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Aboveground herbivory shapes the biomass distribution and flux of soil invertebrates.

Mulder C, Den Hollander HA, Hendriks AJ - PLoS ONE (2008)

Bottom Line: Overall higher biomasses of invertebrates occur in grasslands, and all larger soil organisms differed remarkably.Strong statistical evidence supports a hypothesis explaining from an allometric perspective how the faunal biomass distribution and the energetic flux are affected by livestock, nutrient availability and land use.Our aim is to propose faunal biomass flux and biomass distribution as quantitative descriptors of soil community composition and function, and to illustrate the application of these allometric indicators to soil systems.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology, National Institute for Public Health and the Environment, RIVM-LER, Bilthoven, The Netherlands. Christian.Mulder@rivm.nl

ABSTRACT

Background: Living soil invertebrates provide a universal currency for quality that integrates physical and chemical variables with biogeography as the invertebrates reflect their habitat and most ecological changes occurring therein. The specific goal was the identification of "reference" states for soil sustainability and ecosystem functioning in grazed vs. ungrazed sites.

Methodology/principal findings: Bacterial cells were counted by fluorescent staining and combined direct microscopy and automatic image analysis; invertebrates (nematodes, mites, insects, oligochaetes) were sampled and their body size measured individually to allow allometric scaling. Numerical allometry analyses food webs by a direct comparison of weight averages of components and thus might characterize the detrital soil food webs of our 135 sites regardless of taxonomy. Sharp differences in the frequency distributions are shown. Overall higher biomasses of invertebrates occur in grasslands, and all larger soil organisms differed remarkably.

Conclusions/significance: Strong statistical evidence supports a hypothesis explaining from an allometric perspective how the faunal biomass distribution and the energetic flux are affected by livestock, nutrient availability and land use. Our aim is to propose faunal biomass flux and biomass distribution as quantitative descriptors of soil community composition and function, and to illustrate the application of these allometric indicators to soil systems.

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Related in: MedlinePlus

Repulsed frequency distribution of the faunal biomass (the aforementioned compensation between phyla is further supported by the parallel regression slopes and by the moving averages).With the chosen log(M) interval 86%±22 SD of the bins between −2 and 2 (microfauna and mesofauna) and 96%±7.5 SD of the bins between −1.6 and 0 (microfauna) are filled. All log(M) ranges are provided at the bottom (thin lines, min–max, medium lines, 5–95 percentile, thick lines, quartiles).
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pone-0003573-g003: Repulsed frequency distribution of the faunal biomass (the aforementioned compensation between phyla is further supported by the parallel regression slopes and by the moving averages).With the chosen log(M) interval 86%±22 SD of the bins between −2 and 2 (microfauna and mesofauna) and 96%±7.5 SD of the bins between −1.6 and 0 (microfauna) are filled. All log(M) ranges are provided at the bottom (thin lines, min–max, medium lines, 5–95 percentile, thick lines, quartiles).

Mentions: Although it is known from literature that the total biomass of above-ground and below-ground invertebrates in grasslands is much higher than in other ecosystems [30], [31], we are not aware of examples of faunal biomass distribution in soil systems. To address further the effects of macroherbivory on the soil system, we merged the biomass values for individually-binned size-classes together into Figure 3. The so-obtained coefficients of these two meta-FBS took both statistically indistinguishable values for either grazed or ungrazed systems (0.3917±0.0110 SE and 0.4042±0.0178 SE, respectively), in contrast to the vertical intercepts (4.1623±0.0208 SE and 3.9004±0.0248 SE, respectively). On the other hand, lumping these soil webs together made bimodal patterns detectable: according to the two moving averages, the microfauna clearly reacted in different ways than the mesofauna. Comparable bimodal patterns are known from the benthic biomass distributions for coastal sediments [32].


Aboveground herbivory shapes the biomass distribution and flux of soil invertebrates.

Mulder C, Den Hollander HA, Hendriks AJ - PLoS ONE (2008)

Repulsed frequency distribution of the faunal biomass (the aforementioned compensation between phyla is further supported by the parallel regression slopes and by the moving averages).With the chosen log(M) interval 86%±22 SD of the bins between −2 and 2 (microfauna and mesofauna) and 96%±7.5 SD of the bins between −1.6 and 0 (microfauna) are filled. All log(M) ranges are provided at the bottom (thin lines, min–max, medium lines, 5–95 percentile, thick lines, quartiles).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2570614&req=5

pone-0003573-g003: Repulsed frequency distribution of the faunal biomass (the aforementioned compensation between phyla is further supported by the parallel regression slopes and by the moving averages).With the chosen log(M) interval 86%±22 SD of the bins between −2 and 2 (microfauna and mesofauna) and 96%±7.5 SD of the bins between −1.6 and 0 (microfauna) are filled. All log(M) ranges are provided at the bottom (thin lines, min–max, medium lines, 5–95 percentile, thick lines, quartiles).
Mentions: Although it is known from literature that the total biomass of above-ground and below-ground invertebrates in grasslands is much higher than in other ecosystems [30], [31], we are not aware of examples of faunal biomass distribution in soil systems. To address further the effects of macroherbivory on the soil system, we merged the biomass values for individually-binned size-classes together into Figure 3. The so-obtained coefficients of these two meta-FBS took both statistically indistinguishable values for either grazed or ungrazed systems (0.3917±0.0110 SE and 0.4042±0.0178 SE, respectively), in contrast to the vertical intercepts (4.1623±0.0208 SE and 3.9004±0.0248 SE, respectively). On the other hand, lumping these soil webs together made bimodal patterns detectable: according to the two moving averages, the microfauna clearly reacted in different ways than the mesofauna. Comparable bimodal patterns are known from the benthic biomass distributions for coastal sediments [32].

Bottom Line: Overall higher biomasses of invertebrates occur in grasslands, and all larger soil organisms differed remarkably.Strong statistical evidence supports a hypothesis explaining from an allometric perspective how the faunal biomass distribution and the energetic flux are affected by livestock, nutrient availability and land use.Our aim is to propose faunal biomass flux and biomass distribution as quantitative descriptors of soil community composition and function, and to illustrate the application of these allometric indicators to soil systems.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology, National Institute for Public Health and the Environment, RIVM-LER, Bilthoven, The Netherlands. Christian.Mulder@rivm.nl

ABSTRACT

Background: Living soil invertebrates provide a universal currency for quality that integrates physical and chemical variables with biogeography as the invertebrates reflect their habitat and most ecological changes occurring therein. The specific goal was the identification of "reference" states for soil sustainability and ecosystem functioning in grazed vs. ungrazed sites.

Methodology/principal findings: Bacterial cells were counted by fluorescent staining and combined direct microscopy and automatic image analysis; invertebrates (nematodes, mites, insects, oligochaetes) were sampled and their body size measured individually to allow allometric scaling. Numerical allometry analyses food webs by a direct comparison of weight averages of components and thus might characterize the detrital soil food webs of our 135 sites regardless of taxonomy. Sharp differences in the frequency distributions are shown. Overall higher biomasses of invertebrates occur in grasslands, and all larger soil organisms differed remarkably.

Conclusions/significance: Strong statistical evidence supports a hypothesis explaining from an allometric perspective how the faunal biomass distribution and the energetic flux are affected by livestock, nutrient availability and land use. Our aim is to propose faunal biomass flux and biomass distribution as quantitative descriptors of soil community composition and function, and to illustrate the application of these allometric indicators to soil systems.

Show MeSH
Related in: MedlinePlus