Living Things in the Natural Water Sanctuaries

Earthworms

This page contains images of animals.

Earthworms consume fallen leaves and earth, creating soft soil that is nutrient-rich. They play an essential role in supporting plant growth and are indispensable to the forest ecosystem.

Contents

Master Soil Builders

Naturalist Charles Darwin spent over 40 years studying earthworms, with his final book dedicated to them. His remarkable conclusion was that most of the world's soil is the result of earthworm castings. Interestingly, modern cutting-edge research largely supports this finding.

Earthworms possess very few digestive enzymes of their own. Instead, they feed on partially decayed fallen leaves, already decomposed by leaf-decomposing fungi, and soil abundant in microorganisms that surround plant roots. Inside the earthworm's body, fermentation (digestion) by enzymes of these microorganisms continues, allowing the earthworm to absorb nutrients.

The excreted castings continue to undergo fermentation, eventually forming stable soil aggregates that bind with humus, clay, and sand particles, creating a strong and durable soil structure.

This soil, rich in aggregates, has a sponge-like structure. It drains well during heavy rains yet retains enough moisture to sustain plants during dry periods. Soil created by earthworms is truly the ideal environment for plant growth.

Natural Water Sanctuary Initiatives

In order to have earthworms create soil, it is necessary to promote an environment where earthworms can thrive. An ideal environment for earthworms starts with a forest where a lot of fallen leaves accumulate. It's also important that the soil is home to many microorganisms that help decompose the leaves.

These microorganisms are attracted to secretions from the roots of trees and grasses. That is why earthworms prefer forests where the ground is covered with a variety of grasses and shrubs.

As biodiversity encourages more earthworms, they, in turn, promote even greater diversity and vitality within the forest. Therefore, the various activities for restoring biodiversity in our Natural Water Sanctuaries also serve to attract earthworms.

Experts involved in this Initiative

Nobuhiro Kaneko

Visiting Professor, Shimane University;Professor Emeritus, Yokohama National University and Fukushima University

Organic Things Connected to Earthworms

Here are some organic entities in the forest that are important for earthworms.

Fallen Leaves
Fallen leaves are decomposed by fungi, which release carbon and absorb nitrogen, balancing nutrients and providing food for earthworms.
Mushrooms
Fungi decompose fallen leaves and other materials, releasing carbon through respiration and absorbing nitrogen and minerals through underground mycelium, thus creating food for earthworms.
Tree Roots
Earthworms feed on fallen leaves and other materials. Their castings are rich in nutrients, and tree roots absorb these nutrients that support tree growth.
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