欢迎访问《草业学报》官方网站,今天是 分享到:

草业学报 ›› 2022, Vol. 31 ›› Issue (3): 1-15.DOI: 10.11686/cyxb2020573

• 研究论文 •    

基于无人机激光雷达与多光谱数据的不同放牧强度下草原冠层尺度特征研究

沈洁1(), 丁蕾1, 辛晓平1(), 张翔1,2, 徐大伟1, 侯路路1, 闫瑞瑞1   

  1. 1.中国农业科学院农业资源与农业区划研究所,北京 100081
    2.内蒙古师范大学地理科学学院,内蒙古 呼和浩特 010028
  • 收稿日期:2020-12-23 修回日期:2021-03-01 出版日期:2022-03-20 发布日期:2022-01-15
  • 通讯作者: 辛晓平
  • 作者简介:Corresponding author. E-mail: xinxiaoping@caas.cn
    沈洁(1996-),女,宁夏中卫人,在读硕士。E-mail: JShen_10@163.com
  • 基金资助:
    中央级公益性科研院所基本科研业务费专项(Y2019YJ13);呼伦贝尔市科技计划项目(YYYFH201903);现代农业产业技术体系建设专项资金(CARS-34-11);草地农业生态系统国家重点实验室开放课题(SKLGAE-2019-07)

Canopy scale characteristics of grassland under different grazing intensities based on UAV lidar and multispectral data

Jie SHEN1(), Lei DING1, Xiao-ping XIN1(), Xiang ZHANG1,2, Da-wei XU1, Lu-lu HOU1, Rui-rui YAN1   

  1. 1.Institute of Agricultural Resources and Regional Planning,Chinese Academy of Agricultural Sciences,Beijing 100081,China
    2.College of Geographical Science,Inner Mongolia Normal University,Hohhot 010028,China
  • Received:2020-12-23 Revised:2021-03-01 Online:2022-03-20 Published:2022-01-15
  • Contact: Xiao-ping XIN

摘要:

放牧活动不但影响草原生态过程,而且改变草原群落空间格局。为进行草地冠层连续变化的尺度对放牧强度响应的研究,基于无人机机载激光雷达和多光谱遥感获取亚米级的草原冠层数据,利用小波分析方法研究了不同放牧强度下草原冠层空间格局及其尺度特征,探究草原冠层高度(CH)、植被覆盖度(FVC)、归一化植被指数(NDVI)等不同冠层参数空间尺度特征对放牧强度的响应。结果表明:CH、FVC、NDVI的小波方差随放牧强度增大呈下降趋势,草原冠层空间结构整体趋于均匀;小波方差和系数实部分析显示,CH,FVC和NDVI的空间格局存在170~180 m、116~140 m等2个主特征尺度,不随放牧强度而变化,较为稳定;中度、重度放牧使植物群落在空间中产生了许多小斑块,植被盖度的空间格局在小尺度上的变化较大。

关键词: 空间异质性, 空间格局, 小波分析, 特征尺度, 放牧强度, 植被盖度

Abstract:

Grazing activities not only affect ecological processes of grasslands, but also change the spatial pattern of grassland communities. This research utilized airborne lidar carried by an HS-600 unmanned aerial vehicle (UAV) with a RIEGL laser system and flying at a height of 119 m, and multi-spectral remote sensing to obtain grassland canopy data with sub-meter resolution. The grassland canopy spatial pattern and its scale characteristics under different grazing intensities were studied using wavelet analysis (i.e. the deconvolution of observed lidar waveforms to extract wavelet data), to quantify the spatial characteristics and scales of three canopy parameters: canopy height (CH), fractional vegetation cover (FVC) and normalized difference vegetation index (NDVI), in terms of their response to grazing intensity. It was found that the wavelet variances of grassland CH, FVC, and NDVI show a downward trend with increase in grazing intensity, indicating that the periodic fluctuation energy of its spatial pattern decreases, and the overall grassland canopy spatial structure tends to be more uniform at higher grazing intensity. The analysis of wavelet variance and the real part of coefficients showed that the spatial pattern of FVC and NDVI has two main characteristic scales of 116-140 m and 170-180 m, and a spatial variation period of about 110 m, and the spatial pattern scale characteristics were comparatively stable with change in grazing intensity. The spatial pattern of CH was more complicated. The larger-scale pattern described above was evident, but moderate and heavy grazing resulted in many smaller patches forming with comparatively larger variation in CH and vegetation cover on a smaller spatial scale.

Key words: spatial heterogeneity, spatial pattern, wavelet analysis, characteristic scale, grazing intensity, vegetation coverage