A habitat is an area in which something lives. Soil is a habitat, and it is full of life!
Around 25% of everything alive on the Earth uses soil as a habitat. Some animals live on top of the soil (in leaf litter or other organic matter), and others live below the surface. Some things live in the soil for their entire lives, and others live there for just a part of their lives. There are billions of microorganisms living in the soil too, but they are too small for us to see. Plants also live in soil. They depend on soil for air, water and nutrients.
Things living in the soil depend on each other and on non-living soil components like organic matter and minerals to survive. This interdependence and transfer of food energy is called a soil food web.
Soil habitats differ from place to place
Soil habitats can be quite different. Soil characteristics affect what lives in it. For example, a soil that has lots of pore spaces for water and air usually supports more life than one consisting of hard clods. Temperature and rainfall also influence the types of plants and animals that live in the soil.
New Zealand native soil habitats
New Zealand native forests tend to be humid places that do not have big changes in temperature. Our forests may not have as many different animals as other rainforests around the world, but there is a lot of life under the ground. Believe it or not, the weight of earthworms under our native forests is greater than all of the other animals living in the forest!
Earthworms aren’t the only creatures on the forest floor – the leaf litter may hold hundreds of species of invertebrates like slaters and stick insects. Earthworms, invertebrates and microscopic organisms use the fallen leaves and other decaying matter as food. They break it down and recycle the nutrients so they can be used again and again.
Other native areas like tussock grasslands, alpine shrublands and coastal areas will have their own soil ecosystems. Anywhere there is soil, there will be a soil habitat.
Soil habitats in the city
The lawns and gardens around our houses and schools are home to all kinds of soil life, but we have to look to see it. Most soil organisms don’t like to be exposed to sunlight. We even create soil habitats by building compost systems. A spadeful of soil and food scraps or grass clippings added to an empty bin soon becomes home to insects, earthworms and microscopic creatures.
It’s just as well that soil organisms break down and recycle plant and animal wastes. Consider just one type of waste – insect exoskeletons. If these were never recycled, we’d be knee deep in insect body parts. Imagine all of the fallen leaves, potato peelings and cow dung that would still exist. Life above the ground wouldn’t exist without the help of life below the ground!
Nature of Science
Scientists’ views and children’s views often differ. Scientists recognise that soil is full of life and responsible for energy transfer among millions of living organisms. Children often see soil as a dead, inert material.
Learn more about New Zealand’s soil fauna.