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BANGALORE
Warsaw’s current urban landscape is one of modern and contemporary architecture
MONDAY, NOVEMBER 5, 2012
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Inconvenient truth Urbanisation will have significant implications for biodiversity and ecosystems if the current trends continue,warns a new UN assessment. The report, released at the recent Conference of Parties of the UN Convention on Biological Diversity in Hyderabad, is summarised here by Subir Ghosh
Warsaw seen from satellite. About 65% of Poland’s bird species are found in capital Warsaw
(Below) An aerial view of the European Quarter of Brussels. Over 50% of Belgium’s floral species are found here
A TransMilenio (rapid transit system) station in Bogotá, capital of Colombia. Bogotá’s urban development had placed a strain on its roads, but within the past decade significant efforts have been taken to ease traffic and related issues. for instance, measures such as closing roads on weekends, improving the bus transit system and creating bicycle paths resulted in increased physical activity among residents, and a reduction in greenhouse gases emissions
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f the spectre of urbanisation scares you off, wait till you hear this: global urban population is set to almost double from 2.84 billion in 2010 to 4.9 billion in 2030. And 60 per cent of the area projected to be urban in 2030 has not been built yet. And this will, obviously, come with a price. Urban expansion will be drawing heavily on natural resources, including water, and will consume prime agricultural land, with knock-on effects on biodiversity and ecosystem services elsewhere. Life will become congested and some forms of life may fall by the way side too. Most future urban expansion will occur in areas of low economic and human capacity, which will constrain the protection of biodiversity and management of ecosystem services.
This spelling of doom comes in the form of a comprehensive document, Cities and Biodiversity Outlook (CBO), that was released by the secretariat of the UN Convention on Biological Diversity (CBD) at its recent Conference of Parties (CoP) meeting in Hyderabad in October. It is the first global analysis of how projected patterns of urban land expansion will impact biodiversity and crucial ecosystems. “The way our cities are designed, the way people live in them and the policy decisions of local authorities will define, to a large extent, future global sustainability,” said Braulio Dias, executive secretary of the CBD. “The innovation lies not so much in developing new infrastructural technologies and approaches but to work with what we already have. The results often
1 ariety and richness of g genetic variation) d in and on the edge of biodiversity ranges e urban core. At the el it includes: capes (eg leftovers of onal agricultural areas of arable land). es (eg city centres, al parks, railway areas, brownfields)
A view of Bangalore city, which is fast losing its green cover due to urbanisation and unplanned development. Residential and development projects are mushrooming in tree-rich residential areas, erasing the tree cover. Glass buildings, commercial complexes, mounds of garbage and pollution have become synonymous with the so-called Garden CIty
require fewer economic resources and are more sustainable,” he said. The CBO says points out that urban expansion is occurring fast in areas close to biodiversity “hotspots” and coastal zones. In rapidly urbanising regions, such as large and mid-size settlements in sub-Saharan Africa, India and China, resources to implement sustainable urban planning are often lacking. “More than half the global population already resides in cities. This number is projected to increase, with 60 per cent of the population living in urban areas by 2030,” said Achim Steiner, UN under-secretary general and executive director of the United Nations Environment Programme. “The CBO makes a strong argument for greater attention to be paid by urban planners and managers to the
nature-based assets within city boundaries. Sustainable urban development that supports valuable ecosystems presents a major opportunity for improving lives and livelihoods, and accelerating the transition to an inclusive green economy,” he added. THE FUTURE AND URBAN BIODIVERSITY Hope, perhaps, lies in success stories. Cities can indeed play a role
Asia: The region will be home to almost half the world’s increase in urban land over the next 20 years. The most extensive changes will occur in India and China. India’s growing urban clusters (such as the Mumbai-Delhi industrial corridor) are likely to transform entire regions, with significant impacts on habitat and biodiversity. Loss of agricultural land to urbanisation, combined with insufficient planning for food supply lines, places a severe constraint on future food security for India’s growing population. Lifestyle changes in India due to urbanisation may decrease pressures on forests due to less use of fuel wood and charcoal. In China, urban areas are increasingly encroaching on protected areas
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other continent, and most population growth will occur in cities of less than 1 million people. These cities often have weak governance structures, high levels of poverty and low scientific capacity regarding biodiversity. Low levels of formal employment in cities places high dependency on the provision of ecosystem services (eg water and food production) from areas either within or close to city limits
■ Even backyard gardens can harbour significant biodiversity: a study of 61 gardens in the city of Sheffield, UK, found 4,000 species of invertebrates, 80 species of lichen, and more than 1,000 species of plants ■ Cities can be important habitats for a diverse bee fauna. Bees in urban and suburban settings have a richer, healthier diet than bees in modern intensive farmland settings ■ Medium-sized carnivores such as the red fox, coyote, Eurasian badger and raccoon living in or around urban areas may achieve higher population densities than they do under natural conditions ■ One of the world’s largest cities, Mexico City has 8.8 million inhabitants in the city proper and about 22 million in the metropolitan area. The city supports about 2 per cent of all the known species in the world, including 3,000 species of plants, 350 species of mammals, 316 species of birds and many species of aquatic plants and animals
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■ Nairobi National Park, 7 km from the centre of Nairobi, is renowned for its wildlife. More than 100 species of mammals and 400 species of birds thrive in the park
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THE WAY FORWARD With urbanisation set to change the very nature of the planet, preserving biodiversity in the urban world will require going well beyond the traditional conservation approaches of protecting and restoring what we think of as “natural ecosystems.” Cities already represent a new class of ecosystems shaped by the dynamic interactions between ecological and social systems. This also
calls for urban societies to become more proactive in preserving components of earlier ecosystems and services that they displace. While urbanisation displaces many species, other species have evolved adaptive responses in behaviour and physiology to not only survive but thrive under urban selection pressures. Novel plant and animal communities have evolved in urban areas, often with active management by human society, and some of these now provide important services extending beyond urban boundaries. The CBO report maintains, “There are no global panaceas to urban biodiversity and ecosystem management, or to sustainability. However, there is much to be gained from questioning current trajectories and values while learning from others, producing better evidence and sharing information and experiences. No city can solve the current challenges alone.”
Africa: Africa is urbanising faster than any
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in supporting plant and animal species and diverse ecosystems. One of the best examples comes from Brussels — over 50 per cent of Belgium’s floral species can be found in the city. Better still, 65 per cent of Poland’s bird species occur in capital Warsaw. Urban biodiversity also delivers important health benefits. Studies have shown that proximity to trees can reduce the prevalence of childhood asthma and allergies. Sustainable urban planning, which addresses biodiversity issues along with other priorities such as poverty alleviation, employment, and housing, can bring positive effects for health and the environment. In Bogotá, Colombia, for instance, measures such as closing roads on weekends, improving the bus transit system
and creating bicycle paths resulted in increased physical activity among residents, and a reduction in greenhouse gases emissions. Professor Thomas Elmqvist of the Stockholm Resilience Centre and scientific editor of the report makes a point, “Cities need to learn how to better protect and enhance biodiversity, because rich biodiversity can exist in cities and is extremely critical to people’s health and well-being.”
■ With a population of just under 3.7 million people and a land area of 2,500 square kilometres (0.2 percent of South Africa’s total land area), Cape Town supports 50 per cent of South Africa’s critically endangered vegetation types and about 3,000 indigenous vascular plant species. Cape Town falls within the globally-recognised biodiversity hotspot known as the Cape Floristic Region; of the 18 vegetation types in the city, 11 are critically endangered and 3 are endangered
Latin America and the Caribbean: The number of cities in the region has grown sixfold in the past 50 years. Urban sprawl caused by housing for low-income residents often occurs in important areas for biodiversity and ecosystem services, such as wetland or floodplains. These are mistakenly considered to be of marginal value by planners
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Europe and North America: In Europe, the current urbanisation level is 70-80 per cent, and urban growth in recent decades has mostly been in the form of land expansion rather than population growth. Many European and North American cities have exhibited trends of shrinking and/or shifting patterns of population in central parts of the cities, coupled with sprawl in outer suburbs and exurban areas
■ In the USA, city parks increase the value of nearby residential properties by an average of 5 percent; excellent parks can provide a 15% increase
■ In Lanzhou, China, a 2,789hectare urban forest area provides climate regulation —cooling and evapo-transpiration —valued at RMB 85,800,000 ($14,000,000) annually
■ In 2007, park-derived tourist spending in San Diego, California, amounted to $144.3 million—$40,033,000 of which was estimated to profit the local economy
■ Table Mountain National Park in Cape Town contributed R377 million to South Africa’s GDP between 1998 and 2003. The park also provides numerous employment opportunities in conservation
■ In Canberra, Australia, local authorities plant trees to generate a wealth of benefits. More than 400,000 trees can be found within the city limits. This urban forest helps mitigate the urban heat island effect, thereby reducing the need for energy-intensive airconditioning and ventilation. The trees also improve air quality, intercept and absorb storm water, and sequester carbon
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■ São Paulo, Brazil, is the most populous city in the Southern Hemisphere and the third largest city in the world, with more than 11 million inhabitants. This megacity contains biodiversity from the Brazilian Atlantic Rainforest, a globally recognised biodiversity hotspot. Twenty-one percent of the city is covered by dense forest in various stages of ecological succession, but these remnants are under severe threat from the unrestrained occupation of both low-income housing and luxury condominiums. An impressive 1,909 plant species and 435 animal species have been recorded in the city, with 73 of the animal species endemic to the Brazilian Atlantic Rainforest
■ In Sacramento, California, city residents who exercise in parks tend to have lower medical costs; in 2007, the average medical cost difference between active park users and inactive users was $250 for adults under age 65 and $500 for adults 65 and older
■ In 2005, the trees of Washington, DC, removed 244 tons of carbon dioxide, nitrogen dioxide, ozone, particulate matter, and sulphur dioxide, at a savings value of $1,130,000
PICS: DNA/Wikipedia