New Study Uncovers Benefits of Biophilic Design in Urban Environments
By Fay Harvey
UTRECHT, Netherlands — New research shows that exterior green design, such as plant-covered facades, can boost biodiversity and regulate temperature.
From Utretcht University in the Netherlands, ecologist Kathrina Itecht conducted novel research analyzing the effects of vertical greenery systems (VGSs) in urban environments. Through the study, Itecht found that VGSs can insulate buildings and act as home for a range of species. As natural habitats are lost due to increased industrialization and human population growth, the study shines a light on the indispensable impact biophilic design can have on urban environments.
Study Method
Alongside the Resilient and Inclusive Cities Lab at Singapore’s Nanyang Technological University, led by Perrine Hamel; the Singapore-based company bioSEA, led by Anuj Jain; Utrech University’s microbiologist Han Wösten; and Leanne Haan, a master’s degree student at Utrecht University, Itecht analyzed 20 building facades in Singapore’s urban environments. The study aimed to assess the impact of foliage-rich VGSs on temperature regulation, animal life and ecological synergy in tropical settings.
The results were then compared to rocky cliffs, serving as the natural benchmark, and non-vegetated building walls, which acted as the control group to measure species already present but not specifically drawn to vegetated features.Past studies researching the topic did not compare VGSs to other material locations. Due to the study’s method of comparing VGSs to natural references like cliffs, this research presents a first-of-its-kind framework.
Results
Researchers found that green walls acted as a temperature buffer. The wall’s greenery had insulating effects, creating a cooling layer in the day and a warming layer at night. For example, researchers discovered daytime cooling effects of 0.6-0.7 degrees Celsius between the front and the back side of green walls.
“This might sound like a small difference, but in the context of urban heat, even small reductions can lower energy costs and make buildings more comfortable to [live] and work in,” said Hecht in a statement.
This cooling effect could help counteract the higher temperatures that cities typically face compared to rural areas, in turn improving climate resilience within cities, Hecht added.
VGSs were also shown to be the host for a variety of species. Researchers found 291 species across the observed walls—including insects, spiders and birds—which greatly outperforms the amount of biodiversity on non-vegetated walls.
However, natural green walls in urban environments attracted slightly higher levels of biodiversity compared to VGSs. To Hecht and her team, this proves that there are plenty of notes to take from nature’s natural design. The finding also demonstrated the potential of VGSs to create habitats in locations that are typically unsuitable for certain species.
In addition, surrounding natural greenery proved to have an impact on biodiversity and VGSs, exemplifying how human-made green walls should be a part of bigger eco-rich system if they are to succeed in urban environments.
“What I found really interesting to confirm in our study is how important trees and other vegetation are,” Hecht said in a statement. “The crowns of nearby trees and patches of greenery serve as stepping stones. They allow bees, bugs, and even small birds to hop from tree to tree and eventually reach the green walls.”
Future Research
In prior studies within the Netherlands, students from Utrecht University found outdoor green networks to also be critical in the regions where the weather is cooler. Though Hecht’s recent research took place in Singapore’s humid environment, she believes these new findings could also apply to temperate climates.
“The principles would be similar,” said Hecht in a statement. “Although we would need to tailor the plant species and specific designs to the local biodiversity and weather conditions.”
As green infrastructure projects within the Netherlands grow, Hecht said the Northern European country could be a good region for additional studies. In colder regions, this would involve using native climbing plants to cover urban walls, along with integrating moss and perennials.