Urbanization Alters Soil Microbial Functioning in the Sonoran Desert

Hall, Sharon J.; Ahmed, Bony; Ortiz, Pierina; Davies, Rachel; Sponseller, Ryan A.; Grimm, Nancy B.

doi:10.1007/s10021-009-9249-1

Cited by 49 publications

(45 citation statements)

References 74 publications

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“…Soil nutrient pools that reflect agricultural land use history can persist for decades (12). The elevations and variations in woodland soil nutrient levels are likely to be related to longterm land management practices, and the abundance of functional nitrogen genes could also be related to long-term land management practices.…”

Section: Discussionmentioning

confidence: 99%

“…In soils, the rates of organic matter decomposition, nitrogen fixation, nitrification, and denitrification are largely mediated by the microbiota. Many microbially driven processes in soils can be impacted by land management practices and changes in the plant community (12,20,50), such that alterations in microbial community composition or in the abundance or activity of specific groups can alter nitrogen availability to plants or nitrogen loss from the ecosystem (60).…”

mentioning

confidence: 99%

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The Abundance of Microbial Functional Genes in Grassy Woodlands Is Influenced More by Soil Nutrient Enrichment than by Recent Weed Invasion or Livestock Exclusion

Lindsay

Colloff

Gibb

et al. 2010

Appl Environ Microbiol

104

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A diverse soil microbial community is involved in nitrogen cycling, and these microbes can be affected by land management practices and weed invasion. We surveyed 20 woodlands with a history of livestock grazing, with livestock recently excluded from 10 sites. We investigated whether soil nutrients were lower when grazing was excluded and higher when exotic grasses dominated the understory. Second, using quantitative real-time PCR, we investigated whether microbial nitrogen functional gene (NFG) abundance was altered with soil nutrient enrichment, livestock exclusion, and exotic grass invasion. The target genes were chiA (decomposition-ammonification), nifH (nitrogen fixation), nirK and narG (denitrification), and bacterial amoA (nitrification). Woodland soils were enriched in phosphorus and nitrogen compared to reference condition sites, but soil nutrients were not lower following livestock exclusion. Total nitrogen and nifH were negatively correlated in grazed woodlands, suggesting that aboveground herbivory reduces the capacity for belowground nitrogen fixation. Woodlands dominated by exotic grasses had higher levels of nitrate, narG, and nirK than those dominated by native grasses. We hypothesize that the increase in potential for denitrification was due to increases in soil nitrate, rather than changes in plant composition. Overall, soil physicochemistry explained more variation in NFG abundance than livestock presence or plant invasion, particularly for chiA and bacterial amoA, with significant relationships between the abundance of all five NFGs and total nitrogen or nitrate. All woodlands investigated had a history of anthropogenic disturbance and nutrification, and soil nutrient levels and the abundance of NFGs are likely to be related to long-term land management practices.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

The Abundance of Microbial Functional Genes in Grassy Woodlands Is Influenced More by Soil Nutrient Enrichment than by Recent Weed Invasion or Livestock Exclusion

Lindsay

Colloff

Gibb

et al. 2010

Appl Environ Microbiol

104

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“…Th is increase in soil N and C was hypothesized to have occurred during the last several decades of rapid urban expansion. A more recent study also showed elevated N and C in remnant native vegetation fragments within the urban Phoenix CAP-LTER site that promoted changes in N cycling, such as increased denitrifi cation potential and higher microbial N (Hall et al 2009). Nitrogen deposition in the Phoenix area was measured using wet and dry bucket collectors.…”

Section: Plant Community Responsesmentioning

confidence: 92%

Assessment of Nitrogen deposition effects and empirical critical loads of Nitrogen for ecoregions of the United States

Pardo¹,

Robin-Abbott²,

Driscoll³

2011

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Human activity in the last century has led to a substantial increase in nitrogen (N) emissions and deposition. This N deposition has reached a level that has caused or is likely to cause alterations to the structure and function of many ecosystems across the United States. One approach for quantifying the level of pollution that would be harmful to ecosystems is the critical loads approach. The critical load is defi ned as the level of a pollutant below which no detrimental ecological effect occurs over the long term according to present knowledge.The objective of this project was to synthesize current research relating atmospheric N deposition to effects on terrestrial and aquatic ecosystems in the United States and to identify empirical critical loads for atmospheric N deposition. The receptors that we evaluated included freshwater diatoms, mycorrhizal fungi and other soil microbes, lichens, herbaceous plants, shrubs, and trees. The main responses reported fell into two categories: (1) biogeochemical, and (2) individual species, population, and community responses.The range of critical loads for nutrient N reported for U.S. ecoregions, inland surface waters, and freshwater wetlands is 1 to 39 kg N ha -1 y -1. This broad range spans the range of N deposition observed over most of the country. The empirical critical loads for N tend to increase in the following sequence for different life forms: diatoms, lichens and bryophytes, mycorrhizal fungi, herbaceous plants and shrubs, trees.The critical loads approach is an ecosystem assessment tool with great potential to simplify complex scientifi c information and effectively communicate with the policy community and the public. This synthesis represents the fi rst comprehensive assessment of empirical critical loads of N for ecoregions across the United States.

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“…The choice of landscape type has ecological implications, as yard type influences soil properties (Lewis et al, 2006) and biogeochemical cycling (Hall et al, 2009). In addition, research has documented a legacy of prior land use history, with residential landscapes that were formerly desert or agriculture exhibiting distinct soil properties (Lewis et al, 2006;Hall et al, 2009).…”

mentioning

confidence: 99%

“…In addition, research has documented a legacy of prior land use history, with residential landscapes that were formerly desert or agriculture exhibiting distinct soil properties (Lewis et al, 2006;Hall et al, 2009). While mesic landscapes are and have been a prominent landscape type in Phoenix, there is a trend toward xeric landscapes to promote water conservation, with many municipalities providing rebates for turfgrass removal (Kelly, 2005).…”

mentioning

confidence: 99%

Hydropedological Assessments of Parcel-Level Infiltration in an Arid Urban Ecosystem

Shuster

Dadio²,

Burkman

et al. 2014

Soil Science Society of America Journal

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soil morphology and correspondent hydrologic data can contribute to qualifying and quantifying urban soil suitability and capacity to cycle stormwater runoff. We put particular emphasis on the possibility that residential parcels may manage their own stormwater on pervious yard areas. We assessed the morphology of Aridisol pedons (as deep cores to approximately the 3.6-m depth) via soil taxonomy, performed in situ measurements of infiltration, and measured subsoil hydraulic conductivity in two desert parks, four residential parcels, and three dual-purpose park-stormwater retention basins in the Phoenix, AZ, metropolitan area. Infiltration rates overall ranged between 0.4 and 1.7 cm h −1 . We used borehole hydraulic conductivity as a proxy for drainage, which ranged from a low of 0.0 to 13 cm h −1 . Representing a baseline, or set of "natural" hydrologic processes, native desert sites exhibited a relatively high capacity to infiltrate and redistribute rainfall, which, depending on storm intensity, may drain to washes or ephemeral streambeds via subsurface runoff. simulations of stormwater runoff on residential parcels showed that when rooftop runoff is directed to pervious patches, rainfall is entirely infiltrated and redistributed, which predicts good potential for parcel-level stormwater management. Our observation of an accumulation of fine sediments in retention basin surface soils was corroborated with local observations that drawdown times in the retention basins had increased with time. Although further assessment is needed on a wider variety of semiarid landscapes, our results suggest a positive role for residential parcels in detaining stormwater on site and perhaps easing the wet-weather burden on centralized stormwater infrastructure in semiarid urban ecosystems.

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Urbanization Alters Soil Microbial Functioning in the Sonoran Desert

Cited by 49 publications

References 74 publications

The Abundance of Microbial Functional Genes in Grassy Woodlands Is Influenced More by Soil Nutrient Enrichment than by Recent Weed Invasion or Livestock Exclusion

The Abundance of Microbial Functional Genes in Grassy Woodlands Is Influenced More by Soil Nutrient Enrichment than by Recent Weed Invasion or Livestock Exclusion

Assessment of Nitrogen deposition effects and empirical critical loads of Nitrogen for ecoregions of the United States

Hydropedological Assessments of Parcel-Level Infiltration in an Arid Urban Ecosystem

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