Potential climate change effects on the distribution of agricultural grassland in England and Wales

The spatial distribution of agricultural grassland in England and Wales has been assessed using a land evaluation model applied to information describing soils, climate and topography on a 5 x 5 km grid. The model calculates land suitability for grassland from assessments of trafficability/poaching risk and yield class. The spatial distribution of agricultural grassland was modelled for a 30 year climatic baseline (1941-1970) and for incremental changes in temperature and proportional changes precipitation relative to that baseline. Model estimates for the current distribution of grassland suitability agree well with observed data of actual grassland distribution. The best suited land occurs in south west England, Wales, the Welsh borders and Cheshire with fragmented areas of well suited land in north west England and on the Fens and Humberhead levels. The climatic sensitivity analysis suggests that grassland production in England and Wales is resilient to small perturbations in mean temperature (up to 2 degrees C) and precipitation (+/-10%). The effect of increasing temperature by 1 degrees C is almost completely offset by precipitation increases of 10% resulting in little change to the distribution of grassland suitability. However, greater temperature changes (+4 degrees C) have a major influence on the ability of land to support intensively managed grassland because of increased drought stress. Results indicate that a change in the climate comparable with current best estimates for the future would benefit grassland on good quality land at higher altitudes.