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Eviner, Valerie T.; Chapin, F. Stuart

doi:10.1023/a:1020657107687

Cited by 45 publications

(9 citation statements)

References 56 publications

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“…The significantly positive correlation of WSA with total N values (though the direction of causality remains hidden) might indicate a predominant role of microbial activity in this system (Tripathi et al, 2008), whereas the marginally significant positive relation with total C points toward an involvement of other soil organic matter and C pools (Feller and Beare, 1997;Piccolo and Mbagwu, 1999;Six et al, 2000b). Macrofauna represents another potential candidate, e.g., springtails (Siddiky et al, 2012), but also direct and indirect interactions of plant and microbial communities might play a role (Gransee and Wittenmayer, 2000;Eviner and Chapin, 2002;Piotrowski et al, 2004). Finally, even though we did not detect effects at the level of abundances of biotic factors, it is possible that community composition, and with this community-level trait shifts, were responsible for the observed effects.…”

Section: Discussionmentioning

confidence: 62%

“…Differences in the strength of effect sizes among sampling times might be associated with a strong initial response attenuating in the long-term (Comins and McMurtrie, 1993;Norby et al, 2007), (Jastrow et al, 1998;Six et al, 2004;Barto et al, 2010). Beside the large evidence for the involvement of hyphae and roots in aggregate formation (Rillig and Mummey, 2006;Hallett et al, 2009), other studies previously likewise reported a lack of correlation among these factors (Degens et al, 1994;Eviner and Chapin, 2002;Piotrowski et al, 2004). Additionally, in tropical soils knowledge on soil aggregation processes is scarce, mainly based on agricultural systems (Feller and Beare, 1997;Cardoso and Kuyper, 2006).…”

Section: Discussionmentioning

confidence: 99%

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Increases in Soil Aggregation Following Phosphorus Additions in a Tropical Premontane Forest are Not Driven by Root and Arbuscular Mycorrhizal Fungal Abundances

et al. 2016

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Tropical ecosystems have an important role in global change scenarios, in part because they serve as a large terrestrial carbon pool. Carbon protection is mediated by soil aggregation processes, whereby biotic and abiotic factors influence the formation and stability of aggregates. Nutrient additions may affect soil structure indirectly by simultaneous shifts in biotic factors, mainly roots, and fungal hyphae, but also via impacts on abiotic soil properties. Here, we tested the hypothesis that soil aggregation will be affected by nutrient additions primarily via changes in arbuscular mycorrhizal fungal (AMF) hyphae and root length in a pristine tropical forest system. Therefore, the percentage of water-stable macroaggregates (> 250 µm) (WSA) and the soil mean weight diameter (MWD) was analyzed, as well as nutrient contents, pH, root length, and AMF abundance. Phosphorus additions significantly increased the amount of WSA, which was consistent across two different sampling times. Despite a positive effect of phosphorus additions on extra-radical AMF biomass, no relationship between WSA and extra-radical AMF nor roots was revealed by regression analyses, contrary to the proposed hypothesis. These findings emphasize the importance of analyzing soil structure in understudied tropical systems, since it might be affected by increasing nutrient deposition expected in the future.

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Section: Discussionmentioning

confidence: 62%

Section: Discussionmentioning

confidence: 99%

Increases in Soil Aggregation Following Phosphorus Additions in a Tropical Premontane Forest are Not Driven by Root and Arbuscular Mycorrhizal Fungal Abundances

et al. 2016

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“…Higher N availability—both naturally-occurring and resulting from our nutrient addition (Table S4, Figure 5)—was associated with larger estimated genome size, suggesting that it may have favored the retention of additional genes by easing constraints on replication (Giovannoni et al, 2014). In addition to nutrient levels, fluctuations in oxygen supply and/or in the quantity and types of substrates delivered to individual microbes—which tend to favor generalists with larger genomes (Vieira-Silva and Rocha, 2010; Guieysse and Wuertz, 2012; Barberán et al, 2014; Fierer et al, 2014; Giovannoni et al, 2014; Krause et al, 2014)—may have been greater in resource-rich plots due to factors, such as greater root biomass and soil aggregation (Huenneke et al, 1990; Six et al, 2004; Dukes et al, 2005; Riggs et al, 2015; Bach and Hofmockel, 2016; but see Eviner and Chapin, 2002). Conversely, since the lush serpentine and non-serpentine soils have similar nutrient levels and plant biomass (Eskelinen and Harrison, 2015c), the difference in estimated genome size between those soils was likely driven by their differences in other soil chemical properties, such as pH or Ca:Mg (both strongly correlated with estimated genome size).…”

Section: Discussionmentioning

confidence: 99%

Nutrient and Rainfall Additions Shift Phylogenetically Estimated Traits of Soil Microbial Communities

Gravuer

Eskelinen

2017

Front. Microbiol.

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Microbial traits related to ecological responses and functions could provide a common currency facilitating synthesis and prediction; however, such traits are difficult to measure directly for all taxa in environmental samples. Past efforts to estimate trait values based on phylogenetic relationships have not always distinguished between traits with high and low phylogenetic conservatism, limiting reliability, especially in poorly known environments, such as soil. Using updated reference trees and phylogenetic relationships, we estimated two phylogenetically conserved traits hypothesized to be ecologically important from DNA sequences of the 16S rRNA gene from soil bacterial and archaeal communities. We sampled these communities from an environmental change experiment in California grassland applying factorial addition of late-season precipitation and soil nutrients to multiple soil types for 3 years prior to sampling. Estimated traits were rRNA gene copy number, which contributes to how rapidly a microbe can respond to an increase in resources and may be related to its maximum growth rate, and genome size, which suggests the breadth of environmental and substrate conditions in which a microbe can thrive. Nutrient addition increased community-weighted mean estimated rRNA gene copy number and marginally increased estimated genome size, whereas precipitation addition decreased these community means for both estimated traits. The effects of both treatments on both traits were associated with soil properties, such as ammonium, available phosphorus, and pH. Estimated trait responses within several phyla were opposite to the community mean response, indicating that microbial responses, although largely consistent among soil types, were not uniform across the tree of life. Our results show that phylogenetic estimation of microbial traits can provide insight into how microbial ecological strategies interact with environmental changes. The method could easily be applied to any of the thousands of existing 16S rRNA sequence data sets and offers potential to improve our understanding of how microbial communities mediate ecosystem function responses to global changes.

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“…Several studies have shown that fertilization and grazing can affect grassland ecosystem composition and stability [6,11,48]. Yang et al [7] found that increasing the level of N increased the community stability on the Tibetan Plateau over 10 years.…”

Section: Effects Of Fertilization and Grazing On Community Stabilitymentioning

confidence: 99%

Long-Term Enclosure Can Benefit Grassland Community Stability on the Loess Plateau of China

et al. 2020

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Fertilization and grazing are two common anthropogenic disturbances that can lead to unprecedented changes in biodiversity and ecological stability of grassland ecosystems. A few studies, however, have explored the effects of fertilization and grazing on community stability and the underlying mechanisms. We conducted a six-year field experiment to assess the influence of nitrogen (N) fertilization and grazing on the community stability in a long-term enclosure and grazing grassland ecosystems on the Loess Plateau. A structural equation modeling method was used to evaluate how fertilization and grazing altered community stability. Our results indicated that the community stability decreased in the enclosure and grazing grassland ecosystems with the addition of N. The community stability began to decline significantly at 4.68 and 9.36 N g m−2 year−1 for the grazing and enclosure grassland ecosystems, respectively. We also found that the addition of N reduced the community stability through decreasing species richness, but a long-term enclosure can alleviate its negative effect. Overall, species diversity can be a useful predictor of the stability of ecosystems confronted with disturbances. Also, our results showed that long-term enclosure was an effective grassland management practice to ensure community stability on the Loess Plateau of China.

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Untitled

Cited by 45 publications

References 56 publications

Increases in Soil Aggregation Following Phosphorus Additions in a Tropical Premontane Forest are Not Driven by Root and Arbuscular Mycorrhizal Fungal Abundances

Increases in Soil Aggregation Following Phosphorus Additions in a Tropical Premontane Forest are Not Driven by Root and Arbuscular Mycorrhizal Fungal Abundances

Nutrient and Rainfall Additions Shift Phylogenetically Estimated Traits of Soil Microbial Communities

Long-Term Enclosure Can Benefit Grassland Community Stability on the Loess Plateau of China

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