An assessment of the state of nature in the United Kingdom: A review of findings, methods and impact

Clear, accessible, objective metricsof species statusare critical to communicate the state of biodiversity and to measure progress towards biodiversity targets. However, the population data underpinning current species status metricsis often highly skewed towards particular taxonomic groups such as birds, butterflies and mammals, primarily due to the restricted availability of high quality population data. A synoptic overview of the state of biodiversity requires sampling from a broader range of taxonomic groups. Incorporating data from a wide range of monitoring and analysis methods and considering more than one measure of species statusare possible ways to achieve this. Here, we utilise measures of species’ population change and extinction risk to develop three species status metrics, a Categorical Change metric, a Species Index and a Red List metric, and populate them with a wide range of data sources from the UK, covering thousands of species from across taxonomy. The species status metricsreiterate the commonly reported decline in freshwater and terrestrial species’ statusin the UK in recent decades and give little evidence that this rate of decline has slowed. The utility of species status metricsis further improved if we can extrapolate beyond the species sampled to infer the statusof the community. For the freshwater and terrestrial species status metricspresented here we can do this with some confidence. Nevertheless, despite the range and number of species contributing to the species metrics, significant taxonomic bias remained and we report weighting options that could help control for this. The three metricsdeveloped were used in the Stateof Nature2016 report and indications are they reached a large number of audience members. We suggest options to improve the design and communication of these and similar metricsin the future.