The Abundant Nature of the Yochisha Rikaen Science Garden

(Published September 2024)

The "Rikaen Science Garden" at Keio Yochisha Elementary School is an exceptionally high-quality biotope for a school located in the heart of the city, and it is home to a truly diverse range of living creatures. Many creatures do not complete their life cycles in a single environment; instead, they live by moving between multiple environments, such as between watersides and grasslands. Therefore, to support a diverse range of life, it is important to provide various environmental elements like forests, grasslands, watersides, and fields, and to be mindful of the transitional areas between them, known as "ecotones." For example, between a pond and a grassland, it is desirable to have a marshy, tidal-flat-like waterfront rather than a complete separation by concrete. The Rikaen Science Garden was very intentionally designed with this structure by our school's teacher, Kensuke Shimizu, which is why it is home to such a diverse array of creatures for its size.

I am now in my ninth year at Yochisha Elementary School, and during this time, I have been continuously surveying insects and spiders. Even for a biotope in the city center, once you start investigating, you find a surprising number of insects. My current list includes about 1,100 species, and that number continues to grow. Some of these are designated as endangered species by the Ministry of the Environment or the Tokyo Metropolitan Government, and we've found that creatures with limited habitats in the city center are using the Rikaen Science Garden as their home. For example, among dragonflies, there are *yotsuboshi-tombo* (four-spotted skimmer), *beni-itotombo* (scarlet dwarf), and *ki-itotombo* (yellow-legged damselfly). I was also surprised by a water bug from the Hemiptera order called *ko-oimushi* (giant water bug). This insect is on the verge of extinction in the ward areas of Tokyo and has been found in off-season swimming pools. We have also seen the appearance of the *koganegumo* (wasp spider), a spider that is very rare in central Tokyo but can be found alongside rice paddies in the Tama area.

As part of my classes on searching for living things in the Rikaen Science Garden, I conduct an activity I call "Wanted: Seasonal Flowers," where I have students search for and pick about six to ten different types of flowers. When I make it a competition, everyone searches earnestly. I feel that the experience of finding the real thing helps to build a foundation of interest. This is not something they experience in their daily home lives, and before doing activities like this, individual flowers are just processed as "scenery" and don't enter their personal awareness. Even if they are not initially interested in flowers, once they start, the desire to beat the other teams makes them feel they "have to search," and I think most of the children become engrossed in it.

In this "Wanted" class, even if it's not on the "wanted list," if a student brings me something like an insect or a plant, I tell them its name and award them points. This follows the policy of Mr. Hiroaki Aiba, who retired at the end of last school year. When children bring insects, they tend to be concerned only with their "rarity," because "rarity" is a measure that anyone can understand and becomes a target for praise. Since they often lose interest if it turns out not to be rare, I try not to emphasize "rarity" too much. However, sometimes a child will bring in a truly rare insect, and in those moments, I can't help but say, "That's an amazing find!" Of course, the child is overjoyed. It's also common for children who couldn't touch insects at all to become quite comfortable with them. Also, even children who already like insects are often only interested in stag beetles, rhinoceros beetles, praying mantises, butterflies, and dragonflies, but when I teach them the names of smaller flies and other insects, they start to pay attention to them.

The Rikaen Science Garden also serves as a catalyst for broadening interest in environmental issues. For example, sustainability is one of the major themes in today's society. When collecting plants during our creature hunts in the Rikaen Science Garden, I basically allow them to pick anything, as long as they don't pull out the entire plant. The environment is so healthy that the number of plants picked by the Keio Yochisha Elementary School children is not enough to deplete them. However, I do give them the opportunity to think about how they can continue to pick the plants without them disappearing. The Rikaen Science Garden also has fruit trees like summer oranges, chestnuts, and persimmons. I have a loose rule that they are free to pick the fruit, but they must ensure there is enough left for others who also want some. I believe this is the origin of understanding sustainability.

They can also experience the problem of invasive alien species firsthand. In recent years, an invasive alien plant called *mamegunbai-nazuna* (lesser swine-cress) has become very abundant, and if left alone, there is a danger it will replace native plant species. When I have the children pull them out one by one, they can see for themselves, "Wow, there are so many of them." Then, when they look again six months later, they see it has grown back just as before, and I think they can understand from this experience that it is a very strong plant that cannot be easily eradicated. Such robust invasive species require continuous and thorough removal over a certain period.

In this way, by becoming interested in nature in various forms, I feel that the children's perspectives are broadening, and I hope that they are developing observational skills not only for living things but for other fields as well. I believe that the power of observation, the ability to notice various things, is necessary in any field. Graduates of Keio Yochisha Elementary School will become future leaders of society, so I believe that when these children grow up and have to make decisions, the state of society can change if they consider not only immediate profits but also long-term important issues like biological resources and the environment. I feel a great sense of responsibility in my work to help the children of Keio Yochisha Elementary School grow with an awareness of sustainability.

In terms of responsibility, academic contributions are also important. I publish lists of the insects and spiders that inhabit the Rikaen Science Garden, but there are surprisingly few places in the city center that conduct continuous, high-density surveys. Therefore, I make it a point to cooperate with external researchers who request to conduct surveys in the Rikaen Science Garden.

It is a great blessing that the Rikaen Science Garden is a place that the children and I can easily visit on a daily basis for our various activities. Nowadays, collecting living creatures is no longer freely permitted in many parks and facilities. In the Rikaen Science Garden, you basically won't get in trouble for picking any plant or catching any insect. I think it is a great privilege to have such a place within the school.

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