Abstract Farmland landscapes in developed countries have undergone major habitat changes over the past 60 years leading to the decline of many species. Of these, the little bustard, a medium-sized, long-lived, ground nesting bird, has declined by 95% in France over the last 35 years. Here we present the results of a 21 year survey of the nesting ecology of this elusive species, analyzing 157 breeding attempts, the largest data set ever collated for this species. Females had a strong preference for meadows for breeding, yet this habitat only represented 14% overall habitat. Alfalfa alone accounted for 50% of nest locations. However, apart from vegetation type, females did not show any other pattern of habitat selection (vegetation height, nest position within field, field under agri-environmental contract-AES-). In addition, the laying period was extremely extended, spanning almost 3 months. We did not detect any strong effect of crop, date or whether the nesting field was in AES or not, on clutch size, egg size and egg-laying date. However, there were long-term changes in breeding phenology (females breed earlier than 20 years ago), and selection of vegetation between years and within years. Hatching success was very low (about half of the broods were destroyed by farm work), and both fecundity and productivity per female were found to be approximately one third of the values expected for a stable population. Overall, nesting females of Little Bustards select meadows in regard to their availability, but do not show any particular preference within meadows' vegetation structure or height. We show that in such system, meadows act as ecological traps, and furthermore, because females do not appear selective, it is impossible to manage meadows in order to limit this trap. We finally analyze whether the land-sharing AESs can conserve this species in intensive arable systems and conclude that the land sharing may not be sustainable. We discuss our results in light of the alternative of land sparing, and suggest that this is probably a better fit for the conservation of large-bodied bird species given their ecological constraints (large home ranges, presence of semi-natural landscape components and freedom from human interference).

中文翻译：

---

农耕与鸟类不可调和吗？集约化农业生态系统中鸨筑巢生态学的 21 年研究

摘要 过去 60 年来，发达国家的农田景观发生了重大的生境变化，导致许多物种减少。其中，小鸨，一种中型、长寿、地面筑巢的鸟类，在过去 35 年里在法国的数量减少了 95%。在这里，我们展示了对这种难以捉摸的物种的筑巢生态进行 21 年调查的结果，分析了 157 次繁殖尝试，这是该物种有史以来整理的最大数据集。雌性非常偏爱草地进行繁殖，但这种栖息地仅占总栖息地的 14%。仅紫花苜蓿就占巢穴位置的 50%。然而，除了植被类型外，雌性没有表现出任何其他栖息地选择模式（植被高度、田间巢穴位置、农业环境合同-AES-下的田地）。此外，产蛋期极其延长，跨越近3个月。我们没有检测到作物、日期或筑巢地是否在 AES 中对离合器大小、鸡蛋大小和产卵日期的任何强烈影响。然而，在繁殖物候（雌性早于20年前繁殖）以及不同年份和年份内的植被选择方面存在长期变化。孵化成功率非常低（大约一半的雏鸟被农场工作破坏了），并且发现每只雌性的繁殖力和生产力约为稳定种群预期值的三分之一。总的来说，小鸨的筑巢雌性会根据草地的可用性选择草地，但在草地的植被结构或高度方面没有表现出任何特别的偏好。我们表明，在这样的系统中，草地充当生态陷阱，此外，由于雌性似乎没有选择性，因此无法通过管理草地来限制这种陷阱。我们最终分析了土地共享 AES 是否可以在集约化耕作系统中保护该物种，并得出土地共享可能不可持续的结论。我们根据保留土地的替代方案讨论了我们的结果，并建议考虑到大型鸟类物种的生态限制（大的栖息地、半自然景观成分的存在和自由），这可能更适合保护大型鸟类物种。人为干扰）。