Disentangling the relative effects of semi-natural habitats within different landscape agricultural intensities on bird communities

The process of agricultural intensification has led to significant reductions in biodiversity globally. Previous studies examined the role of semi-natural habitats within agroecosystems in supporting bird communities, but few have considered the effects of landscape agricultural intensity on avian conservation potential of semi-natural habitats. Here, we disentangle the relative effects of semi-natural habitats within different landscape agricultural intensities on bird community composition in central and eastern Jilin Province, China. We established 322 sampling sites distributed across low, middle, and high landscape agricultural intensities, with 103, 118, and 101 sites respectively. Each sampling site was visited two times in May and June 2023 to test the dissimilarities in bird composition between different landscape agricultural intensities. We found that middle-intensity agriculture supported the highest bird diversity in most cases, but low-intensity plays an important role in maintaining insectivorous birds. We used generalized linear models and model selection to assess the relative impacts of semi-natural habitats on bird community along agricultural intensity respectively. Our results showed that the effects of agriculture on bird communities were predominantly influenced by the amount of semi-natural habitats, with effects that differ in accordance with the level of landscape agricultural intensity. Priority should be given to preserve or/and plant these semi-natural habitats in middle-intensity agriculture due to the stronger effect sizes on bird diversity. Specifically, we suggested preserving and promoting woodlands and shrubs in high-intensity agriculture, and simultaneously increasing crop diversity to protect bird diversity in agriculture landscapes in the context of increasing crop intensification globally.