Ecosystem engineers alter, and can be influenced in turn by, the ecosystems they live in. Woodpeckers choose foraging and nesting sites based, in part, on food availability. Once abandoned, these cavities, particularly within areas of high forage, may be crucial to secondary cavity-nesting birds otherwise limited by cavities formed through decay. Our study examined factors that influence the nesting success of primary cavity nesters and the subsequent impact on secondary cavity-nesting birds. Using 5 years of point count data, we monitored the outcomes of cavity-nesting birds in South Texas. We used logistic-exposure models to predict daily survival rates based on cavity metrics and used woodpecker foraging trends and insect surveys to determine if nesting where woodpeckers actively forage benefits secondary cavity-nesting birds. Both woodpeckers and secondary cavity nesters shared predictors of daily survival; nests were more successful in cavities with small openings in minimally decayed trees. All secondary cavity nesters had higher probabilities of success when nesting in an abandoned woodpecker cavity, opposed to ones formed by decay. Woodpeckers tended to forage in areas with higher-than-average levels of the insect orders Coleoptera, Hymenoptera, and Orthoptera, and secondary cavity nesters had higher rates of success when nesting in these areas. Our results suggest abandoned woodpecker cavities may be constructed in a way that directly benefit secondary cavity nesters. Additionally, we suggest an interplay between these ecosystem engineers, food availability, and secondary cavity nesters: Woodpeckers engineer superior nesting cavities in areas where food is more abundant, and the resultant cavities in areas of high forage may benefit local secondary cavity nesters. Our findings indicate that there is still much to be explored in the role of ecosystem engineers, and how they influence local communities on multiple trophic levels.

中文翻译：

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二手房：啄木鸟作为生态系统工程师的多层次影响

生态系统工程师会改变它们所生活的生态系统，并反过来受到它们的影响。啄木鸟在一定程度上根据食物的供应情况来选择觅食和筑巢地点。一旦被遗弃，这些空洞，特别是在高饲料区域内，可能对二次空洞筑巢的鸟类至关重要，否则它们会受到腐烂形成的空洞的限制。我们的研究考察了影响初级洞穴筑巢鸟筑巢成功的因素以及随后对二级洞穴筑巢鸟类的影响。使用 5 年的点计数数据，我们监测了德克萨斯州南部空巢鸟类的结果。我们使用逻辑暴露模型根据空洞指标来预测每日存活率，并使用啄木鸟觅食趋势和昆虫调查来确定在啄木鸟积极觅食的地方筑巢是否有利于二次空洞筑巢鸟类。啄木鸟和次生洞巢鸟都有共同的每日生存预测因子。在腐烂程度最低的树木上有小开口的空洞中筑巢更为成功。与腐烂形成的巢穴相比，所有次生巢穴筑巢者在废弃的啄木鸟巢穴中筑巢时都有更高的成功概率。啄木鸟倾向于在鞘翅目、膜翅目和直翅目昆虫数量高于平均水平的地区觅食，而二次空巢筑巢者在这些地区筑巢时的成功率更高。我们的研究结果表明，废弃的啄木鸟巢穴的建造方式可能会直接有利于二次巢穴的筑巢者。此外，我们建议这些生态系统工程师、食物供应和次生巢穴之间的相互作用：啄木鸟在食物更丰富的地区设计出优质的巢穴，而在高饲料地区产生的巢穴可能有利于当地的次生巢穴。我们的研究结果表明，生态系统工程师的作用以及他们如何在多个营养层面影响当地社区，还有很多值得探索的地方。