## 1 Introduction  
Soil respiration (Rs) is an important ecological process in the global carbon balance and carbon cycle and has an important impact on global climate change [1]. Rs is often used as an indicator to evaluate soil biological activity, soil fertility, and even air permeability [2]. As the only output channel of the soil carbon pool and an important source of atmospheric CO\({}_{2}\), Rs flux has become a major research hotspot [3, 4]. Although Rs is a critical part of the carbon cycle, the current understanding of Rs is relatively poor, and knowledge on the influencing factors of Rs and the variability of Rs among ecosystems remains limited. In addition, the spatial heterogeneity of Rs and its influencing mechanism remain to be clarified [5]. Therefore, studying the Rs process and its influencing factors in depth is the key to exploring the regulation mechanism of regional carbon budgets, the carbon cycle, and carbon balance [6]. Rs is a process in which soil produces and releases CO\({}_{2}\) to the atmosphere [7]. Rs exhibits obvious spatial variation characteristics, mainly at the plot scale, regional scale, and global scale [7]. At the global scale, Rs has obvious zonal characteristics that are mainly affected by zonal changes in vegetation and climate [8; 9]. At the regional scale, landscape [10; 11], land use type [12; 13], and vegetation type [14; 15] affected Rs. At the plot scale, stand and canopy structure [16; 17], root distribution [18], and the heterogeneity of major environmental factors and soil characteristics [19] lead to the spatial heterogeneity of Rs [20; 21]. Currently, the dynamic chamber-infrared CO\({}_{2}\) analyzer (IRGA) method is mostly used to measure Rs in ecosystems with equipment such as LI-COR series instruments (including the 6400 and 8100 instruments: LI-COR Biosciences, Lincoln, NE, USA) [22]. Rs based on a certain number of chambers at the plot scale can be used to represent the average value of Rs in ecosystems [23]. Studies have shown that the spatial heterogeneity of Rs within a plot or between different plots is caused by the differences in soil water content (SWC) and soil physicochemical properties [22; 24; 25]. However, Rs is not only a physiological process that occurs in response to soil abiotic characteristics but is also a result of the combined action of several complex ecosystem processes [26]. Although soil temperature (ST) and SWC can reflect the temporal variability of Rs well, they do not fully explain the spatial heterogeneity of Rs within or between plots [27]. Therefore, strengthening the synchronous observation of Rs and biological factors will help to enhance understanding of the process and the mechanism of biological factors affecting Rs. Biotic factors affect Rs by affecting soil microclimate and structure, litter quantity and quality, and root respiration [28]. During plant growth, Rs is mainly controlled by plant growth [29]. This is mainly manifested in the following ways: (1) the material basis of Rs is derived from plant photosynthesis [30; 31]. High photosynthesis rates lead to high respiration rates [32], and the Rs rate is positively correlated with vegetation photosynthesis and total primary productivity (GPP) [33; 34]. (2) The functional traits that drive carbon assimilation (leaf) and respiration (root) control roof respiration [35]. Compared with leaves, root traits are more complex and are difficult to observe and measure [36]. Studies have shown that easily measured aboveground traits are good predictors of root traits [37]. Fine roots, specific root length, and root biomass are closely related to leaf area, height, or aboveground biomass [38]. In addition, plant functional traits show a pattern of coordination and adaptation along environmental gradients (e.g., soil fertility, water, or light) [37]. Therefore, differences in aboveground plant functional traits may lead to significant changes in Rs [30; 39].