Abstract：
BACKGROUND: Understanding the migration of marine animals is hindered by the limitations of traditional tracking methods. It is therefore crucial to develop alternative methods. Stable isotope-based tracking has proven useful for this task, although it requires detailed isoscapes in the focal area. Here, we present predator-based isoscapes of the coastal zone of the Patagonian Shelf Large Marine Ecosystem (PSLME), which offers a novel tool for geolocation.
METHODS: Whole-blood samples from breeding Magellanic penguins nesting at 11 colonies were used to create δ15N and δ13C isoscapes. Isotopic values were assigned to random positions inside their corresponding foraging area. Spatial analysis and data interpolation resulted in δ15N and δ13C isoscapes for the coastal zone of the PSLME, which were validated through cross-validation.
RESULTS: The isoscapes mean standard error ranged from 0.05 to 0.41 for δ15N and from 0.07 to 0.3 for δ13C, similar to the error range of the mass spectrometer used for measuring isotope ratios. Predictive surfaces reflected the latitudinal trends, with δ13C and δ15N values increasing northwards. δ13C values showed a strong latitudinal gradient, while δ15N values had two distinct domains, with higher values in the north. The error surface indicated the highest certainty within 130 km from the shore and within the reported Magellanic penguin foraging areas.
CONCLUSIONS: Both isoscapes revealed strong spatial variation. The δ13C isoscape showed a latitudinal gradient, consistent with patterns in other oceans. The δ15N isoscape clearly separated northern and southern colonies, likely influenced by nitrogen sources. The error obtained fell within the measurement error ranges, adding credibility to the models.
METHODS: Whole-blood samples from breeding Magellanic penguins nesting at 11 colonies were used to create δ15N and δ13C isoscapes. Isotopic values were assigned to random positions inside their corresponding foraging area. Spatial analysis and data interpolation resulted in δ15N and δ13C isoscapes for the coastal zone of the PSLME, which were validated through cross-validation.
RESULTS: The isoscapes mean standard error ranged from 0.05 to 0.41 for δ15N and from 0.07 to 0.3 for δ13C, similar to the error range of the mass spectrometer used for measuring isotope ratios. Predictive surfaces reflected the latitudinal trends, with δ13C and δ15N values increasing northwards. δ13C values showed a strong latitudinal gradient, while δ15N values had two distinct domains, with higher values in the north. The error surface indicated the highest certainty within 130 km from the shore and within the reported Magellanic penguin foraging areas.
CONCLUSIONS: Both isoscapes revealed strong spatial variation. The δ13C isoscape showed a latitudinal gradient, consistent with patterns in other oceans. The δ15N isoscape clearly separated northern and southern colonies, likely influenced by nitrogen sources. The error obtained fell within the measurement error ranges, adding credibility to the models.
摘要：
背景：了解海洋动物的迁徙受到传统追踪方法的局限性的阻碍。因此，开发替代方法至关重要。基于同位素的稳定跟踪已被证明对这项任务有用，尽管它需要焦点区域的详细等值线。这里,我们介绍了巴塔哥尼亚陆架大型海洋生态系统（PSLME）沿海地区的基于捕食者的等值图，它提供了一种新颖的地理定位工具。
方法：使用在11个菌落中筑巢的繁殖麦哲伦企鹅的全血样品来创建δ15N和δ13C等值。将同位素值分配给其相应觅食区域内的随机位置。空间分析和数据插值导致PSLME沿海地区的δ15N和δ13C等值线，通过交叉验证进行了验证。
结果：δ15N的等值平均标准误差为0.05至0.41，δ13C的等值平均标准误差为0.07至0.3，类似于用于测量同位素比率的质谱仪的误差范围。预测面反映了纬度趋势，δ13C和δ15N值向北增加。δ13C值显示出强烈的纬度梯度，而δ15N值具有两个不同的域，在北方有更高的价值。误差表面表明，在距海岸130公里的范围内以及所报告的麦哲伦企鹅觅食区内，确定性最高。
结论：两种等值线都显示出强烈的空间变异。δ13C等值线显示出纬度梯度，与其他海洋的模式一致。δ15N等值线清楚地将北部和南部殖民地分开，可能受氮源影响。获得的误差落在测量误差范围内，增加模型的可信度。
方法：使用在11个菌落中筑巢的繁殖麦哲伦企鹅的全血样品来创建δ15N和δ13C等值。将同位素值分配给其相应觅食区域内的随机位置。空间分析和数据插值导致PSLME沿海地区的δ15N和δ13C等值线，通过交叉验证进行了验证。
结果：δ15N的等值平均标准误差为0.05至0.41，δ13C的等值平均标准误差为0.07至0.3，类似于用于测量同位素比率的质谱仪的误差范围。预测面反映了纬度趋势，δ13C和δ15N值向北增加。δ13C值显示出强烈的纬度梯度，而δ15N值具有两个不同的域，在北方有更高的价值。误差表面表明，在距海岸130公里的范围内以及所报告的麦哲伦企鹅觅食区内，确定性最高。
结论：两种等值线都显示出强烈的空间变异。δ13C等值线显示出纬度梯度，与其他海洋的模式一致。δ15N等值线清楚地将北部和南部殖民地分开，可能受氮源影响。获得的误差落在测量误差范围内，增加模型的可信度。
