旅游干扰对历山亚高山草甸优势种群种间相关性的影响

The effect of traveling on the interspecific correlation of dominant populations in Lishan subalpine meadow,Shanxi Province

基于2×2列联表,应用方差比率法、χ2检验、Pearson相关系数检验及Spearm an秩相关系数检验等数量分析方法研究了旅游干扰对山西历山舜王坪亚高山草甸种间关联程度的影响。结果表明:(1)不同旅游距离带的联结指数(VR)均大于1,但统计量W均界于χ2分布的上下临界值之间。群落总体呈正关联,但联结性较弱,种的分布相对独立。(2)随着距游径距离的增加,4条不同旅游距离带的联结指数(VR)呈下降趋势;正负关联比有所增加,2χ检验显著率、Pearson相关检验显著率和Spearm an秩相关检验显著率都明显下降,说明旅游干扰对舜王坪亚高山草甸种间关联程度产生了一定的影响,距离游径越远,种间关联越趋于随机性,但这种影响尚未引起种间联结性的改变。(3)χ2检验与Pearson相关系数检验、Spearm an秩相关系数检验结果用来刻划种间相关性具有一定的相似之处,但仍存在一定差异,结合使用效果更好。与Pearson相关检验相比,Spearm an秩相关检验更具灵敏性。4)本研究结果支持随着群落演替进程的发展,群落种群总体向着无关联发展的观点。

Lishan Mountain is located in the eastern of Zhongtiao Ranges in Shanxi Province 35°16′- 35°27′N, 111°51′- 112°30′ E. Its top peak, Shunwangping, is at 2 358m above sea level. Lishan Provincial Natural Reserve was authorized by Shanxi Government in 1983, and Lishan National Natural Reserve was authorized by the State Council of the People＇s Republic of China in 1988. Its area （248km^2） is the biggest and there are the richest plant resources among all Natural Reserves in Shanxi Province. There were 972 species of seed plants, belonging to 491 genera and 123 families. Because of its abundant natural scenery and cultural scenery, it has been one of the famous traveling spots. With the development of tourism, however, its vegetation resource was damaged in some degrees. In order to evaluate the effect of tourism disturbance on interspecific association, the vegetation in Shunwangping subalpine meadow were investigated. Four parallel transects, which were 0m, 4m, 8m and 12m respectively away from the road, included 77 quadrats （21 quadrats in transects 1, 20 quadrats in transects 2, 19 quadrats in transects 3 and 17 quadrats in transects 4, respectively）. Based on the field investigation data, 88 species were recorded.and 18 dominant species were reserved after deleting some species which coverage or frequency was smaller than 5%. The interspecific correlation influenced by traveling in the Shunwangping subalpine meadow was studied by using X^2-test for 2 × 2 contingency table, variance ratio （VR） test, Pearson＇s correlation coefficient test and Spearman＇s rank correlation coefficient test. The results was as follows： The association index （VR） of different distance transects was all bigger than one. Based on the statistics W （X0.95N^2〈W〈X0.05N^2）, the overall association of the community was not significant （p〉0. 05） and tended to no correlation among all species, and it meant that the species of the community were mostly independently distributed. With the increase of the distance between the traveling road and the transects, the overall association index （VR） of four transects declined. The proportion of the positive and negative association increased slightly, and the significant percentage of X^2 test, Pearson＇s correlation coefficient and Spearman rank correlation coefficients decreased respectively. It suggested that traveling interference influenced on the interspecific correlation in some degrees, but did not lead to quality change of interspecific association in this subalpine meadow. The farther the distance was, the bigger the randomness of interspecific association was. In addition, compared with Pearson＇s correlation Coefficient test, Spearman＇s correlation coefficient test was more sensitive and could make up the defect of Pearson＇s correlation coefficient test. The results suggested that it was better to investigate the interspecific correlation by combining X^2-test with Pearson＇s correlation coefficient test and Spearman＇s rank correlation coefficient test. The results agree with the idea that interspecific association tends to no correlation with the development of community succession stages, that is, the more the traveling disturbance is, the stronger the interspecific competitive become, and the bigger the interspecific correlation is; on the contrary, the less the traveling is, the weaker the interspecific competitive become, the smaller the interspecific association is.