Long-term trends in grassland bird populations can be assessed from comprehensive regional data for the United States and Canada. Some long-term regional data within Africa show steady levels of major herbivore populations, but geographic coverage is limited. Other regional, national, and local data for grassland species lack long-term trends. Regional and local coverage of invasive species are more descriptive than quantitative. Carbon storage Conditions and changing capacity.
Grasslands store about one-third of the global stock of carbon in terrestrial ecosystems.
That amount is less than the carbon stored in forests, even though grasslands occupy twice as much area. Unlike forests, where vegetation is the primary source of carbon storage, most of the grassland carbon stocks are in the soil. Thus, the future capacity of grasslands to store carbon may decline if soils are degraded by erosion, pollution, overgrazing, or static rather than mobile grazing. Methods for estimating the size of carbon stores in biomass and soils continue to evolve. Models are needed to incorporate carbon storage modifications based on different management practices.