Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of Oslo, P.O. Box 1066, Blindern, 0316, Oslo, Norway.
Oecologia. 2012 Jul;169(3):685-94. doi: 10.1007/s00442-011-2226-3. Epub 2011 Dec 18.
In a changing environment, the maintenance of communities is subject to many constraints (phenology, resources, climate, etc.). One such constraint is the relationship between conspecifics and competitors. In mixed colonies, seabirds may have to cope with interspecific and intraspecific competition for both space and food resources. We applied competitive interaction models to data on three seabird breeding populations: black-legged kittiwake (Rissa tridactyla), common guillemot (Uria aalge) and Brünnich's guillemot (Uria lomvia) collected over 27-years at Kharlov Island in the Barents Sea. We found a competitive effect only for the kittiwake breeding population size on the common guillemot breeding population size when kittiwakes were abundant. The timing of kittiwake breeding negatively affected the number of breeding Brünnich's guillemots. The timing of breeding was negatively correlated to biomass of the main pelagic fish in the Barents Sea, the capelin (Mallotus villosus), which suggests an indirect action. The community matrix shows that the community was not stable. The kittiwake population did not decrease as seen in north Norwegian populations. Likewise, the common guillemot population, after a crash in 1985, was recovering at Kharlov while Norwegian populations were decreasing. Only the Brünnich's guillemot showed a decrease at Kharlov until 1999. We suggest that the stability of the kittiwake and common guillemot populations at Kharlov is due to better feeding conditions than in colonies of the Norwegian coast, linked to a possible eastward shift of the capelin population with the temperature increase of the Barents Sea.
在不断变化的环境中，社区的维持受到许多限制（物候学、资源、气候等）。其中一个限制是同种生物和竞争者之间的关系。在混合群体中，海鸟可能不得不在同种和种间竞争中争夺空间和食物资源。我们将竞争相互作用模型应用于三个海鸟繁殖种群的数据：黑脚三趾鸥（Rissa tridactyla）、普通海鸠（Uria aalge）和角嘴海雀（Uria lomvia），这些数据是在巴伦支海的哈洛夫岛（Kharlov Island）收集的，时间跨度为 27 年。我们发现，只有当三趾鸥繁殖数量丰富时，三趾鸥繁殖种群的大小才会对普通海鸠繁殖种群的大小产生竞争影响。三趾鸥的繁殖时间会对繁殖角嘴海雀的数量产生负面影响。繁殖时间与巴伦支海主要洄游鱼类毛鳞鱼（Mallotus villosus）的生物量呈负相关，这表明存在间接作用。群落矩阵表明，群落并不稳定。三趾鸥的数量并没有像在挪威北部看到的那样减少。同样，1985 年普通海鸠数量暴跌后，在哈洛夫开始恢复，而挪威的种群数量却在减少。只有角嘴海雀在哈洛夫一直减少，直到 1999 年。我们认为，在哈洛夫，三趾鸥和普通海鸠种群的稳定性是由于比挪威海岸的繁殖地更好的觅食条件造成的，这与毛鳞鱼种群可能随巴伦支海温度升高而向东迁移有关。
