Effects of tree species composition on the CO2 and N2O efflux of a Mediterranean mountain forest soil

Abstract

Background and Aims Tree species composition shifts can alter soil CO 2 and N 2 O effluxes. We quantified the soil CO 2 and N 2 O efflux rates and temperature sensitivity from Pyrenean oak, Scots pine and mixed stands in Central Spain to assess the effects of a potential expansion of oak forests. Methods Soil CO 2 and N 2 O effluxes were measured from topsoil samples by lab incubation from 5 to 25°C. Soil microbial biomass and community composition were assessed. Results Pine stands showed highest soil CO 2 efflux, followed by mixed and oak forests (up to 277, 245 and 145 mg CO 2 -C m −2 h −1 , respectively). Despite contrasting soil microbial community composition (more fungi and less actinomycetes in pine plots), carbon decomposability and temperature sensitivity of the soil CO 2 efflux remain constant among tree species. Soil N 2 O efflux rates and its temperature sensitivity was markedly higher in oak stands than in pine stands (70 vs. 27 μg N 2 O-N m −2 h −1 , Q 10 , 4.5 vs. 2.5).Conclusions Conversion of pine to oak forests in the region will likely decrease soil CO 2 effluxes due to decreasing SOC contents on the long run and will likely enhance soil N 2 O effluxes. Our results present only a seasonal snapshot and need to be confirmed in the field.

Spatial variability of soil N2O and CO2 fluxes in different topographic positions in a tropical montane forest in Kenya

“…Therefore, the secondary vegetation on kiln sites is usually dominated by herbaceous plants for several decades, in agreement with the observed positive correlation between distance to the charcoal kiln and canopy cover. Canopy openness favors the establishment of pioneer and light-demanding species in the forest [Schnitzer and Carson, 2001]; therefore, shifts in tree species composition might cause a difference of soil CO 2 fluxes [Katayama et al, 2009;Díaz-Pinés et al, 2014]. Furthermore, vegetation structure and species composition affect C allocation patterns [Wang et al, 2006] and modify microclimate and substrate availability [Raich and Tufekcioglu, 2000;Butler et al, 2012], all of which may have affected soil N 2 O and CO 2 fluxes as well as their respective spatial patterns.…”

Disentangling the effects of tree species and microclimate on heterotrophic and autotrophic soil respiration in a Mediterranean ecotone forest

“…the nitrogen and lignin content of plant detritus in the litter layer (Gallardo and Merino, 1992;Melillo et al, 1982)-which is closely linked to tree C and its strategy for obtaining nutrients (Cornwell et al, 2008;Fernandez-Alonso et al, 2018). This result contradicts the similarity in the potential decomposability of soil C between forest types that was found during an incubation experiment using mineral topsoil samples from the same study site (Diaz-Pines et al, 2014). Some of the multiple factors affecting the apparent decomposability of soil C in the field and which may lead to differences in the results obtained under controlled conditions include changes in the composition and activity of the soil microbial community throughout the year, the presence of C pools of varying decomposability and physical protection, and the SWB.…”

Soil Carbon Dioxide Fluxes from Three Forest Types of the Tropical Montane Rainforest on Hainan Island, China

“…For instance, according to Nottingham et al (2012), there was no significant difference in soil CO 2 fluxes between the two tropical montane cloud forest systems in the lowland tropical forest and on the garden lawn, but in our study, CO 2 fluxes were significant higher in PF than in SF (P < 0.05). Shifts in tree species composition would likely provoke the difference of soil CO 2 flux (Díaz-Pinés et al 2014;Katayama et al 2009;Osuri et al 2014). From the point of view of ecological system, we considered such difference of soil CO 2 flux was mainly due to the significant differences in environmental conditions including different species composition and biomasses (Chen et al 2010;Li et al 2002), pH, soil temperature, soil moisture, WFPS, and DOC only between SF and PF (Table 2).…”