Abstract
The southern Brazilian grassland biome contains highly diverse natural ecosystems that have been used for centuries for grazing livestock and that also provide other important environmental services. Here we outline the main factors controlling ecosystem processes, review and discuss the available data on soil carbon stocks and greenhouse gases emissions from soils, and suggest opportunities for mitigation of climatic change. The research on carbon and greenhouse gases emissions in these ecosystems is recent and the results are still fragmented. The available data indicate that the southern Brazilian natural grassland ecosystems under adequate management contain important stocks of organic carbon in the soil, and therefore their conservation is relevant for the mitigation of climate change. Furthermore, these ecosystems show a great and rapid loss of soil organic carbon when converted to crops based on conventional tillage practices. However, in the already converted areas there is potential to mitigate greenhouse gas emissions by using cropping systems based on no soil tillage and cover-crops, and the effect is mainly related to the potential of these crop systems to accumulate soil organic carbon in the soil at rates that surpass the increased soil nitrous oxide emissions. Further modelling with these results associated with geographic information systems could generate regional estimates of carbon balance.
Highlights
The southern Brazilian grasslands, known as campos, are natural ecosystems that have characterised the region well before the expansion of forests occurred from the mid-Holocene (Behling et al, 2009; Behling and Pillar, 2007; Dümig et al, 2008)
These grasslands offer important environmental services. They have been the main source of forage for grazing livestock, which in Rio Grande do Sul has been a major economic activity (Pillar et al, 2009)
An estimate of original soil C stocks (0 to 30 cm depth) of the Pampa biome was derived from a statewide soil C stock inventory that included pedons sampled from the mid-1960s to the 1980s in Rio Grande do Sul (Tornquist et al, 2009a) (Figure 2)
Summary
The southern Brazilian grasslands, known as campos, are natural ecosystems that have characterised the region well before the expansion of forests occurred from the mid-Holocene (Behling et al, 2009; Behling and Pillar, 2007; Dümig et al, 2008). They harbour high biodiversity, with about 2,200 plant species, whose knowledge of potential uses is still incipient (Boldrini, 2009), and high diversity of animal wildlife including endangered species (Bencke, 2009) These grassland ecosystems ensure the conservation of surface water resources (Geahl et al, 2010; Kozera et al, 2009) and groundwater (Melo, 2009), and offer scenic attractions with major tourism potential. Their conservation through adequate management has implications for the carbon balance in the soil and on greenhouse gas emissions, contributing to the effort to mitigate global climate change (Soussana, 2009). We present a general outline on factors controlling ecosystem processes in the southern Brazilian grassland biome, review available data on soil carbon stocks and greenhouse gases (carbon dioxide-CO2, nitrous oxideN2O and methane-CH4) emissions from the soils, and discuss opportunities for climate change mitigation by these ecosystems
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
