What is biodiversity and why is it under threat?

Biodiversity is short for biological diversity, and it means the variety of living things on earth, including plants, animals, bacteria and fungi. Biodiversity includes diversity within species, between species, and of ecosystems.

Approximately 1.7 million species have been described, but estimates about how many there are vary from 8 to 100 million. This variation is because there are many species in the tropical rainforests, where there are lots of insects and fungi that we don’t know about. Even larger species such as monkeys are still being discovered in remote forests. This gap between the species we know about and have described, and those that we do not know about, is called the Linnean Shortfall, after Carl Linnaeus. In the 1700s Linnaeus devised the naming system of species that we use today. You probably know this as the ‘Latin name’, for example humans are Homo sapiens. The Linnean shortfall is important, because it highlights how little we know, and also that we are losing species that we don’t even know about.

What is a species? A species is generally considered to be a group of organisms that share common characteristics and can reproduce naturally with one another to produce fertile offspring.

Why does biodiversity matter?

An elephant in Malawi. Credit: Author

Threats to biodiversity

What is an invasive species? Invasive or alien species are those found in areas where they do not naturally occur. They can often outcompete native species, and can also spread quickly because they have no natural predators. Invasive species can be introduced by accident, when they escape from captivity or hitch a ride on a boat or in cargo. Sometimes they have been introduced deliberately to solve another problem or for people to hunt. Occasionally they can arrive in a new area naturally as a species expands its range.

In many parts of the world use of natural resources are vital for people’s day to day existence, not just to contribute to development. We saw that earlier when we looked at the use of firewood for energy in Tanzania, and when we visited Indonesia to see how local communities rely on fishing. There has to be a sustainable way to utilise natural resources without threatening them.

In the next step we are going to find out how this biodiversity loss is measured, and then we will look at what the international community is aiming to do to prevent further biodiversity loss through SDG 15 Life on Land.