生物多样性 ›› 2018, Vol. 26 ›› Issue (10): 1116-1126.DOI: 10.17520/biods.2018130

• 研究报告 • 上一篇    下一篇

干旱区绿洲扩张方式对土壤生物优势类群及功能的影响

刘继亮1,2, 李锋瑞1,2,*()   

  1. 1 (中国科学院西北生态环境资源研究院临泽内陆河流域研究站, 兰州 730000)
    2 (中国科学院内陆河流域生态水文重点实验室, 兰州 730000);
  • 收稿日期:2018-04-28 接受日期:2018-06-20 出版日期:2018-10-20 发布日期:2019-01-06
  • 通讯作者: 李锋瑞
  • 作者简介:# 共同第一作者
  • 基金资助:
    国家自然科学基金(41471210, 41771290)和中国科学院西部之光博士项目(Y529881001)

Effects of oasis expansion regimes on ecosystem function and dominant functional groups of soil biota in arid regions

Jiliang Liu1,2, Fengrui Li1,2,*()   

  1. 1 Linze Inland River Basin Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000
    2 Key Laboratory of Eco-hydrology of Inland River Basin, Chinese Academy of Sciences, Lanzhou 730000
  • Received:2018-04-28 Accepted:2018-06-20 Online:2018-10-20 Published:2019-01-06
  • Contact: Li Fengrui
  • About author:# Co-first authors

摘要:

内陆干旱区人口数量急剧增加驱动了绿洲快速扩张, 扩张方式主要包括: 灌木地、林地和农地扩张, 尚缺乏绿洲扩张方式对土壤生物多样性和生态系统服务功能影响的研究。本文以河西走廊黑河中游张掖绿洲为研究区域, 选择绿洲边缘天然草地及其转变的人工梭梭(Haloxylon ammodendron)灌木地(无灌溉)、人工杨树(Populus gansuensis)林地(灌溉)、玉米(Zea mays)地(灌溉 + 施肥)为研究对象, 测定了4种生境土壤食物网中9种优势功能类群的密度以及反映土壤生态系统功能特征的有机碳储量、氮储量、磷储量与土壤过氧化氢酶、蔗糖酶、脲酶、碱性磷酸酶活性。主要结果如下: (1)灌木地扩张显著降低了甲螨、植食性昆虫密度, 增加了跳虫、捕食性螨密度和真菌的OTUs, 对其余类群无显著影响; 林地扩张增加了捕食性节肢动物、植食性昆虫、捕食性螨、跳虫、甲螨的密度及细菌和真菌OTUs, 对其余类群无显著影响; 农地扩张增加了蚓类、捕食性节肢动物、捕食性螨、跳虫、甲螨的密度及细菌和真菌的OTUs, 对其余类群无显著影响。(2)林地和灌木地扩张显著提高了土壤有机碳储量和氮储量, 而农地扩张显著提高了土壤有机碳储量、氮储量和磷储量。(3) 3种扩张方式显著提高了土壤过氧化氢酶、蔗糖酶、脲酶、碱性磷酸酶活性, 玉米地和杨树林地土壤酶活性的增幅高于灌木地。人工绿洲扩张方式显著和有差异地改变了土壤食物网结构及其生态功能水平, 该结果对建立基于土地利用结构优化调控的人工绿洲生物多样性保护管理新方法具有重要意义, 并为人工绿洲生态系统功能稳定性评价研究提供了基础资料。

关键词: 内陆干旱区, 人工绿洲扩张, 土地利用变化, 土壤生物, 土壤食物网结构, 生态服务功能

Abstract:

Rapid human populations growth in inland arid regions of northwestern China has resulted in rapid oasis expansion, mainly through transforming natural grasslands to arable land, afforested forest and shrub plantations. However, little is known about how different oasis expansion regimes affect soil biodiversity and ecosystem function. In this study, we measured the abundance of nine dominant functional groups of soil biota across multiple trophic levels, including soil macrofauna (oligochaetes, ants, predatory arthropods and herbivorous insects), soil mesofauna decomposers (Oribatida and Collembola) and soil microbial decomposers (bacteria and fungi) in natural grasslands (NG), arable lands (AL), tree (Populus gansuensis) plantations (TP) and shrub (Haloxylon ammodendron) plantations (SP). The study was performed in Zhangye Oasis in the middle reaches of the Heihe River Basin in northwestern China. We measured the contents of soil organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP), as well as the activities of four soil enzymes (catalase, urease, sucrase and phosphatase). The results showed the following important findings. First, the land conversion of NG to SP significantly lowered the abundance of Oribatida and herbivorous insects, while increasing the abundance of Collembola, predatory mites and fungal OTU numbers. However, converting NG to TP significantly increased the abundance of predatory arthropods, herbivorous insects, Collembola, Oribatida, predatory mites and numbers of both bacterial OTUs and fungal OTUs, whereas converting NG to AL significantly increased the abundance of all the above plus oligochaetes. Second, converting NG to either TP or SP significantly enhanced SOC and TN stocks, whereas converting NG to AL significantly enhanced the above plus TP stocks. Finally, converting NG to either SP, TP or AL significantly enhanced the activities of catalase, urease, sucrase and phosphatase, but these four soil enzymes show significantly higher activity in AL and TP sites with irrigation than in SP sites without irrigation. Our results suggest that different oasis expansion regimes significantly and differentially affect the structure and diversity of the desert soil food web, which in turn, cascades down to ecosystem functioning. Understanding the responses of both different soil food web components and of different ecological function variables to changes in land use and management level is essential for developing novel and more effective strategies for oasis ecosystem management in arid regions worldwide. Overall, this study provided key insights into the assessment of the functional stability of the oasis ecosystem.

Key words: inland arid regions, oasis expansion, land use change, soil biota, soil food web structure, ecosystem functioning