Towards a standardized protocol to assess natural capital and ecosystem services in solar parks

1. Natural capital and ecosystem services have emerged as fundamental concepts of ecosystem management strategies in the past two decades, particularly within major international land assessment frameworks, including the UN's Millennium Ecosystem Assessment and the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services' Global Assessment Report. 2. Despite the recent development of several analytical methods and models to quantify changes in natural capital and ecosystem services resulting from land use change, incorporating them into the land planning process can be challenging from a practical point of view without guidance on standard methods. 3. In an attempt to decarbonize energy supply systems to meet internationally agreed targets on climate change, solar energy production, in the form of ground-mounted solar parks, is emerging as one of the dominant forms of temporary land use for renewable energies globally. 4. We propose 19 directly measurable indicators associated with 16 ecosystem services within three major stocks of natural capital (biodiversity, soil and water) that are most likely to be impacted by the development of solar parks. Indicators are supported by well-established methods that have been widely used in pure and applied land use research within terrestrial ecosystems. Moreover, they can be implemented flexibly according to interest or land management objectives. 5. Whilst not intended as a precise recipe for how to assess the effects of solar park development on hosting ecosystems, the protocol will guide the solar energy industry and all actors involved, be they researchers, practitioners, ecological consultancies or statutory bodies, to implement a standardized approach to evaluate temporal and spatial changes in natural capital and ecosystem services resulting from solar park development and operation, with the ultimate aim of generating comparable and reproducible data on ecosystem impact assessment across the solar energy sector.