石漠化程度对苔藓植物多样性及其结皮土壤化学性质的影响

以研究区域不同石漠化等级为代表,分析苔藓多样性特征及其结皮土壤化学性质变化规律,探索其对石漠化进程的响应机制。结果显示:(1)苔藓物种多样性:含苔藓14科29属84种,其中苔类2科2属2种;(2)多样性指数表现为:重度石漠化阶段中度石漠化轻度石漠化极重度石漠化无石漠化;其均匀度为:中度石漠化阶段轻度石漠化重度石漠化极重度石漠化无石漠化;(3)随着石漠化程度加剧,苔藓群落组成中混合群落比重下降而纯群落比重上升;群落生活型则呈现交织型递减而丛集型递增的规律。(4)结皮土壤中全氮、全磷和微生物量碳随石漠化加剧均都呈递减趋势。(5)通过Partial RDA分析发现密枝青藓(Brachythecium amnicolum)、褶叶藓(Palamocladium nilgheriense)和美灰藓(Eurohypnum leptothallum)等可用于石漠化生态修复。石漠化程度对苔藓多样性影响不显著,但对其群落特征和生活型影响显著。因此可以结合苔藓群落和生活型特征监测石漠化,同时也可使用苔藓作为先锋植物引进用于石漠化早期修复。

The effects of rocky desertification degree on bryophyte diversity and soil chemical properties of crusts

Rocky desertification is one of the most serious economic and ecological problems encountered in the development of southwestern China. Understanding the characteristics of bryophyte diversity and soil chemical properties in different stages of rocky desertification, together with their response mechanisms to rocky desertification, is of vital importance in limiting further species loss and in the selection of species suitable for restoration and regeneration. Bryophyte species diversity, evenness, species richness, life forms, community characteristics and soil chemical properties were investigated in areas with differing levels of rocky desertification in Karst Park, Guiyang, Guizhou Province, China. Eighty-four bryophyte taxa from 29 genera and 14 families, were found in the study area; with the exception of 2 liverwort taxa from 2 genera and 2 families, all were mosses. The degree of rocky desertification in the study area was classified into five levels:nil-slight-moderate-severe -extreme. The order of species diversity of bryophytes in each of these categories was:severe (i.e. most species) > moderate > slight > extreme > nil (i.e. least number of species); the order of evenness index was determined as:moderate > slight > severe > extreme > nil. As the degree of rocky desertification increased, there was a corresponding decrease in the proportion of multi-species bryophyte communities and an increase in the proportion of single species communities. Wefts and turfs were the most commonly occurring life forms; with increasing rocky desertification, there was a corresponding increase in the proportion of turfs. Total nitrogen, total phosphorus, and microbial biomass carbon in the underlying soil, were markedly affected by rocky desertification, and decreased as the degree of rocky desertification increased. Partial redundancy analysis determined that three bryophyte taxa, Brachythecium amnicolum, Palamocladium nilgheriense, and Eurohypnum leptothallum, are suitable species for use in ecological restoration of areas affected by rocky desertification. The degree of rocky desertification did not significantly influence bryophyte diversity, but it did significantly affect community characteristics and life forms. Thus, monitoring changes in rocky desertification is possible by using characteristics of bryophyte communities and life forms. Suitable bryophytes can also be used as pioneer species for the restoration and recovery of areas of rocky desertification.