A small step towards a biotope in the city

Construction was completed in the spring of 2008. Observation of the habitat of living creatures began in July of the same year. When I first visited this biotope, I felt a certain nostalgia and gentleness reminiscent of a "satoyama" (a village mountain village), but at the same time, I was a little skeptical as to whether living creatures could really live in such a miniature garden on the rooftop of a building in the city center. However, within a year of its completion, this biotope has brilliantly blown away my doubts. There are no tall trees or bushes, and the vegetation is mainly grass and shrubs, so the variety is limited, but seven bird species were confirmed to live in the biotope once in autumn and winter and twice in spring, and an astonishing 133 insect species were confirmed to live in the biotope once in summer, autumn, and spring. Small birds were observed bathing and feeding, dragonflies and butterflies lived, and nymphs and grasshopper larvae were also observed. Moreover, all of these species were confirmed to live in the Imperial Palace and the surrounding green spaces. It is true that the Imperial Palace, with its vast green space covering an area of approximately 115 hectares, is located about 1 km west of Marunouchi. However, the fact that the creatures had actually flown beyond the outer gardens of the Imperial Palace, across the busy Uchibori-dori and Hibiya streets, and into a small biotope on the rooftop of a building in an office district with an employment population of over 240,000, was a truly moving event.

Not just in biotopes, but recently in parks and open spaces around buildings, we've begun to see new Landscape with small waterfront spaces that evoke a nostalgic "satoyama" (village mountain) vibe. Unlike dynamic landscapes that create a certain tension by arranging carefully selected plant varieties in geometric patterns in response to the modern design of cities and architecture, miniature garden-like designs made up of a wide variety of plants can appear a bit cluttered to the eye, but they are also very refreshing in their own way, as they are friendly to people and contrast well with modern cities and architecture. Landscape author believes that the true value of this "satoyama" design lies in the fact that, just like small rooftop biotopes, it has the potential to attract and inhabit a wide variety of birds and insects, providing a space where wild birds and insects can coexist in a city where people live in high density and engage in economic activity.

The concept of "biodiversity" has begun to be recognized as an important indicator in urban development, and systems for evaluating and certifying such environments have been established. Central Tokyo is home to forests and waterfronts that are home to many living creatures, including the Imperial Palace, Shinjuku Gyoen National Garden, Meiji Shrine, Koishikawa Korakuen Garden, and the former Shirokane Imperial Estate. Isn't it possible to develop and connect these many forests and waterfronts with similar "satoyama" Landscape, even if only on a small scale, in the open spaces and rooftops of buildings surrounding these forests and waterfronts? Perhaps birds and insects previously hidden in forests could be found even in urban office districts. While only a limited number of bird and insect species can coexist with humans in the specialized and limited spaces of cities, this small biotope on a Marunouchi rooftop and other "satoyama" Landscape in the city center are a small first step toward urban development that realizes "biodiversity."