向海自然保护区景观格局变化及湿地梯度分布特征研究

Study on the variation of landscape pattern and the gradient distribution of wetland in the Xianghai Nature Reserve

应用遥感和地理信息系统技术,对向海自然保护区不同年代景观格局特征,及其重要湿地景观梯度分布特征进行深入的分析。研究发现因受人类活动和气候暖干影响,研究区草地和湿地景观减少趋势明显,而耕地、林地和未利用地增加趋势较为突出;景观丰富度指数逐渐降低,多样性指数保持着小幅度的上升趋势,优势景观越来越不明显。向海自然保护区湿地景观分布呈向西南方向递增;向海核心区湿地景观消退速率也明显快于缓冲区;1960年向海自然保护区核心区内湿地景观梯度区域占了总核心区面积的80%,到2004年DI≥30区域所占比例减少到了45%,保护区湿地景观梯度值呈整体性下降,导致了保护区湿地生态系统功能下降趋势明显。人类活动干扰、气候逐年变暖、蒸发强烈、再加上霍林河上游供水不足导致向海保护区内霍林河河道逐渐干涸,是向海自然保护区景观格局变化的主要驱动因素,并导致河道周边湿地退化过程将向西南方向逐渐推进,因此加强人类活动的自我约束,合理地引用有限资源,加大保护区重要湿地的保护力度已迫在眉捷。

With the application of RS and GIS techniques, the variation of landscapes pattem and the gradient distribution of wetland in Xianghai Nature Reserve in different ages were analyzed. The results showed that under the influences of the human activity and the climate warming up, the reduction tendency of the grass and wetland landscape is obvious, contrarily the farmland, the forestland and the badlands increased; the landscape richness index of Xianghai Nature Reserve decreased gradually when the landscape diversity index maintained slowly increasing. This model focuses on describing the landscape spatial pattem and the tendency of distribution of landscape, also indicating the ecological process. Using the landscape gradient model, the gradient distributions of wetland landscape in different ages were analyzed. At the same time, the statistical analysis of gradient change of wetland which was reclassified was carried on in the different functional districts. The result showed that the south - westem of Xianghai Nature Reserve in which the Huolin River distributes has relatively high wetland - landscape gradient compared with other region. The wetland landscape in core region of Xianghai Nature Reserve in which wetland massed obviously degraded at a higher speed than the buffer. Especially the area of in the core region accounted for 45% of total area in 2004, while accounting for 80% in 1960. The degradation of the wetland in Xianghai Nature Reserve resulted in the dropping of ecosystem function of wetland landscape. It is the climate warming up, evaporation intensely and water supply in the upriver of Huolin Rive insufficiently that were the driving forces resulting that the total wetland.all around the Huolin River will be almost degraded and lost along southwest direction. Therefore, we should strengthen the water- resources management of the Huolin river basin and use the water- resources of Huolin river basin in an effective way while controlling the disturbance of the humanity, which is very crucial to protect the important wetland resource in Xi- anghai Nature Reserve.