Responses of terrestrial ecosystems and carbon budgets to current and future environmental variability.
We assess the significance of high-frequency variability of environmental parameters (sunlight, precipitation, temperature) for the structure and function of terrestrial ecosystems under current and future climate. We examine the influence of hourly, daily, and monthly variance using the Ecosystem Demography model version 2 in conjunction with the long-term record of carbon fluxes measured at Harvard Forest. We find that fluctuations of sunlight and precipitation are strongly and nonlinearly coupled to ecosystem function, with effects that accumulate through annual and decadal timescales. Increasing variability in sunlight and precipitation leads to lower rates of carbon sequestration and favors broad-leaved deciduous trees over conifers. Temperature variability has only minor impacts by comparison. We also find that projected changes in sunlight and precipitation variability have important implications for carbon storage and ecosystem structure and composition. Based on Intergovernmental Panel on Climate Change model estimates for changes in high-frequency meteorological variability over the next 100 years, we expect that terrestrial ecosystems will be affected by changes in variability almost as much as by changes in mean climate. We conclude that terrestrial ecosystems are highly sensitive to high-frequency meteorological variability, and that accurate knowledge of the statistics of this variability is essential for realistic predictions of ecosystem structure and functioning.
Medvigy
David
D
Department of Organismic and Evolutionary Biology and School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA. dmedvigy@princeton.edu
Wofsy
Steven C
SC
Munger
J William
JW
Moorcroft
Paul R
PR
D002244:Carbon / Q000032:analysis* / Q000191:economics; D057231:Climate Change; D017753:Ecosystem; D011891:Rain; D013472:Sunlight; D013696:Temperature; D013997:Time Factors
D002244:Carbon
Science. 2003 Jun 6;300(5625):1560-3
12791990
Science. 2003 Mar 28;299(5615):2035-8
12663919
Nature. 2004 Jan 22;427(6972):332-6
14716318
Science. 2000 Mar 24;287(5461):2246-50
10731143
Nature. 2000 Nov 9;408(6809):184-7
11089968
Trends Ecol Evol. 1999 Sep;14(9):361-366
10441312
Science. 2006 Dec 1;314(5804):1442-5
17138899
Science. 2000 Sep 22;289(5487):2068-74
11000103
Science. 2002 Dec 13;298(5601):2173-6
12481133