Introduction

The city of Berlin lies at the heart of what was once East Germany. This once-divided city was reunified following the collapse of the Berlin Wall in 1989. However, for more than four decades following World War II, the city survived as an "urban island" amidst the former Eastern Block, its residents largely confined within the city limits. These circumstances had resounding consequences for the development of the field of urban ecology as, while many of the world's ecologists studied species and ecosystems in rural or highly vegetated areas, those in the former West Berlin analyzed how these systems functioned within a heavily urbanized environment. As a result, Germany (and Berlin in particular) developed what is, perhaps, the world's strongest tradition in the study of urban ecology, as well as the mitigation of the negative environmental impacts of urbanization.

(Ingrid Cloos)

Location, Population and Land Use

Germany is located in North Central Europe, bordering both the Baltic and North Seas, between Poland and the Netherlands. Berlin, the capital city, is located in the northeast part of the country, in the middle of what was once East Germany.

Germany prior to reunification (1989) (East Germany in green; West Germany in gold)	Germany post-reunification
(cnn.com)	(cnn.com)

The city has a population of approximately 3.5 million in an area of 889 square kilometers, with a population density of 3,800 per square kilometer.

45% of the city's area is considered to be "green" or open space (defined as water areas, forests, agricultural land, parks and cemeteries). Residential use constitutes more than half of the built environment (54%). Other primary land uses include public facilities (16%) and business/industry (13%).

The Green Movement in Germany

The 1980s saw the growth of a populist environmental movement which was to become the German Green Party. As the German populace was largely concentrated in cities, there was great emphasis on urban ecology--much of the focus of this movement was on reintroducing "nature" to cities. The German Green movement grew quickly and its popularity was widespread--so much so that all political parties, from left to right, felt obligated to make green policies central to their platforms. The result was widespread federal legislation aimed at greening German cities and improving urban ecology. In the 1980s, this legislation came in the form of greening subsidies. It was not uncommon for the government to pay 50-100% of the cost for private greening initiatives, such as green roofs or vegetating urban courtyards. The impact of this legislation was great. In Berlin alone, 66,000 square meters of green roofs were installed with the aid of federal subsidies in only seven years! While federal greening subsidies were eventually cut in favor of various incentive programs, sustainability remains a priority in German planning and is, today, part of the national identity.

Federal greening subsidies resulted in the installation of many green roofs throughout Berlin.	Urban courtyards, previously all impervious surface, were also vegetated through the subsidy programs. (Ingrid Cloos)

Promoting Sustainability Through Strong Legislation

Germany has strong, often restrictive, laws regarding development of private property. Federal legislation mandates that all environmental disturbance resulting from development be minimized and/or mitigated. As much of this legislation governs greenfield development only, and in order to help promote a strong environmental ethic for urban development, the National Environmental Protection Law empowers local authorities (i.e., city governments) to develop their own landscape plans. Under the authority of this law, the Berlin Landscape Program ("LaPro") puts forth specifications, targets and requirements for:

• ecosystem and enviromental protection
• protection of biotopes & species
• landscape characteristics
• recreation and use of open space
• mitigation of urban ecology

The LaPro, which is legally binding, allows the city to highlight areas of concern and, therefore, develop plans and programs to reach set targets. Under the guidance of the LaPro, the city has developed and implemented numerous programs over the years in order to improve the city's ecology. Programs typically focus on such topics as water quality/quantity, green infrastructure, air quality, greenhouse gas emissions, habitat and stormwater management (Keeley 2004, Keeley 2007).

Recently, the city has tended towards programs which decentralize responsibility for urban ecology. While mandating and/or incentivizing the greening of each parcel, these programs allow developers and land owners to determine how and what types of greening will be implemented on their properties. Two such programs are the "Green Area Ratio" and stormwater management incentives/fees (Keeley 2004, Keeley 2007).