What is biodiversity? And why does it matter?

by Helen Townsend February 16, 2023

Biodiversity is all of the species in an area. It could be a small area, like your garden, or a large area, like planet Earth. Biodiversity includes plants, animals, fungi and microbes. All of these species interact with one another to make up a strong and healthy ecosystem.

New Zealand has very high biodiversity - the best guess is 70,000 different terrestrial (living on land) species! Only 5% of these species are large plants and animals. Most of the rest are going about their lives without us taking much notice. This includes 6000 different types of beetle, 20,000 fungi and 550 mosses! Before humans arrived NZ was home to 245 bird species, but now there are only 91 left.

In NZ we love our charismatic birds like kākāpō, tūī and kiwi and we want to conserve them but does it really matter if we don’t have all those other species?

Take moss for example, what difference does it make if we don’t have 550 different types? Surely moss is just moss?

We need all the 550 moss species because each one grows in a different habitat, supports other species and helps the environment be more resilient.

There are so many species of moss because they have adapted to live in lots of different places: in forests, deserts, rocky mountains and damp hollows. Most of the time we don’t notice them but they’ve been going about their business for 450 million years.

And what is their business? Moss retains water and prevents soil erosion by stabilising the soil surface; this means they can help other plants establish after a forest fire or other disturbance. They regulate the temperature of the soil and protect tree roots from overheating; they provide shelter for insects to feed and lay eggs - and these insects pollinate our plants, and become food for the birds that we love. So if we want kākāpō and kiwi then we need the unassuming species like moss as well!

Areas of high biodiversity are less vulnerable to pests and diseases. Think of a garden for example. If the garden is made up of an uninterrupted lawn, a grass pest can rip through the entire lawn in one go wiping out all the plants. If, on the other hand, the garden has trees, shrubs, flowers and grasses, the grass pest might destroy some of the plants, but there are plenty more that will survive.

Another reason for caring about species like moss is that all plants and animals are part of the ecosystem and have intrinsic value. Humans don’t have the right to destroy other species for our convenience.

As humans we should see ourselves as part of the ecosystem - one of many species that live interdependently. But in the 21st century we tend to live apart from other species and have lost our connection with nature, this has led us to destroy biodiversity and risk not only other species but our own lives. High biodiversity is part of ‘ecosystem services’ - the value we get from the environment for free, just by it being there.

Ecosystem services include pollination, water purification, climate regulation, control of pests and diseases, nutrient cycling and the production of food, fibre and medicines. It also involves spiritual and culture benefits and recreation. It’s estimated that all of these ecosystem services are worth $125 trillion. By comparison, global GDP in 2020 was $85 trillion. We’re getting all this for free and we still keep on reducing biodiversity!

How you can help

Increasing biodiversity can be done at all levels - from your home garden to rainforests. Here are some ways you can increase biodiversity and protect the environment (for us and the moss!)

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