碧峰峡常绿阔叶林不同群落物种多样性和土壤理化性质

Species diversity and soil physicochemical properties of different communities in Bifengxia evergreen broad-leaved forest

为了解四川碧峰峡景区常绿阔叶林群落物种多样性和土壤理化性质现状,提出利于森林经营管理及生物多样性保护的可靠方法,采用典型抽样法调查样地27个,通过聚类和排序将样地归类,探究不同类型群落物种多样性特征和土壤理化性质。结果表明:Bray-Curtis距离为0.53时共聚出6类,山矾栲群落(Ⅰ)、山矾青冈群落(Ⅱ)、木荷山矾群落(Ⅲ)、木荷日本杜英群落(Ⅳ)、栲杉木群落(Ⅴ)和栲枹栎群落(Ⅵ),各群落优势种差异显著;类型Ⅲ多样性水平最高,类型Ⅱ、Ⅵ、Ⅴ居中,类型Ⅰ与Ⅳ多样性水平偏低;该区土壤呈较强酸性,含水量充沛;土壤全氮、全磷、全钾、有机质含量均以类型Ⅲ最低;类型Ⅰ、Ⅳ中各养分含量居中,且类型Ⅰ具有最高的全磷含量;类型Ⅱ、Ⅴ具有最高的全氮、有效磷、全钾、速效钾含量;冗余分析结果显示,有机质、全氮和土壤含水量是影响群落物种多样性的主要因子,与各多样性指数呈显著(P<0.05)或极显著(P<0.01)负相关。类型Ⅲ与Ⅵ物种多样性居1、2位,但多样性丰富的植被消耗大量养分,土壤趋于贫瘠;类型Ⅰ与Ⅳ多样性水平偏低,群落发展态势不佳;类型Ⅱ和类型Ⅴ多样性处于中等水平,土壤肥力保蓄最好,具备向顶极群落演替的潜力,建议适当介入人为措施,以提高林分生态功能和抵御干扰能力。

To better understand species diversity and soil physicochemical properties of evergreen broad-leaved forests in Bifengxia scenic spot,Sichuan Province,and thus put forward a reliable method for forest management and biodiversity protection,we used typical sampling method to investigate 27 plots.Through clustering and sorting,the plots were classified objectively.On this basis,we explored species diversity and soil physicochemical properties of different community types.Six types were classified when Bray-Curtis distance was 0.53,i.e.,Symplocos sumuntia-Castanopsis fargesii community(Ⅰ),Symplocos sumuntia-Cyclobalanopsis glauca community(Ⅱ),Schima superba-Symplocos sumuntia community(Ⅲ),Schima superba-Elaeocarpus japonicus community(Ⅳ),Castanopsis fargesii-Cunninghamia lanceolata community(Ⅴ),and Castanopsis fargesii-Quercus serrata community(Ⅵ).The dominant species of each community was significantly different.TypeⅢhad the highest diversity level;TypesⅡ,ⅥandⅤwere in the middle;TypesⅠandⅣhad low diversity level.The soil in this area was relatively acidic and had ample water content.Soil total nitrogen,total phosphorus,total potassium and organic matter contents were the lowest in typeⅢ.The nutrient contents of typesⅠandⅣwere in the middle,and typeⅠhad the highest total phosphorus content.Types II and V had the highest total nitrogen,available phosphorus,total potassium,and available potassium contents.The results of redundancy analysis showed that organic matter,total nitrogen and soil water content were the main factors affecting species diversity of the community,which were significantly(P<0.05)or extremely significant(P<0.01)negatively correlated with each diversity index.In conclusion,species diversity of TypesⅢandⅥwere ranked first and second,respectively,but these diversity-rich vegetation consumed a lot of nutrients,which made the soil nutrient-deficient.The diversity level of TypesⅠandⅣwere low,and the community development trend was not good.TypesⅡandⅤhad a moderate level of diversity,and their soil fertility conservation were the best,indicating that they had the potential for the succession to climax community.We suggested that appropriate artificial measures should be taken to improve the ecological function and disturbance-resisting ability of stands.