Insight into climate change from the carbon exchange of biocrusts utilizing non-rainfall water

Abstract

Biocrusts are model ecosystems of global change studies. However, light and non-rainfall water (NRW) were previously few considered. Different biocrust types further aggravated the inconsistence. So carbon-exchange of biocrusts (cyanobacteria crusts-AC1/AC2; cyanolichen crust-LC1; chlorolichen crust-LC2; moss crust-MC) utilizing NRW at various temperatures and light-intensities were determined under simulated and insitu mesocosm experiments. Carbon input of all biocrusts were negatively correlated with experimental temperature under all light-intensity with saturated water and stronger light with equivalent NRW, but positively correlated with temperature under weak light with equivalent NRW. LCPs and R/Pg of AC1 were lowest, followed in turn by AC2, LC2 and MC. Thus AC1 had most opportunities to use NRW, and 2.5 °C warming did cause significant changes of carbon exchange. Structural equation models further revealed that air-temperature was most important for carbon-exchange of ACs, but equally important as NRW for LC2 and MC; positive influence of warming on carbon-input in ACs was much stronger than the latter. Therefore, temperature effect on biocrust carbon-input depends on both moisture and light. Meanwhile, the role of NRW, transitional states between ACs, and obvious carbon-fixation differences between lichen crusts should be fully considered in the future study of biocrusts responding to climate change.

Warming reduces the cover, richness and evenness of lichen‐dominated biocrusts but promotes moss growth: insights from an 8 yr experiment

“…In addition, we had already observed that reductions in soil surface moisture negatively affect the C fixation rate of biocrust‐dominated areas during the first years of our experiment (Maestre et al ., ; Ladrón de Guevara et al ., ). We cannot rule out a possible direct effect of warming on lichen physiology because the increase of dark respiration with temperature is well documented in these organisms (e.g., Lange et al ., ; Lange & Green, ; Ouyang & Hu, ). Nevertheless, we do not think it was the main physiological impact as mosses had a positive response to warming, and increases in their respiration with warming can be similar to or even greater than that observed in lichens (Weber et al ., ; Ouyang & Hu, ).…”

Annual net primary productivity of a cyanobacteria-dominated biological soil crust in the Gulf Savannah, Queensland, Australia

“…S3, 4-5 January). This is likely explained by dew formation, a non-rainfall water source found playing an important role in biocrusts Ouyang and Hu, 2017) and also observed at Boodjamulla during the wet season. There are a number of studies that found dew formation was important in biocrust systems, for example the study of Jacobs et al (2000), where in a desert environment in Israel daily amounts of dew ranged between 0.1 and 0.3 mm night −1 .…”

Contrasting mechanisms underlie short‐ and longer‐term soil respiration responses to experimental warming in a dryland ecosystem

“…Biocrust constituents are severely affected by warming; the physiological performance of biocrust-forming lichens and mosses have been found to decrease with warming in experiments conducted in Spain, USA, China and South Africa (Grote, Belnap, Housman, & Sparks, 2010;Maestre, Delgado-Baquerizo, Jeffries, Eldridge, & Ochoa, 2015;Maestre et al, 2013;Maphangwa, Musil, Raitt, & Zedda, 2012;Ouyang & Hu, 2017). These responses have been linked to warming-induced reductions in soil moisture and dew events (Ladrón de Guevara et al, 2014;Ouyang & Hu, 2017).…”