Available translations: English


Ambitious targets were set by the Environment Act 2021 of halting the decline in species populations by 2030 and to increase populations by at least 10% on 2030 levels by 2042. This made England the first country in the world to set a legally binding target for biodiversity. In June the Department for Environment and Rural Affairs (DEFRA) published the Species Abundance Indicator report for England. This new indicator is explicitly designed to measure progress towards the legally binding targets, of which halting and reversing biodiversity loss is just one element.

Co-designing the targets

UKCEH scientists played a critical role in co-designing the targets and constructing the species abundance indicator, as well as reviewing the available data. The indicator is built largely from well-established volunteer-based recording schemes, such as the UK Butterfly Monitoring Scheme and the National Plant Monitoring Scheme. Many of these schemes are run through partnerships between government bodies, NGOs, research organisations and statutory agencies. 

Macroecologist Dr Nick Isaac from the UK Centre for Ecology & Hydrology is the lead scientist behind designing the methodology and process behind the indicator which provides an annual evaluation against the biodiversity targets. This work, spanning the last five years, has been essential in designing how the indicator should be calculated and establishing the criteria for the species to be included, ensuring it is rigorous, robust, and representative. Dr Isaac comments, “The indicator is a barometer for the state of nature in England and an important tool for tracking progress toward the Environment Act targets". 

Measuring species abundance

Species abundance is measured by counting animals and plants in the field, often at many locations across the country. The indicator measures how abundance changes from one year to the next, averaged across species. The Species Abundance Indicator draws on data covering 1,177 species across birds, bumblebees, butterflies, moths, fish, freshwater invertebrates, mammals and vascular plants. 

Bringing together data for these diverse organisms was challenging, because of differences in their biology and in how the data are collected. There is also variation in terms of data quality, as Dr Isaac explains: “The indicator is intended to represent all of biodiversity across England, so there is an argument to bring in as many datasets as possible. On the other hand, the indicator has to be robust to scrutiny, so datasets included need to meet a minimum set of standards”.

Read more in Dr Nick Isaac’s blog from December 2022 which looked at the tension between ambition and achievability for biodiversity targets and the need to find the right balance.