Centre d'Etudes Biologiques de Chizé, UMR 7372, CNRS and La Rochelle Université, F-79360 Beauvoir-sur-Niort, France; Université d'Angers, BiodivAG, 2 Bd Lavoisier, 49045 Angers Cedex 01, France.
BEOPS, 1 Esplanade Compans Caffarelli, 31000 Toulouse, France; Fédération Nationale des Chasseurs, 92136 Issy-les-Moulineaux Cedex, France.
Sci Total Environ. 2022 Jul 10;829:154558. doi: 10.1016/j.scitotenv.2022.154558. Epub 2022 Mar 15.
Predation is a major evolutionary force in animal ecology. Mechanisms by which prey coloration provides camouflage has been widely studied. However, predator response to prey camouflage and concealment has received less attention. Understanding vegetation structure effect on depredation success could help managers design strategies to mitigate the depredation of managed species (e.g., threatened or hunted). We aimed to investigate the relationship between depredation rate, nest camouflage and concealment in ground-nesting birds of farmlands, and their predators. We set up an experiment of 2576 artificial ground nests to assess the role of egg coloration (white, light green, and dark green), egg size (small, medium, and large), and vegetation structure (vegetation height and land use) in nest survival rates. We also explored the role of predator searching strategies by analysing clumped depredation and multiple depredation events. Of the nests, 34.0% were depredated, with corvids as the predators 78.5% of the time. Corvid depredation decreased by 40-60% in grasslands and spring crops above a vegetation height of 30 cm. In contrast, vegetation height and land use may be of far less importance in avoiding depredation by other predators. The probability of depredation was spatially clumped, suggesting that predators increase search effort in areas where a nest was previously encountered. Neighboring depredation and depredation repetition were more frequent in corvids than in other predators. Our study indicates that nests in vegetation higher than 30 cm had a drastic reduction in depredation rates by corvids. Management of vegetation structure is a key tool to mitigate depredation risk, and improving the availability of alternative food resources may be a complementary tool.
捕食是动物生态学中的主要进化力量。猎物的颜色提供伪装的机制已被广泛研究。然而，捕食者对猎物伪装和隐藏的反应受到的关注较少。了解植被结构对捕食成功的影响可以帮助管理者设计策略来减轻受管理物种（例如受威胁或被猎杀的物种）的捕食。我们旨在调查农田中地面筑巢鸟类的捕食率、巢伪装和隐蔽之间的关系，以及它们的捕食者。我们设置了一个 2576 个人工地面巢穴的实验，以评估卵颜色（白色、浅绿色和深绿色）、卵大小（小、中和大）和植被结构（植被高度和土地利用）在巢存活率中的作用。我们还通过分析聚集性捕食和多次捕食事件，探讨了捕食者搜索策略的作用。在这些巢穴中，有 34.0%被捕食，其中 78.5%是由鸦科动物作为捕食者。在草地和植被高度超过 30 厘米的春播作物中，鸦科动物的捕食减少了 40-60%。相比之下，植被高度和土地利用在避免其他捕食者的捕食方面可能重要性要小得多。捕食的可能性是空间聚集的，这表明捕食者在以前遇到巢穴的区域增加了搜索力度。鸦科动物比其他捕食者更频繁地发生相邻捕食和捕食重复。我们的研究表明，在植被高度超过 30 厘米的巢穴中，鸦科动物的捕食率急剧下降。管理植被结构是减轻捕食风险的关键工具，而增加替代食物资源的可获得性可能是一种补充工具。
