Linking genetic diversity and species diversity through plant–soil feedback

Abstract

Genetic diversity and species diversity are typically studied in isolation despite theory showing they likely influence one another. Here, we used simplified communities of one or two populations of one or two species to test whether linkages between genetic and species diversity can be mediated by interactions between plants and their soil microbiota, or microbe‐mediated plant–soil feedback (PSF). Interspecific PSF promotes the maintenance of species diversity when plants grow better with heterospecific soil microbes than with conspecific microbes. Similarly, intraspecific PSF promotes the maintenance of genetic diversity when plants grow better with heterogenotypic than with congenotypic microbes. In a two‐phase greenhouse experiment, we conditioned the soil microbial community with pairs of plants that were either two individuals of the same species (lower species diversity) or one individual of each of two species (higher species diversity), and with pairs of plants that were either two individuals from the same population (lower genetic diversity) or one individual from each of two populations (higher genetic diversity). We then tested the effects of these microbial communities on plant growth in a second phase. We found that higher genetic diversity reduced the ability of interspecific PSF to promote plant species diversity, and for one of our two study species, higher species diversity reduced the ability of intraspecific PSF to promote plant genetic diversity. If these patterns occur in more diverse communities, then our results suggest that PSF may dampen the negative effects of diversity loss by promoting diversity at other levels of biological organization.

Linking freshwater ecotoxicity to damage on ecosystem services in life cycle assessment

“…The possibility that genetic and species diversity influence each other has been acknowledged for decades ( Bolin & Lau, 2022 ). A positive relationship between species diversity and genetic diversity has been observed in communities exposed to certain stressors ( Vellend and Geber, 2005 , Blum et al, 2012 ).…”

“…A positive relationship between species diversity and genetic diversity has been observed in communities exposed to certain stressors ( Vellend and Geber, 2005 , Blum et al, 2012 ). This positive relationship can be linked to the genotypes of a focal species having a competitive advantage against different species within the community, and other species having a competitive advantage against the genotype of common focal species ( Bolin and Lau, 2022 , Vellend, 2006 , Vellend, 2008 ). However, high genetic diversity can also negatively influence species diversity if it reduces available niche spaces for heterospecific species ( Bolin and Lau, 2022 , Vellend and Geber, 2005 ).…”

“…This positive relationship can be linked to the genotypes of a focal species having a competitive advantage against different species within the community, and other species having a competitive advantage against the genotype of common focal species ( Bolin and Lau, 2022 , Vellend, 2006 , Vellend, 2008 ). However, high genetic diversity can also negatively influence species diversity if it reduces available niche spaces for heterospecific species ( Bolin and Lau, 2022 , Vellend and Geber, 2005 ). In some cases, genetic diversity may change without a change in species abundance ( Hoban et al, 2022 ), while changes in species diversity may alter the positive species interactions resulting in changes in the ecosystem processes ( Cardinale et al, 2002 ).…”

Genetic relatedness can alter the strength of plant–soil interactions

“…Individual plant genotypes may also influence the community composition of soil microbes differently due to intraspecific variation in their microbial associations and plant traits (Paul and Clark, 1996; Bukowski and Petermann, 2014; Liu et al, 2015; Semchenko et al, 2017). For this reason, changes in plant traits, even within a species, can affect soil microbial communities and alter plant–microbe interactions (Schweitzer et al, 2008), which may affect plant population diversity (Liu et al, 2015; Eck et al, 2019; Bolin and Lau, 2022).…”

“…Negative intraspecific plant–microbe interactions may be weaker than interspecific interactions (Bukowski et al, 2018), allowing population persistence in communities. However, intraspecific plant–microbe interactions may vary dramatically in magnitude and direction (Bukowski and Petermann, 2014; Foster et al, 2022), can be responsive to local stressors (Gehring et al, 2017), and help to maintain population diversity (Liu et al, 2015; Bolin and Lau, 2022). The direction and magnitude of these microbial effects may ultimately determine genotype‐specific performance within populations.…”