若尔盖高原湿地国家级自然保护区景观格局变化及驱动力 英文标题:The Changes of Landscape and Its Driving Forces in Ruo’ Ergai Plateau National Wetland Reserve in Sichuan， China

若尔盖高原湿地国家级自然保护区是全球类型独特的高寒泥炭沼泽湿地，为我国泥炭沼泽的集中分布区。地处青藏高原东缘的黄河上游，通过湿地汇集降雨和地表径流、冰川融雪，以及调控洪水等过程，对下游水量均衡起到重要作用。独特的气候环境与地理区位，孕育了世界高山带珍稀动、植物的生存环境，另一方面，若尔盖保护区地处少数民族地区，又是藏民游牧区和著名旅游区，是当地社会稳定、经济发展的重要基础，也是生物多样性保护与湿地资源保护、利用矛盾极为突出的地区。若尔盖保护区湿地景观变化不仅改变了其景观的空间结构，而且影响了湿地景观的原有生态服务功能，尤其对生物多样性的栖息生境产生重要影响。该区域已有的研究表明，保护区水环境逐年减少，湿地质心迁移，适宜多种珍稀动、植物生存繁衍的湿地环境不断丧失，生物多样性受到严重威胁并危及到当地经济的可持续发展，从而成为国内外广泛关注的焦点。但长期以来国内外对这一湿地的研究并不深入。论文选取若尔盖高原湿地国家级自然保护区，以景观生态学基本原理为指导，结合3S技术，客观分析若尔盖国家级自然保护区湿地18年(1990～2007)来景观格局的动态变化，探讨湿地景观格局变化的主要或关键驱动力，为控制保护区人类经济活动且合理地持续利用湿地资源，为保护区有效保护管理提供科学依据，指导保护区管理政策制定来应对全球气候环境变化，保护受损高原湿地的珍稀动植物资源，恢复其受损生境，维护黄河流域的生态安全和经济社会可持续发展。本研究基于遥感、地理信息系统和全球定位系统等技术手段对若尔盖高原湿地进行景观格局变化研究。选择了该区域1990年、2000年、2007年时相较为接近的三幅影像为基本数据源进行景观解译，结合相关历史资料、调查数据和采样实验，利用景观分析软件Fragstats3.3计算景观格局指数，统计其变化特征。结果表明，18年来，湿地景观组分演变以沼泽化草甸为主要优势类型，面积从45.36%增加至48.05%，成为景观基底。景观尺度下，多样性指数、景观破碎程度增加，斑块数目2000年到2007年净增27，景观边缘密度2007年增加0.626m/ hm2，Shannon多样性指数由2000年的1.2769至2007年增加到1.2797。斑块水平中，草甸与沼泽化草甸斑块破碎程度、空间异质程度最高，湖泊最低。在排水、人为放牧干扰的长期频繁影响下，沼泽化草甸、草甸破碎程度、空间异质程度升高。景观时空不断演化，有水的生境面积减少，而沼泽化草甸、干草甸(草场)面积持续增加，1990~2000年，沼泽化草甸、草甸面积分别增加了1978.60 hm2和2559.09 hm2，2000 ~2007年，湖沼水面积仍在萎缩，草场放牧面积保持增长，沙地短期增加1945.90 hm2，反映了若尔盖湿地景观由原生湿地景观逐渐往陆生草场的变化过程。论文研究分析获得了若尔盖湿地景观格局变化的关键驱动因子，其在气候变暖自然条件下，保护区社区人口增涨，生存需求胁迫下对湿地排干、超载或高强度放牧引起或加速了沼泽和沼泽化草甸退化，导致草甸沙化;恢复中的沙化草地遭受再次放牧践踏，沙化趋势加剧，鼠害泛滥;另外，经济开发活动如道路建设、城镇化和采矿活动，以及对资源高强度依赖和经济快速发展的冲击，引发的无序旅游及滥挖乱采药材等干扰，驱动着湿地退化。14年来若尔盖在保护区管理局多年的积极管理下，景观尺度总体上破碎程度呈下降趋势，景观聚集度递增，河流小幅增加，湿地环境有所改善，保护区保护管理起到了积极作用，但沼泽湿地向草地牧场退化演替仍是这一时期的主要趋势。加强控制该区人类经济活动，是保护区管理局实现湿地生物多样性保护与湿地资源可持续利用的管理基础，对若尔盖退化湿地进行治理和恢复，须提高对若尔盖高原湿地保护的认识，从景观大尺度上思考若尔盖国家级自然保护区的保护管理，提出应对全球气候变化的湿地保护策略。

The Zoige Plateau Wetland National Nature Reserve is a globally unique alpine peat swamp wetland and a concentrated distribution area of peat swamps in China. Located in the upper reaches of the Yellow River on the eastern edge of the Qinghai-Tibet Plateau, it plays an important role in balancing downstream water volumes through processes such as collecting rainfall, surface runoff, and glacial meltwater via wetlands, as well as regulating floods. Its unique climatic environment and geographical location have nurtured habitats for rare animals and plants in the world's alpine zone. On the other hand, the Zoige Reserve is located in an ethnic minority area, a Tibetan pastoral area and a famous tourist destination, serving as an important foundation for local social stability and economic development, and it is also an area where the conflicts between biodiversity conservation and wetland resource protection/utilization are extremely prominent.

Changes in the wetland landscape of the Zoige Reserve not only alter the spatial structure of its landscapes but also affect the original ecological service functions of wetland landscapes, particularly exerting important impacts on the habitats for biodiversity. Existing studies in this region show that the water environment of the reserve has been decreasing year by year, the centroid of wetlands has migrated, the wetland environments suitable for the survival and reproduction of various rare animals and plants have been continuously lost, biodiversity has been severely threatened, and this has endangered the local sustainable economic development, thus becoming a focus of widespread attention at home and abroad. However, domestic and international research on this wetland has not been in-depth for a long time.

This paper selects the Zoige Plateau Wetland National Nature Reserve as the research object, guided by the basic principles of landscape ecology, combined with 3S technologies, to objectively analyze the dynamic changes in the wetland landscape pattern of the Zoige National Nature Reserve over 18 years (1990–2007), and explore the main or key driving forces of wetland landscape pattern changes. This provides a scientific basis for controlling human economic activities in the reserve, rationally and sustainably utilizing wetland resources, and effectively protecting and managing the reserve, guiding the formulation of reserve management policies to cope with global climate and environmental changes, protect the rare flora and fauna resources of damaged alpine wetlands, restore their damaged habitats, and maintain the ecological security of the Yellow River Basin and sustainable economic and social development.

This study conducts research on landscape pattern changes of the Zoige Plateau Wetland based on technologies such as remote sensing, geographic information systems, and global positioning systems. Three images with relatively similar acquisition times in 1990, 2000, and 2007 were selected as the basic data sources for landscape interpretation. Combined with relevant historical materials, survey data, and sampling experiments, the landscape analysis software Fragstats3.3 was used to calculate landscape pattern indices and count their change characteristics.

The results show that over the 18 years, the evolution of wetland landscape components was dominated by swamp-meadow as the main dominant type, with its area increasing from 45.36% to 48.05%, becoming the landscape matrix. At the landscape scale, the diversity index and landscape fragmentation degree increased: the number of patches increased by 27 netly from 2000 to 2007, the landscape edge density increased by 0.626 m/hm² in 2007, and the Shannon's Diversity Index rose from 1.2769 in 2000 to 1.2797 in 2007. At the patch level, meadows and swamp-meadows had the highest degree of fragmentation and spatial heterogeneity, while lakes had the lowest. Under the long-term and frequent interference of drainage and anthropogenic grazing, the fragmentation degree and spatial heterogeneity of swamp-meadows and meadows increased. The landscape evolved temporally and spatially: the area of aquatic habitats decreased, while the areas of swamp-meadows and dry meadows (grasslands) continued to increase. From 1990 to 2000, the areas of swamp-meadows and meadows increased by 1978.60 hm² and 2559.09 hm² respectively; from 2000 to 2007, the area of lake and marsh water continued to shrink, the grazing grassland area maintained growth, and sandy land increased by 1945.90 hm² in the short term, reflecting the gradual transformation process of the Zoige wetland landscape from the original wetland landscape to terrestrial grasslands.

The paper analyzes and obtains the key driving factors for the changes in the Zoige wetland landscape pattern. Under the natural condition of climate warming, the population growth in the reserve's communities and the pressure from survival needs have led to or accelerated the degradation of marshes and swamp-meadows through wetland drainage and overgrazing or high-intensity grazing, resulting in meadow desertification. Restored desertified grasslands are trampled by grazing again, exacerbating the desertification trend, and rodent pests are rampant. In addition, economic development activities such as road construction, urbanization, and mining activities, as well as the interference caused by high dependence on resources and the impact of rapid economic development, such as unregulated tourism and illegal digging and harvesting of medicinal materials, drive wetland degradation.

Over the past 14 years, under the active management of the Reserve Administration over the years, the overall fragmentation degree at the landscape scale has shown a downward trend, landscape aggregation has increased, rivers have increased slightly, the wetland environment has improved, and the reserve's protection and management have played a positive role. However, the degradation and succession of swamp wetlands to grasslands and pastures remains the main trend during this period. Strengthening the control of human economic activities in this area is the management foundation for the Reserve Administration to achieve biodiversity conservation and sustainable utilization of wetland resources. To govern and restore the degraded wetlands in Zoige, it is necessary to raise awareness of the protection of the Zoige Plateau Wetland, consider the protection and management of the Zoige National Nature Reserve from a large landscape scale, and propose wetland conservation strategies to cope with global climate change.