| Zoobenthos is an important component of mangrove ecosystem as well as the positive consumer and metastasis group of material cycling and energy flowing. It is also a bio-indicator to appraise the sediment quality in mangrove area. In recent years, the research on mangrove ecological restoration and artificial planting has become more and more important. To provide zoobenthic ecological basis for the mangrove ecological restoration, protection, exploitation and management, we are need to recognize the difference of macrofauna community between inner-mangrove and outer-mangrove, as well as the effect of different developing mangroves on macrofauna community.We used Fenglin and Shanhouting artificially planted mangrove areas in Tong'an Bay as the research areas and applied some new concepts and new technology in appraising the ecological effect of artificially planted mangrove on zoobenthos, such as the application of the Macrofaunal Pollution Index (MPI), the biomass size spectra and the secondary production. Systemic research was carried out on the zoobenthic ecological process in artificially planted mangrove based on the meiofauna and macrofauna's species, average density, average biomass, biological indexes, multivariate analysis, biomass size spectra and secondary production. The main results are as follows:1. Sixty-five species of macrofauna were identified in the four seasons in Fenglin artificially planted mangrove area. Polychaete, oligochaetes and gastropod accounted for the highest pecentage in species, average density and average biomass respectively. While in Shanhouting artificially planted mangrove area, sixty-eight species of macrofauna were identified. And the polychaete, Crustacea and Crustacea accounted for high pecentage in species, average density and average biomass respectively. The seasonal changes of macrofaunal average density and average biomass were different in two mangrove areas because of the different community composition.2. The annual average density of macrofauna in Fenglin and Shanhouting mangrove areas were 5575.1 ind·m-2 and 1625.6 ind·m-2 respectively; the annual average biomass were 85.60 g·m-2 and 50.59 g·m-2; and the annual average secondary production were 17.3 gAFDW·m-2·yr and 9.2 gAFDW·m-2·yr. It was obvious that the annual average density, average biomass and average secondary production of macrofauna in Fenglin were all higher than those in Shanhouting mangrove area.3. The Bray-Curtis Cluster and MDS analysis showed not only the difference of macrofauna community between the inner-mangrove and the outer-mangrove areas, but also Fenglin and Shanhouting mangrove areas differed. So did the difference among seasons.4. Eight species of macrofauna on trees were identified in Fenglin and Shanhouting mangrove area. The dominant species on trees in Fenglin were Littoraia melanostoma and Littorinopsis intermedia, while in Shanhouting mangrove area were Saccostrea cucullata and Chthonerpeton braestrupi.5. In Fenglin mangrove area, the annual average density of meiofauna was 1548±512 ind·10cm-2 and the biomass was 1699.66μg (dwt)·10cm-2; in Shanhouting mangrove area, the annual average density of meiofauna was 892±19 ind·10cm-2 and the biomass was 299.56μg (dwt)·10cm-2. The average density and biomass of meiofauna in Shanhouting mangrove area were both lower than in Fenglin mangrove area.6. The average density of macrofauna, Macrofaunal Pollution Index (MPI),and the average density, biomass, secondary production of meiofauna inside mangrove in Fenglin were all higer than outside mangrove,whereas the average biomass, secondary production of macrofauna, Magalef's index(d), Shannon-Wiener diversity index (H') in Fenglin inside mangrove were lower than outside mangrove. The Independent-Samples T Test showed significant difference. The pattern of zoobenthic distribution in Shanhouting mangrove area was a little different, only the MPI index inside mangrove was higer than outside mangrove. But the Independent-Samples T Test showed no significant difference. There were two main factors which influenced the quantity of macrofauna between the inner-mangrove and the outer-mangrove: firstly the intimidation from the negative environmental factors in mangrove area; secondly the effect of the different tidal layers.7. Both in Fenglin and Shanhouting mangrove planted area, the sizes of biomass spectra inner-mangrove were more than outer-mangrove, which showed that there were some bigger macrofauna at the outer-mangrove. Besides, there was a deep trough of 4-6 size class in FL1 and FL2 sampling stations according to the shape of biomass size spectra where is a boundary between meiofauna and macrofauna and only few macrofaunal larva live, while trough of wave at 4-6 size class in FL3 sampling station was flat which showed that the more macrofaunal larva live in FL3 sampling station.
|
PDF Full Text Request