Impacts of carbon farming practices on biodiversity at the farm scale

1. Biodiversity loss from intensive agriculture poses a major threat to the long-term sustainability and resilience of food production systems. Sustainable land management practices, such as carbon farming, offer promising alternatives, but their biodiversity impacts and the most effective methods for detecting these impacts remain poorly understood. 2. We surveyed 19 farms in boreal Finland to assess the effects of four carbon farming practices—cover crops, all-in mixes, adaptive grazing and ley mixtures—on plants, arthropods, nematodes and birds. We evaluated biodiversity responses using four alpha diversity metrics (abundance, species richness, Shannon diversity and Pielou’s evenness) and two beta diversity metrics (Bray–Curtis and Chi-square dissimilarity). 3. Biodiversity responses were strongly context-dependent, varying by farming practice, taxonomic group and diversity metric. Abundance emerged as the most sensitive alpha metric across taxa, often detecting changes not reflected in community composition metrics. These findings suggest that abundance may serve as a useful early indicator of ecological change in managed landscapes. 4. Arthropods were particularly responsive to adaptive grazing, while ley mix and adaptive grazing supported higher nematode abundances. All diversity metrics except species richness detected changes in at least one species group, practice or field status, but abundance consistently captured the broadest responses. 5. Synthesis and applications. Carbon farming practices can support biodiversity when tailored to species group and context. Monitoring approaches that incorporate multiple metrics—and prioritise abundance as a sensitive and early indicator—can improve the detection of ecological responses to sustainable farming interventions.