Mager John N, Walcott Charles, Piper Walter H
Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA.
Naturwissenschaften. 2008 Feb;95(2):141-7. doi: 10.1007/s00114-007-0308-1. Epub 2007 Sep 26.
Artificial manipulations of habitat, such as those that incorporate adding nesting boxes or platforms for birds, often enhance the breeding success of threatened animals. However, such alterations are likely to have unintended behavioral and ecological effects that might negatively impact the target species or others in its community. We conducted a controlled study to investigate the effect of artificial nesting platforms on aggressive behavior and reproductive success of male common loons (Gavia immer). Males residing on territories to which platforms were added produced longer territorial "yodels" (reflecting willingness to escalate a contest), experienced increased levels of confrontation and aggression with territorial intruders, and experienced increased rates of territorial displacement by intruders. Surprisingly, males of treatment territories also experienced lower productivity. Therefore, in addition to providing novel empirical support of sequential assessment models of animal contests that predict contest escalation with increasing resource quality, this study is one of a few to show that tools used to mitigate habitat loss can negatively impact reproductive fitness in a threatened species.
对栖息地的人工改造，比如为鸟类增设巢箱或栖木，常常能提高濒危动物的繁殖成功率。然而，这种改变可能会产生意想不到的行为和生态影响，可能会对目标物种或其群落中的其他物种产生负面影响。我们进行了一项对照研究，以调查人工筑巢平台对雄性普通潜鸟（Gavia immer）攻击行为和繁殖成功率的影响。居住在增设了平台的领地的雄性潜鸟发出的领地“呜叫”时间更长（表明更愿意升级争斗），与领地入侵者的对抗和攻击水平增加，并且被入侵者驱赶出领地的频率增加。令人惊讶的是，接受处理的领地中的雄性潜鸟繁殖率也较低。因此，除了为动物争斗的顺序评估模型提供新的实证支持，该模型预测随着资源质量的提高争斗会升级之外，本研究还表明，用于缓解栖息地丧失的工具可能会对濒危物种的繁殖适应性产生负面影响，此类研究为数不多。
