Predicting the impact of coexistence-guided genetically modified (GM) cropping on Irish biodiversity
Environmental Protection Agency (EPA STRIVE Research Programmes)
This project is now completed and two reports have been published; STRIVE No. 39 and STRIVE No. 69. A peer-reviewed publication detailing the work from Strive No. 39 has also been published and is available for viewing here.
Teagasc Oak Park (STRIVE No. 39 and No. 69)
UCC and NUIM (STRIVE No. 39)
- The collation and assessment of pre-existing research data which describes the impact of conventional crop production on Irish levels of biodiversity
- An assessment of how the proposed National Co-existence Strategy will affect the agri-environment for each of the 5 crops to considered in the study
- The collation and assessment of pre-existing (international) research data and conclusions which describe the biodiversity impact of GM crop cultivation but which are comparable to Irish cropping systems/environment
- An assessment of which GM traits are most suited to Ireland’s agricultural systems and hence have the highest probability of adoption by the tillage sector
- Evaluating the ecological impacts of cultivating GM Herbicide-Tolerant (GMHT) oilseed rape and maize
- The development of an internet-based information system (www.gmoinfo.ie) which will facilitate the dissemination of results and pertinent information gathered during the course of the project
Following the approval of 17 genetically modified crops (GM) crops in 2004 for cultivation across the EU, it it evident that future crop management systems will be reliant upon the implementation of effective coexistence plans for both novel and established crop systems. From an Irish context, a key requirement for the development of coexistence regimes which effectively prevent any adverse effects on biodiversity, will be to increase our knowledge of biodiversity impacts resulting from gene flow between a GM crop and inter-related wild species in the Irish flora
Hence, the goal of these projects is:
To significantly improve our understanding of the actual rates of gene flow arising from existing and future Irish GM cropping systems and more significantly,
The likely consequences for biodiversity conservation of such gene flow and the management of those GM crops most relevant to Irish agriculture
By collating and processing information from national and international GM-based studies, the gene flow-based impacts of GM crop cultivation on Irish biodiversity will be predicted. This information will assist future research and policy decision-making regarding relationships between biodiversity and GM crop cultivation in Ireland
At present no genetically modified (GM) crops are grown in Ireland because the current suite of commercialised GM crops is not suited to the Irish agri-environment. Farmer surveys clearly show willingness on the behalf of Irish farmers to adopt specific GM traits (e.g. blight tolerance) if they will provide an economic and/ or environmental benefit. Therefore, as the second and third generations of GM crops proceed through research pipelines, it is broadly accepted that in the near future Irish farmers will be afforded the choice as to whether they wish to adopt GM technology into their systems.
Their choices will be heavily influenced by the economic realities of the day. Considering the future environmental (e.g. climate change) and legislative challenges (e.g. pesticides regulations), the crops with the most potential for modification from an Irish perspective include oilseed rape, maize, potato, barley and wheat. The principal traits that would benefit Irish farmers would be herbicide tolerance (HT), nitrogen use efficiency (NUE) and enhanced fungal resistance (EFR).
While assessing the potential biodiversity impacts associated with each of these traits, it became evident that minimal research has been completed into gauging the impact of conventional agriculture on species and habitats in the Irish landscape. Only 21 papers investigating the impact of conventional crop cultivation on Irish biodiversity have been published within the past 30 years. Principally, these studies have concluded that conventional crop cultivation has had an adverse impact on biodiversity on Irish farms, with 15 of the 21 studies demonstrating negative trends for the taxa investigated.
It is clear that, as with all forms of tillage agriculture, there is a high likelihood that the potential impacts of GM crops on Irish biodiversity will be both positive and negative. When this issue is examined at a macro scale, the net potential impacts are likely to be beneficial towards the wider diversity of the Irish landscape. The potential modifications that would suit current Irish agricultural practices are designed solely to assist deriving greater profitability from lower inputs, implying that management regimes on Irish GM farms will be different from non-GM farms.
As a follow-on consequence of these new management schemes, GM farms will have lower inputs, less disturbance and lower resource requirements. The benefits to biodiversity are therefore expected to be broadly beneficial but this will be dependent upon the GM trait adopted and the level of compliance by the GM farmer to the recommended crop management. Based on the number of field trials under way across the EU (http://gmoinfo.jrc.ec.europa.eu/) at present, it is predicted that the first GM crops suited to the Irish agri-environment (e.g. HT maize) will be available to farmers by 2015.
While it was not possible to complete a comparative analysis between the potential impact of GM and the actual impact of non-GM tillage systems for this study due to a paucity of data on non-GM systems, an opportunity exists to rectify this through the establishment of a national biodiversity monitoring and evaluation programme for tillage systems which would provide a baseline against which biodiversity loss, mitigation or gain may be assessed and scientifically reviewed prior to GM crop adoption in Ireland.
For STRIVE project No. 69, the specific task was to assess the impact of GM herbicide tolerant (GMHT) maize and oilseed rape on the Irish agri-environment. The research reported here is an extensive analysis of the scientific literature on the subject and was carried out between August 2009 and July 2010. There are several key conclusions from this analysis.
There are many ’wild’ species related to oilseed rape in Ireland, none of which are native and many of which are highly unlikely to survive when crossed with the current oilseed rape crop plant (Brassica napus). The only exception is wild turnip (Brassica rapa), which is an earlier oilseed crop now no longer farmed but anecdotally present in marginal habitats. Worldwide, there have been ongoing and intensive surveys of the potential for GMHT B. napus to transfer herbicide tolerance to B. rapa.
While it has been shown that this will indeed occur, the primary issue remains the consequence of this gene flow event: that is, what will happen the resulting offspring? Critically, in the absence of a selection pressure (spraying with the herbicide for which they have a tolerance), these GM hybrid individuals have no physical advantage over their non-GM neighbours. As they also contain a significant portion of a crop genome, they will not have the competitive ability that weed populations possess and will therefore not survive over time. In Ireland, marginal habitats are not routinely sprayed so it can be concluded that GM hybrids with a HT trait will not proliferate and spread.
Separately, there is no likelihood of maize impacting on wild relatives as none exist in Ireland. In real-world conditions, there are some scenarios where accidental spraying may occur and where management arrangements may give rise to an opportunity for a GMHT plant to prevail in the landscape. This was examined and presented in a series of five hypothetical scenarios. It was shown that there are no credible scenarios where a GMHT crop can persist or prevail over time any more than a non- GM crop outside of the confines of a managed field environment.
Furthermore, it is also shown that it is in the management of the GM or non-GM crop that the potential for biodiversity impact is at its greatest. Glyphosate and glufosinate toxicity was examined in detail and it was concluded that these two compounds have significantly less toxicity than those compounds currently in use across conventional systems. Using a recently developed index of biodiversity impact (CINMa1), the two GMHT crops were subjected to an analysis of their potential for impact. It was shown that in the management of GMHT maize there is the potential for benefiting landscape biodiversity. The same may be said for oilseed rape management, but there is some likelihood for transfer of genetic material to a wild relative. The potential impact of this is minimal and there is a net beneficial impact as with maize.