Ecological Survey of Swallowtail and Other Butterflies Carried Out in Naka-ku, Nagoya

The start of the "Nagoya – the city where butterflies fly" Project is being, used to build the city is ecological network, aiming to contribute to biodiversity conservation

January 18, 2010Takenaka Corporation

Takenaka Corporation (President: Toichi Takenaka) has installed planters containing grass and tree forage, and nectar-containing plants, as mini-biotopes effectively attracting butterflies, which are an index organism for the greenness of the environment, in 10 places in Nagoya's Naka-ku. The company will carry out a survey of the types of butterflies that are attracted to the planters for three years, until November 2012. The results will be made public, and will be used to build the city ecological network by connecting the city's green areas and enabling creatures to freely move about. The project will be used to enhance town environmental planning with symbiosis between man and nature.

<Mini-biotopes (planters) installed in front of a cooperating company >

[The reason for using butterflies as the index organism]

The relationship with plants by the type of butterfly

The plants that adult butterflies suck the nectar from (nectar-containing plants) and the plants that caterpillars eat (grass and tree forage) are determined by the type of butterfly. For this survey, about 20 types of plants that butterflies like have been planted for the 24 or so types of butterflies that fly around Nagoya. Researching the relationship between the types and numbers of butterflies that are found in the area, and the surrounding environment, will clarify how the environment can be developed from the ecological system viewpoint in order to attract butterflies.

<Excerpt of table showing relationship between type of butterfly and type of plant for this survey. Favorable relationships are circled.>

Merits of using butterflies as the index organism

Butterflies are now attracting attention as an index organism for the richness of the environment. In other words, the more the types of butterflies there are in an area, the less environmental pollution, the richer the nature, and the greater the biodiversity. On the other hand, if a large variety of butterflies cannot be found even though there is a lot of greenery, that could mean the environment in that area is monotonous with little biodiversity. Furthermore, it can also be said that a biodiverse environment which attracts butterflies is an environment that also attracts other creatures.

[Outline of the survey]

Recently, the building of a city ecological network by connecting the green areas scattered around a city and enabling creatures to freely move about is attracting attention with regard to town redevelopment and town planning. The home range is different depending on the type of butterfly, so when traveling a long distance, they require habitats and places to rest and eat on the way.
This survey is to be conducted in a city area with relatively close green areas, centering on two core green areas, the area around Meijo Park and Shirakawa Park, which are butterfly habitats (source). There is about two kilometers between the parks, and it is considered a difficult environment as a home range for butterflies to move between. The survey objects were set based on prior biological studies and documents. The planters containing about 20 types of grass and tree forage, and nectar-containing plants including oranges and thistles have been installed at various distances from both parks, to study whether or not they attract the movement of butterflies.

(Survey procedures)

1.  Building of planters containing about 20 types of grass and tree forage, and nectar-containing plants
2. Planters installed at about 10 locations (including the exteriors and rooftops of existing buildings)
3. Types and numbers of butterflies attracted to each planter studied (for about three years until November 2012)
4. Influences of the distances from core green areas and state of roadside plantation on movement of butterflies comprehensively examined and findings made public

[Background to implementation of the survey]

Biodiversity conservation and regeneration in cities has become an issue worldwide, and the aim of this survey is to contribute to biodiversity conservation in cities.
One reason why cities have began to attract attention is because over half the population is concentrated in city areas and consumes about 75 percent of resources, and city residents are in a state of grace from biodiversity.
It is believed that striving to conserve and regenerate the natural environment of cities and town environmental planning easy on humans and nature will increase the sustainability of cities, and also contribute to global sustainability.
This project has been recorded as a "COP10 Partnership Project (No. 419)" with the Conference of the Parties to the Convention on Biological Diversity (COP 10 CBD) Promotion Committee for the 10th COP 10 CBD, scheduled for October 2010.

[Main places that cooperated with the installation]

Ammnat Square, SMBC Park Sakae, Okaya & Co., Ltd. Head Office Building, Kanbayashi Kogyo, Shiga Bank Nagoya Branch, Chunichi Building, Nagoya Panasonic Building, Nagoya Center Building, Nagoya AT Building, etc. *Planters have also been installed in Meijo Park and Shirakawa Park, as they are considered to be the two core green areas.