Detecting ecological traps in human-altered landscapes: A case study of the thick-billed longspur nesting in croplands

Conversion of the North American prairies to cropland remains a prominent threat to grassland bird populations. Yet, a few species nest in these vastly modified systems. The thick-billed longspur (Rhynchophanes mccownii) is an obligate grassland bird whose populations have declined 4% annually during the past 50 years. Thick-billed longspurs historically nested in recently disturbed or sparsely vegetated patches within native mixed-grass prairie, but observations of longspurs in spring cereal and pulse crop fields during the breeding season in northeastern Montana, USA suggest such fields also provide cues for habitat selection. Maladaptive selection for poor-quality habitat may contribute to ongoing declines in longspur populations, but information on thick-billed longspur breeding ecology in crop fields is lacking. We hypothesized that these crop fields may function as ecological traps; specifically, we expected that crop fields may provide cues for territory selection, but frequent h..., ,北美大草原被改造为农田的行为，仍是威胁草原鸟类种群存续的突出威胁之一。然而，仍有少量鸟类物种会在这类经过大幅改造的生境系统中筑巢。厚嘴长爪鹀（Thick-billed longspur，Rhynchophanes mccownii）是一种专性草原鸟类，在过去50年间其种群数量以每年4%的速率持续下降。历史上，厚嘴长爪鹀的筑巢区域多位于原生混合禾草草原内的新近扰动斑块或植被稀疏区域，但在美国蒙大拿州东北部的繁殖季期间，研究人员在春季谷物与豆类作物田中观测到该物种，这表明此类农田同样能够为其提供栖息地选择的线索。对低质量生境的适应性误选，可能是导致厚嘴长爪鹀种群持续衰退的原因之一，但目前关于农田中厚嘴长爪鹀繁殖生态学的研究资料仍较为匮乏。我们提出如下假说：这类农田可能充当了生态陷阱（ecological trap）；具体而言，我们预计农田可能会为其领地选择提供线索，但频繁的……，，