土壤盐分对高寒草甸主要植物生态位的影响

采用Levins生态宽度指数和Cowell生态位相似性公式，计算了巴音布鲁克高寒草甸主要物种在4个盐分梯度上土壤水分、有机质、速效钾3个资源维的生态位宽度及生态位相似性.结果表明：在3个资源维上,随着土壤盐分含量的增加，主要建群种细果苔草的平均生态位由0.4433降至0.1740，伴生种鹅绒委陵菜的平均生态位由0.1263升至0.2215，说明耐盐性较差的物种生态位宽度逐渐减小，耐盐性较好的物种逐渐增大，可能成为重要的演替种.随土壤盐分含量的增加，耐盐性较差物种间的生态位相似性逐渐升高, 而耐盐性较好的物种则逐渐降低.细果苔草和线叶嵩草的生态位相似比例由0.701升至0.842, 而鹅绒委陵菜和山地蒲公英的生态位相似比例由1降至0.708.物种的生物学特性是物种对土壤盐分响应不同的主要原因.

Effects of soil salt on the niche of main plant species in alpine meadow.

By using Levins niche breadth index and Cowell similarity index, the niche breadth and niche similarity of main plant species in Bayanbulak alpine meadow were calculated, based on 3 resources dimensions (soil moisture, organic matter, and available K) along four gradients of soil salt content. The results showed that with the increase of soil salt content, the average niche breadth of main constructive species Carex stenocarpa based on the 3 resources dimensions decreased from 0.4433 to 0.1740, while that of companion species Potentilla anserina increased from 0.1263 to 0.2215, indicating that the niche breadth of the species with low salt-endurance decreased gradually, while the species with relatively high salt-endurance had an increasing niche breadth, being able to be an important succession species. With the increase of soil salt content, the niche similarity between the species with low salt-endurance increased, while that between the species with high salt-endurance was in adverse. The niche similarity between C. stenocarpa and Kobresia capillifolia increased from 0.701 to 0.842, and that between P. anserina and Taraxacum pseudolpinum decreased from 1 to 0.708. The difference in biological characters among plant species should be the main reason for their different responses to soil salt content.