Statement on the suitability of the BEEHAVE model for its potential use in a regulatory context and for the risk assessment of multiple stressors in honeybees at the landscape level
The Panel has interpreted the Terms of Reference by carrying out a stepwise evaluation of the BEEHAVE simulation model with a view to assessing its suitability for use in a regulatory context and for risk assessment of multiple stressors at the landscape level. The EFSA opinion on good modelling practice was used to evaluate the model and its documentation systematically. The overall conclusion is that BEEHAVE performs well in modelling honeybee colony dynamics, and the supporting documentation is generally good but does not fully meet the criteria of the good modelling opinion. BEEHAVE is not yet usable in a regulatory context primarily because it needs a pesticide module. BEEHAVE has a Varroa/virus module, although this seems to underestimate the impact of Varroa/virus on colony survival, and additional stressors (chemical and biological) would need to be added to allow investigation of the effects of interactions of pesticides with multiple stressors. BEEHAVE currently uses a very simple representation of a landscape and this should be extended. There is only one environmental scenario in the present version of BEEHAVE (European central zone—weather scenarios for Germany and the UK) and extension to other European zones would be needed. The supporting data and default parameter values should be further evaluated and justified. The modelling environment used by BEEHAVE (NetLogo) has an excellent user interface but provides limited opportunities for extending the model. The Panel recommends that BEEHAVE should be adopted as the basis for modelling the impact on honeybee colonies of pesticides and other stressors, but that further development should use a standard, object-oriented language rather than NetLogo.