Effects of seasonal precipitation change on soil respiration processes in a seasonally dry tropical forest

Abstract

Precipitation is projected to change intensity and seasonal regime under current global projections. However, little is known about how seasonal precipitation changes will affect soil respiration, especially in seasonally dry tropical forests. In a seasonally dry tropical forest in South China, we conducted a precipitation manipulation experiment to simulate a delayed wet season (DW) and a wetter wet season (WW) over a three-year period. In DW, we reduced 60% throughfall in April and May to delay the onset of the wet season and irrigated the same amount water into the plots in October and November to extend the end of the wet season. In WW, we irrigated 25% annual precipitation into plots in July and August. A control treatment (CT) receiving ambient precipitation was also established. Compared with CT, DW significantly increased soil moisture by 54% during October to November, and by 30% during December to April. The treatment of WW did not significantly affect monthly measured soil moisture. In 2015, DW significantly increased leaf area index and soil microbial biomass but decreased fine root biomass. In contrast, WW significantly decreased fine root biomass and forest floor litter stocks. Soil respiration was not affected by DW, which could be attributed to the increased microbial biomass offsetting the decrease in fine root biomass. In contrast, WW significantly increased soil respiration from 3.40 to 3.90 μmol m −2 s −1 in the third year, mainly due to the increased litter decomposition and soil pH (from 4.48 to 4.68). The present study suggests that both a delayed wet season and a wetter wet season will have significant impacts on soil respiration-associated ecosystem components. However, the ecosystem components can respond in different directions to the same change in precipitation, which ultimately affected soil respiration. K E Y W O R D S climate change, precipitation regime, rainfall change, soil CO 2 , tropics S U PP O RTI N G I N FO R M ATI O N Additional supporting information may be found online in the Supporting Information section. How to cite this article: Yu S, Mo Q, Chen Y, et al. Effects of seasonal precipitation change on soil respiration processes in a seasonally dry tropical forest. Ecol Evol. 2020;10:467-479.

Soil Respiration Variation among Four Tree Species at Young Afforested Sites under the Influence of Frequent Typhoon Occurrences

“…The annual Rs values in the pretyphoon disturbance years in this study ranged from 5.9 to 9.1 t C ha irrespective of the tree species, which is similar to reported values for other tropical forests [18,19,44,45]. The study results also demonstrated that soil temperature was correlated to Rs for the four tree species in the afforested areas (Figure 4), which is similar to the results for other tropical forests [35,[46][47][48][49][50][51]. However, although the temperature sensitivities of the Rs values (Q 10 ) for the four tree species at the afforested sites were similar to those in other tropical forests [45,52,53], it must be noted that the Q 10 values were significantly lower in the post-typhoon year than in the pretyphoon year (p < 0.05, Table 3).…”

“…Extreme climate events such as typhoons alter the patterns of seasonal precipitation, especially in monsoon regions [31], but the scientific understanding of the impact of typhoons on the carbon cycle is still obscure [32]. Typhoons often lead to a large quantity of deposits of green and immature leaves [33,34], and in comparison to natural forests, afforested areas can be more vulnerable to typhoon disturbances [35]. Climate change intensifies typhoon damage to afforested areas and thereby affects Rs.…”

Response of foliar mineral nutrients to long‐term nitrogen and phosphorus addition in a tropical forest

“…In a lowland tropical forest, neither N nor P addition increased foliar K concentrations (Santiago et al., 2012). Due to its relatively greater mobility in soil, soil K + leaches in tropical forests with high precipitation (Yu et al., 2020). In our study, we did not observe significant effects of N or P addition on foliar [K] in the tropical forest near the coast (about 5 km), in agreement with a previous study in a Panamanian tropical forest (Santiago et al., 2012), where rain provides enough K to plants.…”

Soil Respiration Variations in Temperate Rhododendron (Rhododendronarboreum) Forest of Annapurna Conservation Area (ACA) in Nepal

“…The maximum SWC values were measured during evening and minimum were during the afternoon because, in most of the days in our measurements, the short and frequent rain events were detected between the late afternoon and early evening measurements. The occurrence of both varying precipitation with the lower and higher rate than the usual has signi cant impacts on SR with the association of ecosystem components in the seasonally dry tropical forest (Yu et al 2020). However, the tropical forests are more sensitive to the changing rainfall than that of the forests in temperate region where the temperature becomes the most prominent in controlling the SR ( Canopy coverage plays a major role to prevent the light from the sun to the under vegetation and suffers from inadequate light intensity in uencing their adaptability and optimum growth by the limitations of nutrient use e ciency.…”