Abstract Increasing landscape complexity can mitigate negative effects of agricultural intensification on biodiversity by offering resources complementary to those provided in arable fields. In particular, grazed semi-natural grasslands and woody elements support farmland birds, but little is known about their relative effects on bird diversity and community composition. In addition, the relative importance of local habitat versus landscape composition remains unclear. We investigated how the presence of semi-natural grasslands, the number of woody elements and the composition of the wider agricultural landscape affect bird species richness, true diversity (exponential Shannon diversity) and species composition. Bird communities were surveyed four times on 16 paired transects of 250 m each with 8 transects placed between a crop field and a semi-natural grassland and 8 transects between two crop fields with no semi-natural grasslands in the vicinity. The number of woody elements around transects was selected as an important predictor in all models, having a positive effect on species richness and true diversity, while the local presence of semi-natural grasslands was not selected in the best models. However, species richness and true diversity increased with increasing cover of ley and semi-natural grasslands, whereas species composition was modified by the coverage of winter wheat at the landscape scale. Furthermore, bird species richness, true diversity and species composition differed between sampling dates. As bird diversity benefited from woody elements, rather than from the local presence of semi-natural grasslands as such, it is important to maintain woody structures in farmland. However, the positive effect of grassland at the landscape scale highlights the importance of habitat variability at multiple scales. Because species richness and true diversity were affected by different landscape components compared to species composition, a mosaic of land-use types is needed to achieve multiple conservation goals across agricultural landscapes.

中文翻译：

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在以谷物为主的景观中，木质元素比半天然草原更能促进鸟类多样性

摘要 通过提供与耕地资源互补的资源，增加景观复杂性可以减轻农业集约化对生物多样性的负面影响。特别是放牧的半天然草原和木质元素支持农田鸟类，但对它们对鸟类多样性和群落组成的相对影响知之甚少。此外，当地栖息地与景观组成的相对重要性仍不清楚。我们调查了半天然草原的存在、木质元素的数量和更广泛的农业景观的组成如何影响鸟类物种丰富度、真实多样性（指数香农多样性）和物种组成。鸟类群落在 16 对 250 m 的成对样带上进行了 4 次调查，其中 8 样样位于农田和半天然草地之间，8 样样位于两个附近没有半天然草地的农田之间。在所有模型中，横断面周围的木质元素数量被选为重要的预测因子，对物种丰富度和真实多样性具有积极影响，而在最佳模型中没有选择局部存在的半天然草原。然而，物种丰富度和真实多样性随着麦地和半天然草原覆盖率的增加而增加，而物种组成因景观尺度上冬小麦的覆盖率而改变。此外，鸟类物种丰富度、真实多样性和物种组成在采样日期之间存在差异。由于鸟类多样性受益于木质元素，而不是当地存在的半天然草原，因此保持农田的木质结构非常重要。然而，草地在景观尺度上的积极作用凸显了多尺度生境变异的重要性。由于与物种组成相比，物种丰富度和真实多样性受到不同景观成分的影响，因此需要土地利用类型的镶嵌图来实现跨农业景观的多个保护目标。