崇明东滩湿地植被演替过程中生物量与氮含量的时空变化

研究了长江口东滩潮滩植物群落各演替阶段优势种的生物量与氮含量的季节变化以及演替过程中的空间变化格局。结果表明,潮滩植被生物量在生长季内随时间呈增长趋势,氮含量则在植被生长初期最大,生长末期最小。在演替过程中,植被总体生物量变化趋势为:演替中期>演替后期>演替早期。植物单位氮含量的变化是:地下部分氮含量随演替呈降低趋势,地上部分氮含量从演替中期开始随演替呈增长趋势。每1 hm2湿地植被氮含量平均值变化趋势为:演替晚期>演替中期>演替早期。根据计算,崇明东滩鸟类自然保护区内芦苇地上部分蓄积的氮含量为227.5 t,互花米草地上部分蓄积的氮含量45.9 t,海三棱草体内蓄积的氮含量为68.2 t。

Temporal and spatial changes of plant biomass and its N content during vegetation succession at Chongming Dongtan wetland

This paper studied the temporal and spatial changes of the biomass and N content of dominant plant species at their different succession stages in Chongming Dongtan wetland.The results showed that the biomass increased gradually during growth season and reached its peak in summer,while its N content was the maximum at early growth stage and the minimum at late growth stage.During succession,the largest biomass was found at mid-succession stage.The N content in the underground part of the plants decreased with succession,while that in the aboveground part increased from mid-succession stage.The vegetation N sink in 1 hm~2 wetland decreased in the sequence of late succession stage>mid-succession stage>early succession stage.Among the test species,Phraqmites australis accumulated about 227.5 t N in its aboveground part,and Spartina alterniflora and Scirpus mariqueter accumulated 45.9 t and 68.2 t N,respectively.