Andrew J. Suggitt

Habitat associations of species show consistent but weak responses to climate

Different vegetation types can generate variation in microclimates at local scales, potentially buffering species from adverse climates. To determine if species could respond to such microclimates under climatic warming, we evaluated whether ectothermic species (butterflies) can exploit favourable microclimates and alter their use of different habitats in response to year-to-year variation in climate. In both relatively cold (Britain) and warm (Catalonia) regions of their geographical ranges, most species shifted into cooler, closed habitats (e.g. woodland) in hot years, and into warmer, open habitats (e.g. grassland) in cooler years. Additionally, three-quarters of species occurred in closed habitats more frequently in the warm region than in the cool region. Thus, species shift their local distributions and alter their habitat associations to exploit favourable microclimates, although the magnitude of the shift (approx. 1.3% of individuals from open to shade, per degree Celsius) is unlikely to buffer species from impacts of regional climate warming.

Using in situ management to conserve biodiversity under climate change

Summary Successful conservation will increasingly depend on our ability to help species cope with climate change. While there has been much attention on accommodating or assisting range shifts, less has been given to the alternative strategy of helping species survive climate change through in situ management. Here we provide a synthesis of published evidence examining whether habitat management can be used to offset the adverse impacts on biodiversity of changes in temperature, water availability and sea‐level rise. Our focus is on practical methods whereby the local environmental conditions experienced by organisms can be made more suitable. Many studies suggest that manipulating vegetation structure can alter the temperature and moisture conditions experienced by organisms, and several demonstrate that these altered conditions benefit species as regional climatic conditions become unsuitable. The effects of topography on local climatic conditions are even better understood, but the alteration of topography as a climate adaptation tool is not ingrained in conservation practice. Trials of topographic alteration in the field should therefore be a priority for future research. Coastal systems have the natural capacity to keep pace with climate change, but require sufficient sediment supplies and space for landward migration to do so. There is an extensive literature on managed realignment. While the underlying rationale is simple, successful implementation requires careful consideration of elevation and past land use. Even with careful management, restored habitats may not attain the physical and biological attributes of natural habitats. Synthesis and applications. The recent literature provides a compelling case that some of the adverse effects of climate change can be offset by appropriate management. However, much of the evidence for this is indirect and too few studies provide empirical tests of the long‐term effectiveness of these management interventions. It is clear from the existing evidence that some techniques have a higher risk of failure or unexpected outcomes than others and managers will need to make careful choices about which to implement. We have assessed the strength of evidence of these approaches in order to demonstrate to conservation professionals the risks involved.

Extinction risk from climate change is reduced by microclimatic buffering

Protecting biodiversity against the impacts of climate change requires effective conservation strategies that safeguard species at risk of extinction1. Microrefugia allowed populations to survive adverse climatic conditions in the past2,3, but their potential to reduce extinction risk from anthropogenic warming is poorly understood3–5, hindering our capacity to develop robust in situ measures to adapt conservation to climate change6. Here, we show that microclimatic heterogeneity has strongly buffered species against regional extirpations linked to recent climate change. Using more than five million distribution records for 430 climate-threatened and range-declining species, population losses across England are found to be reduced in areas where topography generated greater variation in the microclimate. The buffering effect of topographic microclimates was strongest for those species adversely affected by warming and in areas that experienced the highest levels of warming: in such conditions, extirpation risk was reduced by 22% for plants and by 9% for insects. Our results indicate the critical role of topographic variation in creating microrefugia, and provide empirical evidence that microclimatic heterogeneity can substantially reduce extinction risk from climate change.Topographic variations result in microclimatic heterogeneity that can substantially reduce extinction risk from climate change, according to a study of 430 climate-threatened and range-declining species in England.

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.

A reply to ‘A meta-database of Holocene sediment cores for England: missing data’ (Tooley 2015)

We welcome the response of Tooley (2015) to our article describing a new meta-database of Holocene sediment cores for England. In our article we describe the online publication of this meta-database, arising from systematic meta-search. We define its scope and the meta-data it contains, before providing the data themselves (in the Electronic Supplementary Material online). We note that Prof. Tooley describes the idea of such a database as important and valuable, and we welcome the constructive approach he adopts throughout his article. Tooley highlights that the meta-database can be enhanced by the inclusion of a number of studies of the Coastal Lowlands, highlighting gaps in the Lancashire and Hartlepool Bay areas in particular. While it is undoubtedly true that these studies were omitted, they tend to document boreholes which have shown Holocene sediments, rather than boreholes subject to the analysis of least one palaeoecological proxy, as per our inclusion criterion. For example, based on the information M.J. Tooley provides, we estimate that 17 such analyses from Lancashire would have satisfied this criterion. It is certainly clear that these omissions are genuine, and we would agree that they add to the pool of sites already described in the meta-database. Because of the constraints of systematic search however, it could also be the case that omissions exist outside these areas, and in the original text we highlighted that: ‘‘the resulting meta-database is by no means exhaustive and we would expect further additions to be made in due course’’. We therefore welcome this addition and would similarly do so for others highlighted to the author team. We would however contest the suggestion that ‘much’ of the published data have been overlooked from improper searching. Tooley implores a greater level of focus at the county level; we would only encourage consideration of the attendant effects of his proposed strategy on search volume (the modern counties of England would generate an 84 fold increase to our list of