Exploring the effects of carbon farming on cropland biodiversity in Europe: A review

Biodiversity loss in agricultural landscapes is a significant threat to ecosystem functioning and sustainability. While there is an established relationship between agricultural practices and biodiversity, carbon farming practices, aimed at enhancing soil carbon sequestration, may also affect biodiversity. However, their effects on biodiversity remain insufficiently quantified across taxonomic groups. This study used a meta-analysis, complemented with a narrative method, synthesising data from 89 studies throughout Europe, to evaluate the impacts of seven selected carbon farming practices—catch/cover crops, crop rotations, zero/reduced tillage, organic amendments, mulching, semi-natural habitats, and silvoarable agroforestry—on biodiversity indicators representing multiple taxa. These practices promote certain species while disadvantaging others by altering soil structure and moisture levels, changing the availability of organic matter, and reshaping trophic relationships. The results reveal that practices promoting greater biomass input and structural complexity yield the strongest benefits: organic amendments showed a positive effect (80 %), closely followed by agroforestry (54 %). These benefits primarily accrued to arthropods, birds, earthworms, fungi, and bacteria. Crop rotations predominantly showed neutral effects (59 %), though some negative impacts on nematodes were observed. Zero/reduced tillage yielded mixed outcomes (32 % positive, 11 % negative), mainly affecting bacteria, fungi, and nematodes. Mulching and semi-natural habitats showed a positive overall effect, with some negative effects on microorganisms. Overall, this synthesis provides an integrated assessment of how carbon farming practices affect biodiversity across major taxa in European croplands. It highlights taxon-specific responses, identifies research gaps, and underscores the need to evaluate combined carbon farming practices for comprehensive biodiversity benefits.