Modelled effects of rising CO2 concentration and climate change on native perennial grass and sown grass-legume pastures

Climate Research

I. R. Johnson¹  M. J. Hovenden¹  M. P. Perring¹  B. R. Cullen¹ 

关键词: Lolium perenne;    Ecosystem model;    Simulation;    Nutrient availability;    Productivity;    Tasmania;   

DOI  :  10.3354/cr00863

来源: Inter-Research Science Publishing

【 摘 要 】

ABSTRACT: Native perennial grass and sown grass-legume pastures are an important agricultural and environmental resource. We investigated the impact of rising carbon dioxide concentration ([CO₂]) and projected climate changes on these pasture ecosystems in southeastern Tasmania, Australia, using a biophysical simulation model, EcoMod. The model consists of interdependent modules that describe soil physicochemical and hydrological characteristics, and pasture growth and senescence, with fluxes described by empirical and mechanistic equations. Our simulations showed that in native pastures, projected climate change increased the biomass of C₄ grasses, with limited impact upon C₃ grasses, a trend reversed by rising [CO₂]. In sown pastures, projected climate change decreased the biomass of perennial rye grass Lolium perenne and total biomass markedly by 2070, whilst subterranean clover Trifolium subterraneum biomass increased. Subterranean clover biomass changed little with increased [CO₂] alone, whereas perennial rye grass biomass increased. Responses across pastures reflected species’ tolerances to environmental factors, with projected climate change generally having more of an impact on biomass than rising [CO₂]. Changes in both [CO₂] and climate led to a reduction in protein content and digestibility. Soil inorganic nutrient concentrations decreased with increasing [CO₂] and increased with projected climate change. Further simulations should investigate whether these patterns are robust for different sites and alternative environmental futures. Our results reinforce the need to pursue adaptation strategies in response to environmental change in order to maintain productive pasture ecosystems.

【 授权许可】

Unknown