PNAS：喂鸟消遣娱乐可能扰乱物种平衡

摘要 : 一项研究提出，城市喂野生鸟类的消遣娱乐可能扰乱原产鸟类物种与引入的鸟类物种之间的脆弱平衡。

一项研究提出，城市喂野生鸟类的消遣娱乐可能扰乱原产鸟类物种与引入的鸟类物种之间的脆弱平衡。一些估计认为，仅2002年，在美国有超过4.5亿公斤种子在消遣娱乐中被用于喂野鸟。由于在城市喂鸟有可能导致营养不良、改变鸟类物种丰富程度，并且帮助传播鸟传播疾病，Josie Galbraith等人在新西兰奥克兰的23个居民花园中进行了一个为期18个月的喂鸟实验，将近一半的花园每天早晨在喂食地点提供了一些面包片和250毫升一杯的种子——这是通过一项全国调查确定的喂鸟者提供的最常见的食物;而在另外一半花园不喂鸟。这项研究通过597项调查覆盖了33个物种的超过1.8万只鸟，它发现喂食可逆地影响了常见的花园鸟类物种的群落结构，偶尔有利于具有杂食倾向的引入物种而非常常食蜜、食虫和食果的原产物种。例如，在实验喂食期间，喂食的花园的家雀数量是不喂食花园的2.4倍，斑鸠数量是不喂食花园的3.6倍，它们都是引入的物种;相比之下，喂食与原产的灰莺的丰富程度负相关。这组作者说，尽管这项研究的规模有限，它发现了城市喂鸟对原产和引入物种的平衡的影响。

原文链接：

Supplementary feeding restructures urban bird communities

原文摘要：

food availability is a primary driver of avian population regulation. However, few studies have considered the effects of what is essentially a massive supplementary feeding experiment: the practICE of wild bird feeding. Bird feeding has been posited as an important factor influencing the structure of bird communities, especially in urban areas, although experimental evidence to support this is almost entirely lacking. We carried out an 18-mo experimental feeding study at 23 residential properties to investigate the effects of bird feeding on local urban avian asseMBLages. Our feeding regime was based on predominant urban feeding practices in our region. We used monthly bird surveys to compare avian community composition, species richness, and the densities of local species at feeding and nonfeeding properties. Avian community structure diverged at feeding properties and five of the commonest garden bird species were affected by the experimental feeding regime. Introduced birds particularly benefitted, with dramatic increases observed in the abundances of house sparrow (Passer domesticus) and spotted dove (Streptopelia chinensis) in particular. We also found evidence of a negative effect on the abundance of a native insectivore, the grey warbler (Gerygone igata). Almost all of the observed changes did not persist once feeding had ceased. Our study directly demonstrates that the human pastime of bird feeding substantially contributes to the structure of avian community in urban areas, potentially altering the balance between native and introduced species.

doi: 10.1073/PNAS.1501489112

作者：Josie A. Galbraith

;