植物生态学报 ›› 2022, Vol. 46 ›› Issue (10): 1289-1304.DOI: 10.17521/cjpe.2022.0226

所属专题: 遥感生态学

• 研究论文 • 上一篇    下一篇

黄土高原生态工程实施下基于日光诱导叶绿素荧光的植被恢复生产力效益评价

薛金儒, 吕肖良*()   

  1. 西北农林科技大学水土保持研究所, 黄土高原土壤侵蚀与旱地农业国家重点实验室, 陕西杨凌 712100
  • 收稿日期:2022-06-02 接受日期:2022-09-12 出版日期:2022-10-20 发布日期:2022-09-21
  • 通讯作者: *吕肖良(luxiaoliang@nwafu.edu.cn)
  • 基金资助:
    国家自然科学基金(73041901293);国家自然科学基金(42071328);中央高校基本科研业务费专项资金(24520212452021125)

Assessment of vegetation productivity under the implementation of ecological programs in the Loess Plateau based on solar-induced chlorophyll fluorescence

XUE Jin-Ru, LÜ Xiao-Liang*()   

  1. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China
  • Received:2022-06-02 Accepted:2022-09-12 Online:2022-10-20 Published:2022-09-21
  • Contact: *Lü Xiao-Liang(luxiaoliang@nwafu.edu.cn)
  • Supported by:
    National Natural Science Foundation of China(73041901293);National Natural Science Foundation of China(42071328);Fundamental Research Funds for the Central Universities(24520212452021125)

摘要:

基于日光诱导叶绿素荧光(SIF)揭示黄土高原大面积实施生态工程后植被恢复区域的植被生产力效益。通过分析遥感观测的地表绿度特征变化和土地利用动态, 该研究首先识别了近20年来黄土高原植被恢复区域和原有植被的空间分布范围, 在此基础上, 使用SIF和气象数据, 根据改进机理光响应模型(rMLR)计算了植被总初级生产力(GPP), 对比分析了植被恢复区域绿度特征变化下GPP的差异。结果显示: 空间上, 由于生态工程的广泛实施, 黄土高原整体绿化情况得到了明显改善。在2001-2020年间, 黄土高原上林地恢复面积约3.5万km2, 占区域总面积的7.42%; 草地恢复面积11万km2, 约占区域总面积的25.25%。整体上, 林地恢复区域的光合能力和生产力水平均低于原有林地, 而草地恢复区域较原有草地高; 恢复林地的GPP相当于原有林地GPP的83.86%, 恢复草地的GPP相当于原有草地的121.10%。在相同的叶面积指数(LAI)等级下, 植被恢复区域与原有植被的生产力呈现不同的差异性, 当LAI较大时植被恢复区域与原有植被的GPP差距较大。由裸地转变而来的植被恢复区域生产力效益最差, 而林地生长区域和退耕还草的植被恢复区域分别是林地恢复和草地恢复中的最优模式。植被恢复区域的LAI增长速率和恢复年限也影响了生产力, LAI增长速率越大的区域生产力效益越高, 林地恢复年限越久越利于生产力的提升, 草地恢复年限较短的区域有较高的生产力。总体上, 由于生态工程的实施, 虽然黄土高原上的植被覆盖面积和生物量得到了显著提高, 但植被生产力(尤其是林地)并没有获得同等程度的恢复, 影响了生态工程的生态效益。

关键词: 生态工程, 植被恢复, 日光诱导叶绿素荧光(SIF), 总初级生产力(GPP), 黄土高原

Abstract:

Aims Based on the solar-induced chlorophyll fluorescence (SIF), this study was conducted to reveal the benefit of vegetation productivity in the revegetation region with a significant increase in land surface greenness under the large-scale implementation of ecological programs in the Loess Plateau.

Methods By interpreting satellite-observed terrestrial greenness changes and land use/cover dynamics, we first identified the spatial distribution of revegetation and existing vegetation in the Loess Plateau in the last 20 years. Then, using SIF and meteorological data, the gross primary productivity (GPP) of the revegetation and existing vegetation was calculated according to the revised mechanistic light response (rMLR) model. Finally, we adopted the comparative analysis approach to compare the differences in GPP of the revegetation based on the SIF observations.

Important findings Our results indicated that the ecological programs have made a widespread increase in land surface greenness in the Loess Plateau. In the period 2001 to 2020, the area of revegetated forest was 35 000 km2, accounting for 7.42% of the total area, whereas revegetated grassland area was 110 000 km2, accounting for 25.25% of the total area. Overall, the photosynthetic capacity and vegetation productivity of the revegetated forests were lower than that of existing forests in the Loess Plateau, while revegetated grassland was higher. GPP of the revegetated forest was equivalent to 83.86% of the existing forest, and GPP of the revegetated grassland was equivalent to 121.10% of that of the existing grassland. At the same leaf area index (LAI) level, GPP of revegetation and existing vegetation showed differences that GPP gap increased as LAI became higher. Revegetation transformed from bare land showed the lowest vegetation productivity, whereas forest growth and grassland restoration from cropland were the optimal land use/cover transition pattern for the revegetated forest and revegetated grassland, respectively. LAI increasing rate and restoration time also affected the productivity of revegetation, revegetated areas with higher LAI increasing rate showed more extensive productivity benefits. Vegetation productivity of revegetated forest increased with standage, while revegetated grassland with shorter restoration periods showed higher productivity. Overall, although ecological programs have widely increased vegetation cover and biomass in the Loess Plateau, however, there exists a certain gap in GPP between the revegetation and existing vegetation areas (especially in forests), thereby affecting the ecological benefits of the ecological programs.

Key words: ecological programs, revegetation, solar-induced chlorophyll fluorescence (SIF), gross primary productivity (GPP), the Loess Plateau