Inhibitory effects of soil biota are ameliorated by high plant diversity

Abstract

The idea that plant communities with high species diversity are more stable, productive, and resistant to invasion at small spatial scales has become an important ecological paradigm. Recently, the role of soil biota has emerged as a major driver of this relationship between plant species diversity and ecosystem function. In greenhouse experiments, we found that soil collected from experimentally constructed species-rich plant assemblages (that originally contained between 10 and 16 species) promoted the growth of 4 native target plant species more than soil from species-poor communities (that originally contained between 2 and 5 species). Sterilization of soils from species-poor communities improved the growth of these target species more than sterilization of soils from species-rich plant communities, indicative that inhibitory soil biota had greater negative impacts on plant growth in low versus high diversity soils. These results suggest that strong soil biota effects in soils do not simply accrue in experimental monocultures, but can occur in low diversity assemblages that are more realistic of what occurs in nature. Our findings suggest a mechanistic explanation for the diversity-productivity relationship, and further support the importance of inhibitory soil biota as significant contributors to spatial and temporal patterns of abundance in natural plant communities through negative plant-soil feedback.

Diversity‐dependent plant–soil feedbacks underlie long‐term plant diversity effects on primary productivity

“…The absence of positive PSFs of high‐diversity plant communities in other studies (Yang et al. ) may therefore sometimes be the result of assessing PSFs at the species level and not at the community level, such as done in the present study. High‐diversity communities may positively affect plant productivity by diversifying the abiotic and biotic biotope characteristics that facilitate plant growth (Hooper et al.…”

“…Positive PSFs on plant productivity emerged due to the influence of plant diversity of both the community conditioning the soil and the community growing in the conditioned soil. The absence of positive PSFs of high-diversity plant communities in other studies (Yang et al 2015) may therefore sometimes be the result of assessing PSFs at the species level and not at the community level, such as done in the present study. High-diversity communities may positively affect plant productivity by diversifying the abiotic and biotic biotope characteristics that facilitate plant growth (Hooper et al 2000, Eisenhauer et al 2012b).…”

“…Thus, soil conditioned by low‐diversity plant communities may have a negative effect on plant productivity in the long run (Yang et al. ), and thereby co‐determine the biodiversity–productivity relationship when used as a baseline to calculate diversity effects on ecosystem functioning.…”

“…Low-diversity plant communities may also use soil nutrients in an imbalanced way and thus deplete soil nutrient stocks (Schenk 2006) and/or be less efficient in nutrient retention (Leimer et al 2016). Thus, soil conditioned by low-diversity plant communities may have a negative effect on plant productivity in the long run (Yang et al 2015), and thereby co-determine the biodiversity-productivity relationship when used as a baseline to calculate diversity effects on ecosystem functioning.…”

Linking ecology and plant pathology to unravel the importance of soil-borne fungal pathogens in species-rich grasslands

“…insects and nematodes (Bagchi et al 2014;de Deyn et al 2003;Knops et al 1999)) and pathogens (viruses, bacteria, and fungi (Maron et al 2011;Moore and Borer 2012;Packer and Clay 2000;Petermann et al 2008;Rottstock et al 2014)), has proven difficult, especially belowground (Alexander 2010). There is interest in the role of fungal pathogens to explain the maintenance of biodiversity (Bever et al 2015;Gilbert 2002), but in this review we focus on the other way around: the role of plant species diversity to reduce the build-up of soilborne fungal disease (Latz et al 2012;Mommer et al 2018;Yang et al 2015).…”