Biodiversity Loss

What is biodiversity loss?

Biological diversity or biodiversity is the variety of life in all its forms, and at all levels including genes, species, and ecosystems.

Figure 1: Components of biodiversity and relationships among biodiversity, ecosystems, biomes and the biosphere (From Dasgupta, 2021).

The recognition of biodiversity as an important environmental issue for global recognition emerged at the 1992 Rio de Janeiro Conference on Environment and Development – also known as the Rio Earth Summit. At the conference, the Convention on Biological Diversity (CBD) was ratified, when 150 governments agreed to significantly reduce the rate of biodiversity loss.

Despite some progress to conserve nature and implement policies, we are facing an ever-increasing rate of biodiversity loss. A summary of the most comprehensive assessment of biodiversity to date was published in 2019 by the United Nations Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). The IPBES (2019) concluded that ‘nature is declining globally at rates unprecedented in human history – and the rate of species extinctions is accelerating’.

• In the past four decades, there has on average been a 60% global decline in the populations of mammals, birds, fish, reptiles and amphibians, mostly in the tropics.

• The estimated number of wild bee species worldwide has fallen from 6,700 in the 1950s to only 3,400 in the 2010s.

• It is thought that one million animal and plant species (approximately 25%) are threatened with extinction in most of the animal and plant groups that have been studied.

• Current extinction rates are around 100 to 1,000 times higher than average over the past several million years – and they are accelerating. (IPBES 2019)

What causes biodiversity loss?

According to the IPBES (2019), the five direct drivers of biodiversity loss with the largest relative global impacts so far are, in descending order: (1) changes in land and sea use; (2) direct exploitation of organisms; (3) climate change; (4) pollution; and (5) invasive alien species.

Why is it important?

"Biodiversity is the totality of all inherited variation in the life forms of Earth, of which we are one species. We study and save it to our great benefit. We ignore and degrade it to our great peril." — E.O. Wilson

Biodiversity is recognised as important because of its intrinsic value (value independent of usefulness to human beings), and because of the key role it plays in supporting ecosystem services that benefit human societies and economies (Dasgupta 2021). These ecosystem services belong to four main categories: provisioning services (e.g. food, water, wood, fuel, fibre, medicines and genetic resources); supporting services (e.g. water cycling and soil formation); regulating services (e.g. climate and erosion); and cultural services (e.g. aesthetic and educational).

In addition, biodiversity underpins the resilience and function of ecosystems, i.e. their capacity to sustain such services over time and in the face of various disturbances (Dasgupta 2021). Biodiversity can also regulate the prevalence of disease vectors: many emerging infectious diseases – including the COVID-19 pandemic – have root causes in anthropogenic disturbance of ecosystems and the associated loss of biodiversity (IPBES 2019; Baudron and Liégeois 2020).

You might like to explore this fourth chapter in ‘Living in the Age of Humans', a series of stories examining the planet-wide impacts of our species.

References

Dasgupta, P. The economics of biodiversity: the Dasgupta review. (2021) doi:10.2458/jpe.2289.

IPBES. Global assessment report on biodiversity and ecosystem services of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. (2019).

Baudron, F. & Liégeois, F. Fixing our global agricultural system to prevent the next COVID-19: https://doi.org/10.1177/003072...49, 111–118 (2020).