In South Korea, the endangered Eurasian otter (Lutra lutra) populations have been recovered throughout the country. To examine the status of otter populations, we monitored spraint densities at 250 ~ 355 sites annually from 2014 to 2017 in the Nakdong River basin. The diffusion kernel method was applied to both binary and continuous spraint data. Two geographical popula - tions were identified: northern and southern populations. The northern population continuously increased over a broad area from north to south during the study period. In contrast, the southern population narrowly dispersed, limited by its location in an industrial area. The spatial self-organizing map (Geo-SOM) revealed associations between spraint densities and environmental factors by correlating the geographic locations of the sampling sites. Both populations were negatively affected by anthropogenic factors, including proximi - ty to factories and human population density. However, cumulative association of all environmental factors, including landscape, food sources, and anthropogenic factors, were noted in 2016 after which otter populations fully recovered. Population development stabilized while exhibiting an overall high association with environmental factors. The results of the diffusion kernel method and data variation according to the Geo-SOM consistently presented substantial change in population dispersal (i.e. the merge of two subpopulations, and complete associations between spraint and environmental factors). The combination of the diffusion kernel method and Geo-SOM was effective in portraying temporal changes in population states in association with environmental factors based on spra int data in the last phase of full recovery.

中文翻译：

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欧亚水獭（Lutra Lutra）的空间分布模式与机器学习和扩散核方法揭示的环境因素相关

在韩国，已在全国范围内恢复了濒临灭绝的欧亚水獭（Lutra lutra）种群。为了检查水獭的种群状况，我们从2014年至2017年每年在那东江流域监测250到355个站点的扭伤密度。扩散核方法应用于二进制和连续扭伤数据。确定了两个地理区域：北部和南部人口。在研究期间，北部人口在从北部到南部的广阔区域内持续增长。相反，由于南部人口在工业区中的位置的限制，南部人口狭population地分散。空间自组织图（Geo-SOM）通过关联采样点的地理位置揭示了扭伤密度与环境因素之间的关联。两种人口均受到人为因素的不利影响，包括靠近工厂和人口密度。但是，在2016年注意到了所有环境因素的累积联系，包括景观，食物来源和人为因素，此后水獭种群已完全恢复。人口发展稳定，同时与环境因素总体上高度相关。根据Geo-SOM的扩散核方法和数据变异的结果始终显示人口分布发生了实质性变化（即两个亚群的合并以及扭伤和环境因素之间的完全关联）。