Soil Respiration Is Influenced by Seasonality, Forest Succession and Contrasting Biophysical Controls in a Tropical Dry Forest in Northwestern Mexico

Abstract

Soil respiration (RS) is an important component of the C cycle because it contributes significant CO2 emissions to the atmosphere that result from metabolism and respiration of its autotrophic and heterotrophic components. However, the relative importance of different biophysical controls that drive the variability of this flux and their influence along forest succession pathways is still unknown. We incorporate multiyear RS, ecosystem flux and meteorological measurements in old-growth (OG), mid-secondary (MS) and early-secondary (ES) tropical dry forests (TDFs) with the goal of assessing the temporal variation of RS and identifying the biophysical controls at each site by applying structural equation models (SEM). Along forest succession, RS followed the pattern of precipitation events; we identified by the end of the wet season that RS was sustained by a longer period at OG, while in MS and ES, RS decreased according to the soil moisture availability. According to SEM, soil moisture and soil temperature exert an effect on the variability of RS in all sites. However, we found that RS was also controlled by the vapor pressure deficit at MS and gross primary production at OG and ES. Our results suggest that seasonality has a different impact on RS along forest succession in TDFs found in northwestern Mexico and highlights the relevance of considering additional biophysical controls of RS for a better understanding this critical process of the C cycle.

Tropical vegetation productivity and atmospheric methane over the last 40,000 years from model simulations and stalagmites in Sulawesi, Indonesia

“…For example, vegetation above the cave may become more nutrient limited when temperature, CO 2 , and moisture are readily available (Cowling and Field, 2003). Strengthening of the summer monsoon and strong seasonality could also influence productivity patterns (Vargas-Terminel et al, 2022).…”

“…Soil respiration is the emission of CO 2 from the soil surface (Schlesinger and Andrews, 2000) that is produced within the soil profile by roots and soil organisms (Raich and Schlesinger, 1992). The predominant climatic driver of soil respiration rates is debated, but it is generally agreed that temperature, CO 2 , and soil moisture all play important roles in driving soil respiration rates (Raich and Schlesinger, 1992; Bragg et al, 2013; Hursh et al, 2017), with seasonality and forest structure also exerting control (Vargas-Terminel et al, 2022). It also has been found that wetland drying significantly increases the temperature sensitivity of soil respiration rates (Chen et al, 2018).…”

Chronological dataset of soil respiration fluxes from a seasonally dry forest in Northwest México

“… Even though, about half of the tropics display a seasonally dry climate [6] , there is still an uncertainty about the contribution of soil greenhouse gases from tropical dry forest to ecosystem C balance [7] and the present database contributes to fill this gap. The present soil respiration dataset is worthy to reduce the gaps of knowledge in the seasonal, intra-annual and inter-annual variability of tropical dry forest soils under contrasting environmental settings and across forest succession [1] . This dataset compiles the efforts of monitoring systematically soil respiration in a seasonally dry forest from Northwestern México in order to serve as a baseline information to test, calibrate and validate process-based ecosystem models for water limited regions [8 , 9] .…”

“…The present soil respiration dataset is worthy to reduce the gaps of knowledge in the seasonal, intra-annual and inter-annual variability of tropical dry forest soils under contrasting environmental settings and across forest succession [1] .…”

“…1 Monthly means of soil respiration (R S ) in an old-growth (OG), mid-secondary (MS) and early-secondary (ES) tropical dry forest in Northwestern Mexico modified from Vargas-Terminel et al. [1] (see Fig. 1 in the related research article).…”