Arbuscular mycorrhizal density and propagation are driven by vegetation cover and plant phylogenetic diversity

Abstract

Background and aims: Ecological restoration increasingly use mycorrhizal symbiosis to boost plant growth and stress resilience, with research focusing on optimizing inoculum propagation using trap plants. Arbuscular mycorrhizal fungi (AMF) are obligate symbionts with a degree of specificity in their plant associations, potentially leading to co-adaptation processes. Consequently, properties of plant communities such as cover, diversity, and the presence of native species can influence AMF abundance in natural settings and controlled environments. Our study hypothesises that 1) AMF spore density increases in areas with high plant diversity and permanent vegetation cover; and 2) native AMF propagation thrives best in native and phylogenetically diverse plants consortia. Methods: In an arid and heterogeneous Mediterranean environment, we sampled seven representative microenvironments, conducted a floristic inventory and quantified AMF spores in soil. The AMF propagation capacity was assessed through a pot experiment under controlled conditions using different trap plant consortia (native/non-native, single/multi-family). Results: In natural sites, spore density varied significantly by microenvironment, from 1 (badlands) to 10 (vegetation islands) spores/g of soil. Vegetation cover, rather than plant diversity or richness, increased AMF spore density. Under controlled conditions, spore propagation was 1.28 and 1.19 times higher in native and phylogenetically diverse plant consortia respectively, compared to allochthonous and less diverse ones. Conclusions: Our results support the importance of vegetation cover in conserving AMF abundance in arid environments. The research also highlights the efficiency of using native and diverse plant consortia to propagate AMF inoculum, contributing to optimize non-conventional ecological restoration techniques using nature-based solutions.