| Ecosystem services are the conditions and processes through which natural ecosystems, and the Species that make them up, sustain and fulfill human life. Mangrove forest occurring in coastal tidal zones in tropics and subtropics, It's playing an important role in defending wind and protecting coast, beach protection and siltation accretion, material production, air conditioning, environment purification, biological control and so on. In this paper, the ecological services function of releasing negative air ion, absorbing heavy metals and biological control of the mangrove community of Qi'ao island in Zhuhai as the research subject. In order to provide some reference for building stronger ecological services function of our country mangrove. The conclusions of research findings as follows:(1). The Sonneratia apetala Buch.-Ham's (Sa) characteristic about diurnal variations of negative air ion (NAI) concentration is"V", the lowest value occurs at around 12:00.The NAI of Kandelia candel (L.) Druce (Kc) and Pongamia pinnata (Linn.) Pierre (Pp) show similar bimodal curve variation, the peak occurs at about 10:00 and valley in 14:00, the NAI began to rise reaching a second peak at 16:00pm. The seasonal variation of mangrove communities'NAI show summer and autumn than winter and spring, and highest in summer and lowest in spring in Qi'ao island in Zhuhai.The NAI annual average value of Sa, Kc and Pp are 1249 lons·cm-3,1621 lons·cm-3 and 1379 lons·cm-3 , respectively.The ability of releasing NAI with Kc is superior to Sa and Pp. The four seasons'air quality grade is A or B, exerts excellent air quality in the reserve. The NAI concentration of Qi'ao island in Zhuhai is significant positive relation to relative humidity and negative correlation with temperature, NAI concentration increases with increasing relative humidity, reduces with temperature rises.(2). The heavy metal element of Cu,Hg,As,Pb,Cd absorbed in three mangrove species, mainly stored in root, trunk and branches which weren't grazed by animals, thereby, that reduced the possibility that provided heavy metal to secondary consumers. The five kinds of heavy metal content were highest in the fine roots, the basic rules of root with the heavy metal is fine root>middle root>big root. The different plants accumulated different Cu, Hg, As, Pb, and Cd, Sa accumulated Cu, As , Kc accumulated Pb,Cd, and Pp accumulated Cu were bigger. The three mangrove plants'ability accumulated Cu, Hg, As, Pb, and Cd, of soil, was different with the different plants and different part in plant body. The accumulation index of Sa was largest. Kc second, the minimum was Pp. and, the accumulation index of roots was larger than trunks, branchs and leaves.(3). The Spatina alterniflora height in three different ages of forest were 183.51cm, 69.22cm, 47.50cm, and , the height of three growth and five growth was account for 37.72%,25.88% to the annual growth, the density was 161 plants·m-2,75 plants·m-2,45 plants·m-2, respectively. When Spatina alterniflora grew for three years later, the density of below the forest only to occupy 46.48% compared to CK.The frequency, coverage and richness of Spatina alterniflora below the forest declined as the age of Sa growing and community coverage increasing gradually, especially, when Sa grew to three years, the effect was quite obvious. It's frequency and coverage only accounted for 44%,55% than annual, the richness has also been controlled significantly.The native vegetation of Acanthus ilicifolius substituted the Spatina alterniflora when it's have been controlled actively. The Spatina alterniflora invaded the forest land of mangrove again, as Sonneratia carseolaris freeze to death, regardless of its density, height, abundance and so on have reached a high level and the trend was spreading.
|
PDF Full Text Request