珠海淇澳岛不同类型湿地生态化学因子的差异评价

为探讨外来植物是否导致生境的明显改变，定期测定了珠海淇澳岛外来植物互花米草（Spartina alterniflora）、无瓣海桑（Sonneratia apetala）与本地植物桐花树（Aegiceras corniculatum）、短叶茳芏（Cyperus malaccensis）湿地中的若干生态因子及植物叶片叶绿度，并检验其差异显著性。结果表明，叶片叶绿度互花米草（47.37）<桐花树（58.92）<无瓣海桑（65.35）。表土上部的pH，互花米草湿地（6.33）显著低于桐花树湿地（6.71）。覆盖水与表土下部的氧化还原电位（Eh），互花米草湿地差异不显著，其它3种类型湿地则是覆盖水Eh显著低于表土下部；互花米草湿地表土上部Eh（39.16mV）显著高于桐花树湿地（24.04mV）。互花米草湿地覆盖水电导率（7.96ms/cm）显著高于短叶茳芏湿地（6.92ms/cm）、表土下部电导率（4.4ms/cm）显著高于无瓣海桑湿地（3.26ms/cm）。因此，作为外来入侵植物，互花米草的生长已显著改变了生境中的某些因子，如导致表土上部pH显著下降；覆盖水与表土下部之间Eh差异的消减，表土上部Eh显著高于本地种桐花树湿地；覆盖水电导率显著高于短叶茳芏湿地等，为此应严格控制互花米草，至于外来植物无瓣海桑的潜在生态影响则有待深入研究。

Eco-chemical factor evaluation among different types of wetlands on Qi'ao Island,Zhuhai

Some ecological factors and plant leaf greenness of Spartina alterniflora, Sonneratia apetala, Aegiceras corniculatum, and Cyperus malaccensis wetlands were determined at fixed times, and the significance of differences were analyzed in order to explore potential habitat changes due to species invasion. The results showed that the leaf greenness was in order of S. alterniflora (47.37) < A. corniculatum(58.92) < S. apetala(65.35). The pH value in the upper surface soil within S. alterniflora wetland was 6.33 and significantly lower than that of A. corniculatum wetland (6.71). No significant difference in the redox potential (Eh) was found between overlying water and lower surface soil within S. alterniflora wetland, but the Eh in overlying water was significantly lower than that in lower surface soil within three other wetlands. The Eh in upper surface soil within S. alterniflora wetland was 39.16 mV and significantly higher than that in A. corniculatum wetland (24.04 mV). The conductivity of overlying water within S. alterniflora wetland was 7.96 ms/cm and significantly higher than that in C. malaccensis wetland (6.92 ms/cm); the conductivity of lower surface soil within S. alterniflora wetland was 4.42 ms/cm and significantly higher than that of S. apetala wetland (3.26 ms/cm). Therefore, as an invasive plant, the growth of S. alterniflora had led obvious changes of some ecological factors within habitat, including the significant pH decrease in upper surface soil, the subdued difference of Eh between overlying water and lower surface soil, the significantly higher Eh in upper surface soil than native plant A. corniculatum wetland, the significantly higher conductivity in overlying water than C. malaccensis wetland, and so on. Considering their ecological effects, we strongly suggest that strict management measures should be implemented to limit the growth of invasive species S. alterniflora. Further study for S. apetala is warranted in order to better analyze its potential ecological effects.