基于淹水特征的分时段湿地生态系统管理——以南洞庭湖万子湖为例

利用2013年遥感影像和地形图制作地势图,将万子湖湿地洲滩分为27 m以下、27~28、28~29、29~30、30 m以上共5级地势阶梯。利用1983~2013年万子湖逐日平均水位数据分析不同地势阶梯洲滩在春汛期、洪水期、退水期、枯水期等4个时段的淹水特征,结合生物特性和人为干扰分析,确定万子湖湿地生态系统管理的边界范围和策略。研究表明:4个时段中的生态系统管理边界分别为29、31、29、28 m地势阶梯分界线,3个重点时段和管理区域为:春汛期,管理目标是产卵亲鱼保护,28 m以下洲滩是重点管理区域;退水期,管理目标是保障鱼类洄游,28 m以下洲滩和湖槽洄游通道是重点管理区域;枯水期,管理目标是洲滩上鱼类产卵场、幼鱼索饵场和越冬候鸟栖息地的恢复与保护,28 m以下洲滩是重点管理区域。而生态系统管理重点则是去除过度人为干扰(包括洲滩过度开发、过度捕捞),恢复湿地生态系统整体性功能,应坚决停止重点区域内滩涂水面的养殖承包、引淤抬洲、洲滩植树等系列干扰性活动。

WANZIHU WETLAND ECOSYSTEM MANAGEMENT IN TIME PERIOD BASED ON FLOODING FEATURES

We used 2013 remote sensing images and topographic maps to derive the terrain map, and divided the Wanzi Lake wetland into five terrain ladder including <27 m, 27~28m, 28~29m, 29~30m and >30m. We used 1983-2013 daily average water level data of the Wanzi lake wetland to analyze flooding features of different terrain ladder in spring flood period, flood period, recession period and dry period. We combined biological characteristics and human disturbance analysis to determine the Wanzi Lake wetland ecosystem management ranges and strategies. The results showed that the ecosystem management boundaries in those four periods are 29m, 31m, 29m and 28m terrain ladder dividing line, respectively. These are three key time periods and areas. In the spring flood period, the management target is protecting spawning fish and the key area is the river beach below 28 meters. In the recession period, the management target is protecting fish migration and the key area is migration channel. In the dry period, the management targets are restoring and protecting fish spawning grounds, feeding grounds and migratory bird overwintering grounds, while the key area is the river beach below 28 meters. The key point of ecosystem management is removal of excessive human disturbance (including over exploiting and over fishing) and restoration of wetland ecology function. Human interferences need to be prohibited in the key areas such as contracting beaches and waters for aquaculture, using flood to silt beach and low-lying land, river beach plantation, etc.