Mangroves of China: a brief review

Study Number:

54

Author:

M.S. Li & S.Y. Lee

Abstract:

The distribution, ecology, conservation and management of Chinese mangroves are reviewed. Mangroves naturally occur along the southeast Chinese coast and traverse the provinces of Hainan, Guangdong, Guangxi, Fujian and Taiwan, intermittently extending from 18”N to 27”N. Thirty-seven mangrove tree species, representing 20 families and 25 genera, have been documented, with thermophilic emytopic species being the dominant components. A remarkable decrease of species richness is evident from Hainan (18-20”N) to Fujian (23.5-27”N) (35 vs. 9 species). The existing mangrove area is = 17 800 ha, accounting for slightly more than 0.1% of the world’s total. Nearly two-thirds of China’s mangroves have been lost during the past 40 years, largely due to conversion for rice-farming (agriculture), embankment for aquaculture ponds and, recently, rapid urban (coastal) development. A total of 201 papers on Chinese mangroves were published between 1950 and 1995, 178 of which are in Chinese; thus, they are not easily accessible to the international scientific community. Most of the work was conducted after 1985 (91% of the papers published) and research emphasized floristics with little attention to management related issues. The net primary production of the Chinese mangroves shows a latitudinal trend, also significant deviations from predictions on models generated using non-Chinese data. Although 28 Chinese institutions have dealt with mangrove research, only five maintain long-term projects. The bulk of research has been carried out in six mangrove reserves: Qinglan, Dongzhai (Hainan), Mai PO (Hong Kong), Futian (Guangdong), Shankou (Guangxi) and Jiulongjiang (Fujian). Twelve mangrove reserves have been established so far in mainland China, one in Hong Kong (Mai PO) and one in Taiwan (Tanshui). These reserves cover an area of over 19000 ha, of which 8445 ha are mangroves (47% of existing mangrove area). Six measures that can facilitate mangrove conservation and management are recommended: (a) declare more mangrove areas as nature reserves; (b) set up a national mangrove committee and mangrove research centre to foster research and management; (c) develop concrete management guidelines; (d) enact protective legislation and ensure its strict enforcement; (e) launch education programmes in the major mangrove reserves; and (f) stop further non-sustainable exploitation of mangroves and their habitats.

Main Results and Conclusions:

• The current status of mangroves (in 1997) is as follows:
  • “The total mangrove area in China is estimated to be = 17 800 ha, representing over 0.1% of the world total and 0.24% of the Asian mangrove area (74588 000 ha, including China’s mangroves; Wacharakitti, 1983)”(245).
  • “The total area of protected mangrove areas in China is equal to 8445 ha, accounting for 47% of the existing mangroves (Table 5). Nevertheless, the mangroves in non-reserve regions (> 50% of the total mangrove areas) continue to be degraded”(252).
  • There are a total of 12 mangrove reserves in China (253).
• The major threats to Chinese mangroves are aquaculture development and urbanization (253). Details about these and other minor threats are as follows:
  • “…China’s mangroves do not grow to a size large enough to be used as building materials. Other uses such as food, fodder, medicine and tannin remain small in scale, whereas charcoal production is the most important traditional use of mangroves that sometimes results in dire consequences” (251). (Deforestation).
  • Aquaculture development caused extreme mangrove loss during the 1980’s: “Today, only the seaward mangrove fridge remains, representing about 15% of the original mangrove area”(251).
  • “…urban (coastal) development after the mid-1980s removed vast areas of mangrove forest to create more land for harbor construction, real estate development, highways, and industries, often devastating for more wetlands than what was required, and affecting the lives of subsistence coastal dwellers quite unnecessarily”(251-252). 
• Recommendations for future mangrove conservation (254)
  • Declare more mangrove areas as natural reserves
  • Setup a National Mangrove Committee
  • Create easily understood mangrove conservation guidelines for people in control of mangrove management
  • Legislation should be enacted to ensure the protection of mangroves
  • Create of education programs within mangrove reserves
  • Prohibit any future exploitation of mangroves
• An example of a successful mangrove conservation area in China is the gei wais in Mai Po, Hong Kong: “The gei wais in Mai PO, Hong Kong may represent a sustainable utilisation of mangroves to simultaneously support the dual objectives of wildlife conservation and fisheries production. In contrast to the intensively managed aquaculture ponds common in southeast Asia, patches of marsh and mangrove vegetation are maintained in the large impoundments (10 ha), which are managed in traditional methods without artificial fertilization or stocking of larvae… The success of the Mai Po Marshes has been the result of strict enforcement of conservation legislation (entry is restricted by law), presence of a buffer zone, and active habitat management” (252).
   

Works Cited:

Wacharakitti, S., 1983. Mangrove ecosystem in general. ESCAP/UNESCO/NRCT Regional Remote Sensing Training Course of Mangrove Ecosystem, Bangkok, November 18-December 16, pp. 22-33.