Very few impact evaluation studies exist however on other policy instruments that are also commonly used across countries. Given the large budgetary investments, for example, of agri-environmental schemes, it is perhaps surprising that few if any impact evaluation studies exist that aim to examine their impact on the environment. Moreover, nearly all of the studies identified focus on terrestrial ecosystems, with only a very small minority of studies on marine ecosystems (i.e. three studies, namely: Ahmadia et al (2015) and Miteva et al (2015) on impacts of MPAs, and Verissimo et al (2018) on the impact of social marketing campaigns in fisheries). This could include considerations of geographic representability, ensuring a good balance between different policy instruments and of different types of terrestrial and marine ecosystems, and ideally prioritising larger initiatives that are being planned18.