Simple Patchy-Based Simulators Used to Explore Pondscape Systematic Dynamics

Thousands of farm ponds disappeared on the tableland in Taoyuan County, Taiwan since 1920s. The number of farm ponds that have disappeared is 1,895 (37%), 2,667 ponds remain (52%), and only 537 (11%) new ponds were created within a 757 km2 area in Taoyuan, Taiwan between 1926 and 1960. In this study, a geographic information system (GIS) and logistic stepwise regression model were used to detect pond-loss rates and to understand the driving forces behind pondscape changes. The logistic stepwise regression model was used to develop a series of relationships between pondscapes affected by intrinsic driving forces (patch size, perimeter, and patch shape) and external driving forces (distance from the edge of the ponds to the edges of roads, rivers, and canals). The authors concluded that the loss of ponds was caused by pond intrinsic factors, such as pond perimeter; a large perimeter increases the chances of pond loss, but also increases the possibility of creating new ponds. However, a large perimeter is closely associated with circular shapes (lower value of the mean pond-patch fractal dimension [MPFD]), which characterize the majority of newly created ponds. The method used in this study might be helpful to those seeking to protect this unique landscape by enabling the monitoring of patch-loss problems by using simple patchy-based simulators.自20世纪20年代起，中国台湾桃园县台地的农田水塘已消失逾千座。1926年至1960年间，在台湾桃园县757平方公里的研究区域内，消失的农田水塘共计1895座（占比37%），现存2667座（占比52%），仅新增水塘537座（占比11%）。 本研究采用地理信息系统（Geographic Information System, GIS）与逻辑斯蒂逐步回归模型（logistic stepwise regression model），以测算水塘消失速率并解析塘群景观变化的驱动机制。该模型用于构建受内在驱动因素（斑块面积、周长与斑块形状）影响的塘群景观，与外在驱动因素（水塘边缘至道路、河流及运河边缘的距离）之间的一系列关联关系。 研究团队得出结论：水塘消失与塘体自身属性密切相关，例如塘体周长——较大的周长会提升水塘消失的概率，但同时也会增加新建水塘的可能性。然而，较大的塘体周长与圆形塘体高度相关，这类塘体的平均斑块分形维数（Mean Patch Fractal Dimension, MPFD）数值较低，而绝大多数新建水塘均为此类圆形塘体。 本研究采用的方法可为该独特景观的保护工作提供参考：借助基于简单斑块的模拟器开展斑块消失问题监测，可为相关防护实践提供支撑。