State of nature 2023

This is the fourth State of Nature Report. It provides a comprehensive overview of species trends across the UK, including specific assessments for England, Northern Ireland, Scotland and Wales, and for the UK’s Overseas Territories

Agricultural Management and Climatic Change Are the Major Drivers of Biodiversity Change in the UK

Action to reduce anthropogenic impact on the environment and species within it will be most effective when targeted towards activities that have the greatest impact on biodiversity. To do this effectively we need to better understand the relative importance of different activities and how they drive changes in species’ populations. Here, we present a novel, flexible framework that reviews evidence for the relative importance of these drivers of change and uses it to explain recent alterations in species’ populations. We review drivers of change across four hundred species sampled from a broad range of taxonomic groups in the UK. We found that species’ population change (~1970–2012) has been most strongly impacted by intensive management of agricultural land and by climatic change. The impact of the former was primarily deleterious, whereas the impact of climatic change to date has been more mixed. Findings were similar across the three major taxonomic groups assessed (insects, vascular plants and vertebrates). In general, the way a habitat was managed had a greater impact than changes in its extent, which accords with the relatively small changes in the areas occupied by different habitats during our study period, compared to substantial changes in habitat management. Of the drivers classified as conservation measures, low-intensity management of agricultural land and habitat creation had the greatest impact. Our framework could be used to assess the relative importance of drivers at a range of scales to better inform our policy and management decisions. Furthermore, by scoring the quality of evidence, this framework helps us identify research gaps and needs

Voluntary recording scheme reveals ongoing decline in the United Kingdom hazel dormouse Muscardinus avellanarius population

Author's accepted versionFinal version available from Wiley via the DOI in this recordIn order to conserve threatened species, knowledge of the status, trends and trajectories of populations is required. Co-ordinating collection of these data is challenging, especially for inconspicuous species such as the hazel dormouse Muscardinus avellanarius. The UK National Dormouse Monitoring Programme (NDMP) is comprised of nest box recording schemes organised by volunteers. The number, size, and coverage of these schemes has varied over time. Such changes risk conflation of genuine population trends with covarying artefacts, including survey effort and expansion into sites of variable quality. We provide a robust analysis of count data from 400 NDMP sites from 1993 to 2014 and demonstrate that changes in counts are not an artefact of survey characteristics. In relation to the International Union for Conservation of Nature (IUCN) Red List criteria, we conclude that dormouse counts in nest boxes are an index of abundance appropriate to the taxon and allow the inference of population reduction of 72% (95% confidence intervals 62–79%) over the 22 years from 1993 to 2014, equivalent to a mean annual rate of decline of 5.8% (4.5–7.1%). This decline is ongoing. We highlight difficulties in assigning an IUCN Red List conservation category to a population, given variation in apparent trends over consecutive time-periods. In eight out of 13 sliding window intervals of 10 years from 1993 to 2014, the 95% confidence intervals overlap a decline of 50%. While average population decline over 10-year periods suggests that the hazel dormouse should be classified as Vulnerable, a precautionary approach would not rule out the category of Endangered in the United Kingdom, given the lower bounds of population change estimates, the mean annual rate of decline and ongoing decline. Ongoing decline in the hazel dormouse population is despite a high level of species protection and widespread conservation measures. The hazel dormouse is a UK Biodiversity Action Plan Priority Species and a European Protected Species, and the causes of population reduction are not well understood and may not have ceased. An urgent appraisal of dormouse conservation is required to ensure the species’ favourable conservation status.Many thanks to the dormouse monitors who have collected the data for the NDMP, and to the People's Trust for Endangered Species for their provision of data and co-ordination and management of the NDMP. This work was funded by a research studentship supported by The Forestry Commission and the Natural Environment Research Council

Density and climate effects on age-specific survival and population growth: consequences for hibernating mammals

The impact of factors such as density dependence, food availability and weather are known to be important for predicting population change in a wide range of species. However, a challenge in ecology is understanding the contributory and interactive role of these drivers on populations. This is necessary to design effective conservation and management strategies. Using data from long-term studies of five hazel dormouse Muscardinus avellanarius populations in Europe, we tested the relationship between population density and weather and their impact on demographic rates. We used an integrated population modelling approach, estimating age-specific overwinter survival, annual population growth and fecundity rates. We found strong negative effects of population density, precipitation and winter temperature on population growth rates. This suggests that warmer and wetter weather negatively affects dormouse survival for both adults and juveniles, but we found subtle differences in these effects between age classes. We also identified an interaction between weather measures and population density on age-specific survival, possibly as a result of weather impacts during hibernation. Although we found low winter temperature was positively associated with population growth, we found evidence consistent with density dependence. We discuss our results in the context of woodland habitat conservation management

State of nature

For the first time ever, the UK’s wildlife organisations have joined forces to undertake a health check of nature in the UK and its Overseas Territories. 60% of the 3,148 UK species we assessed have declined over the last 50 years and 31% have declined strongly. Half of the species assessed have shown strong changes in their numbers or range, indicating that recent environmental changes are having a dramatic impact on nature in the UK. Species with specific habitat requirements seem to be faring worse than generalist species. A new Watchlist Indicator, developed to measure how conservation priority species are faring, shows that their overall numbers have declined by 77% in the last 40 years, with little sign of recovery. Of more than 6,000 species that have been assessed using modern Red List criteria, more than one in 10 are thought to be under threat of extinction in the UK. Our assessment looks back over 50 years at most, yet there were large declines in the UK’s wildlife prior to this, linked to habitat loss. The UK’s Overseas Territories hold a wealth of wildlife of huge international importance and over 90 of these species are at high risk of global extinction. There is a lack of knowledge on the trends of most of the UK’s species. As a result, we can report quantitative trends for only 5% of the 59,000 or so terrestrial and freshwater species in the UK, and for very few of the 8,500 marine species. Much needs to be done to improve our knowledge. What we do know about the state of the UK’s nature is often based upon the efforts of thousands of dedicated volunteer enthusiasts who contribute their time and expertise to monitoring schemes and species recording. The threats to the UK’s wildlife are many and varied, the most severe acting either to destroy valuable habitat or degrade the quality and value of what remains. Climate change is having an increasing impact on nature in the UK. Rising average temperatures are known to be driving range expansion in some species, but evidence for harmful impacts is also mounting. The full report is online: www.rspb.org.uk/stateofnature We should act to save nature both for its intrinsic value and for the benefits it brings to us that are essential to our wellbeing and prosperity. Targeted conservation has produced inspiring success stories and, with sufficient determination, resources and public support, we can turn the fortunes of our wildlife around. The State of Nature report serves to illustrate that with shared resolve and commitment we can save nature

Funding and delivering the routine testing of management interventions to improve conservation effectiveness

Evidence-based approaches are key for underpinning effective conservation practice, but major gaps in the evidence of the effectiveness of interventions limit their use. Conservation practitioners could make major contributions to filling these gaps but often lack the time, funding, or capacity to do so properly. Many funders target the delivery of conservation and can be reluctant to fund primary research. We analysed the literature testing the effectiveness of interventions. Of a sample of 1,265 publications published in 2019 that tested conservation interventions, 96% included academics. Only 21% included conservation practitioners, of which just under half were first or last author. A community of conservation funders and practitioners undertook a series of workshops to explore means of improving the quality and quantity of intervention testing. A survey of the suggested proportion of conservation grants that should be allocated to testing intervention effectiveness showed practitioners tended to prefer larger percentages (median 3-6%) than funders (median 1-3%), but the overlap was considerable. Funders can facilitate the testing of interventions through a range of measures, including welcoming applications that incorporate testing, allocating funds to testing, and providing training and support to deliver testing. The funders represented by the authors of this paper have committed to these actions. Practitioners can contribute by committing to routine testing, benefiting from funding allocated specifically to testing, and establishing processes for testing interventions. The organisations of the practitioner authors have committed to test at least one intervention per year and share findings, regardless of outcome. Currently, practitioners rarely lead the testing of conservation actions. We suggest processes by which both funders and practitioners can make this routine. This will not only improve the effectiveness and cost-efficiency of practice, but also make conservation more attractive to funders.This paper arose from a series of workshops attended by funders and practitioners, focused on how to integrate evidence in conservation. We thank all participants. The first workshop was hosted by Lord Mountevans at the House of Lords, UK, with funding from Arcadia. Subsequent workshops were held online. We thank Kate Willott for providing the 2019 references from the Conservation Evidence database. We are also grateful to two anonymous reviewers whose feedback provided helpful suggestions for improving this manuscript

Bionomics and distribution of the stag beetle, Lucanus cervus (L.) across Europe.

1. The European stag beetle, Lucanus cervus, is thought to be widely distributed across its range, but a detailed description of its occurrence is lacking. 2. Researchers in 41 countries were contacted and information sought on various life history characteristics of the insect. Data on adult body size were collected from seven countries. 3. Habitat associations differ between the United Kingdom and mainland Europe. Larvae are most commonly associated with oak, but the duration of the larval stage and the number of instars varies by up to 100% across Europe. 4. Adult size also varies; beetles from Spain, Germany, and the Netherlands are larger than those from Belgium or the UK. In the former countries, populations are composed mainly of large individuals, while in the UK, the majority of individuals are relatively small. Allometric relations between mandible size and total body length differ in Germany compared with the rest of Europe. 5. Distribution maps of the insect, split into records pre- and post-1970, from 24 countries are presented. While these inevitably suffer from recorder bias, they indicate that in only two countries, Croatia and Slovakia, does the insect seem to be increasing in range. 6. Our data suggest that the insect may be in decline across Europe, most likely due to habitat loss, and that conservatio