Grasslands of Tomorrow

Climate change will likely affect the productivity, composition, and distribution of historic grasslands. Grasslands at high elevations and in close proximity to ocean weather will likely receive less of the deleterious effects of increased CO2, increased temperatures, and shifting rainfall patterns (Jones n.d.). Studies show that plants such as grasses will respond differently to increased CO2 saturation. While reactions to higher CO2 levels will depend on particular life histories of the plant as well as the dynamic environmental conditions, preliminary research indicates that C3 grasses will benefit from increased atmospheric carbon up to a point (Jones n.d.). Increases in available CO2 are likely to stimulate increased root production, followed by increased foliar production to a lesser extent (Jones n.d.) through increased photosynthetic capacity. 

The apparent disparity in reaction to climate change will assuredly result in shifts in community composition. Water stress in warm seasons may favor C4 species, while increased CO2 availability may favor C3 species, and nitrogen-fixing plants and their associates may also fare better in increased CO2 conditions. Individualized responses to climate change will likely result in shifting ranges for most species, but does not guarantee the perpetuation of existing plant associations or community assemblages (Jones n.d.). I predict that the most dramatic changes in grassland ecosystems will occur in tropical, arid, and semi-arid regions which are slated to receive the double-whammy of increased temperatures and decreased precipitation. Many regions around the world are projected to receive less precipitation during critical growing periods with a concomitant increase in average temperatures. Despite the boost in photosynthetic capacity, increasing water stress as well as high temperatures which impair plant production may offset any increased vegetative production (Jones n.d.). The next few decades are likely to see southern grasslands shrink as deserts expand their boundaries while northern grasslands grow as temperature, drought, and insect pressures thin existing forests under the new climate regime.

Jones MB. n.d. The impacts of global climate change on grassland ecosystems. Climate Change: Implications and Role of Grasslands:181–188.