水淹干扰对水库水滨带植物群落稳定性与种间关系的影响

Effect of flooding disturbance on plant community stability and interspecific relationship in the riparian zone of reservoir

受城市化与人类活动等因素影响而退化的水滨带植被的恢复与重建是近年来生态环境的热点问题。植物群落的种间关系直接影响植被的演替与恢复。以南水北调中线一期工程通水前的丹江口水库原有水滨带植被为研究对象,对年均多于9个月(海拔142 m以下)、6—9个月(海拔142—147 m)、3—6个月(海拔147—151 m)和少于3个月(海拔151—157 m)的4种不同强度水淹干扰的水滨带植物群落的稳定性和种间关系进行分析,探讨不同水淹干扰强度对水库水滨带植物群落稳定性及种间关系的影响。采用M.Godron稳定性测定法对植物群落稳定性进行分析,通过方差比率(VR)、χ^(2)检验、联结系数(AC)以及Spearman秩相关检验对不同水淹干扰强度下的植物群落优势种进行种间关联分析。结果表明:(1)水库水滨带植物群落稳定性从高到低依次为水淹时长3—6个月、水淹时长6—9个月、水淹时长少于3个月和水淹时长多于9个月。中度水淹干扰下的植物群落稳定性要好于重度和轻度水淹干扰的植物群落;(2)不同水淹干扰强度下水滨带植物群落总体性关联表现为显著正相关。随着水淹时间增加,群落中正联结种对占总对数的比例呈下降趋势,负联结种对比例呈增加趋势,正负联结比值降低,群落内种间联结强度逐渐降低,说明水淹干扰强度增加会导致水滨带植物群落种群间相互依存关系减弱或竞争关系加剧。在此基础上,探讨不同水淹干扰强度下物种的空间分布和生态习性,并提出针对不同水淹干扰强度的水滨带植被恢复的物种选择建议。

The restoration and reconstruction of the degraded riparian vegetation affected by urbanization and human activities have been a hot issue of the ecological environment in recent years.The interspecific relationships of plant communities directly affect the succession and restoration of vegetation.To explore the impact of flooding disturbance on community stability and interspecific relationships in the riparian zone of reservoir,the original riparian vegetation in Danjiangkou Reservoir before the first phase of the Middle Route of the South-to-North Water Diversion Project was investigated.The stability and interspecific relationship of plant communities in the riparian zone under the influence of four different flooding durations were analyzed.Annual average flooding duration was categorized as:those of more than 9 months(below 142 m above sea level),6 to 9 months(between142 m and 147 m above sea level),3 to 6 months(between 147 m and 151 m above sea level),and less than 3 months(between 151 m and 157 m above sea level).The stability of plant communities was analyzed by the M.Godron stability measurement method,and the interspecific correlation analysis of dominant species in plant communities under different flood disturbance was conducted by variance ratio,χ^(2) test,association coefficient value,and Spearman rank correlation test.The results indicated that:(1)the order of community stability of riparian vegetation from high to low was:3 to 6 months flooding duration,6 to 9 months flooding duration,less than 3 months flooding duration,and more than 9 months flooding duration.In a word,the stability of plant community under moderate flooding disturbance was better than the stability of plant community under severe and mild flooding disturbance.(2)There were significantly positive correlations among riparian vegetation of Danjingkou Reservoir at different flooding disturbance.With the increase of flooding duration,the ratio of the positive correlation species to the total species was decreased,the ratio of the negative correlation species to the total species was increased,the ratio of positive and negative correlations species was decreased,and the strength of interspecific association within the community decreased gradually.The results suggested that the interdependence of interspecific association was decreased or the competition of interspecific association was increased within the riparian plant communities along with the increase of flooding disturbance intensity.Based on the results,the spatial distribution and ecological habits of plant species under different flooding duration were discussed.Some suggestions on species selection for vegetation restoration in the riparian zone with different flooding duration were put forward.