Landscape level population and movement modelling for non-target arthropods (NTAs) have demonstrated that it has the potential to improve the understanding of risk at the landscape scale. For instance, honeybee models have increased our knowledge of what factors in the landscapes affect risk as well as what mitigation can help reducing risk. Modelling of other non-target arthropod species have quantified how NTAs use agricultural landscapes and how that can affect risk at population level. However, NTA modelling has also demonstrated that there are some considerable data gaps for applying NTA population modelling at landscape scale in a way that is meaningful for risk assessments. Firstly, exposure for NTAs is less well understood than for most other organisms in PPP risk assessments. Exposure in landscape patches varies over time. Also, exposure is spatially very heterogenous both within habitats and between habitats and the exposure NTAs experience also depends on their movement patterns. For instance, within crop there will be a considerable difference between ground dwelling arthropods and those that live in the crop canopy. In off-crop habitats the situation is even more complex because exposure patterns depend both on drift and vegetation structure. Moreover, some species frequently move across different habitats further complicating exposure estimates. Therefore, a concept is needed for how to estimate exposure within crops and off-crop habitats as well as across landscapes before NTA landscape modelling can be applied to risk assessments in robust way. Secondly, NTAs are an immensely diverse group e.g., in terms of taxonomy, morphology, movement patterns, and life histories. This means that it is not straightforward to find suitable and representative focal species, making the extrapolation from laboratory test species to other species challenging. Therefore, a concept is needed for how to deal with this diversity, for instance by categorising traits and performing a vulnerability analysis.  The way NTA risk assessments have dealt with the heterogeneity of exposure and diversity of NTAs is by calibrating from laboratory studies to field studies to find out what risk quotients lead to no unacceptable risk. This continues to be a pragmatic and scientifically robust approach until better understanding of exposure and diversity is available.

Landscape modelling for non-target arthropod risk assessment of pesticides: challenges and opportunities

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.