北美水貂和欧亚水獭在东北地区的分布与生态位重叠
Distribution and niche overlap of American mink and Eurasian otter in Northeast China
A: 所有环境背景值的主成分分析相关性, cos2值表示各个因子对结果的解释性, 高cos2值表示该变量在主成分上具有良好的解释性, 且指向终点越靠近圆周。B: 水貂和水獭的生态位重叠, 实线和虚线轮廓线分别显示了可用背景环境的100%和50%, 绿色为水獭占据的生态位, 红色为水貂占据的生态位, 紫色为两个物种生态位的重叠部分, Schoener’s D值为0.60。C-F: 单因子生态位分布特征，实线和虚线轮廓线分别显示了可用背景环境的100%和50%, 绿色为水獭占据的生态位, 红色为水貂占据的生态位, 紫色为两个物种生态位的重叠部分; 横坐标轴上方的色条中, 绿色为背景环境的50%中被水獭单独占据的区域, 红色为背景环境的50%中被水貂单独占据的区域, 蓝色为背景环境的50%中共同占据的区域。
A, Correlation circle of PCA of all environmental background values, cos2 value indicates the interpretation of each factor to the results, high cos2 value indicates that the variable has good interpretation on the principal component, and points closer to the circumference of the end point. B, The niche overlap of mink and otter. The solid and dotted lines show 100% and 50% of the available background environment, respectively. The green is the ecological niche occupied by otters, the red is the ecological niche occupied by minks, and the purple is the overlapped niche of the two species, with Schoener’s D value of 0.60. C-F, Single factor niche distribution characteristics, solid line and dotted line contour lines show 100% and 50% of available background environment, respectively, the green is the niche occupied by otters, the red is the niche occupied by minks, and the purple is the overlapping niche of the two species. In the color bar above the horizontal axis, the green is the area occupied by otter alone in 50% of the background environment, the red is the area occupied by mink alone in 50% of the background environment, and the blue is the area occupied jointly in 50% of the background environment.
