1974-2011年白洋淀土地覆盖时空变化特征

在野外调查的基础上,运用遥感和地理信息系统技术对1974年、1979年、1984年、1987年、1989年、1991年、1996年、2001年、2006年和2011年10期遥感影像进行解译和分析,揭示了白洋淀近37年土地覆盖动态变化。结果表明:近37年白洋淀土地覆盖类型变化极为复杂,主要表现为水体、芦苇地、耕地3种土地覆盖类型相互转化。1974-2011年,水体面积从58.01 km2上升到80.07 km2,芦苇地面积从104.94 km2下降到72.95 km2,水生植被从14.02 km2下降到4.27 km2。1974-2011年,耕地、水体、芦苇地、居民点转化为其它类型的比例相对较小,分别为39.25%、34.46%、53.74%和18.15%。水体面积增加主要分布在地势较低的东部和北部地区,水体面积减少主要分布在地势较高的西南地区。水位变化、入淀径流量变化、淀区气候变化、人类活动及管理政策是白洋淀土地覆盖变化的驱动因子。研究揭示了白洋淀土地覆盖与人类活动的相互作用关系,对白洋淀土地管理和生态系统服务可持续供给具有重要意义。

Spatiotemporal Characteristics of the Land Cover Change in Baiyangdian Lake from 1974 to 2011

Based on field investigations, an analysis was conducted using RS and GIS technologies on the RS images of Baiyangdian Lake taken respectively in 1974, 1979, 1984, 1987, 1989, 1991, 1996, 2001, 2006, and 2011 in order to reveal the spatial and temporal characteristics of land cover change during the last 37 years. Results showed that the complicated variation of the land cover types in Baiyangdian from 1974 to 2011 can be mainly contributed to the reciprocal transformation among cropland, reed land, and water body. From 1974 to 2011, water area increased from 58.01 km2 to 80.07 km2, reed land area decreased from 104.94 km2 to 72.95 km2, aquatic vegetation area decreased from 14.02 km2 to 4.27 km2. Ratios of cropland, water body, reed land, and residential area converted to other types were relatively small, respectively 39.25%, 34.46%, 53.74% and 18.15%. The increase of water body mainly occurred in lower locations in the north and east parts of Baiyangdian Lake, and the decrease of water body mainly occurred in higher locations in the southwest parts of the lake. Reed land was mainly converted to water body and cropland. Water level changes, local climate change, inlfow variation, human activities and management policies were the main drivers of Baiyangdian land cover changes. Interactions between human activities and land cover changes revealed by the study are of vital importance to land management and sustainable delivery of ecosystem services.