不同等级石漠化的生态系统服务权衡研究

With multiple demands of food security, ecological protection and economic development, frequent conflict and competition occurs between multiple ecosystem services in karst region. Karst rocky desertification caused the decrease or even loss of ecosystem services supply, which furthermore aggravated the contradiction of ecosystem services demand. Therefore, it calls for revealing the relationship between ecosystem services including the trade-offs and synergies, which can help guide ecosystem restoration and management in karst region. The literatures suggests that there is the spatial difference of ecological elements within different classes of karst rocky desertification, which would cause a non-linear change of the ecosystem services and their relationship. It lacks a quantitative research on the above issue. Therefore, taking Changshun County in Guizhou Province as the study area, this study intends to use the object-based methods with support vector machine to extract the spatial distribution and classes of karst rocky desertification. Based the spatial distribution of different karst rocky desertification classes, it would collect data by the stratified sampling including field surveys, plots measurements and household surveys. Also the land use map reflecting the characteristics of karst rocky desertification is extracted. Based on the above data, the ecosystem service values can be estimated within different karst rocky desertification classes. Using the spatial mapping and statistical tests, this study would reveal the variation of various types of ecosystem services and their trade-offs and synergies at different classes of karst rocky desertification. The implementation of this study would provide differential suggestions and countermeasures of ecosystem management within different karst rocky desertification classes. Then it can help coordinate the contradictory of ecosystem services in karst region, and also facilitate the sustainable development in the region.

粮食安全、生态保护和经济发展的多重需求导致喀斯特地区生态系统服务竞争频现，而石漠化又造成生态系统服务供给的减少甚至丧失，加剧生态系统服务的矛盾和冲突。理解生态系统服务之间此消彼长的权衡或者相互增益的协同关系，有助于指导喀斯特生态系统的恢复与管理。不同等级石漠化下各生态系统要素差异明显，可能导致生态系统服务及其关系呈现非线性变化，而目前研究中尚缺乏对此问题的定量刻画。本研究拟以贵州省长顺县为例，采用面向对象和支持向量机方法，提取石漠化的空间分布并划分等级；基于石漠化等级分布，进行野外调查、样地实测和农户调查等分层数据采样，绘制反映石漠化特征的土地利用图，评估生态系统服务价值及其随石漠化等级增加的变化；通过空间制图表达和统计检验方法，揭示不同石漠化等级下各生态系统服务权衡/协同关系的差异；以此，提出不同等级石漠化下生态系统管理的差别化建议与对策，协调生态系统服务矛盾，促进区域可持续发展。

粮食安全、生态保护和经济发展的多重需求导致喀斯特地区生态系统服务竞争频现，而石漠化更造成生态系统服务供给的减少甚至丧失，导致生态系统服务呈现复杂变化。甄别不同关键生态系统服务时空分布差异，理解土地利用及石漠化对生态系统服务的影响，有助于指导喀斯特生态系统恢复与土地利用管理。本研究采用面向对象和支持向量机方法，提出了石漠化快速制图方法，提取石漠化的空间分布并划分等级。引入石漠化等级，农地利用强度因子以及关键喀斯特本地化参数，有效提高了食物供给、水源涵养、土壤保持和固碳释氧等4项主要生态系统服务的估算精度。综合耕作系统、自然环境和人为因素影响，考虑了化肥施用、机械化作业对实际粮食产出的贡献，实现了粮食生产从统计数据到栅格尺度的空间化。采用经验性方程，引入径流系数，基于实际径流小区实测数据修正降水贮存量法计算了水源涵养量。引入石漠化因子，并结合实际径流小区实验数据进行修正土壤侵蚀方程，计算土壤保持量。考虑岩石风化固碳贡献，基于地表径流和溶解元素的GEM-CO2模型，结合植被净初级生产力反演方法，估算固碳释氧量。发现2000-2015年，产水量和食物供给量减少，2000年-2015年分别从1141.21亿m3和4243.91亿kcal降低到1110.34亿m3和3768.92亿kcal，而土壤保持和固碳释氧量增加，2000年-2015年分别从180.08亿t/a、5986.68万t/a和1.56亿t/a增加到189.02亿t/a、6187.49万t/a和1.61亿t/a。产水量和食物供给量、土壤保持和固碳释氧表现为协同关系，但其余两两之间表现为权衡关系。不同石漠化等级下关键生态系统服务呈现出复杂的关系，权衡和协同的强弱程度有明显的差异，部分关系呈现一定的一定程度的非线性特征。开发了喀斯特石漠化时空演化模拟模型，基于土地利用特征以及生态系统服务变化与关系，设计了历史演化、重点治理和完全修复等三种未来石漠化演替情景，模拟了特定的喀斯特石漠化演替轨迹过程，有利于指导差别化石漠化恢复和治理。