Soil respiration of four forests along elevation gradient in northern subtropical China

Abstract

Background and aimsSoil respiration is the second‐largest terrestrial carbon (C) flux, and soil temperature and soil moisture are the main drivers of temporal variation in soil respiration and its components. Here, we quantified the contribution of soil temperature, soil moisture, and their intersection on the variation in soil respiration and its components of the evergreen broad‐leaved forests (EBF), mixed evergreen and deciduous broad‐leaved forests (MF), deciduous broad‐leaved forests (DBF), and subalpine coniferous forests (CF) along an elevation gradient.MethodsWe measured soil respiration of four types of forests along the elevation gradient in Shennongjia, Hubei China based on the trenching experiments. We parameterized the relationships between soil respiration and soil temperature, soil moisture, and quantified the intersection of temperature and moisture on soil respiration and its components.ResultsTotal soil respiration (R S), heterotrophic respiration (R H), and autotrophic respiration (R A) were significantly correlated with soil temperature in all four forests. The Q 10 value of soil respiration significantly differed among the four types of forest, and the Q 10 was 3.06 for EBF, 3.75 for MF, 4.05 for DBF, and 4.49 for CF, respectively. The soil temperature explained 62%–81% of the variation in respiration, while soil temperature and soil moisture together explained 91%–97% of soil respiration variation for the four types of forests. The variation from the intersection of soil temperature and moisture were 12.1%–25.0% in RS, 1.0%–7.0% in R H, and 17.1%–19.6% in R A, respectively.ConclusionsOur results show that the temperature sensitivity (Q 10) of soil respiration increased with elevation. The intersection between soil temperature and soil moisture had strong effects on soil respiration, especially in R H. We demonstrated that the intersection effects between soil temperature and soil moisture on soil respiration were essential to understand the response of soil respiration and its components to climate change.

Soil respiration variation along an altitudinal gradient in Italian Alps: Disentangling forest structure and temperature effects

“…In fact, temperature resulted in the main controlling factor on SR, explaining most of the variability of SR. This result is in agreement with other studies performed along altitudinal gradients, reporting that temperature can explain between 55% and 76% of the SR variability [6, 9, 14,27,63, 76]. On the other hand, the annual cumulative SR in site B was 2 times larger than in site A, which has the same mean annual temperature.…”

“…The temperature sensitivity of SR is an important ecological model parameter, and according to previous studies, its value is mainly controlled by temperature [14,17,88,89]. The Q10 and SRref values found at site B substantially confirm the values found by Acosta et al [90] at the same site (2.0 and 4.09, respectively).…”

“…Since then, other studies have investigated and quantified the impact of productivity on SR modeling [10, 11]. Apart from productivity, SR is influenced by different abiotic and biotic factors such as soil temperature, moisture, and microbial community, introducing a considerable uncertainty in SR estimates [12,13,14]. Among these factors, the temperature has been the most often studied factor affecting respiratory processes [15,16].…”

“…On the other hand, the elevation is a key driver of climate properties. It plays an essential role in the soil organic matter distribution and may dampen the effects of climate change [14,22,23,24, 25]. In general, temperature declines with elevation, thus elevation gradient has been used to assess soil respiration response to temperature in several studies [12,26,27,28].…”

“…These studies indicate that CO2 exchange between soil and atmosphere varies along climatic gradients and that temperature sensitivity (Q10) of SR increases with elevation. They also found a positive relationship between soil organic matter (SOM) and elevation and reported that global soil organic C stock at high elevation is more sensitive to climate change and is predicted to decrease in a warming climate [14,23,29,30,31,32]. However, several researchers have reported opposite trends and found lower SOM and higher SR at a higher elevation [30,33,34].…”