The nature restoration law that will throw up some interesting design challenges

Game Changers: Biodversity Net Gain is now a legal in the UK stipulates any development has to result in ‘measurable’ biodiversity improvement

Solar panels are worth considering to save money in the medium to long term
Solar panels are worth considering to save money in the medium to long term

There are more acronyms in environmental law than you could shake a sustainably sourced stick at and developers have had to learn another one recently. BNG is short for Biodversity Net Gain and it became a legal requirement for developers of large sites working in the UK in February of this year and for smaller sites from April.

The measure stipulates that any development has to result in a “measurable” improvement in biodiversity of 10 per cent. So if your building is going on a site, which has grasslands, existing tree cover, hedgerows, a lake, stream or river the damage that the development does to that habitat has to be made up on somewhere, that damage and then some so the end result is 10 per cent more biodiversity being created as opposed to the bad old days of 100 per cent biodiversity being destroyed. In order to head off the possibility of greenwashing the law is rigorous.

A professional ecologist must be employed to work out the “units of biodiversity” being lost measured against those being gained. A measuring tool has been drawn up to assess the existing biodiversity and recommend the level of remediation. It should mean that developers who fell a mature tree or trees can’t get away with just planting new trees.

The habitat (or units of biodiversity) of a veteran tree cannot be replaced by new tree planting. The hope is that the measure could result in those incredibly valuable habitats being ring-fenced or protected from development and buildings being designed to incorporate existing natural features rather than just bulldozing them to create the blank brownfield wasteland.

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Although the law is not in effect in Ireland most developers are operating as though it, or something similar, is in the pipeline. The market for “biodiversity credits” opens up where farmers and landowners can be paid for the ecosystem services their existing habitat or newly created biodiversity can create. The hope is that this will be more closely regulated than the carbon credits market which got off to a less than wonderful start.

It will throw up some interesting design challenges. How do you incorporate a green roof and renewable energy when your sedum plants are competing for space with your photovoltaic panels?

The move should also create jobs, experts in managing grassland meadows so they remain biodiverse and full of multiple species of pollinator-friendly plants rather than evolving into species-poor monocultures.

There will be work in maintaining woodlands from invasion by deer, laurel or rhododendron. If BNG and other nature restoration laws are to work, longevity has to be priced into the system. These natural habitats need to last long into the future to make a real difference.

Catherine Cleary

Catherine Cleary

Catherine Cleary, a contributor to The Irish Times, is a founder of Pocket Forests