南极半岛海域南极磷虾资源时空分布格局及尺度研究

Spatio-temporal distribution pattern and scale of density distribution for Antarctic krill (Euphausia superba) in the Antarctic Peninsula

  • 摘要: 生物资源分布格局依赖于空间尺度,不适宜的尺度可能会产生误导性的结果。作为南极生态系统的关键物种,南极磷虾的资源分布存在着极为显著的时空异质性,分布格局难以预测。为了解南极磷虾资源在不同空间尺度下的时空分布格局,实验利用科学调查数据,以5′为间隔将数据处理为5′×5′至60′×60′等12个空间尺度,从而针对南极磷虾资源主要分布区的南极半岛开展多尺度分析,并计算不同空间尺度下南极磷虾资源密度分布的Moran's I指数。结果显示,不同空间尺度下南极磷虾资源密度分布的空间格局存在着差异,其中11个空间尺度下的南极磷虾资源密度分布均呈现出聚集趋势。通过Moran's I指数与空间尺度的相关图确定了南极磷虾资源密度分布的特征空间尺度为25′×25′ (Moran's I指数首次穿过y=0的点)和15′×15′ (相关图上Moran's I指数与0无显著差异的最小尺度)。研究表明,Moran's I指数与0之间无显著差异的方法更符合南极磷虾资源自身的特性,建议将15′×15′作为该区域南极磷虾资源分布研究的最适空间尺度。

     

    Abstract: Distribution pattern of living resources depends on the spatial scale, and inappropriate scales may lead to misleading results. As a key species in the Antarctic ecosystem, Antarctic krill (Euphausia superba) distribution demonstrates significant spatial-temporal heterogeneity. Therefore, the distribution pattern of this species cannot be predicted effectively. In order to understand the spatial-temporal distribution pattern of E. superba resources at different spatial scales, this study preprocessed scientific survey data into 12 spatial scales (5′×5′ - 60′×60′) at 5′ intervals of latitude and longitude and carried out multi-scale analysis of this species in the Antarctic Peninsula, which is the main distributional region of E. superba resources. And the Moran's I index of E. superba density distribution at different spatial scales was also calculated. The results showed that the spatial patterns of E. superba differed in spatial scales. The density distribution of resources showed a clustering trend at 11 spatial scales. According to the correlogram between Moran's I index and spatial scale, the characteristic spatial scales of E. superba density distribution were determined as 25′× 25′, which was determined by the Moran's I index crossing the point y=0 for the first time, and 15′× 15′, which was determined by the smallest scale with no significant difference between Moran's I index and zero, respectively. This study showed that the method with no significant difference between Moran's I index and zero value was more consistent with the characteristics of E. superba resources. It was, therefore, suggested that 15′× 15′ could be the optimum spatial scale for studying the distribution of E. superba density in this region.

     

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