Spatial heterogeneity of soil respiration in a seasonal rainforest with complex terrain

Construction and progress of Chinese terrestrial ecosystem carbon, nitrogen and water fluxes coordinated observation

“…At the same time, a series of important ecological phenomena and their controling mechanism were illustrated. For example, the 'light depress' at ecosystem scale in temperate and alpine grasslands (Fu et al, 2006(Fu et al, , 2009, the nonlinear response of ecosystem carbon flux to temperature variation , heterogeneous response of soil respiration to temperature Jia et al, 2013;Song et al, 2013), the spatio-temporal variation of ecosystem light use efficiency (Yuan et al, 2010;Zhang et al, 2006c;Wu et al, 2008), and the 'carbon pool' in mountain area (Yao et al, 2012). Such studies enhance the understanding of the biotic and abiotic controlling mechanism of ecosystem CO 2 flux across different temporal scales, and the response and adaptation of ecosystem flux to global change.…”

Soil respiration across a permafrost transition zone: spatial structure and environmental correlates

“…Numerous studies have investigated temporal dynamics of SR and most find strong influences of temperature and moisture (e.g., Davidson et al, 1998;Hanson et al, 1993), but much less is known about spatial variation in SR, where temperature and moisture appear to have weaker influences (Yim et al, 2003;Dore et al, 2014;Ohashi et al, 2015;Song et al, 2013).…”

“…Studies that examine spatial variation in SR often find rates to be associated with tree-stand variables such as basal area, species composition, and distance from SR measurement to tree stems (Ohashi et al, 2015;Katayama et al, 2009;Soe and Buchmann, 2005;Khomik et al, 2006), though such relationships are not ubiquitous (Song et al, 2013;Saiz et al, 2006;Sotta et al, 2004). Relatively little work on spatially resolved SR has occurred in permafrost-associated systems, though higher SR in permafrost-free domains has been observed (Vogel et al, 2005).…”

“…Previous work in forests has revealed that SR spatial autocorrelation occurs across a broad range of length scales (referred to as the "range" in variogram models), from less than 1 m to greater than 40 m (Foti et al, 2014;Russell and Voroney, 1998;Song et al, 2013;Singh et al, 2008;Rayment and Jarvis, 2000), but none of these estimates come from boreal forests. In addition, among-study variation in the length scale of spatial autocorrelation may be partially due to differences in the spatial scale of sampling.…”

“…It is therefore difficult to generate quantitative a priori expectations for the parameters of SR variograms (functions that describe spatial continuity or variability) in our study system. Instead, we test the following qualitative hypotheses: (i) given previous work showing that spatial variability in SR is only weakly related to temperature and soil moisture (e.g., Song et al, 2013;Yim et al, 2003), we hypothesize that SR will be predominantly influenced by carbon inputs such that variability in SR throughout the spatial domain will be best explained by tree-stand variables (e.g., basal area); (ii) within the drier, permafrost-free domain we hypothesize that SR will again be best explained by tree-stand variables, but within the wetter permafrost-associated domain SR will be decoupled from carbon inputs and will therefore be poorly explained by treestand variables; and (iii) cold temperatures will fundamentally constrain SR such that we hypothesize a smaller coefficient of variation and less well defined spatial gradients (i.e., weaker spatial structure) in SR under colder temperatures.…”