挠力河流域东方白鹳生境质量变化景观模拟

Landscape simulating of habitat quality change for oriental white stork in Naoli River Watershed

挠力河流域是濒危水禽东方白鹳主要繁殖区域。基于东方白鹳主要生境因子与景观植被类型之间的关系,利用GIS技术,以其生境类型图为基础,通过建立HSI模型,模拟评价了近40年来东方白鹳生境质量变化过程。结果显示(1)该流域湿地面积丧失了87%;(2)两种重要生境类型完全丧失,湖泊数量丧失93%左右,岛状林湿地数量丧失66%;(3)湿地景观的这些变化以及地理隔离导致了东方白鹳最佳适宜生境面积减少了95%,最小繁殖生境面积减少了97%;(4)东方白鹳种群数量迅速下降,20世纪80年代后其繁殖种群逐渐消失;(5)研究也显示,东方白鹳潜在的生境质量使该区依然具有恢复一定种群数量的能力。

The Naoli River Watershed is an important breeding area for rare and endangered Oriental White Stork. Four major habitat factors for Oriental White Stork were identified by fieldwork, including disturbance, food, water regime and shelter in the study area. Although these four habitat factors have indirect relationship with vegetation types, disturbance degree, food richness, water depth and shelter condition can reflect indirectly by vegetation types. So, based on maps of detailed vegetation types in 1960s, 1970s, 1980s, and 2004, each habitat factor map was made by uniting vegetation map through GIS technique. Ten habitat types for Oriental White Stork were identified by overlay of these habitat factor maps. A habitat suitability index （HSI） model reflecting habitat factors and human impacts in landscape scale were built. Seven units were considered in the model： （1） human disturbance; （2） food richness; （3） water regime in wetland; （4） Vegetation shelter type; （5） distance from road and residential area; （6） the smallest breeding area and the best suitable area; （7） distance from food area to nest area. All these units were investigated in the study area. Results document that the suitable habitat quality for Oriental White Stork was declined significantly in the last 40 years. That is because Changes of habitat types and fragmentation of landscape occun＇ed in the study area. As a result, the total area of wetland reduced 87 %. Two important habitat types including Carex lasiocarpa marsh, reed marsh and 95 % open water area were completely lost. The island -like forest wetlands were very important nesting area for Oriental White Storks in the region. Therefore decrease in patch number of island-like forest wetlands and their geographical isolated by human destroying have significant effects on habitat quality and species population for Oriental White Stork. This phenomenon resulted in 95 % of high suitable area reducing. And the smallest habitat area decreased 97 % in 2004. The population of Oriental White Storks declined rapidly and disappeared after 1980s. Research also shows that the potential habitat quality for Oriental White Storks still exists in the study area. There are about 1217.43km^2 middle suitable wetlands in the study area. So it still has ability to restore population of Oriental White Storks. Study also shows that the HSI model has important value for evaluating habitat quality for Oriental White Storks in landscape scale.