Trees and the city: Trends of urban biodiversity

An interview with Dr. Lena Chan, director of the National Biodiversity Centre, National Parks Board, Singapore
Philipp Gassner Business Mirror 11 Jan 14;
2014’S New Year’s resolution—quit smoking, more sport, healthy diet? But certainly not living in the jungle! Oddly, this is true for half the Philippines’s population.

No, this is not the late effect of a New Year’s hangover speaking. The New Year will, indeed, mark more Filipinos living within the outside jungles: concrete jungles.

The biggest of them all, known as Metro Manila, harbors an estimated 25 million people in its greater sprawl. This quarter of the Philippines’s entire population, needless to say, doesn’t live in the trees.

However, Bob Marley’s famous metaphor of a concrete jungle is not too far-fetched. From a bird’s-eye perspective, tangled city labyrinths don’t seem that different from a rain forest or a coral reef. They are just another of Earth’s living systems.

According to the Asean Centre for Biodiversity, just like other ecosystems, cities provide shelter, a lot of shelter. Although cities occupy just 2 percent of the Earth’s surface, they harbor—like in the Philippines—50 percent of the world’s population.

But it’s not only human populations who find a home in cities. Also, numerous plants and animals are city citizens, contributing to important urban biodiversity hot spots.

On the other hand, cities are hot spots of environmental damage, using 75 percent of the planet’s natural resources. City ecosystems are interconnected with and draw on their surrounding ecosystems for goods and services. Their products and emissions, in turn, affect regional and global ecosystems.

Such knock-on effects bring major challenges for 2014 and beyond. By 2050 roughly 70 percent of the world’s population is expected to be urban, with Southeast Asia a little less hurried: Cambodia is still only 20 percent urbanized, followed by Vietnam with 30 percent.

Nevertheless, on the average, 44 percent of Southeast Asians are urban-dwellers, with Singapore taking the lead, wherein every single Singaporean calls the city his or her home.

What such a home feels like, shares Dr. Lena Chan, director of the National Biodiversity Centre, National Parks Board, Singapore, in an interview.

Is Singapore symptomatic for the global trend of urbanization?

Singapore is highly urbanized. Besides being a high-density city, Singapore also has to cater to many other land requirements. Solutions to address these challenges are pressingly needed. Singapore continues to work with agencies, communities and individuals to find innovative ways to improve peoples’ lives and the environment that we live in.

To improve people’s lives, Singapore became a garden city. Or a city in a garden?

On June 16, 1963, Lee Kuan Yew, the first prime minister of Singapore, planted a Mempat tree (Cratoxylon formosum). It symbolized the birth of a garden city which set off tree-planting on an island-wide scale. This campaign transformed Singapore into a beautiful clean city with flowers and trees.

As Singapore becomes more urbanized, we need greenery that functions more than a decorative purpose to ensure that the environment is sustainable and livable. Hence, Singapore decided to transform itself to a “City in a Garden” in which greenery would be pervasive and evident even on the city’s buildings in the form of vertical walls and rooftop gardens. Biodiversity would be rich even in urban landscapes, and the community would have an interest and stake in the greening of Singapore.



Talking about biodiversity, what is behind the Singapore Index on Cities’ Biodiversity?

Many cities around the world, including Singapore, have put in great efforts in biodiversity conservation. How does one know that these efforts are achieving what they aim to do? The Singapore Index on Cities’ Biodiversity, also known as the City Biodiversity Index, is an evaluation tool for assessing the status of biodiversity and ecosystems in a city; the ecosystem services that are provided by biodiversity in the city; and the governance and biodiversity-management practices of the city.

The Singapore Index comprises 23 indicators that are measured quantitatively and can be tracked by cities over time. The composite index will help cities to evaluate whether biodiversity has improved as a result of their conservation efforts and management efforts. Cities from Asia, Europe, North America, New Zealand and South America have applied the Singapore Index.



How many species are there in Singapore, then?

Singapore is located in a biodiversity hot spot. There are many native species found in Singapore from a variety of taxonomic groups. Here’s an indication of the diversity of native flora and fauna still found in Singapore, in spite of its urbanization: 2,145 native vascular plant species, 364 bird species (more than the number of bird species in France), 98 reptile species, 66 freshwater fish species, 306 butterfly species (60 butterfly species are found in the United Kingdom), 35 true mangrove tree species and 256 hard coral species (35 percent of the global total of 731 hard coral species).



Many of these species are nestled in the heart of Singapore and not more than 15 kilometers from the busiest shopping areas, in the Bukit Timah Nature Reserve. What is its importance to the city? And does it face challenges, considering the half-million visitors per year?

Bukit Timah Nature Reserve (BTNR) is conserved for its primary tropical rain-forest ecosystem, especially for the rich native biodiversity that it harbors. It is only one of two primary rain forests in the world located within city limits, and was declared an Asean Heritage Park in October 2011.

BTNR functions as a green lung by cooling the ambient temperature, replenishes the oxygen, cleans the air, moderates the water flow, etc. It is accessible for recreation. It also serves as an educational laboratory for schools and researchers.

With greater appreciation of its multiple values, BTNR has seen a rise in the number of visitors in recent years, and it is important to manage the challenges posed by high numbers of visitors. These include outreach efforts on how to appreciate nature and how to carry out one’s recreation in a way that is sensitive to the biodiversity, as well as to other visitors.



Such ‘islands’ of biodiversity are good and well, but aren’t they completely isolated by streets and buildings? After all, flowers or reptiles can’t cross a traffic light.

Developments potentially result in the fragmentation of sites with natural habitats in cities. It is a growing trend for cities to reconnect these natural areas. Singapore’s efforts to link nature reserves together with green corridors have grown with the placement of the ecological bridge Eco-Link@BKE.

Singapore is not the first city to have done this, and each city has to decide on the appropriateness. In Singapore we believe that the Eco-Link@BKE will add value to the ecological connectivity of the nature reserves and provide a larger effective area for the survival of our native fauna and flora. The park connectors and planting on our roads also contribute to linking up our natural sites.



With S$16 million, the green bridge is not exactly cheap. Moreover, with high competition for space and soaring rents, can we afford green space in cities?

Singapore has decided that greenery should be a major feature in our urban landscape. We believe that greenery will improve people’s lives and make Singapore a great city to work, live and play in. Pervasive greenery will also give Singapore a distinctive edge in attracting foreign investments in this highly competitive global economy.



Nevertheless, there are reports about Singaporeans being terrified of beehives and the like. How does this disconnection from nature fit to the image as green city?

It is inevitable that as people congregate in highly urbanized environments, they become alienated from the natural habitats. Human-wildlife interactions are common in cities. However, it is increasingly being recognized that biodiversity is important for an enriching and good quality of life.

Public awareness and education programs that inform people of the biodiversity and their roles in our lives will help people understand the importance of plants and animals. It is also crucial that people connect with nature by visiting these natural sites and actively participate in biodiversity surveys, gardening, nature walks, etc.

These efforts take time and we are seeing early positive signs that outreach and education are helping people develop a healthy appreciation for nature in their neighborhoods.

To realize our City in a Garden vision, community involvement is key. We actively engage the community through various initiatives like Community in Bloom, which was set up to promote gardening on a national level. There are now more than 600 community gardens island-wide.



Dr. Lena Chan, thank you very much for sharing these insights into the City in a Garden.

Cities like Singapore with rich biodiversity are found all over the world—Berlin, Chicago, Curitiba, Kolkata, Mexico City, Montreal, Nagoya, New York City or São Paulo, to list but a few. Then again, what does it take to turn a concrete jungle into a green jungle again and, at the same time, reduce their impact on the real jungles and other ecosystems out there? One answer comes from an ancient Garden City, Babylon, wherein its famous hanging gardens inspired a new way of farming given the limited space and lack of land for agriculture. Then, just add one dimension: Vertical farming, the cultivation of plant or animal life within skyscraper greenhouses.

Such sky farms reduce the dependence and impact on surrounding areas while reconnecting people to the origin of their food. Importing 90 percent of its food, Singapore took this unlikely idea seriously. In 2012 the world’s first three-story-high commercial vertical farm was opened in the city, already producing 500 kilograms of juicy vegetables per day. Biodiversity can be so yummy.

Eating healthy—a sound New Year’s resolution for the world’s concrete jungles.



(Philipp Gassner is a consultant for the Asean Centre for Biodiversity-Biodiversity and Climate Change Project based in Los Baños, Laguna, Philippines.)