GIS-based analyses for the potential risk of nature conservation areas by the cultivation of genetically modified plants–effects of isolation distances | GIS-gestützte Analysen zur möglichen Gefährdung von Naturschutzgebietendurch den Anbau gentechnisch veränderter Kulturpflanzen

Background, Aim, and Scope The introduction of genetically modified plants (GMP) into the European agriculture primarily has been investigated in respect of economical aspects, its impacts on conventional crops, and direct or indirect effects on human health. Potential ecological impacts, especially their long term and large scale implications, were out of focus, usually. A special task is to protect the integrity of nature reserves. According to § 23 of the German Nature Protection Law (BNatSchG) nature reserves are to protect nature and landscape properties by preserving and developing existing as well as by re-establishing biotopes of wild and endangered species. According to § 34a of the BNatSchG the use of GMP has to be accompanied by an environmental impact analysis of possible risks like it has to be done in projects affecting the integrity of Flora-Fauna-Habitats (FFH) or European bird sanctuaries. Considering this, the joint research project “Recommendations for isolation distances concerning the cultivation of genetically modified plants in the neighbourhood of protected areas” which was promoted by the Federal Agency for Nature Conservation (BfN) aimed at describing possible risks for biocoenoses in conservation areas that could be caused by the cultivation of GMP in their vicinity and at evaluating measures which could mitigate or hinder negative effects. The article at hand concentrates on describing the implications which would emerge when introducing different isolation distances concerning the cultivation of herbicide resistant oil seed rape (HR-OSR) and insect resistant maize (B. t.-maize) near protection areas. On the other hand, a methodology is introduced which was developed to classify the German nature reserves according to their potential endangerment by GMP cultivation and to minimise calculation efforts for modelling possible impacts.Materials and Methods In 2003, there were around 7,400 nature reserves which covered 3 % of the whole territory of Germany. A geographical information system (GIS) was used to integrate geometries of conservation areas, land use data (CORINE landcover), agricultural information on district level as well as a map of German ecoregions. At first, it was evaluated how much arable land for B. t.-maize or HR-OSR cultivation would remain if introducing different isolation distances around nature reserves (NSG). Furthermore, the NSG were aggregated to several homogenous classes reflecting different levels of cultivation intensities in their vicinity and different geometric properties. This was realised calculating a geometric coefficient (GC) which describes the ratio of periphery and area of each NSG in order to abstract the risk of GMP invasion. The density of maize and rape cropping near the NSG was expressed by a cultivation coefficient (CC). According to regional agricultural surveys, this was calculated by adding up the area of maize and rape fields within a radius of 1,000 m (maize) and 4,000 m (rape), respectively, around the NSG.Results Considering an isolation distance of 1,000 m around the NSG, 90 % of the farmland in Germany would be available for GMP cultivation. 50 % would remain when establishing an isolation distance of 4,000 m. The combination of GC and CC resulted in a total of nine risk categories (RC) describing the potential risk of endangerment by GMP cultivation in the vicinity of NSG. Areas with highest risk were grouped in RC nine where the smallest NSG (+ GC) in the main cultivation areas of maize or corn (+ CC) were summarised. With a numerical proportion of 7 % those sites cover only 0.4 % of total area of all NSG. All nature reserves showing highest CC values had a total proportion of 60 %.Discussion The derivation of GC and CC was based on a hierarchical approach and was implemented by complex GIS procedures. This makes it easy to calculate additional values for different GMP, protection areas or isolation distances. The RC were useful for choosing representative modelling sites in order to minimise calculation efforts when modelling possible impacts of GMP cultivation in vicinity of nature reserves.Conclusions The assessment of isolation distances around protection areas should be performed for each area individually concerning the GMP specific effects and dispersal properties as well as the protected organisms and the main protection targets. Especially HR-OSR is critical because of its volunteers and hybridisation partners. Another main source of GMP dispersal into protection areas might be the contamination of conventional seeds with transgene OSR seeds.Recommendations and perspectives Before defining and applying particular measures in order to protect conservation areas from possible impacts due to GMP cultivation a political and societal discussion is necessary in order to assess which GMP induced impacts may be tolerated. This has to be supported by additional scientific studies based on empirical and estimated data evaluating possible dispersal distances of GM pollen and possible environmental impacts of released transgenes and their toxins. According to the EU Directive 2001/18/EC the cultivation of GMP should be accompanied by a case-specific monitoring and general surveillance, as well. It should be realised as soon as possible, since the release and the cultivation of GMP in Germany have been started, already. The monitoring should be complemented by the implementation of a web-based geoinformation system (WebGIS) which enables the compilation and evaluation of the data and relevant geodata.