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Project synopsis:

Advances achieved under a previous SERAD-funded project have enabled the identification of key environmental factors that may limit the establishment or population development of A. triangulatus. Valuable data describing the impact of NZF on earthworm populations have also been gathered. These results have been utilised by specialists in Pest Risk Assessment and EU negotiators to address some of the concerns of member states. The project has also indicated specific areas of investigation that would further strengthen our knowledge of the true level of risk posed by NZF in relation to international trade, and provide further understanding of the ecology of this species in Scotland.

Under the current research programme, experiments will be designed and implemented which will provide the required detailed information on the cold-hardiness of NZF egg cocoons and the mechanisms by which adults succumb to low temperatures. Detailed investigations of NZF responses (adults and egg-cocoons) to high and low moisture levels will be undertaken and any limits to the kind of habitats susceptible to NZF establishment will be defined. Similar investigations of the pH tolerance of NZF will be undertaken to further define habitat characteristics that make a geographical area susceptible to NZF colonization. Possible physiological or behavioural characteristics of A. triangulatus that could ameliorate the effect of these environmental factors on NZF survival, and thus extend the potential range of the species, will be investigated where appropriate. Molecular studies will be implemented to investigate the relative importance of self- and cross-fertilization, and conclusions drawn on the importance for establishment potential of the species. An existing manipulative field experiment investigating the impact of NZF on populations of their earthworm prey will be continued for a further two years, yielding unique information on the effect of the predators in the field over a period of three years. Finally, the long-term monitoring of NZF and earthworm populations at seven sites in Scotland will be extended for a further two years and, where appropriate, intensified.

Note: Use of animals:
No animals, other than A. triangulatus and earthworms, will be used in these experiments.