Numerous studies have demonstrated the positive effects of organic farming and landscape heterogeneity on agricultural biodiversity. However, these studies are almost exclusively based on comparisons between agricultural farms or areas managed in different ways. This introduces the potential for site-specific factors to bias the data, leading to inconsistent or contradictory conclusions. Long-term monitoring studies on individual farms offer a conceptually different approach to investigating causal relationships between management practices, site-specific conditions, and biodiversity. Here, we present results from a 22-year breeding bird survey (2003–2024) conducted on a ~70-hectare site in central Germany. Breeding bird territories were recorded across three distinct study periods: 2003–2007 (shortly after conversion to organic farming), 2008–2010 (during and immediately following the implementation of conservation measures, including the establishment of woody elements), and 2022–2024 (after the maturation of these elements). While species richness and territory densities of open farmland birds remained relatively stable between the first and second periods, a significant increase in breeding bird diversity was observed between the second and third study periods, despite declining regional population trends for many of the species recorded. Our data demonstrate that the transition to organic farming, followed by the implementation of nature conservation measures, required at least 10–20 years to yield a measurable recovery of ecosystem diversity and multitrophic functioning. Furthermore, our findings underscore the critical role of structural landscape complexity—particularly woody structures—in promoting biodiversity within open agricultural landscapes.
