Rethinking land-use strategies: a multi-objective analysis of combined sparing and sharing approaches applied across Great Britain

The land-sharing versus land-sparing debate represents a critical juncture in agricultural policy development. However, applying either of these approaches uniformly at a national scale has been challenged suggesting that more effective strategies may require a context-dependent mix of methods. This study evaluates plausible strategies of land sparing and land sharing at regional scale in Great Britain using the Long-Term Large Scale integrated modelling framework. We consider these strategies in various combinations to get national scale outcomes for nutrient losses to freshwater and agricultural productivity. By simulating various land-use configurations across 11 International Territorial Level regions, we generated over 1.79 trillion scenarios with differing regional distributions of arable and semi-natural land. We used multiple objective optimization to find an optimal solution set. Our analysis identified 24,412 Pareto-optimal solutions that also improved on business-as-usual. The Pareto-optimal solutions all favoured combining land-sparing and land-sharing approaches. These optimized scenarios achieved increases of up to 9.7 % in livestock calories and 5.2 % in crop calories, while reducing phosphorus losses by 6.9 % and nitrate losses by 11.9 % in comparison to a business-as-usual scenario. Our findings demonstrate that spatially differentiated land-use strategies tailored to regional characteristics outperform uniform national sharing or sparing approaches. However, these modest improvements suggest that transformative change will require complementary innovations beyond land allocation strategies alone. This approach advances landscape planning from binary sharing-sparing debates towards a multidimensional optimization of food production and environmental quality that acknowledges the inherent complexity of dynamic landscapes while supporting evidence-based agricultural policy development.