When diggers move in, trees come down and concrete is poured, the chances of nature surviving in the altered environment beyond a few neatly positioned planters seem slim.
A recent report by the Climate Change Advisory Council (CCAC) says, however, that biodiversity must be built into construction projects from now on.
It is calling for a “no net loss” approach, meaning that whatever biodiversity is moved, felled or flattened by development must be replaced on-site or in an alternative location.
The ask is less ambitious than in Britain, where a 2021 law introduced the principle of “biodiversity net gain” requiring developers to leave nature 10 per cent better off.
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But it would still require a change in how planners, developers and builders go about their business.
Guidance prepared by the Irish branch of the Chartered Institute of Ecology and Environmental Management includes a long list of measures that could be considered.
Bird and bat boxes and replacement planting are common enough features, but the greater challenge is creating biodiversity corridors around and through developments that connect seamlessly with newly created semi-wild green areas and with natural hinterlands beyond.
Heavy emphasis is placed on sustainable drainage systems that prioritise green space and ponds over paving so rain is soaked up naturally.
The look is not the pruned and polished finish generally depicted in artists’ impressions in property brochures.
[ New buildings must present ‘no net loss’ to nature, says Climate Change CouncilOpens in new window ]
It also requires a more tailored approach to individual development sites and, potentially, the foregoing of some valuable square footage, which suggests higher costs.
Not necessarily so, says Marion Jammet of the Irish Green Building Council, which has researched developments that have successfully preserved or even enhanced biodiversity.
Examples include the new Central Mental Hospital in Portrane, Dublin, where existing woodlands were expanded and new grasslands and wetlands were created for drainage.
“It doesn’t have to be more expensive. In fact, the HSE saved money [about €100,000] by this approach instead of installing the traditional underground attenuation tanks,” Ms Jammet said.
“The way to do this is to make sure that ecologists are involved early and that everyone is working together and willing to listen to each other early in the process.”
The HSE had the advantage of a large site with pre-existing natural features to work with but another, more typical example is the Observatory building. This six-storey office block in Dublin’s Docklands is surrounded by tar and concrete at ground level but has a lush green roof above.
It is essentially a roof garden designed as a semi-natural habitat with rooted plants and grasses that alleviate stormwater run-off, keep the building cool on hot days, support birds and pollinators, cleans the air and provides breathing space for workers.
The Irish Green Building Council is working on examples of how “no net loss” principles could be incorporated into a much wider range of buildings and is involved with the Housing Agency and Trinity College in a “Bio-Neighbour” project that focuses specifically on housing developments.
“If we are really going to build 50,000 homes every year, we have a potential to cause a lot of problems or do a lot of good for biodiversity,” Ms Jammet said.
“The Bio-Neighbour project is very much about making sure that biodiversity-led residential development becomes the new norm.”
Making “no net loss” the norm in all planning and development requires formalising the principle, the CCAC said in its report.
“Regulation is needed on how no net loss of biodiversity should be practically achieved in the planning and execution of individual projects,” it said.
“This will require further clarity and systems on key issues such as metrics on how biodiversity is measured and valued, as well as the impact of applying measures on- and off-site to benefit biodiversity.”
The National Planning Framework, published last summer, says local authorities, in their role as planners, “should seek to address no net loss of biodiversity”.
In a statement, the Department of Housing added that all local authorities are required to have a biodiversity action plan in place by the end of next year to strengthen their approach.
However, the Irish Green Building Council supports the CCAC in calling for specific regulations.
“It’s already happening in some local authorities but it’s quite fragmented and it’s not consistent, which makes it difficult for developers,” Ms Jammet said.
Dr Mark Mulville, head of the School of Surveying and Construction Innovation in Technical University Dublin, sees another difficulty: the application of no net loss principles to existing buildings.
“The best kind of building is the one you don’t build. From an embodied carbon perspective, you want to hold what you have, but the financing of working on that building becomes really difficult,” he said.
Many buildings are left sitting vacant because it is not economically viable to refurbish them, he said.
“In a way, it would be easier to knock them down and start again and then you could incorporate all these features from inception. We’re in a difficult situation in that the right thing to do and the feasible thing to do are not necessarily aligned.”
