Institut de Ciències del Mar-ICM-CSIC, P. Marítim de la Barceloneta, Barcelona, Spain.
PLoS One. 2013 Apr 30;8(4):e62897. doi: 10.1371/journal.pone.0062897. Print 2013.
The principle of competitive exclusion postulates that ecologically-similar species are expected to partition their use of resources, leading to niche divergence. The most likely mechanisms allowing such coexistence are considered to be segregation in a horizontal, vertical or temporal dimension, or, where these overlap, a difference in trophic niche. Here, by combining information obtained from tracking devices (geolocator-immersion and time depth recorders), stable isotope analyses of blood, and conventional morphometry, we provide a detailed investigation of the ecological mechanisms that explain the coexistence of four species of abundant, zooplanktivorous seabirds in Southern Ocean ecosystems (blue petrel Halobaena caerulea, Antarctic prion Pachyptila desolata, common diving petrel Pelecanoides urinatrix and South Georgian diving petrel P. georgicus). The results revealed a combination of horizontal, vertical and temporal foraging segregation during the breeding season. The stable isotope and morphological analyses reinforced this conclusion, indicating that each species occupied a distinct trophic space, and that this appears to reflect adaptations in terms of flight performance. In conclusion, the present study indicated that although there was a degree of overlap in some measures of foraging behaviour, overall the four taxa operated in very different ecological space despite breeding in close proximity. We therefore provide important insight into the mechanisms allowing these very large populations of ecologically-similar predators to coexist.
竞争排斥原则假定，生态相似的物种预计会对资源的利用进行分区，从而导致生态位的分化。允许这种共存的最可能机制被认为是在水平、垂直或时间维度上的隔离，或者在这些维度重叠的情况下，是营养生态位的差异。在这里，我们通过结合跟踪设备（地理定位仪-浸入和时间深度记录器）获得的信息、血液的稳定同位素分析以及常规形态测量，详细研究了解释南大洋生态系统中四种丰富的、以浮游动物为食的海鸟共存的生态机制（蓝海燕 Halobaena caerulea、南极贼鸥 Pachyptila desolata、普通潜鸟 Pelecanoides urinatrix 和南乔治亚潜鸟 P. georgicus）。结果表明，在繁殖季节存在水平、垂直和时间觅食隔离的组合。稳定同位素和形态分析强化了这一结论，表明每个物种占据了独特的营养空间，这似乎反映了飞行性能方面的适应。总之，本研究表明，尽管在某些觅食行为的度量上存在一定程度的重叠，但总体而言，尽管这些分类群在非常接近的地方繁殖，但它们在非常不同的生态空间中运作。因此，我们提供了重要的见解，了解了允许这些生态相似的捕食者非常大的种群共存的机制。
