1975—2020年环巢湖湿地景观格局演变及驱动分析

基于1975—2020年间7期遥感数据,分析环巢湖湿地景观格局变化,揭示研究区域的演变特征及其驱动因素。采用基于样本的面向对象分类法,辅以高分辨率影像对错分地类进行目视修正。通过计算转移矩阵、动态度和景观格局指数分析景观格局特征与动态变化,通过主成分分析讨论演变驱动力。结果表明:①1975—2020年,研究区域湿地面积总体上处于缩减状态,由971.77 km²缩减到905.29 km²,主要转换成建设用地、农用地和植被用地;人工湿地在2013—2020年面积增加至39.58 km²,主要由农用地转化而来;非湿地景观中,建设用地面积增长最快,由13.85 km²增长到566.56 km²。②在景观指数分析中,斑块数量增加,不同类型斑块指数的波动变化存在一定差异;整体上景观破碎化指数从0.49增加到1.26,景观异质性增加,研究区域趋于复杂化;多样性指数总体呈现缓慢增长趋势,趋于均衡化分布。③由驱动力分析得出,自然因素在景观格局演变前期影响显著,随着社会经济的发展,自然因素作用逐渐弱化,社会经济成为景观变化的重要驱动因素;政策因素在研究区域景观演变方向中起主导作用,随着一系列政策调控的实施,有效改善了景观类型的分布。

Evolution and Driving Forces Analysis of Wetland Landscape Pattern around Chaohu Lake from 1975 to 2020

The changes of wetland landscape pattern around Chaohu Lake was examined to reveal the evolution characteristics and driving factors of the study area based on the remote sensing data during 1975-2020. The object-oriented classification method based on sample is adopted in association with high-resolution image to correct the wrong classification. The characteristics and dynamic changes of landscape pattern were analyzed by calculating land use transition matrix, dynamic degree and landscape pattern index; the driving forces of the changes were discussed through principal component analysis. Results unveiled that: 1) the area of wetland around Chaohu Lake presented a declining trend in general, from 971.77 km² to 905.29 km² in 1975-2020, most of which is converted into construction land, agricultural land and vegetation land; the area of constructed wetland expanded to 39.58 km² during 2013-2020, mainly converted from agricultural land; among non-wetland landscapes, the area of construction land expanded the most rapidly, from 13.85 km² to 566.56 km². 2) In the analysis of landscape index, the number of patches increased, and the fluctuation of different types of patch index varied; on the whole, the landscape fragmentation index climbed from 0.49 to 1.26, indicating a more heterogeneous and complex landscape; the diversity index displayed a slow growth trend and tended towards a balanced distribution. 3) According to driving force analysis, natural factors played a significant role in the early stage of landscape evolution; with the development of social economy, the effect of natural factors is gradually weakened and social economy became an important driving factor; policy factor played a guiding role in regional landscape evolution by changing the distribution of landscape types via policy regulation.