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Abstract Plants affect associated biotic and abiotic edaphic factors, with reciprocal feedbacks from soil characteristics affecting plants. These two‐way interactions between plants and soils are collectively known as plant–soil feedbacks (PSFs). The role of phylogenetic relatedness and evolutionary histories have recently emerged as a potential driver of PSFs, although the strength and direction of feedbacks among sympatric congeners are not well‐understood. We examined plant–soil feedback responses ofAsclepias syriaca, a common clonal milkweed species, with several sympatric congeners across a gradient of increasing phylogenetic distances (A. tuberosa,A. viridis,A. sullivantii, andA. verticillata, respectively). Plant–soil feedbacks were measured through productivity and colonization by arbuscular mycorrhizal (AM) fungi.Asclepias syriacaproduced less biomass in soils conditioned by the most phylogenetically distant species (A. verticillata), relative to conspecific‐conditioned soils. Similarly, arbuscular mycorrhizal (AM) fungal colonization ofA. syriacaroots was reduced when grown in soils conditioned byA. verticillata, compared with colonization in plants grown in soil conditioned by any of the other threeAsclepiasspecies, indicating mycorrhizal associations are a potential mechanism of observed positive PSFs. This display of differences between the most phylogenetically distant, but not close or intermediate, paring(s) suggests a potential phylogenetic threshold, although other exogenous factors cannot be ruled out. Overall, these results highlight the potential role of phylogenetic distance in influencing positive PSFs through mutualists. The role of phylogenetic relatedness and evolutionary histories have recently emerged as a potential driver of plant–soil feedbacks (PSFs), although the strength and direction of feedbacks among sympatric congeners are not well‐understood. Congeneric, sympatric milkweeds typically generated positive PSFs in terms of productivity and AM fungal colonization, suggesting the low likelihood of coexistence among tested pairs, with a strength of feedback increasing as the phylogenetic distance increases.
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Diversity‐dependent plant–soil feedbacks underlie long‐term plant diversity effects on primary productivity
Abstract Although diversity‐dependent plant–soil feedbacks (PSFs) may contribute significantly to plant diversity effects on ecosystem functioning, the influences of underlying abiotic and biotic mechanistic pathways have been little explored to date. Here, we assessed such pathways with a PSF experiment using soil conditioned for ≥12 yr from two grassland biodiversity experiments. Model plant communities differing in plant species and functional group richness (current plant diversity treatment) were grown in soils conditioned by plant communities with either low‐ or high‐diversity (soil history treatment). Our results indicate that plant diversity can modify plant productivity through both diversity‐mediated plant–plant and plant–soil interactions, with the main driver (current plant diversity or soil history) differing with experimental context. Structural equation modeling suggests that the underlying mechanisms of PSFs were explained to a significant extent by both abiotic and biotic pathways (specifically, soil nitrogen availability and soil nematode richness). Thus, effects of plant diversity loss on plant productivity may persist or even increase over time because of biotic and abiotic soil legacy effects.
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- PAR ID:
- 10461276
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Ecosphere
- Volume:
- 10
- Issue:
- 4
- ISSN:
- 2150-8925
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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