Agricultural intensification seriously threatens European biodiversity. To mitigate this threat, farmland habitat suitability should be improved. Mid-field woodlots surrounded by intensively cultivated fields or grasslands, represent one of the promising tools for such improvement. However, woodlots can be dominated by non-native plants and their impacts on woodlot function as refugees for biodiversity remains unclear. Therefore, we studied the impact of the invasive black locust (Robinia pseudoacacia L.) on bird species richness in woodlots in intensively cultivated Central European farmland. We surveyed 27 mid-field woodlots (13 covered by native vegetation and 14 dominated by black locust) in the Czech Republic, relating the species richness of all birds, habitat specialists and habitat generalists to woodlot characteristics: black locust occurrence, distance to the main forest, age of the woodlot, vegetation structure, arthropod biomass (representing food supply for birds), surrounding habitats and type of crops in which they are embedded. Our results suggest that the woodlots covered by the black locust had lower species richness of all birds, habitat specialists and habitat generalists than the woodlots covered by native tree species. The negative impact of the invasive woody plant on birds was likely driven by changes in vegetation structure since such woodlots had lower coverage of the shrub layer and less continuous canopy. This mechanism was particularly supported in habitat generalists, whereas habitat specialists additionally showed positive relationships to the other vegetation characteristics (namely the coverage of herbs in the ground layer and the proportion of medium-sized trees). Our study shows that even though mid-field woodlots host numerous bird species, their role in the delivery of conservation benefits for breeding birds is compromised if non-native woody plants dominate the vegetation. Therefore, from the perspective of breeding birds’ conservation, the native woody plant species should be used for woodlot establishment.

农业集约化严重威胁了欧洲的生物多样性。为了减轻这种威胁，应提高农田生境的适应性。中耕林地被集约耕地或草原包围，代表了进行此类改良的有前途的工具之一。然而，非本地植物可能主导着林地，由于对生物多样性的难民，它们对林地功能的影响尚不清楚。因此，我们研究了侵入性黑刺槐（刺槐）的影响。L.）关于中欧精耕细作林地的鸟类物种丰富度。我们调查了捷克共和国的27个中场林地（其中13个被原生植被覆盖，14个被黑刺槐所占），将所有鸟类，栖息地专家和生境通才的物种丰富程度与林地特征相关：黑刺槐发生，与主要蝗虫的距离森林，林地年龄，植被结构，节肢动物生物量（代表鸟类的食物供应），周围的栖息地以及将其嵌入其中的农作物类型。我们的结果表明，与刺槐所覆盖的林地相比，黑刺槐所覆盖的林地对所有鸟类，生境专家和生境通才的物种丰富度均较低。入侵性木本植物对鸟类的负面影响很可能是由于植被结构的变化所致，因为这种林地的灌木层覆盖率较低，而冠层的连续性较低。这种机制在栖息地通才专家的支持下得到了特别的支持，而栖息地专家还表现出了与其他植被特征的正相关关系（即草本植物在地层的覆盖率和中型树木的比例）。我们的研究表明，即使中场林地拥有许多鸟类，但如果非本地木本植物在植被中占主导地位，那么它们在提供保护鸟类繁殖利益方面的作用就会受到损害。因此，从保护鸟类的角度出发，应该使用本地木本植物来建立林地。