植物生态学报 ›› 2022, Vol. 46 ›› Issue (4): 394-404.DOI: 10.17521/cjpe.2021.0342

• 研究论文 • 上一篇    下一篇

科尔沁沙质草地植物群落高度空间异质性对不同放牧方式的响应

白悦1, 刘晨1,*(), 黄月2, 董亚楠1, 王露1   

  1. 1西北工业大学生态环境学院, 西安 710129
    2中国科学院沈阳应用生态研究所, 沈阳 110016
  • 收稿日期:2021-09-27 接受日期:2021-12-01 出版日期:2022-04-20 发布日期:2022-01-05
  • 通讯作者: 刘晨
  • 作者简介:*(liuchen@nwpu.edu.cn)
  • 基金资助:
    国家自然科学基金(31700393);中国博士后科学基金(2018T111091)

Response of spatial heterogeneity of plant community height to different herbivore assemblages in Horqin sandy grassland

BAI Yue1, LIU Chen1,*(), HUANG Yue2, DONG Ya-Nan1, WANG Lu1   

  1. 1School of Ecology and Environment, Northwestern Polytechnical University, Xi’an 710129, China
    2Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
  • Received:2021-09-27 Accepted:2021-12-01 Online:2022-04-20 Published:2022-01-05
  • Contact: LIU Chen
  • Supported by:
    National Natural Science Foundation of China(31700393);China Postdoctoral Science Foundation(2018T111091)

摘要:

放牧是影响草地植被空间异质性的重要生物驱动因素。大型草食动物会通过采食、践踏和排泄粪便等方式影响草地植被空间异质性。同时, 植物群落高度是重要的草地结构参数, 但目前关于不同放牧方式对草地植物群落高度空间异质性的研究较少。该研究基于传统及地统计学方法, 设置未放牧(NG)、牛单牧(CG)、羊单牧(SG)、牛羊混牧(MG) 4种处理, 探究科尔沁沙质草地植物群落高度空间异质性对不同放牧方式的响应。结果表明: 研究样地内植物群落平均高度为SG (38.86 cm) > NG (21.01 cm) > MG (17.29 cm) > CG (13.36 cm)。各处理下变异系数的结果均为中等变异, 且变异范围在37.82%-66.97%之间, 依次为NG > MG > CG > SG。通过对半方差函数参数进行最适模型拟合, NG、MG、CG、SG 4种处理分别对应球状模型、指数模型、线性模型、线性模型, 且结构比大小为MG (82.7%) > NG (80.3%) > SG (40.2%) > CG (39.1%)。此外, 采用Kriging插值法和分形维数对研究样地内植物群落高度空间格局分析表明, NG样地中植被高度呈现斑块化空间分布特征, MG维持了植被群落高度斑块化的空间格局, CG、SG则均质化植被群落高度空间格局。各放牧处理中分形维数(D0)均较接近2, 即各放牧样地内植被高度格局简单, 空间结构较好。综上所述, 牛羊混牧能够维持草地植物群落高度的空间异质性, 而牛单牧和羊单牧则降低了其空间异质性, 由此建议科尔沁沙质草地可采取牛羊混合放牧的管理制度来维持草地植被空间异质性, 进而可能间接促进草地动物多样性。

关键词: 空间异质性, 放牧方式, 植物群落高度, 地统计学, 沙质草地

Abstract:

Aims Grazing, as one of the important biological driving factors, plays a key role in the spatial heterogeneity of grassland plant community. Large herbivores can affect the spatial heterogeneity of grassland plant community by foraging, trampling and excreting dung. At the same time, plant community height is a key parameter to describe the structure of grassland. However, little attention has been paid to exploring the spatial heterogeneity of plant community height under different herbivore assemblages. Aim to this issue, this work examined the response of the spatial heterogeneity of plant community height to different herbivore assemblages in Horqin sandy grassland, which is helpful to better understand the importance of grazing in maintaining spatial heterogeneity of grassland plant community and promote grassland animal biodiversity.

Methods An experiment was conducted with four grazing treatments, including no grazing (NG), cattle grazing (CG), sheep grazing (SG) and mixed grazing (MG) of cattle and sheep. We established two perpendicular 15 m transects crossing at the centre point of each plot to reduce the variation caused by environmental gradient. Along the two transects, samples were taken from 0.25 m × 0.25 m quadrates with 0.5 m space interval, and totally 244 sampling points were measured. We used traditional and geostatistical methods to analyze the data from different grazing treatments.

Important findings Results showed that the mean of plant community height in our study plots satisfied the following ranking: SG (38.86 cm) > NG (21.01 cm) > MG (17.29 cm) > CG (13.36 cm). The coefficient of variation of all treatments had moderate level, and the variation range was 37.82%-66.97%, followed by NG > MG > CG > SG. According to the optimal model fitting by the parameters of semi-variance function, NG, MG, CG and SG corresponded to spherical model, exponential model, linear model and linear model respectively, and the structural proportion satisfied MG (82.7%) > NG (80.3%) > SG (40.2%) > CG (39.1%). Furthermore, Kriging interpolation and fractal dimension were used to analyze the spatial pattern of plant community height. It clearly showed NG had a patchy spatial distribution of plant height, MG could maintain the patchy spatial pattern, and CG and SG homogenized the spatial pattern. The fractal dimension value (D0)of each grazing treatment was close to 2, which indicated the spatial structure of four treatments was good with simple spatial pattern. Thus, mixed grazing of cattle and sheep could maintain plant community structural heterogeneity, while the single grazing of cattle or sheep would reduce the spatial heterogeneity. Our findings shed novel light into management of mixed grazing of cattle and sheep, which should be adopted to maintain the spatial heterogeneity of grassland plant community in Horqin sandy grassland.

Key words: spatial heterogeneity, herbivore assemblages, plant community height, geostatistics, sandy grassland