Earth’s flourishing biodiversity is unique. Life in every conceivable shape and size permeates our planet. It also sustains it.
As Edward O. Wilson, the American biologist and writer wrote in The Diversity of Life: “This is the assembly of life that took a billion years to evolve. It has eaten the storms – folded them into its genes – and created the world that created us. It holds the world steady.”
But what exactly is biodiversity and why is it so important to us?
1. What is biodiversity?
The UN’s Convention of Biological Diversity defines biodiversity as “the variability among living organisms from all sources”. How much variability are we talking about? At last count, it was estimated that there were about 8.7 million different species on earth, ranging from bacteria to blue whales, from jellyfish to the giant redwood tree. Amazingly, of this figure, scientists estimate that about 86% of land species and 91% of marine species remain unknown.
Of course, from an evolutionary perspective, there are no clear breaks between one species and another and biodiversity is never in a fixed state: all life changes incrementally over time. Every living thing – from a rocket scientist to the lettuce in your sandwich – can trace their family trees back to an organism called the Last Universal Common Ancestor (LUCA), thought to have lived around 4.3 billion years ago. However, for the interests of practicality, we classify different species using the same system of biological taxonomy devised by the Swedish Scientist Carl Linnaeus in 1735. He ascribed a two-part Latin name (binomial nomenclature) to every organism on earth. For instance, in 1758 he called the common house sparrow: Fringilla domestica, from the Latin for ‘house’ and ‘finch’.
2. Why is biodiversity so important?
Biodiversity is intrinsically interconnected across landscapes and species depend on each other to live. For humans, biodiversity provides many underappreciated ecosystem services that are critical to our well-being. For instance, earth worms help regulate water and cycle mineral nutrients in the soil, contributing to its fertility and supporting plant growth.
Biodiversity obviously also provides us with direct goods, such as food or medicine. For example, pharmacological drug development can rely on a wide range of natural products – and this is without even counting the millions of people around the world who still use local plants as their primary form of medicine.
3. Where can you find biodiversity?
Biodiversity is everywhere, but there are certain habitats and ecosystems around the world that contain a huge variety of plant and animal species found nowhere else on earth. One of the most famous of these biodiversity hotspots is Madagascar, an island country with an extremely high rate of endemism (species unique to that location). The vast majority of the species of life found on the island – including the famous Lemurs and Grandidier Baobab trees – developed and thrived only there, isolated from the rest of the world.
Other hugely biodiverse habitats include coral reefs, which occupy just 0.1% of the area of the ocean but support 25% of all maritime wildlife. Similarly, rainforests contain around 80% of all documented species and yet cover just 6% of the earth’s land area.
4. Is biodiversity under threat?
Every so often, the levels of biodiversity drop dramatically, with many different species going extinct all at once. These are known as extinction events, and we’ve gone through five of them so far, stretching back across hundreds of millions of years. The most recent extinction occurred approximately 65 million years ago, when an asteroid impact wiped out 75% of all species on earth, including all the non-avian dinosaurs (and yes, that means present-day birds are, taxonomically speaking, real live dinosaurs!).
Worryingly, scientists believe we are currently moving towards a sixth extinction event, with species disappearing about 1,000 times faster than normal rates of extinction. A recent report by IPBES suggests that biodiversity continues to decline in every region of the world and calls for urgent action. However, this extinction is not caused by natural disasters – as in the past – but by human activity. The destruction and fragmentation of habitats by urban sprawl and overexploitation, and the spread of invasive alien species – made possible by the rapid rise in travel, trade and transformation – are among the key factors. Together they pose a serious challenge to maintaining biodiversity.
5. Can biodiversity be enhanced?
With habitats so important for survival, it’s imperative that we learn to take steps to better conserve them and the biodiversity that they support. Thankfully, there are things each and every one of us can do.
Those living in urban areas can contribute to providing food, shelter and nesting possibilities for insects and birds by making gardens, roof tops and balcony flowers more attractive to animals. In many city parks, local authorities are planting flower meadows to boost biodiversity.
In the countryside, improving agricultural practices can make a huge difference to biodiversity conservation. This is particularly the case in intensive crop production areas – where fewer habitats remain, a balance has to be struck between land for production and for conservation. Here habitat re-establishment and maintenance initiatives can play a crucial role in enhancing biodiversity, as they contribute to establishing a network of habitat at landscape level. In other regions of the world, where production levels are low, improving good practices and supportive technologies can avoid land use change for crop production.
Nature park areas designed to protect wildlife also help the local biodiversity to thrive. Targeted efforts can even reverse populations once in decline, as in the successful case of the Southern White Rhino. Increasingly, these efforts are also being supported by digital tools and databases. These tools can help conservationists better monitor how their efforts are helping and where best to target them, and can help others, like farmers, go about their day-to-day business as sustainably as possible.
Biodiversity is all about interconnection, creating corridors of habitats across the landscape will benefit all organisms, both big and small.