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退化高寒草甸狼毒群落分类特征及其环境影响因子

花匠小妙招
2025-01-03 00:24

摘要：

狼毒的入侵扩散对青藏高原高寒草甸生态系统的影响和当地畜牧业健康发展的制约日益严重。基于祁连山中段典型样地的群落调查、土壤采样和高精度地形测量数据，采用双向指示种分析（TWINSPAN）、除趋势对应分析（DCA）和冗余分析（RDA）在微观尺度上探讨了退化高寒草甸狼毒群落的分类特征及其对环境因子的响应关系。结果表明：1）TWINSPAN分类将退化草甸狼毒群落划分为3种群丛类型，即Ⅰ）狼毒+紫花针茅+线叶嵩草+披针叶黄华群丛；Ⅱ）狼毒+紫花针茅+委陵菜+美丽风毛菊群丛；Ⅲ）紫花针茅+草玉梅+狼毒+早熟禾群丛。2）RDA分析显示土壤全磷、全钾含量是影响退化草甸狼毒群落分布的主要环境因子，其次是坡向。土壤养分对于狼毒群落空间格局的形成发挥着重要作用，覆盖度高的狼毒群丛对低磷、低钾的土壤环境更敏感。3）随着入侵程度加重，狼毒群丛Ⅲ、Ⅱ、Ⅰ的物种优势度发生明显更替，禾本科植物（早熟禾、紫花针茅）重要值减小（4.10、3.12、2.10），豆科植物（异叶米口袋、花苜蓿）重要值先增后减（0.28、0.57、0.25），莎草科植物（线叶嵩草、矮生嵩草）重要值增加（0.23、1.18、2.19）、毒杂草（狼毒、草玉梅、披针叶黄华、乳白香青、青海刺参等）重要值明显上升（6.10、5.14、10.08），群落Ⅰ和Ⅱ中狼毒替代紫花针茅成为最重要的建群种，狼毒覆盖度呈规律地梯度增加（5.5%、11.0%、29.7%）。本研究反映了狼毒型退化草甸逆向演替过程中的群落构成和环境因子变化特征，可为草地资源管理、退化草甸修复及狼毒综合治理提供参考和依据。

关键词: 狼毒, 退化高寒草甸, 土壤地形因子, 双向指示种分析, 除趋势对应分析, 冗余分析

Abstract:

The invasion of Stellera chamaejasme has exerted an increasing impact on the alpine meadow ecosystem and animal husbandry on the Qinghai-Tibetan Plateau. In this study， we explored the relationships between S. chamaejasme communities and environmental factors on a local scale， using data for plant communities， soil characteristics， and topography collected from a typical degraded meadow in the central Qilian Mountains. The data were analyzed using two-way indicator species analysis （TWINSPAN）， detrended correspondence analysis （DCA）， and redundancy analysis （RDA）. The main findings were as follows： 1） TWINSPAN divided the 45 plots into three association types： Association Ⅰ-S. chamaejasme+Stipa purpurea+Kobresia capillifolia+Thermopsis lanceolata； Association Ⅱ- S. chamaejasme+S. purpurea+Potentilla chinensis+Saussurea pulchra； and Association Ⅲ-S. purpurea+Anemone rivularis+S. chamaejasme+Poa annua.2）The RDA analysis indicated that the distribution of S. chamaejasme was significantly affected by soil total phosphorus and soil total potassium content， followed by aspect. Soil nutrient contents played an important role in the spatial patterning of the three association types， and S. chamaejasme associations with high coverage were more susceptible to low-phosphorus and low-potassium conditions. 3）Species dominance in Associations Ⅲ， Ⅱ， and Ⅰ changed with the spread of S. chamaejasme， the importance values of the Poaceae forages P. annua and S. purpurea decreased （4.10， 3.12， 2.10），those of the Fabaceae species Gueldenstaedtia diversifolia and Medicago ruthenica initially increased and then decreased （0.28， 0.57， 0.25）， those of the Cyperaceaespecies K. capillifolia and Kobresia humilis increased （0.23， 1.18， 2.19）， and those of forbs and poisonous plants （S. chamaejasme， A. rivularis， T. lanceolata， Anaphalis lactea， and Morina kokonorica） markedly increased （6.10， 5.14， 10.08）. Over time， S. chamaejasme replaced S. purpurea and became the dominant species in Associations Ⅰ and Ⅱ， and the S. chamaejasme coverage increased （5.5%， 11.0%， 29.7%）. The results of this study reveal changes in the characteristics of plant communities in a degraded alpine meadow during S. chamaejasme invasion. These findings provide a scientific basis for the development of strategies to manage， restore， and develop the degraded alpine meadow and to effectively control S. chamaejasme.

Key words: Stellera chamaejasme, degraded alpine meadow, soil and topographic factors, two-way indicator species analysis, detrended correspondence analysis, redundancy analysis