Direct and indirect effects of climatic variations on the interannual variability in net ecosystem exchange across terrestrial ecosystems

Figures & data

Table 1. Information of study sites

Site	Lat (°)	Long (°)	Alt (m)	Eco	n (years)	Ta (°C)	PPT (mm)	References
US-Blo	38.90	−120.63	1315	ENF	9	11.9	1073	Goldstein et al. (2000)
US-Dk3	35.98	−79.09	163	ENF	8	15.0	1050	Stoy et al. (2008)
US-Fmf	35.14	−111.73	2160	ENF	5	9.7	521	Dore et al. (2008)
US-Fuf	35.09	−111.76	2180	ENF	5	8.9	497	Dore et al. (2008)
US-Ho1	45.20	−68.74	60	ENF	13	6.7	840	Richardson et al. (2009)
US-Ho2	45.21	−68.75	91	ENF	11	6.6	842	Xiao et al. (2005)
US-Ho3	45.21	−68.73	61	ENF	5	6.5	877	Davidson et al. (2006)
US-Me2	44.45	−121.56	1253	ENF	9	7.4	441	Thomas et al. (2009)
US-NC2	35.80	−76.67	12	ENF	5	15.8	1212	Noormets et al. (2010)
US-NR1	40.03	−105.55	3050	ENF	10	2.4	663	Blanken et al. (2009)
US-SP3	29.75	−82.16	36	ENF	11	20.1	1034	Powell et al. (2008)
DE-Tha	50.96	13.57	380	ENF	12	7.6	820	Prescher et al. (2010)
DE-Wet	50.45	11.46	703	ENF	7	6.6	967	Rebmann et al. (2010)
ES-ES1	39.35	−0.32	1	ENF	5	17.5	495	Reichstein et al. (2005)
FI-Hyy	61.85	24.29	185	ENF	11	4.8	702	Suni et al. (2003)
FI-Sod	67.36	26.64	189	ENF	7	1.1	425	Aurela (2005)
FR-Pue	43.74	3.60	211	ENF	8	13.6	904	Allard et al. (2008)
IT-Cpz	41.71	12.38	9	ENF	8	15.0	729	Garbulsky et al. (2008)
NL-Loo	52.17	5.74	25	ENF	10	10.3	843	Dolman et al. (2002)
RU-Fyo	56.46	32.92	265	ENF	9	5.2	762	Milyukova et al. (2002)
SE-Nor	60.09	17.48	28	ENF	5	6.4	486	Lagergren et al. (2005)
CN-Qia	26.74	115.06	100	ENF	7	18.3	1139	Zhang et al. (2011)
US-Bar	44.06	−71.29	272	DBF	5	7.4	1330	Jenkins et al. (2007)
US-Dk2	35.97	−79.10	168	DBF	7	15.2	1097	Stoy et al. (2008)
US-Ha1	42.54	−72.17	340	DBF	15	8.5	1153	Urbanski et al. (2007)
US-MMS	39.32	−86.41	275	DBF	5	12.7	1186	Dragoni et al. (2011)
US-MOz	38.74	−92.20	219.4	DBF	5	13.0	1035	Yang et al. (2010)
US-Slt	39.91	−74.60	30	DBF	5	12.4	1032	Hollinger et al. (2010)
US-Syv	46.24	−89.35	540	DBF	5	4.5	696	Desai et al. (2005)
US-UMB	45.56	−84.71	234	DBF	6	7.2	412	Hardiman et al. (2011)
US-WCr	45.91	−90.08	515	DBF	7	5.7	744	Cook et al. (2004)
DE-Hai	51.08	10.45	433	DBF	8	8.3	803	Kutsch et al. (2008)
FR-Hes	48.67	7.07	293	DBF	12	10.4	918	Granier et al. (2000)
IT-Ro1	42.41	11.93	153	DBF	7	15.5	769	Rey et al. (2002)
CN-Din	23.17	112.53	240	EBF	6	20.1	1481	Zhang et al. (2010)
BE-Bra	51.31	4.52	15	MF	9	11.4	792	Carrara et al. (2003)
BE-Vie	50.31	6.00	491	MF	11	8.3	719	Aubinet et al. (2001)
CH-Lae	47.48	8.37	645	MF	5	8.3	605	Eugster et al. (2007)
DK-Sor	55.49	11.64	35	MF	13	8.7	656	Pilegaard et al. (2001)
CN-Cha	42.40	128.10	738	MF	6	3.9	498	Guan et al. (2006)
US-Los	46.08	−89.98	480	SHR	6	3.7	716	Sulman et al. (2009)
MX-Lpa	24.13	−110.44	21	SHR	5	23.4	137	Bell et al. (2012)
US-Aud	31.59	−110.51	1469	GRA	6	15.9	366	Krishnan et al. (2012)
US-Bkg	44.35	−96.84	510	GRA	5	6.3	540	Gilmanov et al. (2005)
US-Dk1	35.97	−79.09	168	GRA	7	15.1	1022	Stoy et al. (2008)
US-FPe	48.31	−105.10	634	GRA	8	5.7	391	Gilmanov et al. (2005)
US-Fwf	35.45	−111.77	2270	GRA	5	8.4	562	Dore et al. (2008)
US-SRM	31.82	−110.87	1116	GRA	7	19.0	324	Scott et al. (2009)
US-Ton	38.43	−120.97	177	GRA	9	16.9	504	Ma et al. (2007)
US-Var	38.41	−120.95	129	GRA	9	15.9	493	Xu and Baldocchi (2004)
US-Wkg	31.74	−109.94	1531	GRA	6	17.2	274	Scott et al. (2010)
AT-Neu	47.12	11.32	1095	GRA	7	6.9	731	Wohlfahrt et al. (2008)
DE-Gri	50.95	13.51	385	GRA	5	7.8	901	Prescher et al. (2010)
DK-Lva	55.68	12.08	15	GRA	5	9.0	655	Gilmanov et al. (2007)
HU-Bug	46.69	19.60	106	GRA	6	10.3	499	Nagy et al. (2007)
NL-Ca1	51.97	4.93	1	GRA	6	11.0	759	Gilmanov et al. (2007)
CN-Dan	29.67	91.33	4333	GRA	5	2.47	470	Xu et al. (2007)
CN-Hab	37.62	101.28	3220	GRA	6	−0.8	484	Kato et al. (2006)
US-ARM	36.61	−97.49	314	CRO	7	15.3	658	Fischer et al. (2007)
US-Bo1	40.01	−88.29	219	CRO	11	11.6	748	Hollinger et al. (2005)
US-Ne1	41.17	−96.48	361	CRO	8	10.7	846	Suyker et al. (2004)
US-Ne2	41.16	−96.47	362	CRO	8	10.2	872	Suyker et al. (2004)
BE-Lon	50.55	4.74	165	CRO	5	11.2	611	Moureaux et al. (2006)
DE-Geb	51.10	10.91	157	CRO	6	9.9	503	Anthoni et al. (2004)
DE-Kli	50.89	13.52	478	CRO	6	7.7	951	Prescher et al. (2010)

Lat, latitude; Long, longitude; Alt, altitude; Eco, ecosystem type; n, data record length; Ta, mean annual air temperature; PPT, annual precipitation; ENF, evergreen needleleaf forest; DBF, deciduous broadleaf forest; EBF, evergreen broadleaf forest; MF, mixed forest; SHR, shrubland; GRA, grassland; CRO, cropland.

Fig. 1 The direct and indirect effects of climatic variation on the interannual variability (IAV) in net ecosystem exchange (NEE) for evergreen needleleaf forests (a), deciduous broadleaf forests (b), grasslands (c) and croplands (d). Green and red lines represent positive and negative effects, respectively. Solid and dashed lines represent significant (p<0.05) and non-significant (p≥0.05) effects, respectively. The values beside the paths are the standardised (0–1) path coefficients (ρ), which are only shown for significant effects. PAR, photosynthetically active radiation; Ta, air temperature; Ts, soil temperature; VPD, vapour pressure deficit; WBI, water balance index; A _m, maximum photosynthetic rate; α, apparent quantum yield; WUE, water use efficiency; R ₁₀, reference respiratory rate at 10 °C; Q ₁₀, temperature sensitivity.

Fig. 2 The direct and indirect effects of climatic variation on in the interannual variability (IAV) in gross primary productivity (GPP) and ecosystem respiration (RE) for evergreen needleleaf forests (a), deciduous broadleaf forests (b), grasslands (c) and croplands (d). Green and red lines represent positive and negative effects, respectively. Solid and dashed lines represent significant (p<0.05) and non-significant (p≥0.05) effects, respectively. The values beside the paths are the standardised (0–1) path coefficients (ρ), which are only shown for significant effects. PAR, photosynthetically active radiation; Ta, air temperature; Ts, soil temperature; VPD, vapour pressure deficit; WBI, water balance index; A _m, maximum photosynthetic rate; α, apparent quantum yield; WUE, water use efficiency; R ₁₀, reference respiratory rate at 10 °C; Q ₁₀, temperature sensitivity.

Fig. 3 The direct and indirect effects of climatic variation on the interannual variability (IAV) in net ecosystem exchange (NEE, a–c), gross primary productivity (GPP) and ecosystem respiration (RE, d–f) for wet (water balance index, or WBI, below −500 mm; a, d), moist (−500 mm<WBI<0 mm; b, e), and dry (WBI>0 mm; c, f) ecosystems. Note that a larger WBI indicates a drier environment. Green and red lines represent positive and negative effects, respectively. Solid and dashed lines represent significant (p<0.05) and non-significant (p≥0.05) effects, respectively. The values beside the paths are the standardised (0–1) path coefficients (ρ), which are only shown for significant effects. PAR, photosynthetically active radiation; Ta, air temperature; Ts, soil temperature; VPD, vapour pressure deficit; WBI, water balance index; A _m, maximum photosynthetic rate; α, apparent quantum yield; WUE, water use efficiency; R ₁₀, reference respiratory rate at 10 °C; Q ₁₀, temperature sensitivity.

Table 2. Correlation coefficients (r) of the physiological parameters in different ecosystem types

Ecosystem group	r(A m , α)	r(A m , WUE)	r(α, WUE)	r(R 10, Q 10)
ENF	0.21*	0.10	0.11	0.14
DBF	0.10	0.11	0.28*	0.07
GRA	0.29*	0.41*	0.27*	0.07
CRO	0.02	0.56*	0.10	0.07
Wet	0.05	0.11	0.02	0.10
Moist	0.15*	0.29*	0.19*	0.10
Dry	0.09	0.49*	0.09	0.14

ENF, evergreen needleleaf forests; DBF, deciduous broadleaf forests; GRA, grasslands; CRO, croplands; Wet, ecosystems with a water balance index (WBI) below −500 mm; Moist, ecosystems with −500 mm<WBI<0 mm; Dry, ecosystems with WBI>0 mm; A _m, maximum photosynthetic rate; α, apparent quantum yield; WUE, water use efficiency; R ₁₀, reference respiratory rate at 10 °C; Q ₁₀, temperature sensitivity.

*p<0.05.

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