喀斯特生态恢复下土壤大型动物群落结构与基本肥力的协同恢复

摘要

[目的]揭示土壤大型动物在喀斯特生态恢复过程中的指示作用,为了解喀斯特生态恢复的土壤学过程机制和构建生态恢复技术体系提供理论依据.[方法]采用空间代替时间的方法,选择系列种植年限(2、4、8和12年)人工林样地,分别编号为F-2a(2年龄人工林)、F-4a(4年龄人工林)、F-8a(8年龄人工林)和F-12a(12年龄人工林),并以石漠化自然生长样地为对照(CK),调查分析土壤表层(0~10 cm)大型动物群落对人工林生态恢复的响应特征及其与土壤基本肥力的关系.[结果]孔隙度、湿度、总有机碳、可溶性有机碳、全氮、速效氮和微生物碳含量等土壤基本肥力指标均随喀斯特生态恢复年限的延长而逐渐增加或升高,其年均恢复速率分别为1.18%、0.63%、0.48 g/kg、33.92 mg/kg、0.05 g/kg、2.77 mg/kg和62.08 mg/kg.从5个样地中共捕获土壤大型动物7621只,鉴定为13个类群,其中优势类群为腹足纲、膜翅目和鞘翅目.除鞘翅目和半翅目外,其余各类群特别是稀有类群的鳞翅目、地蜈蚣科和双翅目数量整体上随生态恢复年限的延长呈增加趋势.人工林生态恢复样地的土壤大型动物类群数(12~13种)、丰富度指数(SR, 1.51~1.63)、Shannon-Wiener指数(H′,1.91~2.02)和均匀度指数(J′,0.77~0.81)均显著高于CK样地(P<0.05,下同).喀斯特生态恢复后土壤大型动物的总数显著增加,且与土壤主要肥力指标呈显著或极显著(P<0.01)正相关;冗余分析结果也表明,鳞翅目、膜翅目、腹足纲、蚁科、直翅目和蜘蛛目等土壤动物的数量与土壤孔隙度和微生物碳含量等肥力指标关系密切.[结论]喀斯特生态恢复下土壤大型动物群落结构与土壤基本肥力的恢复具有一定协同作用,也表明土壤大型动物群落指标对喀斯特地区土壤生态系统恢复效果具有良好的指示作用.%[Objective]Indicating functions of soil macrofauna during restoration of karst vegetation were revealed to provide scientific basis for further understanding the mechanism of soil science process of karst ecological restoration and building the technical system of ecological restoration.[Method]In the method of space-for-time substitution,a series of plantation plots with planting age gradients(2,4,8,12 years)were selected,which were numbered F-2a(2-year-old plantation),F-4a(4-year-old plantation),F-8a(8-year-old plantation)and F-12a(12-year-old plantation),and response characteristics of macrofauna community on the soil surface(0-10 cm)to the ecological restoration of plantation and their relationship with basic soil fertility were investigated and analyzed by taking samples of natural growth rocky desertifica-tion as control(CK).[Result]Soil basic fertility indicators,including soil porosity,moisture,total organic carbon,solu-ble organic carbon,total nitrogen,available nitrogen and microbial biomass carbon contents gradually increased with the extension of karst ecological restoration years,and their average annual recovery rates were 1.18%,0.63%,0.48 g/kg,33.92 mg/kg,0.05 g/kg,2.77 mg/kg and 62.08 mg/kg respectively.A total of 7621 soil macrofaunas were collected from 5 sample plots and classified as 13 groups,among which,Gastropoda,Coleoptera and Hymenoptera were dominant groups.Soil macrofauna number for all the groups especially Lepisoptera,Geophilidae and Diptera in rare groups(except for Coleoptera and Hemiptera)grew following the extension of eco-restoration years. Soil macrofaunal species number (12-13 species),richness index(SR,1.51-1.63),Shannon-Wiener index(H′,1.91-2.02)and evenness index(J′,0.77-0.81) in the plantation plots were significantly higher than those in CK plot(P<0.05,the same below). Total number of soil macrofauna increased significantly after karst ecological restoration,and was extremely positively correlated(P<0.01) with the main soil fertility indicators.According to redundancy analysis,the number of soil macrofauna such as Lepisop-tera,Hymenoptera,Gastropods,Formicidae,Orthoptera and Araneae showed strong positive correlation with fertility in-dicators such as soil porosity and microbial carbon content.[Conclusion]The results indicate that,soil macrofauna com-munity structure had certain synergistic effects with the restoration of soil basic fertility under karst ecological restoration, and it also shows that soil macrofauna community indicators plays an important role as bio-indication on soil ecosystem restoration in karst areas.