云南省六个国家级自然保护区外来入侵草本植物与本地植物的关系

Relationships between invasive alien grasses and native plants across different national nature reserves, Yunnan Province

为明确不同自然保护区外来入侵草本植物及其与本地植物多样性之间的关系,以我国生物多样性丰富的云南省为研究对象,于2014年对云南省6个国家级自然保护区的82个1 m2小样方(78个100 m2大样方)中外来入侵草本植物和本地植物物种丰富度和密度进行调查,并分析外来入侵草本植物物种丰富度与本地草本植物物种丰富度、外来入侵草本植物密度与本地草本植物密度的关系及对不同自然保护区外来入侵草本植物物种丰富度的差异进行分析。结果显示,共调查发现22种外来入侵草本植物,其中纳板河流域国家级自然保护区种类最多,达14种,金平分水岭国家级自然保护区仅有2种;6个国家级自然保护区本地草本植物的物种丰富度与外来入侵草本植物的物种丰富度之间、本地草本植物密度与外来入侵草本植物密度之间均呈现正、负2种相关关系,其中哀牢山国家级自然保护区本地草本植物的物种丰富度与外来入侵草本植物物种丰富度呈显著负相关,其它5个国家级自然保护区的相关性均不显著。简单回归分析表明自然保护区外来入侵草本植物物种丰富度与本地草本植物物种丰富度、本地草本植物盖度、本地乔灌木物种丰富度呈显著负相关,多元回归分析结果表明乔灌木物种丰富度和经纬度是造成不同自然保护区外来入侵草本植物物种多样性差异的主要原因。

To examine the distribution of invasive alien grasses and the relationship between native and invasive alien grass richnesses, six national nature reserves located in Yunnan Province, one of biodiversity hotspots, were selected as study areas. Eighty-two subplots (1 m^2) in 78 plots (100 m^2) were investigated for the richness, abundance and cover of plant species in the six national nature reserves. The relationships between the richness and density of native and invasive alien grasses were compared among different nature reserves. The factors influencing the richness in different nature reserves were also analyzed. Twenty-two invasive alien grasses were found in the six national nature reserves, and 14 invasive alien species were distributed in the Nabanhe River Basin National Nature Reserve, but only two invasive alien species were distributed in the Jinping Watershed National Nature Reserve. At the one-sequare-meter scale, postive and negative relationships of the species richness and density between native and invasive alien grasses were found in the six national nature reserves. With increasing richness of native grass, the richness of invasive alien grass significantly decreased in Ailao Mountain National Nature Reserve, but no significant correlations trends were found in other nature reserves. The results of simple linear regressions showed that alien grass richness in different national natural reserves was negatively correlated with the native grass richness, cover of native grass and the species richness of native trees and shrubs. The results of multiple regression showed that the variance of invasive alien grass richness was mainly explained by the richness of native trees and shrubs, and the longitude and latitude.