Cities and Biodiversity Outlook
With proper planning and management, cities can retain substantial components of native biodiversity

With proper planning and management, cities can retain substantial components of native biodiversity

Despite what is often commonly believed, fact is that many cities have high species richness. Several are even located within globally recognized "biodiversity hotspots"—areas with exceptionally high biodiversity (at least 1,500 endemic plant species) that have lost at least 70% of their original habitat area.

Some notable examples of cities with rich biodiversity are found on nearly all continents and latitudes - Berlin, Chicago, Curitiba, Kolkata, Mexico City, Montreal, Nagoya, New York City, São Paulo, and Singapore, to name but a few.

Many cities also contain protected areas within or just outside their borders that provide important contributions to biodiversity. In Cape Town, Table Mountain National Park, an iconic landmark extraordinarily rich in endemic plants and animals, is entirely surrounded by the municipality. In Mumbai, Sanjay Gandhi National Park—known for its dense semi-evergreen forests, 280-plus species of birds, 150 species of butterflies, and 40 species of mammals, including a small population of leopards—protects 104 square kilometers entirely within a megacity. In Stockholm, the National Urban Park comprises 2,700 hectares with high biodiversity, right in the city center.

Connecting fragmented ecosystems is also likely to increase ecological functionality as a whole and therefore to maximize the ecosystem services offered. There are diverse and innovative ways to connect natural ecosystems. Planting trees with overarching canopies can help small mammals, birds, and insects cross roads and highways. Roadside planting that mimics the multilayering of forests—for example, composite of tall trees, medium-sized trees, shrubs, and understory vegetation—can cater to a diversity of animal users. Ecolinks such as underground tunnels and vegetated overhead bridges can help connect natural areas. All of these efforts can complement the important roles played by protected areas in cities.

Many tools exist to help cities manage their biodiversity. One such tool is the City Biodiversity Index (or CBI, also known as the Singapore Index). This and many other initiatives can help cities conserve and manage their biodiversity.

AICHI TARGET 5: By 2020, the rate of loss of all natural habitats, including forests, is at least halved and where feasible brought close to zero, and degradation and fragmentation is significantly reduced.

Cities can help preserve forests and wetlands of critical biodiversity by ensuring the connectivity of existing and future protected areas. Managing footprints (best done at the provincial, state, or regional level) can also make a difference.

AICHI TARGET 12: By 2020 the extinction of known threatened species has been prevented and their conservation status, particularly of those most in decline, has been improved and sustained.

Campaigns by scientific institutions, zoos, museums, and aquaria— where city and regional authorities often have a managing interest—can raise critical attention and funds and provide technical assistance for the conservation of threatened species, even across the globe.

Cape Town

With a population of just under 3.7 million people and a land area of 2,500 square kilometers (0.2 percent of South Africa's total land area), Cape Town supports 50 percent of South Africa's critically endangered vegetation types and about 3,000 indigenous vascular plant species. Cape Town falls within the globally recognized biodiversity hotspot known as the Cape Floristic Region; of the 18 vegetation types in the city, 11 are critically endangered and 3 are endangered. Although this statistic in part reflects severe land-use pressure, it also disproves the common assumption that cities cannot have high levels of biodiversity. What's more, many of the plant species found in metropolitan Cape Town are endemic—found nowhere else on Earth.

São Paulo

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 recognized 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. The city's Green Belt Biosphere Reserve, part of UNESCO's Mata Atlantic Biosphere Reserve, protects remnants of this rainforest as well as associated ecosystems.

City Biodiversity Index

The City Biodiversity Index, or CBI (see p. 53), also known as the Singapore Index on Cities' Biodiversity, is a self-assessment tool that encourages cities to monitor and evaluate their progress in conserving and enhancing biodiversity. More than 50 cities around the world are in various stages of testing the CBI and providing data for it. It currently comprises 23 indicators in three components: native biodiversity, ecosystem services provided by biodiversity, and governance and management of biodiversity. Stakeholders such as universities and civil society can assist in providing data. A platform for cities to share their experiences in applying the index has been particularly useful to cities considering using the CBI.

Other applications for the CBI have also surfaced. For example, information from it can be used in the decision-making and master planning of cities; it can assist policy- and decision-makers in allocating resources and prioritizing projects; good practices can be made into case studies for sustainable development; and some of the indicators can form the basis for calculating the economic value of biodiversity and ecosystem services. The CBI is also a useful public communication tool for city authorities. With ongoing refinement and improvement, it is continually becoming more valuable.

Singapore

By virtue of its geographical location, Singapore has a rich natural heritage. More than 10 ecosystems are found in this highly urbanized city— state of 5 million people. Although much of its biodiversity disappeared during the British colonization, Singapore still has a wealth of flora and fauna. Among the native species recorded are 2,145 vascular plants, 52 mammals, 364 birds, 301 butterflies, 127 dragonflies, 103 reptiles, 400 spiders, 66 freshwater fishes, and 255 hard corals. Between 2000 and 2010, intensive surveys found more than 500 species of plants and animals new to Singapore, of which more than 100 were new to science. Nestled in the heart of Singapore and not more than 15 kilometers from the busiest shopping areas are the Central Catchment Nature Reserve and Bukit Timah Nature Reserve. A network of parks and park connectors permeate the island, allowing easy access to varied habitats rich in plant and animal life.

Image source: Matthew Knight, Flickr

Our Biosphere

Figure 1: Our Biosphere
Life is an integral part of the Earth system. Living things influence the composition of the atmosphere by "inhaling" and "exhaling" carbon dioxide and oxygen. They play a part in the water cycle by pulling water from the soil and the air, and they help put it back again by exhaling water vapor and aerating the soil so rain can soak into the ground. They regulate ocean chemistry by taking carbon out of the atmosphere. Earth would not be the planet that it is without its biosphere, the sum of its life.
Source: NASA Earth Observatory

Biodiversity Hotspots

Figure 2: Biodiversity Hotspots
The biodiversity hotspots hold especially high numbers of endemic species, yet their combined area of remaining habitat covers only 2.3 percent of the Earth's land surface. Each hotspot faces extreme threats and has already lost at least 70 percent of its original natural vegetation. Over 50 percent of the world's plant species and 42 percent of all terrestrial vertebrate species are endemic to the 34 biodiversity hotspots.
Source: Conservation International

World Protected Areas

Figure 3: World Protected Areas
Protected areas or natural parks are locations which receive protection because of their recognized natural, ecological and/or cultural values.
Source: Protected Planet

Rua Gonçalo de Carvalho, Porte Alegre

Figure 4: Rua Gonçalo de Carvalho, Porte Alegre
Rua Gonçalo de Carvalho in Porto Alegre, Brazil, is a stunning example of a natural urban ecolink. When this tree-lined street was threatened by development, local residents and environmental groups mobilized to protect it. In June 2012, Porto Alegre passed a law protecting this and more than 70 other "green tunnels" in the city.
Source: Adalberto Cavalcanti Adreani (Picture)

Global Species Richness

Figure 5: Global Species Richness
Centers of richness for mammals, amphibians and birds listed with the International Union for the Conservation of Nature.
Source: IUCN & PNAS

Stockholm

Figure 6: Stockholm
Stockholm, the most populous city in Scandinavia, comprises 216 square kilometres and includes 160 kilometres of waterfront and 14 islands. More than 14 percent of the city consists of aquatic environments. Among terrestrial environments, lush parks and residential areas with old, densely vegetated gardens complement protected areas and remnant patches of trees and grassland. Although the twentieth century saw a significant homogenization of Stockholm's hinterlands, the city still supports a rich and diverse flora and fauna. More than 1,000 species of vascular plants have been recorded. Of 69 species of mammals known to breed in Sweden, 43 reproduce in or near Stockholm, including, somewhat controversially, wolves (Canis lupus) only a few tens of kilometers from the city. This rich biodiversity can be attributed in part to the city's radial layout of infrastructure, which has left several green wedges connecting Stockholm to its hinterlands, and to a history of environmental efforts that date to the late 1800s. More than 40 percent of the city's land area still consists of green spaces.
Photo: Digital Globe / Google Earth (Picture)

Population growth and biodiversity hotspots

Figure 7: Population growth and biodiversity hotspots
The map shows the world's biodiversity hotspots, i.e. areas with extremely rich biodiversity that have lost 70 percent of their natural habitats, and the areas expected to have the largest populations by 2020.
Source: Conservation International & UN