Rowan Williams Davies & Irwin Inc., Senior Executive Consultant & Past President
The unprecedented wave of exceptionally tall buildings being designed and constructed around the world is only one of the most eye catching manifestations of the rapid urbanization of mankind. As we urbanize we also need to be very cognisant of the consequences of the way we design and live in our urban habitat to ensure we are moving in a sustainable direction. I think of sustainability as living in a way that will allow both our current and future generations to lead a high quality of life. This quality will not be there unless we maintain and preserve what remains of the incredibly diverse ecosystem in which the human race evolved.
Architects, designers and urban planners are increasingly aware of the need to build more sustainable buildings and infrastructure. But there is a need to give equal knowledge-based attention to creating and preserving an ecologically sustainable natural environment within our urban areas. Most architects and planners are aware that green spaces, parks and woodlands are essential elements of the urban habitat and that they contribute greatly to the livability of cities and to the health and well-being of citizens. Trees provide shade, help retain water and control run-off; flowering plants and shrubs beautify and attract wildlife such as birds and butterflies and can provide shelter from winds. However, designers and landscapers often take a narrow view of what this means in practical terms.
Planting hardy and drought-resistant plants to minimize maintenance and reduce water usage is simply part of creating sustainable natural environments in urban areas. We need to green our cities in a way that fosters an ecologically diverse natural environment; one that supports the lifecycles of the insects, birds and other small mammals that are part of a healthy and sustainable eco-system. These creatures need food and water as well as nesting, roosting and overwintering sites--a habitat that for thousands of years has been provided by the plants growing naturally in the local area. Landscaping that emphasizes turf grass and a narrow range of non-native shrubs and flowering plants will not support viable eco-systems and will hasten the decline in the number of birds, butterflies and other beneficial insects, found in urban areas. Among these beneficial insects are those responsible for pollination and the production of seeds and fruits.
The quality of the natural environment within urban areas has taken on increased importance with the loss of diversity and ecological integrity in adjacent rural areas, due to current agricultural practices. The removal of trees, hedgerows and all non-crop plants from farmland, together with the emphasis on mono-culture --huge fields of genetically identical plants--has so reduced the natural populations of pollinating insects, primarily bees, that farmers and fruit growers in some areas of North America must now “import” truckloads of beehives to ensure that their crops are pollinated. There is a whole industry of bee keepers in North America who truck in their beehives from long distances at the right time of year and feed the bees on a narrow diet the rest of the year. These colonies of honeybees native to Europe have become vulnerable to disease and we are now hearing about the collapse of the honey bee population. This problem need not have arisen if a diversity of plants had been left in the crop areas to provide habitat for the many native bees and other pollinators who would have performed this function in the past.
A lack of diversity of native plants results in loss not only of bees but also many other insects. This subsequently impacts the population of birds and animals that feed on these insects and a general collapse in diversity occurs, which represents a terrible loss to our quality of life.
But the urban habitat can actually help restore diversity if we plan it right, by including parks and landscaping features that are deliberately planted with species that cater to pollinators and other native insects. There are now many interesting examples of ways to create ecologically diverse and sustainable green infrastructure in urban areas: the High Line project in Manhattan, Ken Yeang’s bioclimatic skyscrapers and the proliferation of green roofs in a number of cities are just a few examples. The Royal York Hotel in Toronto uses its 13th floor roof terrace as a garden to grow fresh herbs, tomatoes and edible flowers for its kitchens and also has beehives to ensure pollination occurs. In my hometown of Guelph, Ontario, Canada, a local charity, Pollination Guelph, is raising awareness of the need for pollinator-friendly gardening and landscaping and planting demonstration gardens in parks and domestic and commercial properties. They also plan to re-naturalize and create a pollinator meadow on a 45-hectare decommissioned landfill site. I suspect we are only at the beginning of exploiting the urban habitat’s capacity to provide both green and liveable spaces while supporting ecological diversity.
One of the interesting points to note about the urban habitat is that it is an area where we have some control over the microclimate. Studies of global warming have shown how sensitive plant, insect and animal species are to relatively small changes in microclimate. Therefore we should be able to create local areas in our urban habitats to nurture plants, insects and other creatures and help them adapt naturally to climate change thereby enhancing not only our present quality of life but that of our descendents. I look forward to seeing an increasing emphasis on thoughtful and science-based greening of our urban habitat in future conferences and congresses of the CTBUH.