Pathogen-Induced Tree Mortality Modifies Key Components of the C and N Cycles with No Changes on Microbial Functional Diversity

Ávila, J. M.; Gallardo, Antonio; Ibáñez, Beatriz; Gómez‐Aparicio, Lorena

doi:10.1007/s10021-020-00528-1

Cited by 9 publications

(5 citation statements)

References 72 publications

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“…Independent from direct drought effects, tree mortality can influence soil properties via microclimatic effects of available or unavailable litter, or through changes in the availability of resources (e.g., recalcitrant deadwood or root exudates) (Gottschall et al, 2019). In addition, soil respiration can be reduced due to changes in the C and N cycles (Ávila et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Tree community composition stabilizes ecosystem functions in response to drought

et al. 2023

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In summer 2018, Central Europe was hit by an extreme drought event that widely impacted ecosystems and markedly increased tree mortality in forest ecosystems across the continent. As climate models predict an increase in frequency and severity of such events, there is an urgent need to adapt forests in order to maintain the diverse benefits they provide. Soil processes play an essential role in this context and are key for a plethora of terrestrial ecosystem functions, but they are strongly dependent on water availability. Here, we investigated how tree species richness (TSR), composition, and identity in a 13‐year‐old temperate tree diversity experiment influenced selected ecosystem functions (as important representatives of different ecosystem processes) during the 2018 summer drought. We focused on the stability of soil microbial biomass and standard litter decomposition, as well as tree species‐specific mortality rates. Contrary to our expectations, TSR did not generally increase the resistance of soil functions or decrease tree mortality rates. However, the resistance of these functions was determined by tree species identity and community composition. For the resistance of both soil functions (microbial biomass and litter decomposition), we found that TSR effects depended on the presence of certain tree species. Moreover, we found that the performance of a specific tree species in monoculture, Norway spruce, was a poor predictor of its response to drought in tree species mixtures. Taken together, the results of our study demonstrate that the species composition of tree stands determines tree mortality and the resistance of soil functions under drought. This indicates that enhancing multiple ecosystem functions under environmental disturbance requires maintaining diverse forests.

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Section: Introductionmentioning

confidence: 99%

Tree community composition stabilizes ecosystem functions in response to drought

et al. 2023

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“…The latter is of particular importance in many forests worldwide, as they may suffer from widespread tree die-off events due to climate change, pest outbreaks and wildfires, drastically affecting their productivity and habitat quality (Allen et al, 2010;Hammond et al, 2022). Tree die-off can directly affect the composition of the plant community underneath and the availability of soil nutrients, with potential effects on soil biota (Ávila et al, 2021;Gómez-Aparicio et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

“…The latter is of particular importance in many forests worldwide, as they may suffer from widespread tree die‐off events due to climate change, pest outbreaks and wildfires, drastically affecting their productivity and habitat quality (Allen et al, 2010; Hammond et al, 2022). Tree die‐off can directly affect the composition of the plant community underneath and the availability of soil nutrients, with potential effects on soil biota (Ávila et al, 2021; Gómez‐Aparicio et al, 2022). Fourth, habitat fragmentation increases the distance between habitat patches and diminishes connectivity between populations (Staddon et al, 2010; Tewksbury et al, 2002), which can increase population sensitivity to environmental change.…”

Section: Introductionmentioning

confidence: 99%

On the relative importance of resource availability and habitat connectivity as drivers of soil biodiversity in Mediterranean ecosystems

et al. 2023

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Soil biota influences nutrient cycling and climate regulation and represents an important fraction of global biodiversity, yet we know very little about how this soil biota responds to habitat fragmentation and degradation of habitat quality. We studied the response of different soil trophic groups (microbes and soil fauna), and their trophic structure, to changes in their habitat derived from forest long‐term management and extensive tree die‐off in a Mediterranean ecosystem. Specifically, we evaluated changes in (i) habitat size, (ii) habitat resource availability and heterogeneity and (iii) habitat connectivity. To do this, we sampled the soil biota of 43 holm oak trees (and five open interspaces) differing in size, quality, heterogeneity, connectivity and the effect of die‐off (healthy or affected). We sorted soil biota by trophic group and related their richness to habitat characteristics. Seven of the 12 trophic groups evaluated increased their species richness with soil organic carbon content, which was the most frequently selected driver of soil biota (both microbial and faunal richness). Habitat connectivity positively affected the richness of larger organisms (fauna) and plant attributes (richness, productivity and specific leaf area) also showed significant but contrasting effects depending on the group evaluated. Due to the idiosyncratic responses of different groups, the entire trophic structure (microbes and fauna) was affected by a more complex set of factors than most trophic groups in isolation, including interactions between habitat size and resource availability or connectivity. A major factor influencing habitat resource availability was the die‐off of the dominant tree species (drastically altering tree productivity). We found weaker and more negative relationships between trophic groups under trees suffering from die‐off than beneath healthy trees, particularly between microbial rather than faunal groups. Synthesis. We provide a comprehensive assessment of the response of key members of the soil food web to habitat fragmentation and tree die‐off (landscape‐level plant–soil interactions), illustrating the major role of soil carbon, habitat connectivity and tree die‐off in driving soil biodiversity and trophic structure.

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“…biogeochemical cycles, defoliation, dehesa, Quercus ilex, soil functional genes, soil microbial communities of soil nutrients (Avila et al, 2021;García-Angulo, 2020). Hence, although some studies have described the influence of the canopy cover on soil microclimatic conditions, soil microbiome (García-Angulo et al, 2020) and carbon and nutrient cycling (Ibañez et al, 2021;Scarlett et al, 2020) few studies have assessed the influence of the crown health on biogeochemical soil functional genes, soil chemistry and vice versa.…”

Section: Introductionmentioning

confidence: 99%

“…For instance, changes in the abundance of microbial nitrifiers have been related to changes in the canopy cover (Ibañez et al., 2021; Shvaleva et al., 2015) and tree girdling (Rasche et al., 2011). Soil microbial community changes driven by tree decline may result in a net loss of soil nutrients (Avila et al., 2021; García‐Angulo, 2020). Hence, although some studies have described the influence of the canopy cover on soil microclimatic conditions, soil microbiome (García‐Angulo et al., 2020) and carbon and nutrient cycling (Ibañez et al., 2021; Scarlett et al., 2020) few studies have assessed the influence of the crown health on biogeochemical soil functional genes, soil chemistry and vice versa.…”

Section: Introductionmentioning

confidence: 99%

Alteration of the tree–soil microbial system triggers a feedback loop that boosts holm oak decline

Encinas‐Valero,

Esteban,

Hereş

et al. 2023

Functional Ecology

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In anthropic savanna ecosystems from the Iberian Peninsula (i.e. dehesa), complex interactions between climate change, pathogen outbreaks and human land use are presumed to be behind the observed increase in holm oak decline. These environmental disturbances alter the plant–soil microbial continuum, which can destabilize the ecological balance that sustains tree health. Yet, little is known about the underlying mechanisms, particularly the directions and nature of the causal–effect relationships between plants and soil microbial communities. In this study, we aimed to determine the role of plant–soil feedbacks in climate‐induced holm oak decline in the Iberian dehesa. Using a gradient of holm oak health, we reconstructed key soil biogeochemical cycles mediated by soil microbial communities. We used quantitative microbial element cycling (QMEC), a functional gene‐array‐based high‐throughput technique to assess microbial functional potential in carbon, nitrogen, phosphorus and sulphur cycling. The onset of holm oak decline was positively related to the increase in relative abundance of soil microbial functional genes associated with denitrification and phosphorus mineralization (i.e. nirS3, ppx and pqqC; parameter value: 0.21, 0.23 and 0.4; p < 0.05). Structural equation model (χ2 = 32.26, p‐value = 0.73), moreover, showed a negative association between these functional genes and soil nutrient availability (i.e. mainly mineral nitrogen and phosphate). Particularly, the holm oak crown health was mainly determined by the abundance of phosphate (parameter value = 0.27; p‐value < 0.05) and organic phosphorus (parameter value = −0.37; p‐value < 0.5). Hence, we propose a potential tree–soil feedback loop, in which the decline of holm oak promotes changes in the soil environment that triggers changes in key microbial‐mediated metabolic pathways related to the net loss of soil nitrogen and phosphorus mineral forms. The shortage of essential nutrients, in turn, affects the ability of the trees to withstand the environmental stressors to which they are exposed. Read the free Plain Language Summary for this article on the Journal blog.

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Pathogen-Induced Tree Mortality Modifies Key Components of the C and N Cycles with No Changes on Microbial Functional Diversity

Cited by 9 publications

References 72 publications

Tree community composition stabilizes ecosystem functions in response to drought

Tree community composition stabilizes ecosystem functions in response to drought

On the relative importance of resource availability and habitat connectivity as drivers of soil biodiversity in Mediterranean ecosystems

Alteration of the tree–soil microbial system triggers a feedback loop that boosts holm oak decline

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