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林业科学 ›› 2020, Vol. 56 ›› Issue (7): 12-21.doi: 10.11707/j.1001-7488.20200702

所属专题: 森林培育与经营

• 论文与研究报告 • 上一篇    下一篇

民勤荒漠绿洲过渡带不同发育阶段白刺灌丛沙堆点格局特征

孙涛1,2,3,贾志清1,*,刘虎俊2,尚雯2,刘江2,张立恒1,2   

  1. 1. 中国林业科学研究院荒漠化研究所 北京 100091
    2. 甘肃省治沙研究所 甘肃省荒漠化与风沙灾害防治国家重点实验室培育基地 兰州 730070
    3. 美国科罗拉多州立大学农业科学学院 柯林斯堡 80523
  • 收稿日期:2019-05-22 出版日期:2020-07-25 发布日期:2020-07-17
  • 通讯作者: 贾志清
  • 基金资助:
    国家自然科学基金项目(31660237);国家自然科学基金项目(31300595);国家重点研发计划项目(2017YFC0504305-02);甘肃省重点研发国际科技合作项目(17YF1WA155);国家留学基金委西部地区人才培养特别项目(201708625016)

Spatial Pattern of Points Distribution of Sandpiles of Nitraria tangutorum Nebkhas at Different Developmental Stages in Desert-Oasis Ecotone of Minqin

Tao Sun1,2,3,Zhiqing Jia1,*,Hujun Liu2,Wen Shang2,Jiang Liu2,Liheng Zhang1,2   

  1. 1. Institute of Desertification Studies, CAF Beijing 100091
    2. State Key Laboratory Breeding Base of Desertification and Aeolian Sand Disaster Combating Gansu Desert Control Research Institute Lanzhou 730070
    3. College of Agricultural Sciences, Colorado State University, USA Fort Collins 80523
  • Received:2019-05-22 Online:2020-07-25 Published:2020-07-17
  • Contact: Zhiqing Jia

摘要:

目的: 研究不同发育阶段白刺灌丛沙堆植被特征、沙堆形态特征及沙堆空间点格局分布,分析发育过程中白刺灌丛沙堆随尺度增加的空间点格局分布特征和变化规律,以期阐明各发育阶段不同级别白刺灌丛沙堆的空间关联性,揭示白刺灌丛发育过程中的种群形成特征及其生态格局维持机制。方法: 基于野外调查观测,在民勤绿洲荒漠过渡带选择4个不同发育阶段(雏形阶段、发育阶段、稳定阶段和活化阶段)的白刺灌丛沙堆典型样地,根据空间二维坐标,采用数量统计方法,按照沙堆体积大小将灌丛沙堆分为1级小沙堆、2级中沙堆和3级大沙堆3个等级,利用单变量O-ring函数对灌丛沙堆进行空间格局分析,并用双变量O-ring函数进行不同尺度各级沙堆关联性分析。结果: 随沙堆发育过程的进行,白刺灌丛的整体生长状况由好显著变差,植被覆盖度先增后减(雏形阶段最低为51.4%,逐渐升高到稳定阶段最高68.8%,活化阶段降低为60%),而植被枯枝率基本呈增加状态(由雏形阶段的15%增加到活化阶段的27%);各级沙堆在不同尺度中表现出不同的分布格局:雏形阶段,白刺灌丛沙堆在0~5 m的尺度上趋于均匀分布,在5~25 m尺度上为随机分布,而在>25的尺度上趋于聚集分布;发育阶段,白刺灌丛在0~5 m的尺度上倾向于均匀分布,在5~30 m尺度上为随机分布;稳定阶段与活化阶段,各级白刺灌丛在小尺度上(< 5 m)都表现出均匀分布的倾向,但在>5 m尺度上为随机分布。各发育阶段大小级别不同的白刺灌丛沙堆随尺度变化表现出不同的关联特性,除发育阶段小沙堆间(1、2级)无关联外,其他阶段小沙堆间(1级和2级)主要表现为随空间尺度增加正关联性逐渐增强,2级和3级沙堆在< 10 m尺度上表现为负关联,而在>10 m的尺度上表现为负向联系加强或无关联。结论: 各发育阶段不同级别白刺灌丛沙堆所占比重不同但均未表现出明显的聚集现象,随沙堆发育过程的逐渐推进,大沙堆趋于随机分布;各级沙堆之间的关联性在小尺度上表现出小沙堆间的正关联性逐渐增强,而在中大尺度上中大沙堆表现出负关联加强或无关联,表明白刺灌丛沙堆植物群落组成和沙堆结构随发育过程的进行越来越不稳定。

关键词: 白刺灌丛沙堆, 发育阶段, 植被特征, 空间格局, 荒漠-绿洲过渡带

Abstract:

Objective: The vegetation and shape characteristics and spatial distribution of Nitraria tangutorum Nebkhas in different developmental stages were studied to characterize the spatial point distribution and patterns of variation of N. tangutorum Nebkhas with the increase of size of the sandpiles in order to reveal the characteristics of community formation and the mechanism of maintaining ecological patterns of N. tangutorum Nebkhas during the development process. Methods: Based on field investigation,four typical sample plots of N. tangutorum Nebkhas in 4 different developmental stages,i.e,prototype,developing,stabilizing,and activating,in Minqin desert-oasis ecotone were selected. In light of the two-dimensional coordinates,the N. tangutorum Nebkhas were graded into 3 classes,i.e. small,medium and large,respectively,according to the volumes of sandpiles. Their spatial distribution were analyzed with the univariate O-ring function while the correlation among different grades of the sandpiles at different scales was determined by the bivariate O-ring function under the quantitative statistical methods. Results: With the development of the sandpiles,the overall growth changed from good to poor,and the vegetation coverage tended to increase at the beginning and followed by a decrease,which was 51.4% at the prototype stage,reached to the highest 68.8% at the stabilizing stage,then decreased to 60% at the activating stage,whereas the bush deadwood rate showed an opposite trend,which increased from 15% at the prototype stage to 27% at the activating stage. Different distribution patterns appeared for different grades of sandpiles at different scales. At the prototype stage,they tended to be evenly distributed under the scale of 0-5 m,and randomly distributed on the scale of 2-25 cm,whereas distributed in aggregate under the scale of >25 m; at the developing stage,they tended to be uniformly distributed under the scale of 0-5 m,but were randomly distributed under the scale of 5-30 m; at the stabilizing stage and activating stage,they showed a uniform distribution under small scales(< 5 m),a random distribution under the scales >5 m,respectively. The sandpiles of different sizes at different developmental stages showed different association with changing scales. For the small grade sandpiles(grade 1 and 2),except that there was no correlation between the small sandpiles(grade 1 and 2) at the developing stage,it was positively correlated with each other in small sandpiles(grade 1 and 2) along with the increasing spatial scale in other different stages. For the grades 2 and 3,their spatial correlations with other sandpiles showed as a negative correlation under the scale of < 10 m,whereas there were gradually strengthen negative correlation or even disappearing with increasing scales under the scale of >10 m. Conclusion: The sandpiles of N. tangutorum Nebkhas showed no significant aggregation although the different grades of sandpiles at different development stages have different proportions in each sample plot. With the gradual progress of the sandpile development,large sandpiles tended to be randomly distributed,but,the correlations between the small sandpiles grades showed positive on the small scale,while,the negative correlations appeared strengthen or uncorrelated on the medium and large scales,indicating the composition and structure of the sandpiles of N. tangutorum Nebkhas community become less stabilized as the development progresses.

Key words: Nitraria tangutorum nebkhas, developmental stage, vegetational characteristic, spatial distribution, desert-oasis ecotone

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