濒危药用植物掌裂兰在青藏高原东源地带种群结构及群落特征分析

Population structure and community characteristics of endangered medicinal plant Dactylorhiza hatagirea in the eastern source region of the Qinghai-Xizang Plateau

关键词:  掌裂兰, 种群密度, 高度级结构, 物种组成, 种间关联性, 藏药

Key words:  Dactylorhiza hatagirea, population density, height structure, species composition, interspecific correlation, Tibetan medicine

摘要:

为明确青海省同德县、海晏县和泽库县分布的掌裂兰(Dactylorhiza hatagirea)种群的结构及群落特征,该研究分析掌裂兰种群密度、高度等数量特征及其伴生群落的物种组成,并运用物种重要值、种间相关性、物种多样性指数等方法对掌裂兰与伴生物种的种间关联性进行分析。结果表明:(1)3个地点掌裂兰种群密度和高度均较低,平均种群密度不足10 ind.·m^-2,种群高度以<20 cm和20～30 cm为主,海晏地点生境退化明显,掌裂兰种群高度<20 cm,占比为80%以上。(2)掌裂兰的伴生群落以线叶嵩草(Kobresia capillifolia)、马蔺(Iris lactea)、小嵩草(Kobresia humilis)、黄帚橐吾(Ligularia virgaurea)、小苔草(Carex parva)等为优势种。(3)在种间关系上,掌裂兰与群落中绝大多数物种无显著相关性,但与优势种线叶嵩草、马蔺具有显著的正相关性(P<0.05),与黄帚橐吾、小米草(Euphrasia pectinata)存在显著的负相关性(P<0.05)。该研究认为掌裂兰适生区狭窄、自身更新能力不足,气候因素以及人类活动可能是导致其濒危的主要原因。建议采取就地保护、自然回归等措施以扩大其种群数量。在生产实践中,可将黄帚橐吾、小米草视为掌裂兰不利生境的指示植物,而线叶嵩草可视为掌裂兰有利生境的指示植物,马蔺则不适宜作为掌裂兰有利生境的指示物种。

Abstract:

Dactylorhiza hatagirea is an endangered medicinal plant with significant ecological and cultural value in the Qinghai-Tibet Plateau. To clarify the population structure and community characteristics of Dactylorhiza hatagirea in Tongde County, Haiyan County, and Zeku County of Qinghai Province, China, this study analyzed the quantitative characteristics such as its population density, height, and the species composition of its associated communities. Species importance value, interspecific correlation, and species diversity indices were employed to analyze the interspecific correlations between Dactylorhiza hatagirea and its associated species. The results were as follows:(1)Population density and height of Dactylorhiza hatagirea was relatively low across all three sites(average population density<10 ind.·m^-2), with population height dominanted by individuals < 20 cm and 20 - 30 cm.(2)Associated communities mainly comprised Kobresia capillifolia, Iris lactea, Kobresia humilis, Ligularia virgaurea, and Carex parva.(3)In terms of interspecific relationships, Dactylorhiza hatagirea showed no signilicant correlation with the majority of species in the community, and had positive correlations with Kobresia capillifolia a and Iris lactea (P<0.05), but negative correlations with Ligularia virgaurea and Euphrasia pectinata(P<0.05). This study suggests that Dactylorhiza hatagirea has a narrow suitable habitat and limited self-renewal capacity. Climate factors and human activities may be the primary reasons for its endangerment. For conservation, in-situ protection and natural restoration measures are recommended to enhance its population. In practical applications, Ligularia virgaure and Euphrasia pectinata can serve as indicator species for unfavorable habitats, while Kobresia capillifolia is a reliable indicator of favorable habitats for Dactylorhiza hatagirea, and Iris lactea is not suitable as an indicator species due to its inconsistent relationship with the target plant. This study provides a framework for identifying critical habitats and designing targeted conservation and habitat management of Dactylorhiza hatagirea in the Qinghai-Tibet Plateau.