黄土高原丘陵沟壑区狼牙刺群落恢复过程中的种间联结性研究

Study on interspecific association in course of Sophora davidii communities recovering in Loess Plateau hilly region

为了阐明狼牙刺群落恢复过程中种间关系动态特征及其与群落稳定性关系,通过对29个样地调查,采用2×2列联表、方差分析、χ2检验及Jaccard指数分析,对黄土高原丘陵沟壑区经过8a,20a,30a封禁的狼牙刺群落中主要种群间联结性进行了比较研究.结果表明,在封禁8a的的群落中,种群间总体联结性表现出一定程度的正相关,但种间关系不够稳定.封禁20a的群落中,主要种群间总体相关性表现出显著正相关,主要种群间显著负关联种对明显减少,正关联种对增加.封禁30a的群落,种群间负关联进一步减少,主要种群间总体间表现出极显著的正相关,种间关系逐步趋于稳定.随着狼牙刺种群恢复,主要种群间关系日趋复杂,种间关系除过受非生物因素影响,还有物种对环境的改善、物种之间相互适应与竞争等生物因素影响,部分种间关系逐渐演化成共存互利关系.群落中强阳性的植物减少,中生性的植物增加,种群间关系逐步达到相对稳定的阶段.采取封禁措施,减少人为干扰,是狼牙刺群落恢复的有效途径.

In order to explain the interspecific association dynamic characters and it with the stability of Sophora davidii communities, the interspecific correlations in different steps after 8 a, 20 a, 30 a recovery in Loess Plateau hilly region have been analyzed by the series of techniques including the analysis of variance, χ~2 test and Jaccard index with a 2×2 contingency table after investigation of 29 plots. The associations among some species in the communities recovering for 8 years were positive slightly, whereas associations of the species were unstable. The associations in the communities recovering for 20 years were significantly positive and relations among were stable, the number of species-pairs of negative correlation among species reduced sharply. The correlations in the communities recovering for 30 years were extremely significantly positive and more stable. Along with the community recovery, the relations among the species were complicated increasingly. The correlations among species were influenced not only by no-biological factors, but also by the biological factors from environmental improvement, the species competition, species adaptation. Some correlations among species became stages with benefiting each other. The Sophora davidii community was tended to be more stable stage due to the mesophytism species increased and the typical sunny species decreased. The countermeasures of closing and reducing human disturbances are the effective measures for Sophora davidii community recovery.