Data transparency regarding the implementation of European ‘no net loss’ biodiversity policies

‘No net loss’ (NNL) conservation policies seek to address development impacts on biodiversity. There have been no peer-reviewed multinational assessments concerning the actual implementation of NNL policies to date. Such assessments would facilitate more informed debates on the validity of NNL for conservation, but assessing implementation requires data. Here, we explore data transparency concerning NNL implementation, with four European countries providing a case study.