Climate, landscape, habitat, and woodland management associations with hazel dormouse Muscardinus avellanarius population status

Although strictly protected, populations of the hazel dormouse Muscardinus avellanarius in the UK declined by 72% from 1993 to 2014. Using National Dormouse Monitoring Programme data from 300 sites throughout England and Wales, we investigated variation in hazel dormouse population status (expressed as Indices of Abundance, Breeding, and population Trend) in relation to climate, landscape, habitat, and woodland management. Dormice were more abundant and produced more litters on sites with warmer, sunnier springs, summers, and autumns. Dormouse abundance was also higher on sites with consistently cold local climate in winter. Habitat connectivity, woodland species composition, and active site management were all correlated with greater dormouse abundance and breeding. Abundances were also higher on sites with successional habitats, whereas the abundance of early successional bramble Rubus fruticosus habitat, woodland area, and landscape connectivity were important for population stability. Diversity in the structure of woodlands in Europe has decreased over the last 100 years, and the habitats we found to be associated with more favourable dormouse status have also been in decline. The conservation status of the hazel dormouse, and that of woodland birds and butterflies, may benefit from reinstatement or increased frequency of management practices, such as coppicing and glade management, that maintain successional and diverse habitats within woodland

Shifting baselines for species in chronic decline and assessment of conservation status. Are hazel dormice Muscardinus avellanarius endangered?

•1. Long-term data are beneficial for monitoring the conservation status of species. Assessments of population change over recent periods of fixed duration will, however, be subject to ‘shifting baselines’, where the accepted norm for the population at the start of the period already represents a reduction from historical levels. International Union for Conservation of Nature Red List criteria for categorizing conservation threat rely on assessing declines against quantitative thresholds, generally measured over 10 years, as indications of the likelihood of extinction in the near future. By contrast, legal frameworks such as the European Habitats Directive require states to achieve and sustain ‘Favourable Conservation Status’ for protected species, while domestic conservation legislation can have more diverse objectives and mechanisms, based on local contexts that extend beyond biological or quantitative criteria. •2. We explore the challenges associated with assessing the risk of extinction and the conservation status that arise from the availability of long-term monitoring data for hazel dormice Muscardinus avellanarius in the United Kingdom. •3. Numbers of adult dormice counted in the National Dormouse Monitoring Programme are in ongoing decline, amounting to an overall decline of 78% (95% confidence interval = 72%–84%) over 27 years, 1994–2020. If the observed annual rate of decline of 5.7% (95% CI = 4.7%–6.8%) were to continue unabated, dormouse counts would decline by >90% from 1994 to 2034. Despite this, the species would never be categorized as Endangered, under IUCN criteria, which specify a reduction of >50% within 10 years. •4. While such chronic decline may not indicate imminent risk of extinction, justifying a higher Red List category, it is a demonstration of unfavourable conservation status at a national scale. Prioritization based on demonstration of such chronic declines might direct more effective action towards species conservation at a point when their recovery is more attainable, rather than attempting later to reverse a journey to the brink of extinction when the species is finally ‘Endangered’

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

30 years of Dormouse Monitoring

The People's Trust for Endangered Species (PTES) owns a private woodland on the Isle of Wight (IoW) that is managed predominantly for woodland bats, Red Squirrels and Hazel Dormice. Dormice are considered to be widespread across the island in suitable habitat. The IoW is different from the mainland as it has no wild deer species. PTES has been monitoring dormice in its woodland since 1992, when nest boxes were first put up by Paul Bright. However, in spite of appropriate woodland management for dormice at the reserve, dormouse numbers there appear to be declining. This raised the question: “Is the apparent decline in dormice recorded in nest boxes, real or perceived?” If the decline was real, it may be necessary to reconsider management advice that we give for dormice. If the decline was perceived, then it may be necessary to reconsider advice that we give for monitoring dormice. The first challenge was to identify what the woodland may have looked like 30 years ago and identify why high numbers of dormice were recorded. We could then apply the known woodland management that was done in the intervening years, to determine why dormouse nest box occupancy changed by varying amounts in different parts of the wood. We were able to check some of our ideas using data from footprint tunnels and this work is ongoing in 2022. This talk will discuss woodland state, woodland management and dormouse next box occupancy in a dormouse hotspot in southern England

Why link diverse citizen science surveys? Widespread arboreal habits of a terrestrial amphibian revealed by mammalian tree surveys in Britain.

Terrestrial anurans, with their typically short limbs, heavy-set bodies and absent claws or toe pads are incongruous tree climbers, but even occasional arboreal locomotion could offer substantial advantages for evading predators or accessing new shelter or food resources. Despite recent interest, arboreal behaviour remains rarely and unsystematically described for terrestrial amphibians in Europe, likely due to fundamental differences in survey methods and therefore a lack of field data. However, other taxa surveys specifically target trees and tree cavities. We undertook collaborations and large-scale data searches with two major citizen science projects surveying for arboreal mammals in Britain to investigate potential tree climbing by amphibians at a national scale. Remarkably, we found widespread arboreal usage by amphibians in England and Wales, with occupancy of hazel dormouse (Muscardinus avellenarius) nest boxes, tree cavities investigated as potential bat roosts and even a bird nest, by common toads (Bufo bufo), but few additional records of frogs or newts. Of the 277-400 sites surveyed annually for dormice since 2009 at least 18 sites had amphibians recorded in nest boxes while of the 1388 trees surveyed for bats a total 1.4% (19 trees) had toads present. Common toads were found using cavities in seven tree species and especially goat willow (Salix caprea). Toads are potentially attracted to tree cavities and arboreal nests because they provide safe and damp microenvironments which can support an abundance of invertebrate prey but the importance of such tree microhabitats for toad conservation remains unknown and our results should be interpreted cautiously. We encourage expanding and linking of unrelated biodiversity monitoring surveys and citizen science initiatives as valuable tools for investigating ecological traits and interactions

When is a dormouse ‘Endangered’? Continued population decline of Hazel Dormice (Muscardinus avellanarius) in Great Britain. (Poster)

It is important to monitor species populations to identify changes in Red List assessment, whether increases from conservation or continued declines. This can be more difficult when there are multiple modelling options available. Using data from the National Dormouse Monitoring Programme, provided by the People’s Trust for Endangered Species, we explore the change in British Hazel Dormice (Muscardinus avellanarius) populations using two appropriate generalised additive models. The first uses the negative binomial distribution, and second the Poisson distribution, with a fixed effect of month included. Both models indicate that dormice have declined by >70% between 1994 and 2018 in Great Britain, indicating a continuation of the chronic decline of the species. Our models do not differ significantly in their evaluation of the population trend, but do indicate different Red List categories, leading us to ask: when is the dormouse population considered ‘endangered’

Co‐designing a toolkit for evidence‐based decision making in conservation: Processes and lessons

Funder: Arcadia Fund; doi: http://dx.doi.org/10.13039/100012088Funder: MAVA Foundation; doi: http://dx.doi.org/10.13039/100013324Improving the effectiveness of conservation practice requires better use of evidence. Since 2004, researchers from the Conservation Evidence group (University of Cambridge) have engaged with over 1100 named practitioners, policymakers, funders and other academics from across the world to identify needs and develop a range of principles, tools and resources to embed evidence in decision making. The goal of this engagement (the Conservation Evidence Programme) was to deliver improved conservation practice leading to benefits for nature and society. Together, we developed a theory of change with five key strategies for delivering change, alongside a freely available Evidence Toolkit to support decision makers in achieving that change. The authors describe the toolkit, a collection of freely available tools and resources developed by the collaborative programme, and how co‐design, employing different levels of partner engagement, enabled its development. Reflecting on our experiences highlighted a number of insights and recommendations, including the need to identify where deep engagement is a necessary condition for success; the importance of collective agreement of the roles of different partners; the need to consider how to facilitate uptake of new tools or practices, particularly where that requires changes to organisational practices or culture; and the importance of establishing processes/channels for ongoing engagement with stakeholders, with a willingness to be flexible and open to incorporating new suggestions and perspectives as needed. The Conservation Evidence Programme has enabled practitioners, funders and policymakers to become part of a network of forward‐thinking organisations that is working collaboratively to help drive more effective conservation practice through improved evidence use

Co‐designing a toolkit for evidence‐based decision making in conservation: Processes and lessons

Abstract Improving the effectiveness of conservation practice requires better use of evidence. Since 2004, researchers from the Conservation Evidence group (University of Cambridge) have engaged with over 1100 named practitioners, policymakers, funders and other academics from across the world to identify needs and develop a range of principles, tools and resources to embed evidence in decision making. The goal of this engagement (the Conservation Evidence Programme) was to deliver improved conservation practice leading to benefits for nature and society. Together, we developed a theory of change with five key strategies for delivering change, alongside a freely available Evidence Toolkit to support decision makers in achieving that change. The authors describe the toolkit, a collection of freely available tools and resources developed by the collaborative programme, and how co‐design, employing different levels of partner engagement, enabled its development. Reflecting on our experiences highlighted a number of insights and recommendations, including the need to identify where deep engagement is a necessary condition for success; the importance of collective agreement of the roles of different partners; the need to consider how to facilitate uptake of new tools or practices, particularly where that requires changes to organisational practices or culture; and the importance of establishing processes/channels for ongoing engagement with stakeholders, with a willingness to be flexible and open to incorporating new suggestions and perspectives as needed. The Conservation Evidence Programme has enabled practitioners, funders and policymakers to become part of a network of forward‐thinking organisations that is working collaboratively to help drive more effective conservation practice through improved evidence use

The priority species indicator: measuring the trends in threatened species in the UK

We describe the development of two complementary priority species indicators (PSIs) to help the UK to report progress towards Aichi target 12 on the status of known threatened species. Based on species identified as national conservation priorities, the indicators present average changes in (i) 213 species for which trends in relative abundance are available from structured monitoring schemes, and (ii) 179 species for which trends in frequency of occurrence were modelled from data sets of unstructured biological records. Both indicators show substantial declines in priority species since 1970, of 67% and 40%, respectively, although the rate of decline in the relative abundance-based PSI may have lessened over the last five years (2007–2012). We discuss the biases and weaknesses of the indicators at present, and put forward suggestions as how these may be addressed, including through the development of a third PSI