“5·12”汶川地震极重灾区生态服务功能恢复总体评估

2008年"5·12"汶川特大地震,对生态系统造成巨大威胁。为了解汶川地震灾区生态恢复总体状况,以期为灾区中长期生态恢复跟踪监测、生态恢复措施的制定和调整提供决策支持,分别以2007年、2009年、2013年代表地震前、地震后以及恢复期3个时期,采用土壤侵蚀敏感性、林冠截留量、生境适宜性等指标,分别评估了汶川地震极重灾区10个县市水土保持功能、水源涵养功能、生物多样性保护功能的状况及变化动态。结果表明:研究区的水土保持功能、水源涵养功能,以及生物多样性保护功能在震后遭到了严重破坏。总体来说5a后,区域生态服务功能得到了一定程度的恢复,但未达到震前水平。在极重灾区10个县市中,地理上位于中南部的6个县市(汶川、都江堰、什邡、彭州、绵竹、安县)在地震中总体受损程度较大。6个县市处于中国西部泥石流、滑坡的活跃区,震后因降雨诱发滑坡泥石流,导致了龙门山、茶坪山局部区域的水土保持功能、水源涵养功能、生物多样性保护功能在恢复期进一步下降,甚至低于震后。其中汶川县草坡乡、银杏乡、耿达乡、卧龙镇、三江乡有较大范围的功能下降,另外,都江堰市、彭州市、什邡市、绵竹市、安县等也分别有较大面积的功能下降区。区域生态服务功能在未来10a内,有可能进一步恶化。灾后重建一定程度上改善了区域生态功能状况,加快了生态功能恢复进程。但是,也存在对生态服务功能的恢复与维持重视不足等问题。部分灾后重建项目的实施,甚至又导致局部地区出现生态服务功能的退化。建议(1)加强汶川地震极重灾区中长期生态恢复遥感及地面监测、评估,进行生态服务功能恢复效应评估;(2)加强干旱河谷、龙门山及茶坪山等重点区域的生态修复。

ASSESSMENT OF "5.12" WENCHUAN EARTHQUAKE RESTORATION:ECOLOGICAL SERVICES FUNCTION IN SEVERELY AFFLICTED AREAS

Since the super earthquake happened on May 12^th 2008 in WenChuan, ecosystems in WenChuan have significant been affected. The purpose of this research is to provide strategical supports for medium to long term ecological recovery monitoring ecological restoration. and three different time periods were assessed, including 2007 (before earthquake), 2009 (after earthquake), and 2013(restoration). The research adopts a lot of index number such as sensitivity of soil erosion, canopy interception, and suability of habitat condition to assess the status change among function of water and soil conservation, water conservation, and species diversity ten areas that were severely afflicted areas. The result shows that water and soil conservation, water conservation, and species diversity protective functions have been destroyed in study area after the earthquake. Overall, after five years to some extent the ecological service in the study area has recovered, while it was still short of the standard before the earthquake. Six cities (Wenchuan, Dujiangyan, Shifang, Pengzhou, Mianzhu, Anxian) located in central-south were have high degree of damage compare to other four cities. These areas are the dynamic districts of debris flow and landslide. Due to large amount of rainfall after the earthquake, landslide and debris flow caused the recovery rate of water conservation function and species diversity protective function decreased; including Caoping village, Yinxin village, and Gengda village, Wolong village, and Sanjiang village. In addition, the function of water conservation and species diversity protective function in Dujiangyan, Pengzhou, Shifang,Mianzhu, and Anxian were also slight declined. Although, the reconstruction of post-disaster to some extent has changed ecological function status and improved ecological function recovery progress, less maintained attention to ecological function recovery would become a problem to the whole project progress. For example, enforcement project of post-disaster reconstruction causes the ecological service function degraded in local area. Therefore this research provides two recommendations: 1) reinforcement of medium to long term ecological recovery remote sensing and ground monitor, as well as to provide the assessment of the effect of ecological function recovery in study area; 2) reinforcement of ecological restoration in key areas such as drought river- valley, Longmen Mountain, and Chaping Mountain etc.