Australian cities are home to more than people.
More than thirty percent of endangered species live in urban areasbut one of the biggest problems many animals face is that the places that were once their homes no longer exist.
Urban development destroys habitats, forcing many organisms into smaller or degraded environments that provide poor quality of life and reduced prospects for long-term survival.
The disturbing decline in the number of large old trees worldwide, and the resulting loss of hollows that develop in their trunks and branches is a typical example. Tree hollows provide shelter for many birds, mammals and reptiles.
Unfortunately, these old hollow trees are becoming more and more very rare in the towns. Managers and residents cut them down thinking they might fall or cause heavy branches to fall. Replacement shafts may take centuries to mature.
There is an urgent need to provide habitat structures that can allow wildlife to thrive in cities, but it is a difficult challenge. For example, one response to the lack of hollows in trees is to install artificial hollows like birdhouses. Although these boxes can help, they have several shortcomings – they can deteriorate easily and some animals do not like to use them.
In our recent studywe show how computer-aided design and manufacturing can improve the design of artificial cavities, opening up new opportunities to restore animal habitats in urban settings.
Computer-aided design uses software to create 3D models of objects, while computer-aided manufacturing automates their manufacture. These technologies have risen to prominence since the 1960s, helping to design cars, planes, boats, rockets and buildings.
From laser cut reefs at 3D printed dykes, computers make it possible to create complex structures on several sites. We show that computer-aided design and fabrication can produce structures that resemble natural hollows while incorporating organic and thermally stable materials. The resulting structures are easy to reproduce, adapt, assemble and install.
These benefits result from the process we have developed to help designers explore new technologies, materials and approaches. The process takes into account the needs of the target species, the people installing the cavities and other members of the local ecosystems, including animals and plants.
Recently featured on ABC Catalystour project tested these ideas in a pilot project targeting the largest cavity-dwelling bird in Australian cities – the mighty owl (Ninox strenua).
Using computers, we designed cavities that are inspired by structures in the natural habitat that mighty owls use for nesting – tree cavities and termite nests.
Like tree cavities, our man-made cavities feature rounded entrance pads for landing, tunnels for feeding, and stepped interiors for easy climbing. Like termite nests, they adapt precisely to the complex geometries of host trees. 3D scanning helps adjust hollows on branches to owl-preferred positions and in areas where arborists find installation easier.
We built two types of computer-designed cavities – one out of 3D-printed wood and the other out of hempcrete (a construction product that is a mixture of hemp wood fibers with lime and water). Our assembly process uses augmented reality headsets that overlay digital guides on physical models to simplify assembly using modular components.
We are currently monitoring the performance of these computer-designed hollows against birdhouses and sculpted logs. We installed the prototype cavities at sites across Melbourne and fitted them with sensors to collect microclimate and habitation data. Monitoring will inform our computational models and material selections to improve future designs.
It will take some time to find out if the computer-designed hollows will attract mighty owls. Targeting these elusive birds is an extremely ambitious goal. Mighty owls are rare, listed as threatens in Victoria, and there was almost no success encouraging them to use artificial cavities.
Other species, including lorikeets and opossums, have shown interest in using our hollows. It’s a promising sign for conservationists and land managers looking to support local biodiversity or increase owls’ prey base.
There are exciting opportunities to extend our approach to create more ambitious and effective designs for other sites and species. Future research will explore the use of new biomaterials that are durable, feasible, and suitable for target animals. Possibilities include robotic printing claysprayed by drone mudor 3D printed aggregates of The sticks.
This work on artificial cavities is part of the broader change in design practices that increasingly recognize the need for the creation of innovative habitats. Innovative examples range from environmentally friendly lighting and designs that support moss growth on buildings at light tensegrity structures which provide birdhouses on power poles.
These proposals show what urban areas could look like when designers use technologies for ecocentric purposes instead of focusing solely on human purposes. They present relevant ideas for architects and others who have declared their commitment to address the climate and biodiversity crises.
We hope that innovations that retrofit existing structures or construct new buildings can use computer-aided design to present compelling visions for successful coexistence with wildlife in urban environments.
The project shows what is possible when interdisciplinary teams work together on difficult ecological problems. This research is the result of a collaboration between the University of Melbourne (Deep Design Lab; Melbourne School of Design; School of Ecosystem and Forest Sciences; School of Biosciences; Soils and Sustainability), Monash University, Deakin University, Knox City Council, Melbourne Tree Careand the Hemp construction company among others.
Banner: A 3D printed wooden hollow being installed at the System Garden at the University of Melbourne. Photo: provided