Reimagining urban transport and utility corridors to restore and connect an endangered ecosystem.

Urban road, rail and utility corridors transport people, electricity, gas and water across the world’s cities. In some cases, they contain valuable remnant ecosystems but most urban corridors do not support significant biodiversity. However, what if they could?

We are working with municipal governments, a rail operator and a water utility to reinstate species from the critically endangered native grasslands and grassy woodlands of southeastern Australia to urban corridors. This has included creating 3 ha to connect fragmented remnants along a major rail line, 1 ha along a water pipe easement, 500 m on top of a high-pressure gas main and multiple road verge projects. Ecologically this has been achieved by developing methodologies to sow diverse (up to 50 grass and wildflower species), scientifically calibrated seed mixes on to low nutrient technosols made from recycled construction wastes selected after chemical, biological and geotechnical evaluation. This allows diverse native wildflower seed mixes to be designed for projects that span the ecological restoration continuum, from highly designed urban green spaces responding to social pressures for attractive socially acceptable landscapes to a vegetation community that mimics the adjacent endangered native grassland. However, the method has also required changes to how organisations manage corridors, governance arrangements and extensive collaborations between ecologists, environmental engineers, urban corridor managers and the community.

These projects have created a biodiversity positive pathway by reintegrating endangered ecosystems into the urban matrix and transforming the way organisations think about infrastructure projects whilst achieving circular economy objectives. We have also demonstrated that they have more diverse pollinator communities and can increase rare plant, pollinator connectivity. We are now working to scale up. Research underway will determine whether trait-based restoration approaches are faster and more cost effective. For example, can a diverse seed mixes selected for wind dispersal traits colonise lower diversity areas of the corridor better than a random species seed mix and whether mixes with traits designed to maximise public preference (i.e. uniform height) increase connection to nature and well-being.  We also investigating how community assembly of the same seed mix varies with microclimate (influence of trees) and season of sowing.