The Meta-Analysis of Response Ratios in Experimental Ecology

Hedges, Larry V.; Gurevitch, Jessica; Curtis, Peter S.

doi:10.2307/177062

Cited by 1,301 publications

(1,787 citation statements)

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“…In the minority of cases where total plant biomass was not available or could not be calculated, we used shoot biomass as a proxy for total plant biomass. We then used the response ratio Ln(R) = Ln(X AMF /X c ) as the effect size, where X AMF and X c are the mean total biomass values for the inoculated and control treatments, respectively (Hedges et al 1999). A positive value of Ln(R) indicates a positive effect of arbuscular mycorrhizal fungi inoculation on total plant biomass.…”

Section: Discussionmentioning

confidence: 99%

Crop-specific and single-species mycorrhizal inoculation is the best approach to improve crop growth in controlled environments

Geel

Beenhouwer

Lievens

et al. 2016

Agron. Sustain. Dev.

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Arbuscular mycorrhizal fungi are root symbionts that play a key role in crop growth. A systematic quantitative analysis of the response of crops to arbuscular mycorrhizal inoculation, however, remains to be done. Additionally, little is known regarding the role of mycorrhizal specificity and the diversity of the inoculum on crop growth. Therefore, we collected data from 115 inoculation studies, including 435 experiments. We then used meta-analysis to examine the effect of crop identity, arbuscular mycorrhizal fungus identity, and mycorrhizal diversity on crop biomass increase, following inoculation. Our results show that total crop biomass was on average 34.9 % higher in inoculated versus non-inoculated plants. We found that specific combinations of arbuscular mycorrhizal fungus genera and host plant families were more beneficial for growth promotion as compared to other combinations. Moreover, a single-species inoculum increased crop growth response on average by 41.2 % compared to a multi-species inoculum. Overall, our findings show that a broad range of crops highly benefit from the inoculation with arbuscular mycorrhizal fungi. They also strongly suggest that selecting specific arbuscular mycorrhizal taxa for specific crops is the most promising approach to enhance crop growth. There is no "onesize-fits-all" arbuscular mycorrhizal fungus. Finally, and at least in stable and controlled environments, inoculation with a single arbuscular mycorrhizal species is more effective, compared to inoculation with a mixture of different arbuscular mycorrhizal taxa. This may be explained by fungi superior in extraradical growth, but less beneficial to the host, that outcompete the more mutualistic fungi. Therefore, it may be beneficial to maintain a high dominance of one beneficial arbuscular mycorrhizal taxon in simplified agricultural systems.

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Section: Discussionmentioning

confidence: 99%

Crop-specific and single-species mycorrhizal inoculation is the best approach to improve crop growth in controlled environments

Geel

Beenhouwer

Lievens

et al. 2016

Agron. Sustain. Dev.

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show abstract

“…E calculated in this manner is equivalent to a ln effect size (Hedges et al, 1999) typically used to compare the magnitude of responses across multiple response variables in meta-analysis (e.g., Kroeker et al, 2013). When the trait decreased with temperature (e.g., net growth rates), the ratio was rearranged (i.e., ln…”

Section: Methodsmentioning

confidence: 99%

Footprints of climate change on Mediterranean Sea biota

et al. 2015

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The Mediterranean Sea ranks among the ocean regions warming fastest. There is evidence for impacts of climate change on marine Mediterranean organisms but a quantitative assessment is lacking. We compiled the impacts of warming reported in the literature to provide a quantitative assessment for the Mediterranean Sea. During the last three decades the summer surface temperature has increased 1.15 • C. Strong heat wave events have occurred in years 1994, 2003, and 2009. Impacts of warming are evident on growth, survival, fertility, migration and phenology of pelagic and benthic organisms, from phytoplankton to marine vegetation, invertebrates and vertebrates. Overall, 50% of biological impacts in the Mediterranean Sea occur at summer surface temperature anomaly 4.5 • ≤ C and at summer surface temperature of 27.5 • C. The activation energy (geometric mean 1.58 ± 0.48 eV), the slope of the Arrhenius equation describing the temperature-dependence of biological processes, for the response of Mediterranean marine biota to warming reveals that these responses in the Mediterranean are far steepest than possibly explained by the direct effect of warming alone. The observations are biased toward the northern and western sectors of the basin, likely underestimating the impacts of warming in areas where warming is particularly intense.

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“…There are also other metrics available for this type of primary data (means, variances and sample sizes), such as the log response ratio lnR (Rosenberg et al 2000), but we chose d because our data were not suitable for use of the response ratio (e.g. in some studies, the control group value was zero; Hedges et al 1999). Positive values of d indicate that the predator treatment had a positive effect on prey species, zero means that there was no difference between treatment and control, and negative values signify a greater response in controls.…”

Section: Methodsmentioning

confidence: 99%

Alien predators are more dangerous than native predators to prey populations

et al. 2007

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Alien predators are widely considered to be more harmful to prey populations than native predators. To evaluate this expectation, we conducted a meta-analysis of the responses of vertebrate prey in 45 replicated and 35 unreplicated field experiments in which the population densities of mammalian and avian predators had been manipulated. Our results showed that predator origin (native versus alien) had a highly significant effect on prey responses, with alien predators having an impact double that of native predators. Also the interaction between location (mainland versus island) and predator origin was significant, revealing the strongest effects with alien predators in mainland areas. Although both these results were mainly influenced by the huge impact of alien predators on the Australian mainland compared with their impact elsewhere, the results demonstrate that introduced predators can impose more intense suppression on remnant populations of native species and hold them further from their predator-free densities than do native predators preying upon coexisting prey.

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The Meta-Analysis of Response Ratios in Experimental Ecology

Cited by 1,301 publications

References 0 publications

Crop-specific and single-species mycorrhizal inoculation is the best approach to improve crop growth in controlled environments

Crop-specific and single-species mycorrhizal inoculation is the best approach to improve crop growth in controlled environments

Footprints of climate change on Mediterranean Sea biota

Alien predators are more dangerous than native predators to prey populations

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