A global synthesis of plant extinction rates in urban areas.

Plant extinctions from urban areas are a growing threat to biodiversity worldwide. To minimize this threat, it is critical to understand what factors are influencing plant extinction rates. We compiled plant extinction rate data for 22 cities around the world. Two-thirds of the variation in plant extinction rates was explained by a combination of the city's historical development and the current proportion of native vegetation, with the former explaining the greatest variability. As a single variable, the amount of native vegetation remaining also influenced extinction rates, particularly in cities > 200 years old. Our study demonstrates that the legacies of landscape transformations by agrarian and urban development last for hundreds of years, and modern cities potentially carry a large extinction debt. This finding highlights the importance of preserving native vegetation in urban areas and the need for mitigation to minimize potential plant extinctions in the future.

Managing the megacity for global sustainability: the new york metropolitan region as an urban biosphere reserve.

The UNESCO World Network of Biosphere Reserves (WNBR), while not originally conceived to include urban areas, was intended to include sites representing all significant ecosystems with the goal of support for sustainable development locally and globally. Drawing on the example of the New York Metropolitan Region (NYMR), which has a population of 21.4 million, it is argued here that the eventual inclusion of the largest of the world's cities in WNBR not only is within the logic of the biosphere reserve concept, but would also benefit the network and its goals. The ecological significance of the NYMR, its role as a driver for global environmental change, as well as the efforts under way in the city to improve urban environmental management and governance are all examined. Potential added value to the WNBR of including megacities such as the NYMR is considered, in particular, regarding the sharing of best practices, lessons learned, and the strengthening of links between megacities and their global natural resource bases.