中国三北防护林工程第二阶段生态效益综合评价

doi:10.11707/j.1001-7488.20221104

摘要/Abstract

摘要：

目的: 三北防护林工程第二阶段（2001—2020年）实施以来取得了巨大的生态效益，但局部地区仍然存在问题，甚至出现生态退化。以生态系统结构、质量、服务为核心，综合定量评价工程实施前后生态系统变化，厘清第四期（2001—2010年）和第五期（2011—2020年）工程对生态系统恢复的影响，为后续三北工程的滚动实施提供科学和有针对性的理论依据。方法: 基于"历史动态本底—恢复现状—恢复指数"的生态工程生态效益综合评估方法，以遥感解译反演和模型估算结果为基础，构建生态系统宏观结构变化指数（EMSCI）、质量变化指数（EQCI）、服务功能变化指数（ESCI）和生态系统恢复指数（ERI），全面评估三北防护林工程区生态系统类型结构、质量和关键服务功能的时空格局变化。利用空间叠加分析功能，厘清工程实施期间的生态系统变化过程，定量评价生态系统恢复程度。结果: 1）在三北防护林工程第二阶段，生态系统类型显著变动，整体动态度为12.22%，森林覆盖率持续增加，森林面积占比10.18%，且第四期增量（1.60万km²）大于第五期增量（0.69万km²）。2）生态系统质量显著改善，平均植被覆盖度和平均植被净初级生产力分别增加了3.77%和82.33 gC·m^-2a^-1，增长率为24.50%和34.96%。生态系统质量持续转好面积占比20.15%。3）与本底期相比，生态系统服务功能全面提升，单位面积水源涵养量增长1.25万m³ · km^-2，单位面积植被固碳量增长134.19 gC·m^-2a^-1，单位面积土壤保持量增长6.76 t · hm^-2a^-1，单位面积防风固沙量增长9.81 t · hm^-2a^-1，分别提升了45.89%、34.96%、74.29%和24.96%。单位面积水蚀模数增加23.88%（因为近年来年均降水量比前期增加，造成侵蚀量和保持量均有所增加），风蚀模数下降25.58 t · hm^-2a^-1，风沙侵蚀危害程度降低46.49%。生态系统服务功能持续转好面积占比15.83%。4）生态系统恢复状况良好，持续转好和保持稳定区域面积占比为21.95%和20.29%。结论: 三北防护林工程区经第二阶段多期连续实施重点生态工程，已取得显著成效。东北华北平原农区、内蒙古高原中部风沙区和黄土高原丘陵沟壑区的生态系统恢复良好，森林覆盖率提高，平均植被覆盖度增加，平均植被净初级生产力提高，单位面积水源涵养量、植被固碳量、土壤保持量和防风固沙量等生态系统服务功能明显转好。但西北荒漠区生态系统仍较脆弱，整体生态系统状况并未得到有效改善。在天山附近、准葛尔盆地、柴达木盆地、南疆盆地固沙农牧区、坝上高原、内蒙古西部荒漠半荒漠草原等生态系统脆弱区域，森林面积增长放缓，草地面积减少，荒漠面积增加，防治草地沙漠化仍为未来工程实施的重点。

关键词: 三北防护林工程区, 生态效益评估, 生态系统, 监测与评估

Abstract:

Objective: Since the implementation of the second phase (2001-2020) Shelter Forest Program in the Three North Region, huge ecological benefits have been achieved, but there are still problems in some areas, and even ecological degradation has occurred. Focusing on the structure, quality and service of the ecosystem, comprehensively and quantitatively evaluate the changes in the ecosystem, and clarify the impacts of the implementation of the fourth and fifth periods of the program on the restoration of the ecosystem, intend to provide a scientific and pertinent theoretical basis for the rolling implementation of the program. Method: This paper is based on the comprehensive evaluation method of "historical dynamic background-restoration status-restoration index" to construct the ecosystem macro-structure change index (EMSCI), ecosystem quality change index (EQCI), ecosystem service function change index (ESCI), and ecosystem restoration index (ERI) for a comprehensive evaluation of the spatial and temporal changes in structure, quality and key service functions of the ecosystem in the Three-North Program region. The spatial overlay analysis function was used to clarify the process of ecosystem changes and quantitatively evaluate the extent of ecosystem restoration. Result: 1) In the second phase of the Three-North Shelter Forest Program, ecosystem type has changed significantly with an overall dynamic degree of 12.22% and the forest coverage continued to increase with an area accounting for 10.18%. Moreover, the forest coverage increase in the fourth period (16 000 km²) was greater than that in the fifth period (6 900 km²). 2) The quality of the ecosystem has been significantly improved. The vegetation coverage and vegetation net primary productivity have increased by 0.038 and 82.33 gC·m^-2a^-1, with a growth rate of 24.50% and 34.96%, respectively. Moreover, 20.15% of the area continues to improve. 3) Compared to historical background, the service function of the ecosystem has been improved significantly. Water conservation per unit area, the amount of carbon sequestered per unit area, the amount of soil conservation per unit area and the amount of windbreak and sand fixation per unit area has been increased by 12 500 m³·km^-2, 134.19 gC·m^-2a^-1, 6.76 t·hm^-2a^-1 and 9.81 t·hm^-2a^-1, respectively, with a respective growth rate of 45.89%, 34.96%, 74.29% and 24.96%.The degree of soil water erosion, and wind and sand erosion damage is reduced, with the water erosion modulus increased 23.88% (the average annual precipitation increased in recent years compared to the previous period, resulting in an increase in the amount of erosion and the amount of retention), and the wind erosion modulus decreased by 25.58 t · hm^-2a^-1, leading to the reduction of damages by wind erosion by 46.49%. Finally, there are 15.83% area ecosystem service functions continued to improve. 4) The restoration of the ecosystem is very significant, with 21.95% and 20.29% area has continued to improve and remain stable. Conclusion: Through the implementation of successive periods of the Three-North Shelter Forest Program, significant improvements have been achieved, the ecosystem have recovered well and entered a sustained, stable and healthy development trend in farmlands in the Northeast and North China Plains, the Inner Mongolia Plateau and the Loess Plateau with improved forest coverage, increased average vegetation coverage, increased average net primary vegetation productivity, and ecosystem service functions such as water holding capacity per unit area, carbon sequestration by vegetation, soil conservation capacity and wind-breaking and sand-fixation capacity have been significantly improved. However, the northwest desert area is still relatively fragile, and the ecosystem status has not been effectively improved. In Tianshan Mountains, Zhungeer Basin, Qaidam Basin, the agricultural and pastoral areas in southern Xinjiang basin, Bashang Plateau, the desert and semi-desert grassland areas in western Inner Mongolia where the ecosystem is fragile, the increase of forest area is slowing down, the area of grassland is decreasing and the desert area is still increasing. Therefore, the prevention and control of grassland desertification is still the focus of future program implementation.

Key words: Three-North Shelter Forest Program, ecological benefits, ecosystem, monitoring and assessment

中图分类号:

S757.3

纪平,邵全琴,王敏,刘华,王晓慧,凌成星,侯瑞霞. 中国三北防护林工程第二阶段生态效益综合评价[J]. 林业科学, 2022, 58(11): 31-48.

Ping Ji,Quanqin Shao,Min Wang,Hua Liu,Xiaohui Wang,Chengxing Ling,Ruixia Hou. Monitoring and Assessment of Ecological Benefits of the Shelter Forest Program in the Three-North Region during 2001—2020[J]. Scientia Silvae Sinicae, 2022, 58(11): 31-48.

图/表 15

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生态系统质量及服务功能变化模式图谱分类"

序号 Number	变化模式类型 Change modetype	变化模式类型说明 Change modetype description
1	持续转好 Keep improving	第四期变化：较明显转好、明显转好、显著转好；第五期变化：较明显转好、明显转好、显著转好 The change in four period: slightly better, obviously better, significantly better; the change in five period: slightly better, obviously better, significantly better
2	先转好后转差 Improving，worsening	第四期变化：较明显转好、明显转好、显著转好；第五期变化：显著转差、明显转差、较明显转差 The change in four period: slightly better, obviously better, significantly better; the change in five period: significantly worse, obviously worse, slightly worse
3	先转好后稳定 Improving，stabilize	第四期变化：较明显转好、明显转好、显著转好；第五期变化：微弱转差、基本不变、微弱转好 The change in four period: slightly better, obviously better, significantly better; the change in five period: roughly worse, no change, roughly better
4	先转差后转好 Worsening，improving	第四期变化：显著转差、明显转差、较明显转差；第五期变化：较明显转好、明显转好、显著转好 The change in four period: significantly worse, obviously worse, slightly worse; the change in five period: slightly better, obviously better, significantly better
5	持续转差 Keep worsening	第四期变化：显著转差、明显转差、较明显转差；第五期变化：显著转差、明显转差、较明显转差 The change in four period: significantly worse, obviously worse, slightly worse; the change in five period: significantly worse, obviously worse, slightly worse
6	先转差后稳定 Worsening，stabilize	第四期变化：显著转差、明显转差、较明显转差；第五期变化：微弱转差、基本不变、微弱转好 The change in four period: significantly worse, obviously worse, slightly worse; the change in five period: roughly worse, no change, roughly better
7	先稳定后转好 Stabilize，improving	第四期变化：微弱转差、基本不变、微弱转好；第五期变化：较明显转好、明显转好、显著转好 The change in four period: roughly worse, no change, roughly better; the change in five period: slightly better, obviously better, significantly better
8	先稳定后转差 Stabilize，worsening	第四期变化：微弱转差、基本不变、微弱转好；第五期变化：显著转差、明显转差、较明显转差 The change in four period: roughly worse, no change, roughly better; the change in five period: significantly worse, obviously worse, slightly worse
9	保持稳定 Keep stabilize	第四期变化：微弱转差、基本不变、微弱转好；第五期变化：微弱转差、基本不变、微弱转好 The change in four period: roughly worse, no change, roughly better; the change in five period: roughly worse, no change, roughly better

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评价指标 Classification	显著转差 Significantly worse	明显转差 Obviously worse	较明显转差 Slightly worse	微弱转差 Roughly worse	基本不变 No change	微弱转好 Roughly better	较明显转好 Slightly better	明显转好 Obviously better	显著转好 Significantly better
变化率 Change percent(%)	< -15	-15~-10	-10~-5	-5~-1	-1~1	1~5	5~10	10~15	≥15
归一化值 Normalized value	1	2	3	4	5	6	7	8	9

评价指标 Classification	显著转差 Significantly worse	明显转差 Obviously worse	较明显转差 Slightly worse	微弱转差 Roughly worse	基本不变 No change	微弱转好 Roughly better	较明显转好 Slightly better	明显转好 Obviously better	显著转好 Significantly better
变化率 Change percent(%)	< -15	-15~-10	-10~-5	-5~-1	-1~1	1~5	5~10	10~15	≥15
归一化值 Normalized value	-4	-3	-2	-1	0	1	2	3	4

项目 Item		第四期初 Beginning of fourth period(2001年Year)
项目 Item		森林 Forestland	草地 Grassland	农田 Farmland	湿地与水体 Wetland and water	荒漠 Desert	城镇 Settlement	其他 Others	合计 Total
第五期末 End of fifth period (2020年Year)	森林 Forestland	31.66	9.43	4.56	0.19	0.65	0.14	0.03	46.65
	草地 Grassland	7.63	103.18	10.84	1.01	12.04	0.36	0.51	135.58
	农田 Farmland	3.97	13.91	59.76	0.84	1.99	2.54	0.00	83.02
	湿地与水体 Wetland and water	0.27	1.38	0.84	3.90	0.96	0.07	0.00	7.41
	荒漠 Desert	0.51	20.10	0.73	0.42	149.18	0.04	1.42	172.41
	城镇 Settlement	0.29	1.30	5.07	0.12	0.31	1.80	0.00	8.87
	其他 Others	0.04	0.64	0.00	0.00	0.94	0.00	2.71	4.32
	合计 Total	44.36	149.94	81.81	6.48	166.06	4.95	4.67

生态系统质量参数 Ecosystem quality type	评估时段 Assessment period			第四期 Fourth period		第五期 Fifth period		第二阶段 Second stage
生态系统质量参数 Ecosystem quality type	第四期初 Beginning of fourth period	第四期末 End of fourth period	第五期末 End of fifth period	变化量 Change amount	变化率 Change rate(%)	变化量 Change amount	变化率 Change rate(%)	变化量 Change amount	变化率 Change rate(%)
平均植被覆盖度 Average vegetation coverage(%)	15.42	16.93	19.19	1.51	9.84	2.26	13.35	3.77	24.50
平均植被净初级生产力 Mean vegetation net primary productivity/(gC·m^-2a^-1)	235.49	300.88	317.82	65.39	27.77	16.94	5.63	82.33	34.96

生态系统服务功能参数 Ecosystem service function type	评估时段 Assessment period			第四期 Fourth period		第五期 Fifth period		第二阶段 Second stage
生态系统服务功能参数 Ecosystem service function type	第四期初 Beginning of fourth period	第四期末 End of fourth period	第五期末 End of fifth period	变化量 Change amount	变化率 Change rate(%)	变化量 Change amount	变化率 Change rate(%)	变化量 Change amount	变化率 Change rate(%)
单位面积水源涵养量 Water conservation per unit area/(10⁴ m³ · km^-2 a^-1)	2.72	3.53	3.97	0.81	29.78	0.44	12.46	1.25	45.96
单位面积固碳量 Carbon sequestration per unit area/(gC · m^-2 a^-1)	383.85	490.43	518.04	106.58	27.77	27.61	5.63	134.19	34.96
单位面积土壤水蚀模数 Water erosion modulus per unit area/(t · hm^-2 a^-1)	10.77	12.16	13.34	1.39	12.91	1.18	9.72	2.57	23.88
单位面积土壤保持量 Soil conservation per unit area/(t · hm^-2 a^-1)	9.10	10.05	15.86	0.95	10.44	5.81	57.81	6.76	74.29
单位面积土壤风蚀模数 Wind erosion modulus per unit area/(t · hm^-2a^-1)	55.03	36.94	29.45	-18.09	-32.87	-7.49	-20.29	-25.58	-46.49
单位面积防风固沙量 Sand fixation per unit area/(t · hm^-2a^-1)	39.31	29.52	49.12	-9.79	-24.90	19.60	66.40	9.81	24.96