小兴安岭五种林型早春草本植物多样性及其环境解释

Early-spring herb diversity and its environmental interpretation of five forest types in Xiaoxing′an Mountains, China

早春草本层植物作为草本层动态变化的早期阶段,是森林的重要组成部分,对于维持森林生态系统功能及其多样性具有重要意义。为探究小兴安岭地区早春草本层植物对人为干扰后引起的林型改变的响应,以黑龙江凉水国家级自然保护区内的五种林型(白桦次生林(Betula platyphylla)、红松(Pinus koraiensis)人工林、落叶松(Larix gmelinii)人工林、阔叶红松择伐林以及阔叶红松林)为研究对象,分析林下早春草本层植物多样性的差异及其影响因素。结果显示:(1)研究区林下早春草本层植物共60种,隶属26科52属,林下优势种主要以银莲花(Anemone cathayensis)、东北羊角芹(Aegopodium alpestre)为主,五种林型早春草本层植物组成相似度较高;(2)五种林型不同生活史对策早春草本层植物的密度、盖度以及多样性指数均呈现显著差异;(3)土壤pH对早春生长期植物的密度、盖度及多样性指数,林下光对早春开花植物的密度和盖度以及早春展叶植物的多样性指数具有较高的解释率;(4)早春生长期植物的密度、盖度及多样性指数与土壤pH呈显著的正相关关系,其多样性指数与土壤全氮呈显著的单峰型关系;林下光与早春开花植物的密度呈显著的单峰型关系,与盖度呈显著的负相关关系;早春展叶植物的多样性指数与林下直射光和林下总光照呈显著的“U”型关系、与林下散射光呈显著的正相关关系。林型改变引起不同生活史对策的早春草本层植物的密度、盖度以及多样性的显著差异,但变化趋势不一致;土壤pH和林下光是影响林下早春草本层植物群落数量特征的主要环境因子,影响程度因草本植物自身生活史对策特性而存在差异。本研究结果为理解小兴安岭地区植物群落的生长发育特征及其影响因素提供理论依据。

Early spring herbaceous plants,as the early stage of the dynamic change of the herbaceous layer,are an important part of the forest and are of great significance for maintaining the function and diversity of forest ecosystem.In order to explore the response of early spring herb plants to forest type changes caused by human disturbance in Xiaoxing′an Mountains,five forest types(Secondary birch forest,Korean pine plantation,Dahurian larch plantation,Selectively cut mixed broadleaved-Korean pine forest and Mixed broadleaved-Korean pine forest)in Liangshui National Nature Reserve of Heilongjiang Province were selected as the research objects,and the diversity of early spring herb plants under forest and its influencing factors were analyzed.The results showed that:(1)a total of 60 species of herbaceous plants in early spring were found under the forest in the study area,belonging to 52 genera and 26 families.The dominant species under the forest were mainly Anemone cathayensis and Aegopodium alpestre.High similarity of plant community composition in herb layer of five forest types in early spring.(2)The density,coverage and diversity index of early spring herb plants in the five forest types with different life-history strategies showed significant differences.(3)Soil pH had a high explanation rate for the density,coverage and diversity index of early-spring growing herbs,and understory light had a high explanation rate for the density and coverage of early-spring flowering herbs and for diversity index of early-spring foliating herbs.(4)The density,coverage and diversity index of early-spring growing herbs were positively correlated with soil pH,and the diversity index was unimodal with soil total nitrogen(TN).The relationship between understory light and density of early-spring flowering herbs showed a single peak,and a negative correlation with coverage.The diversity index of early spring foliating herbs showed an aboriginal‘U’type relationship with transmitted direct light(TDir)and transmitted total light(TTot),and a significant positive correlation with transmitted diffused light(TDif).There were significant differences in density,coverage and diversity index of early spring herb plants in different life-history strategies due to changes of forest type,but the trend was inconsistent.Soil pH and light conditions were the main environmental factors affecting the quantitative characteristics of herbaceous plants in early spring under forest,and the degree of influence varied according to the characteristics of life-history of herbaceous plants.The results of this study provided a theoretical basis for understanding the growth and development characteristics and influencing factors of plant communities in Xiaoxing′an Mountains.