元江干热河谷植物群落特征及土壤肥力研究

对云南省元江县境内元江河谷山坡上的5种主要植被类型的群落特征、植物多样性现状、植物区系组成以及不同群落土壤理化性质进行了比较研究.结果表明:干热河谷区内,植物群落生活型组成主要以小乔木、灌木和草本植物为主,基本没有高大的乔木树种和大型藤本植物.草本植物生长旺盛,物种多样性和丰富度均较乔灌层高,但均匀度较其低.5种群落之间的相似性程度较低,且各群落均处于相对稳定的状态.各群落中共记录有61个科,144个属,194个物种,其植物区系的泛热带特征比较明显,其中泛热带分布科有31个,占除去广布科以外所有科的77.5%,泛热带分布属有50个,占除去广布属以外所有属的38.2%.蝶形花科Papilionaceae、禾本科Gramineae、大戟科Euphorbiaceae、菊科Compositae、锦葵科Malvaceae等科在元江干热河谷植被中占有极为重要的地位.群落土壤理化性质的研究表明,元江干热河谷各类植被的土壤元素中,除了磷元素极其缺乏以外,大多数处于中等以上水平.土壤肥力状况与植被的生长状况之间关系紧密,其中,土壤肥力最好的是群落结构比较复杂、残存的稀树旱生林.

Characteristics of Plant Communities and Their Soil Fertilities in Dry-hot Valley of Yuanjiang County, Yunnan, China

Phytosociological characteristics, plant diversity, floristic composition and soil physicochemical properties of five main plant communities in the dry-hot valley of Yuanjiang County, Yunnan Province were studied. The results indicate: (1) the plant communities are composed mainly of small trees, shrubs and herbs, with fewer large trees and lianas; (2) the herbaceous plants have a higher plant diversity and greater species richness than trees and shrubs, but lower evenness indexes; (3) the similarity is small among the five communities; (4) 194 species of 144 genera in 61 families are recorded from the five communities; (5) the flora of the communities mainly consists of pan-tropic geographical elements at family and generic levels; (6) Papilionaceae, Gramineae, Euphorbiaceae, Compositae and Malvaceae are the dominant families in the dry-hot valley in Yuanjiang; (7) the soil is rich in chemical elements except phosphorus and soil fertility is closely correspondent to ground vegetation; and (8) the dry open woodland with a complex community structure has the highest soil fertility.