喀斯特季节性雨林优势种群生态位特征及其对石漠化地区植被修复的启示

Niche Characteristics of Dominant Populations of Tropical Karst Seasonal Rainforest Implications for Vegetation Restoration in Rock Desertification Region

关键词:  喀斯特季节性雨林  优势种群  生态位特征  石漠化  植被修复

Key words:  karst seasonal rainforest  dominant population  niche characteristics  rock desertification  vegetation restoration

摘要:

[目的]研究北热带喀斯特季节性雨林优势木本植物种群生态位特征，了解群落内各种群对资源的利用状况及生态适应性，为生物多样性保护及退化生态系统的植被恢复提供参考。[方法]在对弄岗15 hm²北热带喀斯特季节性雨林进行样方划分及植被调查的基础上，以375个20 m×20 m的样方作为不同的资源位，以各样方物种重要值作为生态位计测的状态指标，运用Levins和Pianka公式计算、分析样地内30个优势种群的生态位宽度和生态位重叠度。[结果]生态位宽度较大的种群为苹婆、广西牡荆、茎花山柚、假玉桂和日本五月茶等，生态位宽度分别为207.04，195.01，176.88，142.05和126.23；生态位宽度较小的是三角车、肥牛树、对叶榕、米扬噎和中国无忧花等，分别为37.95，35.79，33.83，25.87和15.76；重要值排序靠前的闭花木、蚬木、海南椴和劲直刺桐的生态位宽度居于中间位置，生态位宽度为107.54，77.54，113.48，95.12。生态位重叠值等于1的种对有0对；生态位重叠值大于或等于0.5、小于1的种对有20对，占总种对数的4.6%，生态位重叠值大于0小于0.5的种对有401对，占92.2%；生态位重叠度等于0的种对有14对，占种对数3.2%。[结论]喀斯特季节性雨林中适应性强、分布范围广的种群，生态位宽度较大，且绝大部分种对的生态位重叠度较小。苹婆、金丝李和茎花山柚等生态位宽度比较大，资源利用和环境适应能力较强、而且兼具生态和经济价值，在岩溶石漠化地区进行植被恢复时应作为优先考虑物种。要建立完整的石漠化地区植被恢复参照系统，应在不同岩溶气候带建立不同演替阶段的天然植被监测样地，分析其环境条件、群落结构及种间关系等。在针对某个地区某个恢复阶段进行植被恢复设计时，应参照该地区这个恢复阶段的天然群落，选择生态位宽度大的物种作为先锋种，选择生态位重叠度较小的物种作为伴生种。

Abstract:

[Objective] To understand resource utilization status and ecological adaptability of various populations in the tropical karst seasonal rainforest,and provide reference for biodiversity conservation and vegetation restoration in degraded ecosystem,the niche characteristics of dominant woody plant populations of tropical karst seasonal rainforest were studied.[Methods] Based on the quadrat division and vegetation survey of the 15 hm² north tropical karst rain forest plot in Nonggang,375 20 m×20 m quadrats were used as different resource sites,and the species importance values in the quadrat were used as the state index of niche instrumentation. The Levins and Pianka formulas were employed to calculate and analyze niche breadth and niche overlaps of 30 dominant population in Nonggang plot.[Results] The niche breadth of Sterculia monosperma,Vitex kwangsiensis,Champereia manillana var.Longistaminea,Celtis timorensis and Antidesma japonicum were much larger than that of others and their niche breadth values were 20 704,195.01,176.88,142.05 and 126.23 respectively,while Rinorea bengalensis,Cephalomappa sinensis,Ficus hispida,Streblus tonkinensis and Saraca dives had narrower niche breadths and their niche breadth values were 37.95,35.79,33.83,25.87 and 15.76 respectively. The niche breadths of the Cleistanthus sumatranus,Excentrodendron tonkinense,Diplodiscus trichosperma and Erythrina stricta whose important values were ranked first were in the middle and their niche breadths were 107.54,77.54,113.48 and 95.12 respectively. There were 0 pairs of species with niche overlap value equal to 1,20 pairs with niche overlap value greater than or equal to 0.5 and less than 1,accounting for 4.6% of the total species. There were 401 pairs of niche overlap values greater than 0 and less than 0.5,accounting for 92.2%,14 pairs of niche overlaps equal to 0,accounting for 3.2% of the total species pairs.[Conclusion] In the seasonal karst rain forest,the highly adaptable and widely distributed species have larger niche breadths,and the niche overlap values of most species counterpart are small.S.monosperma,Garcinia paucinervis and C.manillana var.Longistaminea have larger niche breadths,their resource utilization and environmental adaptability are strong,and have both ecological and economic values. Therefore they should be considered as a priority species for vegetation restoration in karst rocky desertification areas. In order to establish a complete reference system for vegetation restoration in rocky desertification areas,natural vegetation monitoring sample in different succession stages should be established in different karst climate zones,and analyze their environmental conditions,community structures and inter-specific relationships and so forth. When designing vegetation restoration for a succession stage in a certain area,the natural community at this stage of succession should be referred to,and species with broad niche breadth should be selected as pioneer species,and species with a large niche overlap should be selected as companion species.