New thinking is needed to make the most of formerly improved upland pastures

Abstract Natural handicaps generally restrict farming in the upland areas to grassland-based livestock systems. Previous UK policies aimed at increasing food security by improving productivity in these regions led to large areas of native grassland being cultivated and replaced by sown pastures. Over time, the grasses and legumes that constituted the mixes introduced have been replaced by unsown grass species, leading to a decline in performance. Advances in plant breeding offer the potential to not only radically improve livestock production efficiencies in marginal areas but to enhance wider ecosystem service provision, including carbon storage and water management. However, a fundamental shift from traditional frameworks for developing and testing new grass and legume varieties is urgently needed if we are to make the necessary changes required to promote the sustainable management of natural resources, encourage nature recovery, adapt to climate change, and support a just transition to zero carbon agriculture.