Theme 5-2: Drought Management and Climate Change--Poster Sessions
Description
Grassland ecosystems play significant role in mitigating the climate change by sequestering atmospheric CO2. One fifth of the total terrestrial C is stored in the root zone of grasslands as soil organic carbon. However, because of lack of proper management, overgrazing, and conversion to crop lands, these grasslands are becoming a source of CO2 emissions. It has been observed that in Imperata grasslands of Northeast India, a third of total C captured annually is lost though CO2 emissions. In the absence of intensified grazing and burning, these grasslands exhibit significantly high capacity to store SOC stocks. On the other hand, Southern grasslands of China inherently have a weak C sink. Grazing and burning together significantly increased CO2 fluxes as observed in Andean grasslands. With the introduction of high yielding grass species and with liberal use of chemical fertilizers, grazing land intensification has been found to rather promote SOC sequestration. It has been observed that in C4 grass species dominated tropical and sub-tropical grasslands; there occurs a rapid transfer of plant C into mineral-dominated C pools. With change of C3 to C4 grass species, the grazer effects rather shift from negative to positive even under decreasing precipitation conditions. Similarly, rise in atmospheric temperatures due to climate change affects grasslands differently depending on the dominating grass species. Graminoids and shrubs appear to benefit from elevated temperatures while forbs are likely to decrease in abundance through competitive elimination. Extreme heat waves and frequent drought events is decreasing the extent and capacity of forests as C sink as compared to grasslands. Grasslands have been shown to be comparatively more resilient to changes in climate. The resilience of grasslands to rising temperatures, drought and fire events helps to preserve sequestered terrestrial C in the root-zone of grassland soil and prevent it from re-entering atmosphere.
Included in
Comparative Soil Organic Carbon Dynamics in Tropical and Subtropical Grassland Ecosystems
Grassland ecosystems play significant role in mitigating the climate change by sequestering atmospheric CO2. One fifth of the total terrestrial C is stored in the root zone of grasslands as soil organic carbon. However, because of lack of proper management, overgrazing, and conversion to crop lands, these grasslands are becoming a source of CO2 emissions. It has been observed that in Imperata grasslands of Northeast India, a third of total C captured annually is lost though CO2 emissions. In the absence of intensified grazing and burning, these grasslands exhibit significantly high capacity to store SOC stocks. On the other hand, Southern grasslands of China inherently have a weak C sink. Grazing and burning together significantly increased CO2 fluxes as observed in Andean grasslands. With the introduction of high yielding grass species and with liberal use of chemical fertilizers, grazing land intensification has been found to rather promote SOC sequestration. It has been observed that in C4 grass species dominated tropical and sub-tropical grasslands; there occurs a rapid transfer of plant C into mineral-dominated C pools. With change of C3 to C4 grass species, the grazer effects rather shift from negative to positive even under decreasing precipitation conditions. Similarly, rise in atmospheric temperatures due to climate change affects grasslands differently depending on the dominating grass species. Graminoids and shrubs appear to benefit from elevated temperatures while forbs are likely to decrease in abundance through competitive elimination. Extreme heat waves and frequent drought events is decreasing the extent and capacity of forests as C sink as compared to grasslands. Grasslands have been shown to be comparatively more resilient to changes in climate. The resilience of grasslands to rising temperatures, drought and fire events helps to preserve sequestered terrestrial C in the root-zone of grassland soil and prevent it from re-entering atmosphere.
