洞庭湖区生态用地生态服务价值时空演化的地形梯度效应

从数量变化和垂直分布两个层面分析了洞庭湖区1990-2015年期间生态用地及其生态服务价值时空演化的垂直空间分布特征，结果表明:（1） 洞庭湖区生态用地由1990年的17 215.77 km²增加到2015年的17 258.28 km²。其中湿地数量增加，林地、草地数量减少。（2） 生态用地生态服务价值由1990年的856.72亿元增加到2015年的1 393.28亿元，湿地生态服务价值增加明显。（3） 低地形梯度（1~10）为湿地的优势分布区；高地形梯度（30~50）是林地和草地的优势分布区。生态用地的转入和转出在不同时期交替进行，转入主要集中在较低的地形梯度上，而转出覆盖的梯度更广。（4） 生态服务价值优势分布区逐渐向低梯度聚集，中高梯度贡献的生态服务价值比例明显下滑。在明晰生态用地及其生态服务价值的垂直分布变化规律的基础上，进行精准的生态管控和建设，实现洞庭湖区生态系统的健康发展。

Terrain Gradient Effect of Spatiotemporal Evolution of Ecological Land and Ecosystem Service Value in Dongting Lake Area

We accomplished a pattern analysis of ecological land use pattern and its ecosystem service value evolution from the two aspects of quantitative change and vertical distribution in Dongting Lake from 1990 to 2015. The results indicated that:(1) the total amount of ecological land increased from 17 215.77 km² to 17 258.28 km² during 1990 and 2015 with the increase of wetland and the shrink of forest and grassland; (2) during the study period, ecosystem service value of ecological land has experienced multiple times of fluctuations, and finally rose to 139.93 billion yuan in 2015 from 85.67 billion yuan in 1990, meanwhile the ecosystem service value of wetland had increased significantly; (3) the dominant distribution area of wetland was found in the lower terrain gradients (1~10), the dominant distribution areas of forest and grassland were found in the higher terrain gradients (30~50); the transfer of ecological land appeared alternately in different periods, input mainly concentrated in the lower terrain gradients, while outflow covered the wider gradients; (4) the dominant distribution area of ecosystem service value converged into lower terrain gradients and the concentration kept increasing. The contribution of ecosystem service value from forestland and grassland in middle and higher gradient areas had decreased significantly. Ecological control and construction could carry out precisely under the unambiguous understanding of vertical distribution pattern of ecological land and its ecosystem service value, which is important to accomplish the healthy development of the compound ecosystem under the high-intensity impulse of rapid urbanization in Dongting Lake area.