横断山区干旱河谷研究现状和发展方向

干旱河谷及其所在的横断山区是独特的自然、气候和地理单元，是我国民族多样性、文化多样性、环境异质性以及生物多样性最为丰富的地区，少数民族分布最为集中的地区之一，也是西南经济最为落后、交通偏远、地质灾害最为严重的区域。干旱河谷以其较好的光热等条件成为整个横断山区人口和城镇分布集中的核心地带，但是由于干旱河谷脆弱的生态系统和特殊的交错带分布格局，决定了干旱河谷具有低阈值生态安全和高风险生态退化的特点。近几十年来在干旱河谷治理方面做了大量工作，在个别区域生态恢复方面取得了一些进展，农林可持续经营模式受到关注，经济资源植物引种和开发日益受到重视，基于地方特色的产业逐步得以兴起并取得初步成效。但从整个区域来看，干旱河谷研究方面还存在研究区域过分集中、人地关系研究缺乏、生态恢复模式过于单一等问题，加上人口和经济发展的压力，干旱河谷治理和开发的选择有限，使整个干旱河谷区次生干旱化仍然在发展中，生态环境退化状况仍在加剧，水土流失严重威胁本地和下游安全，资源和环境压力日益增加。干旱河谷进一步的研究应立足发展的需要，着重从干旱河谷本身演变机制的研究、全球变化背景下干旱河谷响应特征及规律、干旱河谷人地关系与上下游利益协同关系、干旱河谷景观结构和功能演变规律方面入手，在此基础上区分干旱河谷的自然和人为过程，全面制定整个干旱河谷区域的生态环境治理、经济与资源环境可持续战略，实现整个干旱河谷区域经济和环境持续协调发展。

Present Situations and Its R&D of Dry Valleys in the Hengduan Mountains of SW China

Hengduan Mountains, with most abundant diversity in the nationality, culture, biology and environment heterogeneity in China, is one of the particularities with unique natural, climatic, and geographical landscape. The area is also characterized by economy depression, communication marginality, and frequent geological calamity. Dry valleys with dry season and monsoon are enchased in the parallel mountains like series dry strips. Most of population and townships of this area distribute in the dry valleys due to relatively preferable living conditions and more level cropland. However , secondary drying expansion, serious soil erosion, landslide, frequently flood and seasonal droughts, and ecological deterioration and desertion have been endangering local people subsistence and lowland ecological safety due to slopeland over-exploitation and fuelwood collection under the increasing pressure of local population expansion and economy development. Although more and more investment have been input, and experiments of reforestation and studies of revegetaion have been carried out for the restoration of the degraded ecosystem in recent three decades, almost all the results are gloomy or completely frustrated, which has proved that dry valley is not only a stress conditions but a resource, and ecological degradation is not only a on-site problem but a off-site problem, and a new visual angel should be taken into consideration in the dry valley research and management. Dry valley management should firstly focus on the resources, especially drought, and how to exploring these resources sustainably and untraditionally. In the research, more attention should be attracted to evolution mechanism of dry valley, relationships between human being and environment, benefits sharing between the upland and lowland, characteristic responses under the condition of global changes, and natural and human-induced process should be differentiated. On the basis wisely steps can be made out and carried out for the sustainable development of economy and reasonable management of environment and natural resources in the fragile dry valley area.