Precipitation drives interannual variation in summer soil respiration in a Mediterranean-climate, mixed-conifer forest

University of California at Santa Cruz Department of Environmental Studies 1156 High Street Santa Cruz CA 95060 USA
Climatic Change (Impact Factor: 3.43). 01/2008; 92(1):109-122. DOI: 10.1007/s10584-008-9475-0


Predictions of future climate change rely on models of how both environmental conditions and disturbance impact carbon cycling
at various temporal and spatial scales. Few multi-year studies, however, have examined how carbon efflux is affected by the
interaction of disturbance and interannual climate variation. We measured daytime soil respiration (R
s) over five summers (June–September) in a Sierra Nevada mixed-conifer forest on undisturbed plots and plots manipulated with
thinning, burning and their combination. We compared mean summer R
s by year with seasonal precipitation. On undisturbed plots we found that winter precipitation (PPTw) explained between 77–96% of interannual variability in summer R
s. In contrast, spring and summer precipitation had no significant effect on summer R
s. PPTw is an important influence on summer R
s in the Sierra Nevada because over 80% of annual precipitation falls as snow between October and April, thus greatly influencing
the soil water conditions during the following growing season. Thinning and burning disrupted the relationship between PPTw and Rs, possibly because of significant increases in soil moisture and temperature as tree density and canopy cover decreased. Our
findings suggest that R
s in some moisture-limited ecosystems may be significantly influenced by annual snowpack and that management practices which
reduce tree densities and soil moisture stress may offset, at least temporarily, the effect of predicted decreases in Sierran
snowpack on R

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    • "Secondly, the low interannual variation in annual mean soil temperature with a CV of only 6% contributes little to annual litter respiration and contribution rate (Asensio et al., 2007; Ma et al., 2007; Concilio et al., 2009). The results of this study clearly showed that annual cumulative litter respiration and contribution rate were not related to annual mean soil temperature (P > 0.05). "
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    ABSTRACT: A better understanding of the factors affecting interannual variability in litter respiration is critical to precisely understand local carbon cycling, especially under the changing climate. In this study, litter respiration was obtained by subtracting in situ soil respiration in a control (LCK) treatment by that in a litter removal (LR) treatment for the period 2009-2013 in a 30-year-old black locust plantation (Robinia pseudoacacia L.) on a ridge slope in a small watershed of Loess Plateau, China. Annual cumulative litter respiration ranged from 48 ± 15 to 165 ± 36 g C m-2 y-1, with mean value of 113 ± 45 g C m-2 y-1 and coefficient of variation (CV) of 40%; annual contribution rate of litter respiration to total soil respiration (hereafter refer to as litter contribution rate) also exhibited a similar interannual variability (ranged from 8 ± 3% to 20 ± 7%; mean = 15 ± 5%; CV = 31%). Additionally, annual mean soil moisture was highest in 2010 (53.2 ± 8.4% WFPS) and lowest in 2013 (31.4 ± 9.5% WFPS), with mean value of 41.6 ± 7.9% WFPS and CV of 19%; annual litter production rates also exhibited a similar interannual variability (ranged from 379 ± 34 to 565 ± 69 g m-2 y-1; mean = 477 ± 71 g m-2 y-1; CV = 15%). Annual mean soil moisture was mainly affected by the frequency and distribution of precipitation, and annual litter production rates varied with summer precipitation. Annual cumulative litter respiration and litter contribution rate increased linearly with both annual litter production rates and mean soil moisture content. The contribution of soil water to litter respiration was larger than that of litter production rates. Therefore, litter production rates and soil moisture resulted from precipitation needs to be taken into account for precisely predicting litter respiration in the dryland ecosystems, especially under the changing climate.
    Journal of Arid Environments 02/2016; 125:43-51. DOI:10.1016/j.jaridenv.2015.09.016 · 1.64 Impact Factor
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    • "Seasonal patterns of R S have been attributed to soil temperature [5] [18], soil moisture [10] [19], precipitation, productivity [20], or combinations of these factors [11]. Inter-annual variation of R S is usually controlled by productivity [21], soil water condition [22], or precipitation amount [23] and pattern [10]. Therefore, sampling schedule (in terms of both frequency and pattern) that captures these factors is important for adequately capturing the temporal variation of R S [8] [20] and estimating annual R S . "
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    ABSTRACT: Optimizing a manual measurement schedule (both frequency and pattern) for estimating annual soil respiration (RS) is an important but unresolved issue. We hypothesized that (i) an optimal sampling setup can be found to obtain a reliable annual RS, and (ii) if the desired outcome is a multi-year mean annual RS, a lower sampling frequency might be adequate. Here we explored these issues using a three-year chamber-based dataset, with a sampling frequency of twice per week (defined as control), in an exotic slash pine (Pinus elliottii Englem.) plantation in subtropical China. The results showed that RS during 9:00–11:00 a.m. represented diurnal mean RS well. In order to obtain an annual RS as reliable as the control (deviation within ±5%), the optimal measurement strategy is a biweekly sampling across a year and not a trade-off sampling pattern (monthly sampling combined with weekly sampling depending on the seasons). Furthermore, despite an obvious inter-annual variability in RS (548.4–757.5 g C m−2 year−1, CV = 16.3%), a monthly sampling was sufficient to obtain an unbiased multi-year mean annual RS (deviation within ±5%). Such findings are useful when easy looking for estimates of annual ecosystem carbon budgets. However, the generality needs to be examined in other ecosystems.
    European Journal of Soil Biology 09/2012; 52:41–47. DOI:10.1016/j.ejsobi.2012.06.002 · 1.72 Impact Factor
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    • "Consequently, temperature is still regarded as the key factor for predicting soil respiration because it directly controls plant and microorganism metabolisms on a daily time scale and is indirectly related to the seasonal supply of photosynthesis-derived substrate (Ma and others 2004; Campbell and Law 2005). Timber harvest activities can influence forest soil respiration by altering soil carbon input (Johnson 1992; Johnson and Curtis 2001; Li and others 2007; Jandl and others 2007), organic matter in the soil (Mallik and Hu 1997), forest structure and microclimate (Chen and others 1999; Xu and others 2002), microbial biomass and microorganism community structure (Ponder and Tadros 2002; Fraterrigo and others 2006; Chatterjee and others 2008), litter depth (Concilio and others 2005; DeForest and others 2009), and root distribution and biomass (Henderson 2007). Most previous soil respiration studies have addressed the effects of clearcutting (Weber 1990; Striegl and Wickland 1998) or thinning (Ma and others 2004; Tang and others 2005), whereas comparisons of both silvicultural strategies in the same forest type are rare. "
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    ABSTRACT: We investigated the variability of soil respiration and several potential regulatory factors and modeled their interrelationships from May to August over a 5-year period in oak forests subjected to alternative harvesting treatments as part of the Missouri Ozark Forest Ecosystem Project (MOFEP). Treatments included even-aged management (EAM), uneven-aged management (UAM), and no-harvest management (NHM) and were implemented 7–8years prior to this study. Summer mean soil respiration did not differ among the treatments, possibly because of changes in treatment differences in the separate months and years that tended to cancel each other out when averaged. Summer mean soil respiration and soil moisture tended to be higher in wet years (2004, 2006, and 2008) and lower in dry years (2005 and 2007) in EAM and UAM than in NHM. Summer precipitation was assumed to be the primary driver of variability in summer mean soil respiration through its control on soil moisture and the normalized difference vegetation index (NDVI) in the harvested forests. Nonlinear models using soil temperature, soil moisture and day-of-the-year (DOY) were used to predict within-summer soil respiration for all the treatments. A sensitivity analysis of the model using 30min interval data suggested that soil respiration was more sensitive to soil moisture in the EAM and UAM treatments than in NHM. We also found a change in the soil respiration–soil temperature relationship in the summer for all the treatments. Simulated data sets that removed the covariance structure between soil temperature and moisture suggested that the change in the respiration–temperature relationship resulted from the combined effect of moisture stress and low temperature sensitivity at high temperatures during July and August. Simulations also showed the effect of moisture stress to be more limiting to soil respiration in the harvested forests than in the control at high temperatures, even resulting in a negative relationship at high temperatures. Keywordssoil respiration–soil moisture–temporal variability–precipitation–forest management–Missouri Ozark Forest Ecosystem Project (MOFEP)–NDVI
    Ecosystems 12/2011; 14(8):1310-1327. DOI:10.1007/s10021-011-9482-2 · 3.94 Impact Factor
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