Edge effect is a strong driver of change in fragmented landscapes. In the last few decades, agricultural land-use intensity at field scale has increased and, consequently, the edges between crops and natural vegetation matrix have sharpened. Interspersed crops produce now negative effects not only by direct habitat destruction, but also by inputs of agrochemicals that may spread their effects on the surroundings. These processes are taking place worryingly in steppe habitats in Iberian Peninsula where the high diversity of bird communities and other taxa they hold is at risk. The aims of this study were to evaluate the edge effect of crops on i) the microhabitat quality of a natural landscape matrix and ii) the space use of a threatened habitat-specialist steppe bird, the Dupont’s lark (Chersophilus duponti). We carried out microhabitat sampling and bird surveys within and around crops interspersed in a typical Iberian shrub-steppe matrix during spring and autumn 2016 and spring 2017. Microhabitat quality was measured by sampling vegetation structure and arthropod biomass (as proxy of food availability) within and at increasing distances (1, 10 and 50 m) to seven crops. The intensity of space use by the Dupont’s lark was estimated applying a Kernel density function on the spatial point pattern of the males’ territories. Vegetation structure variables were summarized by Principal Components Analysis. Linear Mixed Models and model averaging were used to test for effects of distance to crop on microhabitat quality and space use by the Dupont’s lark. Distance to crop significantly affected microhabitat quality. A patchy structure of herbaceous and shrub was found outside crops in all sampling dates, with more shrub cover and less herbaceous cover as the distance to crops increased. Biomass of hypogeous arthropods significantly decreased when the distance to crops was lower than 50 m. The intensity of space use by Dupont’s lark varied according to the sampling date, being higher in spring, and as the distance to crops and the biomass of hypogeous arthropods increased. Negative effects of crops on the space use of this bird species might be shaped both by the effect of the crop itself and by its edge effect on hypogeous arthropods. Our results point to an edge effect of crops of 10–50 m on natural vegetation structure, arthropod availability and use of space by the Dupont`s lark, which suggests that the effective area of optimal habitat available for true steppe species could be overestimated.

边缘效应是碎片化景观变化的强大驱动力。在过去的几十年里，田间规模的农业土地利用强度有所增加，因此作物与自然植被基质之间的边缘变得更加尖锐。散布的作物现在不仅会直接破坏栖息地，还会产生负面影响，还会产生可能将其影响扩散到周围环境的农用化学品的投入。这些过程正在伊比利亚半岛的草原栖息地发生，令人担忧，那里的鸟类群落和其他类群的高度多样性处于危险之中。本研究的目的是评估作物对 i) 自然景观矩阵的微生境质量和 ii) 受威胁的栖息地专家草原鸟类杜邦云雀 ( Chersophilus duponti ) 的空间利用的边缘效应）。我们在 2016 年春季和秋季以及 2017 年春季期间对散布在典型伊比利亚灌木草原基质中的作物内部和周围进行了微生境抽样和鸟类调查。通过采样植物结构和节肢动物生物量（作为食物可用性的代表）来衡量微生境质量。在增加距离（1、10 和 50 m）到七种作物时。杜邦云雀的空间使用强度是通过对雄性领地的空间点模式应用核密度函数来估计的。通过主成分分析总结了植被结构变量。线性混合模型和模型平均用于测试距离作物的距离对杜邦云雀微生境质量和空间使用的影响。与作物的距离显着影响微生境质量。所有采样日期的作物外均发现草本和灌木的斑片状结构，随着距离作物的增加，灌木覆盖率增加，草本覆盖率减少。当距作物的距离小于 50 m 时，地下节肢动物的生物量显着下降。杜邦百灵的空间利用强度因采样日期而异，春季更高，以及与作物的距离和下位节肢动物生物量的增加。作物对这种鸟类空间利用的负面影响可能受作物本身的影响及其对下肢节肢动物的边缘效应的影响。我们的结果表明 10-50 m 的作物对自然植被结构、节肢动物的可用性和杜邦云雀对空间的利用有边缘效应，