Wildlife Survey in Handmade "Biotope" - An Ecosystem Where Spot-billed Ducks May Also Visit? in Yatabe, Tsukuba City

On Saturday, July 4th, the "Biotope Watch Team," composed of volunteer staff from Pal System Consumers' Cooperative Union (Headquarters: Shinjuku-ku, Tokyo; Chairman: Atsuyuki Shibusawa), conducted its second "Wildlife Survey" of the year in a "biotope" ecosystem created in a rice paddy in Tsukuba City, Ibaraki Prefecture. The number of confirmed species increased by 8 from the first survey, with 26 types of insects and fish found.

A Season of Dragonflies

The "Wildlife Survey" was held in the biotope beside a rice paddy where rice planting was completed at the end of May. This is a handmade ecosystem created in March 2025 by staff who dug up the soil with heavy machinery, laid down vinyl, and channeled water from the paddy. The survey records the types of organisms that gather in the biotope as the rice grows, confirming the biodiversity of a paddy field that does not use chemically synthesized fertilizers or pesticides.

The survey was conducted in conjunction with farm work by 10 staff members from the Pal System Group and related organizations such as business partners, who rented farmland from the NPO Satoyama Saisei to Kangaeru Kai (Tsukuba City, Ibaraki Prefecture; Representative: Takashi Iizumi). New staff members, bringing their children, also joined, with about 4 people focusing on examining the organisms.

▲ 2-year-old Yuto-kun also a valued member of the survey ▲ The biotope holding water beside the growing rice plants.

In the biotope and surrounding irrigation ditches, in addition to the numerous oligochaetes and chironomid larvae confirmed previously, Japanese crucian carp, juvenile exotic largemouth bass, and several types of shrimp were found. Aquatic insects like diving beetles and water striders, as well as frogs, were also present. Several types of dragonflies were flying around, possibly indicating that the damselfly larvae found last time had hatched.

In the rice paddy ridges and grassy areas, many insects such as grasshoppers, cabbage butterflies, and spiders were also found. The farm work participants informed us that they had discovered spot-billed ducks visiting the biotope, confirming that a rich ecosystem is being nurtured from the water to the land.

Analysis of the First Survey Also Shows 18 Species Including Exotics

The team reviewed the analysis of the species discovered in the first survey conducted at the end of May. In the biotope and irrigation ditches, which have been established for one year, 18 types of organisms were confirmed, including the exotic ramshorn snails and American crayfish.

Four species susceptible to the effects of chemical pesticides were identified: damselfly larvae of the crimson-tip dragonfly and the great golden darner, the chrysanthemum cocoon spider, and cricket larvae. Because no chemical pesticides are used in the rice paddy, these organisms survive without dying. Five species—ramshorn snails, chironomid larvae, oligochaetes, cladocerans, and Japanese freshwater shrimp—are affected by chemical fertilizers. Their non-use appears to be suppressing excessive eutrophication of the soil and maintaining a balance where diverse species can coexist.

Oligochaetes and chironomids decompose organic matter and also serve as food for other organisms. The biotope serves as a feeding ground for small aquatic insects like Hydrophilidae, and a food chain has been established within a year, extending to carnivorous insects like diving beetles and tadpoles.

▲ Damselfly larvae of the common skimmer, susceptible to chemical pesticides ▲ Japanese freshwater shrimp, susceptible to chemical fertilizers.

In the irrigation ditches, 12 species of organisms were confirmed, including fish such as goldfish, loaches, Japanese catfish, and Japanese crucian carp, as well as Japanese tree frog tadpoles, American crayfish, and leeches.

It was observed that the surrounding environment and the biotope are connected by waterways, serving as feeding grounds and habitats for fish, and attracting aquatic insects, functioning as part of an ecosystem network.

▲ Exotic American crayfish ▲ Japanese tree frog tadpoles.

Since ramshorn snails, which are food for Japanese fireflies, were confirmed, there is a possibility that they laid eggs within the biotope. Although the hatching season for this year has passed, preventing us from witnessing a landscape of fireflies, we aim to maintain the ecosystem within the biotope with expectations for next year's observations.

Communicating the Significance of Environmentally Friendly Agriculture to Staff

The "Biotope Watch Team" is a group established utilizing "Pal System Collective," a voluntary activity system for staff initiated by Pal System Union in fiscal year 2024. Staff members from different departments are working together to realize the "Creating Communities Where We Live Together: Eating, Making, Supporting Each Other," as stated in the Pal System 2030 Vision.

The "Biotope Watch Team" aims to deepen the understanding of the significance of the rice paddy "Wildlife Survey," which Pal System has been conducting continuously with production areas since 2004, among staff members outside of the responsible departments. Six members from various departments are involved in this activity.

In production areas where Pal System has direct trade agreements, environmentally friendly agriculture that minimizes reliance on pesticides is promoted. The "Wildlife Survey" is conducted to visualize the significance of agriculture in protecting biodiversity in production regions. By having staff from diverse departments experience the survey and watch over the biotope, the circle of Pal System's environmental conservation activities will expand.

Pal System will continue to support sustainable Japanese agriculture together with consumers, staff, and production areas.

Pal System Consumers' Cooperative Union

Location: Rakus East Shinjuku, 2-2-6 Okubo, Shinjuku-ku, Tokyo; Chairman: Atsuyuki Shibusawa Total business sales of 12 member cooperatives and unified business system users: 268.96 billion yen / Total number of members: 1.77 million (as of the end of March 2026) Member Cooperatives: Pal System Tokyo, Pal System Kanagawa, Pal System Chiba, Pal System Saitama, Pal System Ibaraki Tochigi, Pal System Yamanashi Nagano, Pal System Gunma, Pal System Fukushima, Pal System Shizuoka, Pal System Niigata Tokimeki, Pal System Kyosai Ren, Ai Coop Miyagi HP: https://www.pal-system.co.jp/