苏州市吴江区湿地缓冲区景观格局对人类活动强度的响应OA

[Objective]This study aims toelucidate the differentiated threshold responses of landscape patterns within lake and river wetland buffer zones along a gradient of human activity intensity,thereby providing a scientific foundation for hierarchical protection of wetland ecological spaces and targeted regulation of human activities.[Method]The lake and river wetlands in Wujiang District,Suzhou was targeted,and buffer zones were established along the shorelines.Based on a comprehensive characterization of the spatial characteristics of human activities in the region,a human activity intensity(HAI)index was constructed by weighting five indicators including proportion of construction land,proportion of cultivated land,proportion of pond area,road network density,and density of transportation service facilities using an AHP-entropy combined weighting method.The HAI was spatially expressed within unified spatial units to analyze its gradient distribution characteristics in lakeside and riverside buffer zones.Further,FRAGSTATS was used to calculate multiple landscape metrics and reveal spatial differentiation patterns of landscape structure within wetland buffer zones.Finally,binary regression models were employed to explore nonlinear relationships between HAI and landscape patterns and to identify critical thresholds of HAI.[Result]1)Human activity intensity and landscape patterns displayed distinct spatial differentiation in the buffer zones of lakeside and riverside.In lakeside buffer zones,HAI exhibited"peak-type"or"valley-type"disturbance patterns within the buffer zone of 0-3 600 m,while landscape indices such as patch density,largest patch index,connectivity index,and aggregation index fluctuated considerably within the buffer zone of 0-1 800 m.In contrast,riverside buffer zones showed a gradient decay in HAI,with landscape indices responding consistently within the buffer zone of 0-1 800 m.2)Landscape patterns responded to HAI in a significantly nonlinear manner:indices such as patch density,connectivity index,aggregation index,Shannon's diversity index,and Shannon's evenness index followed an inverted U-shaped trend,while largest patch index exhibited a U-shape pattern.This reflects an evolutionary trajectory of landscape patterns characterized by"fragmentation→diversity enhancement→reintegration".3)Different disturbance thresholds were identified for lakeside and riverside buffer zones(0.22 and 0.18,respectively),suggesting stronger disturbance resistance in lakeside buffers and higher ecological vulnerability and degradation risk in riverside buffers.Among the metrics,patch density and aggregation index were the most sensitive to human disturbance.[Conclusion]The impact of human activities on landscape patterns within wetland buffer zones exhibits significant distance dependence and threshold effects.Controlling human activity intensity within critical thresholds can effectively maintain the connectivity and diversity of wetland landscapes.