Ecological risk assessment of transgenic pasture plants: a community gradient modelling approach

Godfree, Robert C.; Young, Andrew G.; Lonsdale, W. M.; Woods, Matthew J.; Burdon, Jeremy J.

doi:10.1111/j.1461-0248.2004.00664.x

Cited by 12 publications

(11 citation statements)

References 24 publications

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“…These results may have important implications for the ecological risk-assessment of genetically modified organisms at the community level [21,28]. Bacteria are abundant and very diverse [29][30][31][32][33] and can respond rapidly to environmental perturbations [32][33][34][35][36], for instance during competition for nutrients required for bacterial growth and activity [34][35][36].…”

Section: Discussionmentioning

confidence: 99%

Can Transgenic Maize Affect Soil Microbial Communities?

Mulder¹,

Wouterse²,

Raubuch³

et al. 2005

PLoS Comp Biol

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The aim of the experiment was to determine if temporal variations of belowground activity reflect the influence of the Cry1Ab protein from transgenic maize on soil bacteria and, hence, on a regulatory change of the microbial community (ability to metabolize sources belonging to different chemical guilds) and/or a change in numerical abundance of their cells. Litter placement is known for its strong influence on the soil decomposer communities. The effects of the addition of crop residues on respiration and catabolic activities of the bacterial community were examined in microcosm experiments. Four cultivars of Zea mays L. of two different isolines (each one including the conventional crop and its Bacillus thuringiensis cultivar) and one control of bulk soil were included in the experimental design. The growth models suggest a dichotomy between soils amended with either conventional or transgenic maize residues. The Cry1Ab protein appeared to influence the composition of the microbial community. The highly enhanced soil respiration observed during the first 72 h after the addition of Bt-maize residues can be interpreted as being related to the presence of the transgenic crop residues. This result was confirmed by agar plate counting, as the averages of the colony-forming units of soils in conventional treatments were about one-third of those treated with transgenic straw. Furthermore, the addition of Bt-maize appeared to induce increased microbial consumption of carbohydrates in BIOLOG EcoPlates. Three weeks after the addition of maize residues to the soils, no differences between the consumption rate of specific chemical guilds by bacteria in soils amended with transgenic maize and bacteria in soils amended with conventional maize were detectable. Reaped crop residues, comparable to post-harvest maize straw (a common practice in current agriculture), rapidly influence the soil bacterial cells at a functional level. Overall, these data support the existence of short Bt-induced ecological shifts in the microbial communities of croplands' soils.

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Section: Discussionmentioning

confidence: 99%

Can Transgenic Maize Affect Soil Microbial Communities?

Mulder¹,

Wouterse²,

Raubuch³

et al. 2005

PLoS Comp Biol

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“…2000; Meagher 2000). New plant species will include turfgrass, pasture and tree species, and aquatic plants (Godfree et al. 2004; NRC 2004b; Van Frankenhuizen & Beardmore 2004; Watrud et al.…”

Section: Some Future Issuesmentioning

confidence: 99%

“…Many of these new transgenic species are more likely to establish feral populations and hybridize with wild relatives than the present commercial transgenic plants – maize, soybean, cotton and oilseed rape (Godfree et al. 2004; Van Frankenhuizen & Beardmore 2004; Watrud et al.…”

Section: Some Future Issuesmentioning

confidence: 99%

Assessing environmental risks of transgenic plants

Andow¹,

Zwahlen²

2005

Ecology Letters

279

216

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By the end of the 1980s, a broad consensus had developed that there were potential environmental risks of transgenic plants requiring assessment and that this assessment must be done on a case-by-case basis, taking into account the transgene, recipient organism, intended environment of release, and the frequency and scale of the intended introduction. Since 1990, there have been gradual but substantial changes in the environmental risk assessment process. In this review, we focus on changes in the assessment of risks associated with non-target species and biodiversity, gene flow, and the evolution of resistance. Non-target risk assessment now focuses on risks of transgenic plants to the intended local environment of release. Measurements of gene flow indicate that it occurs at higher rates than believed in the early 1990s, mathematical theory is beginning to clarify expectations of risks associated with gene flow, and management methods are being developed to reduce gene flow and possibly mitigate its effects. Insect pest resistance risks are now managed using a high-dose/refuge or a refuge-only strategy, and the present research focuses on monitoring for resistance and encouraging compliance to requirements. We synthesize previous models for tiering risk assessment and propose a general model for tiering. Future transgenic crops are likely to pose greater challenges for risk assessment, and meeting these challenges will be crucial in developing a scientifically coherent risk assessment framework. Scientific understanding of the factors affecting environmental risk is still nascent, and environmental scientists need to help improve environmental risk assessment.

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“…Assessment of the potential impact of fitness-enhancing transgenes therefore involves investigation of these factors on a case-by-case basis underpinned by explicit treatment of the biotic and abiotic factors that limit the size of the potential recipient plant populations in the environment (Schmitt and Linder 1994). To date, few studies have investigated these factors for any transgenic pasture plant, but the available evidence suggests that the fitness advantage of transgenic plants can depend highly on the specific transgene and management system involved (Dear et al 2003) and the composition of the recipient plant community (Godfree et al 2004c).…”

Section: Introductionmentioning

confidence: 98%

“…These constructs pose a challenge to ERA because many pasture plants have the ability to persist in diverse and competitive plant communities and because some pasture species are known invaders of non-agricultural systems (Lonsdale 1994). This includes species that have been targeted for genetic modification such as Trifolium subterraneum L. (Godfree et al 2004c) and Trifolium repens L. (Godfree et al 2004b). Assessing the fitness effects of transgenes conferring pathogen resistance is particularly challenging (Tepfer 2002), because non-target impacts of trangene release are likely to be contingent on complex interactions between the transgenic plant, the recipient plant community, and a diverse array of other biotic and abiotic factors that interact spatially and temporally with pathogen load.…”

Section: Introductionmentioning

confidence: 99%

Risk Assessment of Transgenic Virus-resistant White Clover: Non-target Plant Community Characterisation and Implications for Field Trial Design

2006

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One of the most difficult elements of the ecological risk assessment of transgenic plants is investigation of their potential impact on biodiversity in complex non-target communities. This problem is particularly acute for pasture plants, since many have a track record of invasiveness. In this paper we develop an understanding of some aspects of the ecology of Trifolium repens L. (white clover) in montane vegetation communities in southeastern Australia as part of a larger project investigating potential ecological risks associated with commercial release of newly-developed transgenic virus-resistant T. repens cultivars. We use a combination of floristic surveys and biomass sampling to determine the habitat affinity of T. repens, the structure and composition of associated communities, and the scale at which different abiotic and biotic factors correlate with T. repens abundance. We also compare the abundance of native and exotic species within specific morpho-functional groups and use this to determine the relative significance of T. repens as a community constituent, and to identify native species that would be most at risk by expanding populations of T. repens. We found that T. repens comprises a relatively small component of the total community cover and biomass, but is one of the most abundant herbaceous species in mesic Poa -dominated grasslands and Poa-Eucalyptus woodlands in the study area, and that T. repens abundance is correlated at the withincommunity scale primarily with soil moisture and fertility. At smaller scales T. repens is limited by the hierarchical dominance of native graminoids and we conclude that competition for inter-tussock space in mesic communities is the most likely mechanism by which expanding populations of T. repens would influence populations of associated native species. These results have significant implications for the manner in which future analysis and risk quantification stages of the risk assessment of virus-resistant T. repens and other transgenic pasture plants in complex plant communities are performed.

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Ecological risk assessment of transgenic pasture plants: a community gradient modelling approach

Cited by 12 publications

References 24 publications

Can Transgenic Maize Affect Soil Microbial Communities?

Can Transgenic Maize Affect Soil Microbial Communities?

Assessing environmental risks of transgenic plants

Risk Assessment of Transgenic Virus-resistant White Clover: Non-target Plant Community Characterisation and Implications for Field Trial Design

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