Drought neutralises plant–soil feedback of two mesic grassland forbs

Abstract

Plant–soil feedbacks (PSFs) describe the effect of a plant species on soil properties, which affect the performance of future generations. Here we test the hypothesis that drought alters PSFs by reducing plant–microbe associations and nutrient uptake. We chose two grassland forb species, previously shown to respond differently to soil conditioning and drought, to test our hypothesis. We conditioned unsterilised grassland soil with one generation of each species, and left a third soil unconditioned. We grew a second generation consisting of each combination of plant species, soil, and drought in a full factorial design, and measured soil microbial community and nutrient availability. Scabiosa columbaria displayed negative PSF (smaller plants) under non-droughted conditions, but neutral under drought, suggesting that drought disrupts plant–soil interactions and can advantage the plant. Photosynthetic efficiency of S. columbaria was reduced under drought, but recovered on rewetting regardless of soil conditioning, indicating that PSFs do not impede resilience of this species. Sanguisorba minor showed positive PSFs (larger plants), probably due to an increase in soil N in conspecific soil, but neutral PSF under drought. PSF neutralisation appeared to occur through drought-induced change in the soil microbial community for this species. When S. minor was planted in conspecific soil, photosynthetic efficiency declined to almost zero, with no recovery following rewetting. We attributed this to increased demand for water through higher demand for nutrients with positive PSF. Here we show that drought neutralises PSFs of two grassland forbs, which could have implications for plant communities under climate change.Electronic supplementary materialThe online version of this article (10.1007/s00442-018-4082-x) contains supplementary material, which is available to authorized users.

Soil multifunctionality and drought resistance are determined by plant structural traits in restoring grassland

“…Recent studies on chalk species showed that positive plant–soil feedback was associated with poor resistance to drought because the exploitative strategy of these plants meant severe problems and lack of structural integrity, which became problematic when drought occurred (Fry et al. ).…”

“…However, it is possible that the taller plants are poorly adapted to the hardships chalk imposes, particularly because they are likely to have higher requirements for nutrients and water, and that this may cause problems for acquisitive species, particularly early on in succession before plant-microbial relationships are established. Recent studies on chalk species showed that positive plant-soil feedback was associated with poor resistance to drought because the exploitative strategy of these plants meant severe problems and lack of structural integrity, which became problematic when drought occurred (Fry et al 2018).…”

Why are plant–soil feedbacks so unpredictable, and what to do about it?

“…PSFs detected in the glasshouse often do not manifest under natural conditions (Heinze et al, ; Kulmatiski & Kardol, ; Kulmatiski et al, ). This is because glasshouse studies typically do not account for external drivers of PSFs (but, see Kaisermann et al, ; Fry et al, ). Therefore, taking above‐ and belowground drivers that affect PSFs in the glasshouse and then setting them to interact with other drivers in the field is the only way to fully understand their importance in driving PSFs in natural ecosystems; (4) Conduct PSF experiments across large‐scale nutrient, pH, climate and disturbance gradients by setting up global networks across ecosystems that investigate how above‐ and belowground drivers affect PSFs.…”

Effects of shade stress on morphophysiology and rhizosphere soil bacterial communities of two contrasting shade-tolerant turfgrasses

“…Given that soil microorganism could directly and indirectly affect most plant functional traits [14]. We analyzed the role of soil-plant feedback to plant shade tolerance to further clarify the different shade tolerance mechanisms of OJ and LP.…”

“…The changed microclimates caused by shade stress influence soil microbial structure and diversity [12]. Numerous studies suggest that plants' responses to abiotic stresses may be mediated by soil microorganisms [13,14]. Dahl et al [15] pointed out that warming and shading changed fungal community composition in Arctic soils.…”