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| Titel |
Continental-scale impacts of intra-seasonal rainfall variability on simulated ecosystem responses in Africa |
| VerfasserIn |
K. Guan, S. P. Good, K. K. Caylor, H. Sato, E. F. Wood, H. Li |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 23 ; Nr. 11, no. 23 (2014-12-11), S.6939-6954 |
| Datensatznummer |
250117727
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| Publikation (Nr.) |
 copernicus.org/bg-11-6939-2014.pdf |
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| Zusammenfassung |
| Climate change is expected to modify intra-seasonal rainfall variability,
arising from shifts in rainfall frequency, intensity and seasonality. These
intra-seasonal changes are likely to have important ecological impacts on
terrestrial ecosystems. Yet, quantifying these impacts across biomes and
large climate gradients is largely missing. This gap hinders our ability to
better predict ecosystem services and their responses to climate change, especially
for arid and semi-arid ecosystems. Here we use a synthetic weather generator
and an independently validated vegetation dynamic model (SEIB-Dynamic Global Vegetation Model, DGVM) to
virtually conduct a series of "rainfall manipulation experiments" to study
how changes in the intra-seasonal rainfall variability affect continent-scale
ecosystem responses across Africa. We generate different rainfall scenarios
with fixed total annual rainfall but shifts in (i) frequency vs. intensity,
(ii) rainy season length vs. frequency, (iii) intensity vs. rainy season
length. These scenarios are fed into SEIB-DGVM to investigate changes in
biome distributions and ecosystem productivity. We find a loss of ecosystem
productivity with increased rainfall frequency and decreased intensity at
very low rainfall regimes (<400 mm year−1) and low frequency
(<0.3 event day−1); beyond these very dry regimes, most ecosystems
benefit from increased frequency and decreased intensity, except in the wet
tropics (>1800 mm year−1) where radiation limitation prevents
further productivity gains. This result reconciles seemingly contradictory
findings in previous field studies on the impact of rainfall
frequency/intensity on ecosystem productivity. We also find that changes in
rainy season length can yield more dramatic ecosystem responses compared with
similar percentage changes in rainfall frequency or intensity, with the
largest impacts in semi-arid woodlands. This study demonstrates that
intra-seasonal rainfall characteristics play a significant role in
influencing ecosystem function and structure through controls on
ecohydrological processes. Our results suggest that shifts in rainfall
seasonality have potentially large impacts on terrestrial ecosystems, and
these understudied impacts should be explicitly examined in future studies of
climate impacts. |
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