南极磷虾资源分布热点分析的空间尺度效应

Effect of spatial scale on hotspot analysis of Antarctic krill (Euphausia superba) distribution

  • 摘要: 空间尺度是生态学的一个重要研究领域,但少有研究关注空间尺度对生物资源热点分析产生的影响。为了分析不同空间尺度对南极磷虾环南极分布热点的影响,以10年为间隔,将1926—2016年南极磷虾资源密度数据插值为10′×10′、20′×20′、30′×30′、40′×40′、50′×50′、1°×1°、2°×2°、3°×3°、4°×4°、5°×5°这10个空间尺度,利用线性、对数、指数、幂律和多项式函数计算了南极磷虾资源全局密度、磷虾资源热(冷)点区密度与空间尺度之间的关系,分析了热(冷)点区在不同空间尺度下质心与面积的变化。结果显示,南极磷虾资源全局密度的最大值、偏度、峰度、变异系数与空间尺度之间存在显著的比例关系,热点区的最大值、偏度、峰度、Q3、变异系数与空间尺度之间存在显著的比例关系,而冷点区的最大值、平均值、标准差、偏度、峰度、Q3、变异系数与空间尺度之间存在显著的比例关系。热(冷)点区的面积随着空间尺度的增大而增大,其位置受空间尺度变化的影响较大。当空间尺度大于1°×1°时,热(冷)点区的质心偏移严重,故不建议将大于1°×1°的空间尺度用于识别南极磷虾的局部空间格局。

     

    Abstract: While the importance of spatial scale in ecology is well established, few studies have investigated the impact of spatial scale on hotspot analysis of biological resources. In this study, in order to analyze the impact of spatial scale on hotspot analysis of Antarctic krill (Euphausia superba) density distribution around Antarctica, the krill density data from 1926 to 2016 by 10-year period was interpolated into ten spatial scales, i.e., 10′×10′, 20′×20′, 30′×30′, 40′×40′, 50′×50′, 1°×1°, 2°×2°, 3°×3°, 4°×4°, and 5°×5°, respectively, and linear, logarithmic, exponential, power-law, and polynomial functions were used to calculate the relationship between the global krill density, krill density in hotspot (coldspot) areas and the spatial scale, and the variations in centroid and hotspot (coldspot) areas at different spatial scales were also analyzed. The results showed that there was a significant scaling relationship between the maximum, skewness, kurtosis, Coefficient of Variation (CV) of global krill density and the spatial scale. Significant scaling relationship between the maximum, skewness, kurtosis, third quartile (Q3), and CV of the krill density in hotspot area and the spatial scale was found. A significant scaling relationship was also found between the maximum, mean, standard deviance (SD), skewness, kurtosis, Q3, CV and spatial scale for the coldspot area. The size of the hotspot (coldspot) area increased with the increasing of the spatial scale, and the offset of centroid indicated the locations of the hotspot (coldspot) areas were greatly affected by the spatial scale. Significant shift of centroid for hotspot (coldspot) areas occurred when the spatial scale was greater than 1°×1°. Therefore, it is not recommended to use spatial scale that is greater than 1° × 1° to identify the local spatial pattern for hotspot analysis of krill density.

     

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