Aiming for the restoration of degraded ecosystems, many ecological engineering projects have been implemented around the world. This study investigates the ecological engineering project effectiveness on vegetation re...Aiming for the restoration of degraded ecosystems, many ecological engineering projects have been implemented around the world. This study investigates the ecological engineering project effectiveness on vegetation restoration in the Beijing-Tianjin Sand Source Region(BTSSR) from 2000 to 2010 based on the rain use efficiency(RUE) trend in relation to the land cover. More than half of the BTSSR experienced a vegetation productivity increase from 2000 to 2010, with the increasing intensity being sensitive to the indicators chosen. A clear tendency towards smaller increasing areas was shown when using the net primary productivity(NPP, 51.30%) instead of the accumulated normalized difference vegetation index(59.30%). The short-term variation in the precipitation and intra-seasonal precipitation distribution had a great impact on the remote sensing-based vegetation productivity. However, the residual trends method(RESTREND) effectively eliminated this correlation, while incorporating the variance and skewness of the precipitation distribution increased the models′ ability to explain the vegetation productivity variation. The RUE combined with land cover dynamics was valid for the effectiveness assessment of the ecological engineering projects on vegetation restoration. Particularly, the result based on growing season accumulated normalized difference vegetation index(ΣNDVI) residuals was the most effective, showing that 47.39% of the BTSSR experienced vegetation restoration from 2000 to 2010. The effectiveness of the ecological engineering projects differed for each subarea and was proportional to the strength of ecological engineering. The water erosion region dominated by woodland showed the best restoration, followed by the wind-water erosion crisscross regions, while the wind erosion regions dominated by grassland showed the worst effect. Seriously degraded regions still cover more area in the BTSSR than restored regions. Therefore, more future effort should be put in restoring degraded land.展开更多
To mitigate impacts of sandstorms on northern China, the Chinese government launched the Beijing- Tianjin Sand Source Control Program （BTSSCP） in 2000. The associated practices （i.e., cultivation, enclosure, and ae...To mitigate impacts of sandstorms on northern China, the Chinese government launched the Beijing- Tianjin Sand Source Control Program （BTSSCP） in 2000. The associated practices （i.e., cultivation, enclosure, and aerial seeding） were expected to greatly enhance grassland carbon sequestration. However, the BTSSCP-induced soil organic carbon （SOC） dynamics remain elusive at a regional level. Using the Xilingol League in Inner Mongolia for a case study, we examined the impacts from 2000 to 2006 of the BTSSCP on SOC stocks using the IPCC carbon budget inventory method. Results indicated that over all practices SOC storage increased by 1.7%, but there were large differences between practices. SOC increased most rapidly at the rate of 0.3 Mg C.ha-1 ＂yr-1 under cultivation, but decreased signifi- cantly under aerial seeding with moderate or heavy grazing （0.3 vs.0.6 Mg C-ha-I .yr-1）. SOC increases varied slightly for grassland types, ranging from 0.10 Mg C-ha-1 .yr-a for temperate desert steppe to 0.16 Mg C.ha-l.yr-1 for temperate meadow steppe and lowland meadow. The overall economic benefits of the SOC sink were estimated to be 4.0 million CNY. Aerial seeding with no grazing was found to be the most cost-effective practice. Finally, we indicated that at least 55.5 years （shortest for cultivation） were needed for the grasslands to reach their potential carbon stocks. Our findings highlight the importance and effectiveness of BTSSCP in promoting terrestrial carbon sequestration which may help mitigate climate change, and further stress the need for more attention to the effective- ness of specific practices.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.41571421)National Science and Technology Major Project of China(No.21-Y30B05-9001-13/15)
文摘Aiming for the restoration of degraded ecosystems, many ecological engineering projects have been implemented around the world. This study investigates the ecological engineering project effectiveness on vegetation restoration in the Beijing-Tianjin Sand Source Region(BTSSR) from 2000 to 2010 based on the rain use efficiency(RUE) trend in relation to the land cover. More than half of the BTSSR experienced a vegetation productivity increase from 2000 to 2010, with the increasing intensity being sensitive to the indicators chosen. A clear tendency towards smaller increasing areas was shown when using the net primary productivity(NPP, 51.30%) instead of the accumulated normalized difference vegetation index(59.30%). The short-term variation in the precipitation and intra-seasonal precipitation distribution had a great impact on the remote sensing-based vegetation productivity. However, the residual trends method(RESTREND) effectively eliminated this correlation, while incorporating the variance and skewness of the precipitation distribution increased the models′ ability to explain the vegetation productivity variation. The RUE combined with land cover dynamics was valid for the effectiveness assessment of the ecological engineering projects on vegetation restoration. Particularly, the result based on growing season accumulated normalized difference vegetation index(ΣNDVI) residuals was the most effective, showing that 47.39% of the BTSSR experienced vegetation restoration from 2000 to 2010. The effectiveness of the ecological engineering projects differed for each subarea and was proportional to the strength of ecological engineering. The water erosion region dominated by woodland showed the best restoration, followed by the wind-water erosion crisscross regions, while the wind erosion regions dominated by grassland showed the worst effect. Seriously degraded regions still cover more area in the BTSSR than restored regions. Therefore, more future effort should be put in restoring degraded land.
文摘To mitigate impacts of sandstorms on northern China, the Chinese government launched the Beijing- Tianjin Sand Source Control Program （BTSSCP） in 2000. The associated practices （i.e., cultivation, enclosure, and aerial seeding） were expected to greatly enhance grassland carbon sequestration. However, the BTSSCP-induced soil organic carbon （SOC） dynamics remain elusive at a regional level. Using the Xilingol League in Inner Mongolia for a case study, we examined the impacts from 2000 to 2006 of the BTSSCP on SOC stocks using the IPCC carbon budget inventory method. Results indicated that over all practices SOC storage increased by 1.7%, but there were large differences between practices. SOC increased most rapidly at the rate of 0.3 Mg C.ha-1 ＂yr-1 under cultivation, but decreased signifi- cantly under aerial seeding with moderate or heavy grazing （0.3 vs.0.6 Mg C-ha-I .yr-1）. SOC increases varied slightly for grassland types, ranging from 0.10 Mg C-ha-1 .yr-a for temperate desert steppe to 0.16 Mg C.ha-l.yr-1 for temperate meadow steppe and lowland meadow. The overall economic benefits of the SOC sink were estimated to be 4.0 million CNY. Aerial seeding with no grazing was found to be the most cost-effective practice. Finally, we indicated that at least 55.5 years （shortest for cultivation） were needed for the grasslands to reach their potential carbon stocks. Our findings highlight the importance and effectiveness of BTSSCP in promoting terrestrial carbon sequestration which may help mitigate climate change, and further stress the need for more attention to the effective- ness of specific practices.
