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Drought dominates the interannual variability in global terrestrial net primary production by controlling semi-arid ecosystems.

Huang L, He B, Chen A, Wang H, Liu J, Lű A, Chen Z - Sci Rep (2016)

Bottom Line: Drought-dominated NPP, which mainly occurs in semi-arid ecosystems, explains 29% of the interannual variation in global NPP, despite its 16% contribution to total global NPP.More surprisingly, drought prone ecosystems in the Southern Hemisphere, which only account for 7% of the total global NPP, contribute to 33% of the interannual variation in global NPP.Our observations support the leading role of semi-arid ecosystems in interannual variability in global NPP and highlight the great impacts of long-term drought on the global carbon cycle.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Earth Surface Processes and Resource Ecology, College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875, China.

ABSTRACT
Drought is a main driver of interannual variation in global terrestrial net primary production. However, how and to what extent drought impacts global NPP variability is unclear. Based on the multi-timescale drought index SPEI and a satellite-based annual global terrestrial NPP dataset, we observed a robust relationship between drought and NPP in both hemispheres. In the Northern Hemisphere, the annual NPP trend is driven by 19-month drought variation, whereas that in the Southern Hemisphere is driven by 16-month drought variation. Drought-dominated NPP, which mainly occurs in semi-arid ecosystems, explains 29% of the interannual variation in global NPP, despite its 16% contribution to total global NPP. More surprisingly, drought prone ecosystems in the Southern Hemisphere, which only account for 7% of the total global NPP, contribute to 33% of the interannual variation in global NPP. Our observations support the leading role of semi-arid ecosystems in interannual variability in global NPP and highlight the great impacts of long-term drought on the global carbon cycle.

No MeSH data available.


Role of drought-controlled ecosystems in interannual variation in global NPP.(a) Spatial pattern of maximum correlation coefficients (Pearson coefficient, R) between annual NPP and multi-timescale SPEI. The SPEI timescales range from 12 to 24 months. Red areas represent robust relationships at the 95% confidence level. (b) Variations in normalized NPP in drought-controlled ecosystems and global NPP. Drought-controlled ecosystems were defined as those ecosystems with a significant relationship between NPP and SPEI (P < 0.01). Variations in normalized NPP in drought-controlled ecosystems and NPP over (c) Northern Hemisphere and (d) Southern Hemisphere. ***Denotes 99% confidence level estimated with a t-test. This map was created using the ArcGIS 10.2 (http://www.esri.com/software/arcgis/arcgis-for-desktop).
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f2: Role of drought-controlled ecosystems in interannual variation in global NPP.(a) Spatial pattern of maximum correlation coefficients (Pearson coefficient, R) between annual NPP and multi-timescale SPEI. The SPEI timescales range from 12 to 24 months. Red areas represent robust relationships at the 95% confidence level. (b) Variations in normalized NPP in drought-controlled ecosystems and global NPP. Drought-controlled ecosystems were defined as those ecosystems with a significant relationship between NPP and SPEI (P < 0.01). Variations in normalized NPP in drought-controlled ecosystems and NPP over (c) Northern Hemisphere and (d) Southern Hemisphere. ***Denotes 99% confidence level estimated with a t-test. This map was created using the ArcGIS 10.2 (http://www.esri.com/software/arcgis/arcgis-for-desktop).

Mentions: The relationship between annual NPP and 12- to 24-month SPEI from 2000 to 2013 was examined for each grid cell, and the maximum correlation (Fig. 2a) and corresponding drought timescales were determined (Fig. S4). In the NH, strong positive correlations were identified in central Asia, the Indian Peninsula, and the southern part of North America. Significant positive relationships (P < 0.05) were identified in 51% of areas in the SH, mainly distributed in southern regions of South America and Africa, and Australia. Figure S4 shows the spatial patterns of SPEI timescales for which the maximum correlation between NPP and SPEI was found, indicating great differences in drought response among ecosystems.


Drought dominates the interannual variability in global terrestrial net primary production by controlling semi-arid ecosystems.

Huang L, He B, Chen A, Wang H, Liu J, Lű A, Chen Z - Sci Rep (2016)

Role of drought-controlled ecosystems in interannual variation in global NPP.(a) Spatial pattern of maximum correlation coefficients (Pearson coefficient, R) between annual NPP and multi-timescale SPEI. The SPEI timescales range from 12 to 24 months. Red areas represent robust relationships at the 95% confidence level. (b) Variations in normalized NPP in drought-controlled ecosystems and global NPP. Drought-controlled ecosystems were defined as those ecosystems with a significant relationship between NPP and SPEI (P < 0.01). Variations in normalized NPP in drought-controlled ecosystems and NPP over (c) Northern Hemisphere and (d) Southern Hemisphere. ***Denotes 99% confidence level estimated with a t-test. This map was created using the ArcGIS 10.2 (http://www.esri.com/software/arcgis/arcgis-for-desktop).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835775&req=5

f2: Role of drought-controlled ecosystems in interannual variation in global NPP.(a) Spatial pattern of maximum correlation coefficients (Pearson coefficient, R) between annual NPP and multi-timescale SPEI. The SPEI timescales range from 12 to 24 months. Red areas represent robust relationships at the 95% confidence level. (b) Variations in normalized NPP in drought-controlled ecosystems and global NPP. Drought-controlled ecosystems were defined as those ecosystems with a significant relationship between NPP and SPEI (P < 0.01). Variations in normalized NPP in drought-controlled ecosystems and NPP over (c) Northern Hemisphere and (d) Southern Hemisphere. ***Denotes 99% confidence level estimated with a t-test. This map was created using the ArcGIS 10.2 (http://www.esri.com/software/arcgis/arcgis-for-desktop).
Mentions: The relationship between annual NPP and 12- to 24-month SPEI from 2000 to 2013 was examined for each grid cell, and the maximum correlation (Fig. 2a) and corresponding drought timescales were determined (Fig. S4). In the NH, strong positive correlations were identified in central Asia, the Indian Peninsula, and the southern part of North America. Significant positive relationships (P < 0.05) were identified in 51% of areas in the SH, mainly distributed in southern regions of South America and Africa, and Australia. Figure S4 shows the spatial patterns of SPEI timescales for which the maximum correlation between NPP and SPEI was found, indicating great differences in drought response among ecosystems.

Bottom Line: Drought-dominated NPP, which mainly occurs in semi-arid ecosystems, explains 29% of the interannual variation in global NPP, despite its 16% contribution to total global NPP.More surprisingly, drought prone ecosystems in the Southern Hemisphere, which only account for 7% of the total global NPP, contribute to 33% of the interannual variation in global NPP.Our observations support the leading role of semi-arid ecosystems in interannual variability in global NPP and highlight the great impacts of long-term drought on the global carbon cycle.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Earth Surface Processes and Resource Ecology, College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875, China.

ABSTRACT
Drought is a main driver of interannual variation in global terrestrial net primary production. However, how and to what extent drought impacts global NPP variability is unclear. Based on the multi-timescale drought index SPEI and a satellite-based annual global terrestrial NPP dataset, we observed a robust relationship between drought and NPP in both hemispheres. In the Northern Hemisphere, the annual NPP trend is driven by 19-month drought variation, whereas that in the Southern Hemisphere is driven by 16-month drought variation. Drought-dominated NPP, which mainly occurs in semi-arid ecosystems, explains 29% of the interannual variation in global NPP, despite its 16% contribution to total global NPP. More surprisingly, drought prone ecosystems in the Southern Hemisphere, which only account for 7% of the total global NPP, contribute to 33% of the interannual variation in global NPP. Our observations support the leading role of semi-arid ecosystems in interannual variability in global NPP and highlight the great impacts of long-term drought on the global carbon cycle.

No MeSH data available.