The Gwent Levels SSSI is supposed to protect an ancient landscape, rich in culture and important for biodiversity, recreation, flood alleviation, carbon storage and food production. This include the Magor Marsh, one of the last remaining pieces of natural fenland that once covered the Levels and as a wetland, one of the UK’s most threatened habitats. Unfortunately, NextEnergy built the Llanwern Solar PV Park inside the SSSI, a ground-mounted solar project which is spread over an area of 260 acres. Gwent Wildlife Trusts report that the post-construction monitoring report for the Llanwern solar farm on the Levels shows a massive spike in damaging pollutants arising from the construction, with silt produced over 14 times higher than pre-construction levels. This is in an area known for its excellent water quality. Lapwings, a ground-nesting bird fell from 8 breeding pairs to two pairs post construction with only one nest recorded despite the provision by the developers of a “lapwing mitigation area. A breeding pair of cranes, a bird which is only just returning to the U.K. through vigorous conservation efforts have disappeared from the site. Reading all this you cannot but conclude that the development of a solar farm in such a sensitive site has been a disaster for biodiversity. Other solar proposals have been put forward for the Gwent Levels totalling 1,200 acres.
As an ecologist this is not a surprise to me as painful as it is to read. Mitigation measures for such developments often fail to the point where one wonders whether we’re engaged in a strange form of environmental Emperor’s New Clothes. The scientists know these mitigation measures are unlikely to work, I’m pretty sure the developers do as well and the relevant government planning departments and environmental regulators must know it too. Biodiversity Net Gain is unlikely to make a difference. These are new measures whereby developers will have to show, using a government biodiversity metric, that as a result of mitigation and compensatory measures in their plans there will be a gain in biodiversity. The metric is based on basic habitat surveys which score various habitats within the proposed development area to produce a baseline score of biodiversity units. The developer must show that as a result of measures they take, this baseline score increases. Looking at areas where Biodiversity Net Gain has been adopted early has revealed many issues with this rather crude approach to assessing biodiversity and the measures to improve it post development. Firstly, the calculation of biodiversity metrics appears to be a somewhat subjective process and different experts can have very different opinions especially about habitat type but also, to a lesser extent, habitat condition. There is also the issue that consultants may lack sufficient expertise to make such assessments or are pressurized by their consultants to reduce the biodiversity unit score. Other studies have identified significant errors in filling out the biodiversity metric spreadsheets. Highly distinctive habitats have also been not included in such baseline studies even though they lie within the boundaries of the development or will be impacted by them. Another major concern is that there is a lack of expertise within planning authorities to assess whether mitigation or biodiversity net gain plans put forward by the developer are realistic. Such plans should be based on sound scientific evidence, they should be subject to management to maximise the chances of success and monitoring should be in place to ensure that this is the case. These conditions have rarely been met so far and examples like the Gwent Levels demonstrates that mitigation measures can be nonsense. However, the situation is worse in that the legislation covering biodiversity netgain has very weak mechanisms of compliance monitoring and enforcement to the point where one academic study has concluded that the regulations are unenforceable.
Britain is one of the most biodiversity impoverished countries in the world. We need strong measures to halt a decline in biodiversity which has been going on for centuries but which accelerated following World War II. The current planning system leaves nature with few defences against enormous developments like Botley West. It is very much up to us to point out where such plans are damaging and where mitigation is unlikely to work.
Duffus, N., Atkins, T., Nicholas, H., Butler, A., Milner-Gulland,E.J., Addison, P., Bull, J., zu Ermgassen, S. (2023) Assessing Biodiversity NetGain plans: A quick guide for planners and developers. Oxford Martin School& NERC Agile programme.
Ermgassen S.O.S.E., Marsh, S.,Ryland, K., Church, E.,Marsh, R., Bull, J.W. 2021. Exploring the ecological outcomes of mandatorybiodiversity net gain using evidence from early-adopter jurisdictions inEngland. Conservation Letters 14: e12820.
Gwent Wildlife Trust (2023) https://www.gwentwildlife.org/news/protected-gwent-levels-under-threat-solar-power-station-takeover