Biocrusts buffer against the accumulation of soil metallic nutrients induced by warming and rainfall reduction

Abstract

The availability of metallic nutrients in dryland soils, many of which are essential for the metabolism of soil organisms and vascular plants, may be altered due to climate changedriven increases in aridity. Biocrusts, soil surface communities dominated by lichens, bryophytes and cyanobacteria, are ecosystem engineers known to exert critical functions in dryland ecosystems. However, their role in regulating metallic nutrient availability under climate change is uncertain. Here, we evaluated whether well-developed biocrusts modulate metallic nutrient availability in response to 7 years of experimental warming and rainfall reduction in a Mediterranean dryland located in southeastern Spain. We found increases in the availability of K, Mg, Zn and Na under warming and rainfall exclusion. However, the presence of a well-developed biocrust cover buffered these effects, most likely because its constituents can uptake significant quantities of available metallic nutrients. Our findings suggest that biocrusts, a biotic community prevalent in drylands, exert an important role in preserving and protecting metallic nutrients in dryland soils from leaching and erosion. Therefore, we highlight the need to protect them to mitigate undesired effects of soil degradation driven by climate change in this globally expanding biome.

Studying the Microbiome of Cyanobacterial Biocrusts From Drylands and Its Functional Influence on Biogeochemical Cycles

“…It would confer to Pseudomonas representatives not only of certain microbial specialisation within the cyanobacterial biocrust microbiome but also advantages on competitive dynamics in soil as drivers of ecological and evolutionary dynamics as well as an essential role in cooperation interactions in natural communities [212] as pyoverdine was already reported as a public good that can be shared among cells, and be exploited by siderophore non-producers being cheats [213]. The presence of an potential active microbial group in Fe uptake would therefore support what was previously suggested by other studies regarding the positive correlation between the presence of biocrusts in arid ecosystems and improvements in the bioavailability of soil metallic micronutrients such as Fe [214] as well as the potential role of biocrusts as modulators of the responses of soil metallic nutrients to altered temperature and rainfall regimes caused by climate change and, consequently, as preserving and protecting agents of metallic nutrients in dryland soils [215].…”

Soil element coupling is driven by ecological context and atomic mass

“…Thus, reductions in plant cover due to land use intensification and aridity increases may have important consequences associated with the biogeochemical decoupling of elements, with still unpredictable consequences for ecosystem functioning. These unpredictable consequences may include greater leaching of nutrients from ecosystems, thus further reinforcing their degradation (Moreno‐Jiménez et al ., 2020), and greater fluxes of greenhouse gases, all of them associated with the disconnection of the multiple natural relationships among soil elements (Rumpel and Chabbi, 2018).…”

Moss crusts mitigate the negative impacts of shrub mortality on the nutrient multifunctionality of desert soils

“…mental degradation, making them particularly critical in dry regions (Delgado-Baquerizo et al, 2016;Moreno-Jiménez et al, 2020;Su et al, 2021). Additionally, microenvironmental changes resulting from different microhabitats also impact the soil multifunctionality of BSCs (Y.…”