Contrasting responses of shrubland carbon gain and soil carbon efflux to drought and warming across a European climate gradient
Research output: Contribution to journal › Conference abstract in journal › Research
Understanding the relationship between above- and belowground processes
is crucial if we are to forecast feedbacks between terrestrial carbon
(C) dynamics and future climate. To test if climate-induced changes in
annual aboveground net primary productivity (aNPP) will drive changes in
C loss by soil respiration (Rs), we integrated data across a European
temperature and precipitation gradient. For over a decade, six European
shrublands were exposed to repeated drought (-30 % annual rain) during
the plants' growth season or year-round night-time warming (+1.5 oC),
using an identical experimental approach. As a result, drought reduced
ecosystem C gain via aNPP by 0-25 % (compared to an untreated control)
with the lowest C gain in warm-dry sites and highest in wet-cold sites
(R2=0.078, p-value = 0.544, slope = 14.35 %). In contrast, drought
induced C loss via Rs was of a lower magnitude (10-20 %) and was most
pronounced in warm-dry sites compared to wet-cold sites (R2=0.687,
p-value = 0.131, slope = 7.86 %). This suggests that belowground
activity (microbes and roots) is stabilizing ecosystem processes and
functions in terms of C storage. However, when the drought treatment
permanently altered the soil structure at our hydric site, indicating we
had exceeded the resilience of the system, the ecosystem C gain was no
longer predictable from current (linear) relationships. Results from the
warming treatment were generally of lower magnitude and of opposing
direction compared to the drought treatment, indicating different
mechanisms were driving ecosystem responses. Overall, our results
suggest that aNPP is less sensitive than Rs to climate stresses and soil
respiration C fluxes are not predictable from changes in plant
productivity. Drought and warming effects on aNPP and Rs did not weaken
over decadal timescales at larger, continental scales if no catastrophic
threshold is passed. However, indirect effects of climate change on soil
properties and/or microbial communities need to be further explored
Original language | English |
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Journal | Geophysical Research Abstracts |
Volume | 18 |
ISSN | 1607-7962 |
Publication status | Published - 2016 |
Event | EGU General Assembly 2016 - Vienna, Austria Duration: 18 Apr 2016 → 24 Apr 2016 |
Conference
Conference | EGU General Assembly 2016 |
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Country | Austria |
City | Vienna |
Period | 18/04/2016 → 24/04/2016 |
Links
- http://adsabs.harvard.edu/abs/2016EGUGA..1816183R
Final published version
ID: 289237581