Niche characteristics of dominant species in Napahai wetland plant communities under different disturbance regimes

Abstract

2011年5、7、10月在纳帕海湖滨湿地选择3种不同人为干扰生境类型,每个干扰生境布设3个固定样方,对湖滨湿地植物群落中主要种群的空间生态位和季节特征进行研究.结果表明:在3种干扰水平维度上,春、夏、秋3个季节湖滨湿地植物生态位宽度指数前4位由大到小变化的顺序分别是:春季:绵毛酸模叶蓼(0.9731) >华扁穗草(0.8040) >平车前(0.6468) >毛果弹裂碎米荠(0.5021);夏季:平车前(0.8674) >荠(0.8581) >华扁穗草(0.8440) >绵毛酸模叶蓼(0.7814);秋季:华扁穗草(0.9698) >绵毛酸模叶蓼(0.7730) >平车前(0.6650) >西南委陵菜(0.6647).因此,湖滨湿地植物的生态位宽度在不同干扰水平上会随着季节的变化出现显著的改变.同样,生态位重叠和生态位分化随着季节的变化也会发生明显的改变,其中春、秋季的生态位重叠程度低,分化程度高,且春季较秋季略强,而夏季的生态位重叠程度高且分化程度低.这些结果为揭示纳帕海湖滨湿地植物群落格局与动态及人为干扰影响生物多样性的生态过程提供了基础资料,同时为进一步深入研究不同人为干扰下湖滨湿地植物群落中主要种群敏感性反应的规律提供了科学依据.;This study investigated the spatial and seasonal niche characteristics of the dominant wetland plants in Napahai wetand.Under each disturbance regime,three plots were selected in 2011,and the data were collected in May,July,and October of the year.The results showed that there was a seasonal variation in species niche values under three different disturbance regimes.In spring,the order of the variation in niche breadth (from the highest to the lowest) is Polygonum lapathifolium (0.9731) >Blysmus sinocompressus (0.8040) >Plantago depressa(0.6468) >Cardamine impatiens (0.5021).In summer,the order is changed into Plantago depressa(0.8674) >Cardamine impatiens (0.8581) >Blysmus sinocompressus (0.8440) >Polygonum lapathifolium (0.7814).In fall,the order is Blysmus sinocompressus (0.9698) >Polygonum lapathifolium (0.7730) >Plantago depressa (0.6650) >Potentilla fulgens (0.6647).Similarly,niche overlap and niche differentiation also alter remarkably with seasons.The lowest niche overlap and the highest niche differentiation occur in spring and fall,whereas the highest niche overlap and the lowest niche differentiation occur in summer.Our results provide important information in regard to plant community composition,structure,dynamics,and diversity in Napahai wetland under different disturbance regimes,and help the understanding of the sensitivity of varying wetland plants in responses to different disturbances.