PREDICTS and policy

Biodiversity indicators are important tools for summarising and communicating complex biodiversity data

Using PREDICTS data for policy

The Biodiversity Intactness Index (BII) is an intuitive summary of local biodiversity and an indicator for global biodiversity targets.

The BII can be used to:

• understand the biodiversity status of a region
• track biodiversity trends around the world
• compare biodiversity intactness status and trends in a way that is fair to all countries
• track progress towards biodiversity targets
• test the likely impact of specific policies aimed at increasing biodiversity
• explore biodiversity changes under a range of future scenarios

Predicting biodiversity change

The Biodiversity Trends Explorer can project how the BII will change in response to future policy changes. This can help decision makers compare different courses of action.

The BII is a local indicator, so it is best used alongside other biodiversity indicators that take a global view of species extinction, such as the Sampled Red List Index for Plants. 

The Biodiversity Intactness Index and the Convention on Biological Diversity

The BII is an indicator within the post-2020 biodiversity framework. 

In this framework, the BII is a suitable headline indicator for species abundance. The BII places all countries fairly on the same scale, where 100% means a pristine ecosystem while 0% is entirely depleted. 

This contrasts with other abundance indicators that might show a stable or even improving species abundance trend, which hides the widespread historical loss of animal and plant populations in countries such as Europe and the UK.

The BII also integrates information from a wider range of animal, plant and fungal groups than any other abundance indicator, and is directly proportional to average abundance. 

Unlike many other indicators that are available, when the BII is modelled at a finer resolution it will also be able to be used as a headline indicator to monitor ecosystem intactness.

Using the Biodiversity Intactness Index in a planetary boundary framework

The planetary boundary framework aims to describe a set of nine boundaries within which humanity can continue to thrive. Only if we stay within these boundaries are we likely to avoid the major shocks to our lives that will occur due to the climate crisis. 

Two of the variables within the planetary boundary framework that are useful for policy makers are: species extinction and the BII.  

Within this framework, if the BII of an area is 90% then it is below what we consider a safe space for humanity. Crossing this boundary increases the risk of losing the key elements in ecosystems that are needed for the area to be healthy for the plants and animals which live there. Crossing this boundary means there will not be as much biodiversity in the area, and it may require substantial intervention from humans to be habitable and productive.

The Biodiversity Intactness Index in the UK Parliament 

'The UK is one of the most depleted countries in the world in terms of biodiversity. The Natural History Museum has calculated an index of biodiversity intactness. Using this measure of the health of our natural environment, we rank 189th in the world, and we are bottom of the G7 countries. In the past 10 years, 41% of our bird species have decreased and 15% of our wildlife is threatened with extinction. 

'The dreadful state of our nature is at least in part a result of living in a densely populated country in which nearly three-quarters of our land is used for farming or the built environment. We have simply squeezed nature out of its home.' 

Lord Krebs, zoologist and Member of the House of Lords, in the debate on the Environment Bill, 10 June 2021