All-in-one assessment of grassland health,degradation,and restoration:The concepts and methods
Healthy grasslands provide an optimum range of material and non-material benefits to human beings.However,when grasslands are degraded,their ability to,provide benefits to humans can be undermined by multiple declines in biodiversity,ecological functions and services.As an international and domestic problem that has not yet been thoroughly solved,although many scholars have proposed theories,methods and standards of grassland health and degradation,most researches endeavors largely fall short in explicating the nuanced relationship between the health and degradation of grasslands.The relevant criteria are controversial,and lack systematic and comprehensive understanding.They are still at the stage of superficially describing and characterizing governance.It is therefore imperative to explore the complex relationship between health status and the processes of degradation and restoration.Furthermore,the health,degradation and restoration of grasslands are all hot issues that are of concern to both academia and management communities.Disparities in the conceptualization of their definitions have resulted in a lack of consistent understanding of relevant assessment theories and methods.Diverse assessment methods,indicators and approaches have been adopted to quantify the health status and degradation degree of grasslands,resulting in the promulgation of various national,industrial and local standards.The outcomes in determining the health,degradation or restoration of grasslands manifest variances,making it difficult to provide scientific guidance for the management,conservation and restoration of grasslands.This paper clarifies the relationships between grassland health,degradation and restoration.Grassland degradation and restoration are the processes by which grassland health changes.Based on this understanding,we propose a technical framework for the integrated assessment of grassland health,degradation and restoration.The framework allows not only to monitor the health of grasslands according to actual needs,but also to assess the severity of grassland degradation and the effectiveness of grassland restoration.A comprehensive assessment index system for grassland health,degradation and restoration has been developed.The Vegetation Community Index(VCI),Land Surface Characteristic Index(LCI),Biodiversity Index(BDI),Forage Performance Index(FPI)were applied to reflect the growth condition of grassland vegetation,the quality of the grassland surface,the richness of biodiversity,and the degree of grassland production capacity,respectively.We define a Grassland Health Index(GHI)to facilitate operational assessment and provide a scheme for calculating the GHI,and then the methods for classifying the health status according to expert knowledge assigned weights and reference values.Preliminary reference values have been assigned to the indicators based on the results of a historical grassland survey in the 1980s,and in combination with expert knowledge.By analyzing the difference or trend value of the change in GHI between the assessment year and the base year,we can assess the direction and degree of grassland degradation or restoration.Changes in grassland health were classified into three classes of grassland degradation,three classes of grassland restoration,and one steady state type.The three degradations include mild,moderate,and severe degradation.The three restorations include very significant,obvious,and slight restoration.Considering the principles of science,reasonableness,and feasibility,we have designed spatialization methods such as type assignment,remote sensing inversion and model simulation,to realize the coupling of ground monitoring and investigation with remote sensing observation and simulation,subsequently forming a"one map"of grassland health,degradation,and restoration.In the future,in-depth research and optimization will be needed to refine the zoning classification,optimize the reference system,and spatialization methods for indicators.
grassland health indexgrassland degradationgrassland restorationall-in-one assessment
黄麟、樊江文、杨智、王冠聪、李愈哲、张海燕、张雅娴、石俊华、王穗子
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中国科学院地理科学与资源研究所,中国科学院陆地表层格局与模拟重点实验室,北京 100101
国家林业和草原局草原管理司,北京 100714
西南民族大学草地资源学院,成都 610041
国家林业和草原局林草调查规划院,北京 100714
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grassland health index grassland degradation grassland restoration all-in-one assessment
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