New Maps Show How Urban Sprawl Threatens the World’s Remaining Biodiversity

Hotspot map of Baku, Azerbaijan / The Atlas for the End of the World

At the United Nations World Urban Forum in Kuala Lumpur, Malaysia, next month, the McHarg Center for Ecology and Urbanism at the University of Pennsylvania will display an alarming set of new maps. They show, in bright red, that the growth of cities worldwide is on a direct collision course with the world’s remaining biodiversity.

The study, of which these maps are a part, is titled Hotspot Cities and focuses on urban growth in the world’s 36 so-called biodiversity hotspots – large regions where unique flora and fauna is threatened with extinction. By combining data sets of 2030 urban growth forecasts from the Seto Lab at Yale University with the habitats of endangered species from the International Union for the Conservation of Nature (IUCN) Red List, the study has mapped over 400 Hotspot Cities to reveal that over 90 percent of them appear likely to sprawl directly into remnant habitat harboring the world’s most endangered biodiversity.

Hotspot map of Tel Aviv, Israel / The Atlas for the End of the World

The study also zooms in on 33 of the biggest and fastest growing of these hotspot cities to assess the degree of imminent conflict between growth and biodiversity. The cities are Sao Paulo, Los Angeles, Houston, Cape Town, Port-au-Prince, Baku, Brasilia, Santiago, Dar es Salaam, Nairobi, Sydney, Lagos, Rawalpindi, Mecca, Guangzhou, Esfahan, Osaka, Antananarivo, Ciudad de México, Durban, Tel Aviv, Guadalajara, Tashkent, Chengdu, Auckland, Davao, Honolulu, Perth, Jakarta, Bogotá, Guayaquil, Makassar (Ujung Padang), Colombo.

The 2016 UN-Habitat World Cities Report states that “urban and environmental planning provides opportunities and formal legal mechanisms for biodiversity conservation through design guidelines, building codes, zoning schemes, spatial plans and strategic choices, all coupled with effective enforcement.” Through detailed analysis, the study gauges the degree to which these sorts of mechanisms are being leveraged in the sample set of the 33 hotspot cities.

The conclusion is the overwhelming majority of these cities have not adopted long-term planning visions or mechanisms that include biodiversity values or, if they do, then they do not make such planning documents available or refer to the existence of such documents online. A notable subset set of cities such as Sydney, Perth, Cape Town, Sao Paulo, and Los Angeles do, however, and have transparent, readily available, variously-integrated planning documents inclusive of biodiversity protection across levels of governance.

Hotspot map of Los Angeles, California / The Atlas for the End of the World

A survey of the cities’ promotional materials, popular press, and institutional publications also indicates a low degree of cultural association with being hotspot cities, let alone hotspot stewards. Typically, one finds a city’s projected identity pertains to the characteristics of its urban core rather than its peripheral landscapes. Yet, the peri-urban landscape and its regional connections beyond, can not only support biodiversity but also provide cities with the essential ecosystem services they require. As Harvard ecologist Richard T.T Forman writes “you can have a small impact in a city center, but if you want to have a big impact, go out to this dynamic urban edge where solutions really matter for both people and nature.”

A major obstacle to the development of spatial biodiversity planning is also the apparent lack of baseline biodiversity data for each city. Furthermore, this data, where it does exist, tends to focus on wildlife in the city rather than on ecosystem integrity at the periphery. If cities are to properly understand their relationships with biodiversity, there is a significant need to develop and share measurement and monitoring practices that relate to the peri-urban zone and how this zone functions as a filter and conduit for biodiversity.

It is also important to note here that attention to biodiversity is not just a matter of protecting certain charismatic species, rather, biodiversity is a proxy for a healthy ecosystem, without which there can be no healthy city.

The overarching question to ask then is whether the growth trajectories of these hotspot cities can be redirected to avoid the further destruction of biodiversity, and if so how? Having taken the first step of identifying likely conflict areas as this study does, it is important now to recognize and understand the true complexity of the problem. The conflict between sprawl and biodiversity cannot be approached reductively or simplistically, as if sprawl (formal and informal) is only an outcome of economic and demographic growth and conservation only a matter of fencing off areas in its path.

The peri-urban territory of cities is a complex mosaic of different and often contradictory land uses in high states of flux. Indeed, the alteration of peri-urban land is not caused solely by urbanization but is also a consequence of extracting many of the resources required to support cities and their residents. The often invisible and myriad forces shaping these landscapes are not yet well understood by the urban design and planning professions, just as the novel ecology of these lands is not yet well understood by the scientific community.

Hotspot map of Antananarivo, Madagascar / The Atlas for the End of the World

The profession best able to negotiate complex landscapes such as the peri-urban is landscape architecture. Landscape architects work in equal measure with ecological and cultural data to build up holistic understanding of cities in their regional contexts. From that basis, with teams of ecologists and planners, scenarios for alternative forms of urban growth can be visualized and their costs and benefits weighed.

As both the custodians and immediate beneficiaries of the unique biodiversity at their doorsteps, the hotspot cities have a global responsibility and leading role to play in integrating biodiversity with development. It is our belief a better understanding of peri-urban territory, and the forces shaping it, is a prerequisite to the mitigation of further loss of biodiversity. This is not only relevant to cities in the world’s biodiversity hotspots, but cities everywhere.

To that end, we propose hotspot cities come together to form a global knowledge-creation and knowledge-sharing alliance to develop demonstration projects that show how urban growth and biodiversity can co-exist. The hotspot cities should lead the way in making the intent of the New Urban Agenda and the Sustainable Development Goals, which will be discussed in Kuala Lumpur next month, a reality.

This guest post is by Richard Weller, ASLA, the Martin and Margy Meyerson chair of urbanism, professor and chair of landscape architecture, and co-director of the McHarg Center for Urbanism and Ecology at the University of Pennsylvania. He is the author of Atlas for the End of the World-Atlas for the Beginning of the Anthropocene, a comprehensive audit of protected areas in the world’s biological hotspots. Research team includes: Chieh Huang, Sara Padgett Kjaersgaard, Zuzanna Drozdz, Nanxi Dong, Rong Cong, and Josh Ketchum.

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