengthening infrastructure construction to activate hydrological connectivity, reinforcing the stability of man-made mangrove communities, and controlling the pollution sources for sustainable mangrove protection and management on the western coast of Bao’an, Shenzhen, China.

Current Status and Potential Invasiveness Evaluation of an Exotic Mangrove Species, Laguncularia racemosa (L.) C.F. Gaertn, on Hainan Island, China

“…Indeed, a previous study reported that L. racemosa was widely considered a typical pioneer species found in the interior of mangroves and the transition to restinga forests [39]. This result was roughly identical to our latest study reporting that the importance values of the planted K. obovata and S. caseolaris were significantly higher than those of their accompanying species, such as S. apetala and B. gymnorrhiza, in the Pearl River Estuary, China [40]. Interestingly, the importance values of L. racemosa in terms of its tree and shrub layers first decreased and then increased with the increase in planting years; however, the dynamic result was the opposite in its seedling layer, which implied that with the increase in planting years, L. racemosa grew into shrubs and trees and dominated in their layers, while L. racemosa decreased gradually with the increase in planting years in the seedling layer since it was a light-loving species and not shade tolerant (Figure 2).…”

Satellite Data Reveal Concerns Regarding Mangrove Restoration Efforts in Southern China

“…As the implementers, local governments are required to abide by the negotiated restoration goal. However, for local governments, achieving the mangrove restoration goals on time is often a challenge [7][8][9][10].…”