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Canopy dieback and concerning rates of tree mortality have been noted in iconic forests of the Mount Lofty Ranges (MLR), South Australia, dominated by the stringybark eucalypt speciesEucalyptus baxteri(Brown Stringybark) andE. obliqua(Messmate Stringybark). The extent and causes of stringybark forest decline are not yet fully understood, prohibiting evidence-based management strategies. Here, we explore the distribution of MLR populations of the two species and their position in climate space relative to eastern populations. We also conducted field assessments to investigate stand health and dieback aetiology, and analysed existing tree monitoring data. Stringybarks in the MLR are disjunct from eastern populations and occupy a more summer-arid niche. The species are also susceptible to summer water stress andPhytophthora. Periods of drought during 2006–2009 and 2018–2019 may have contributed to observed dieback. However, field assessments suggest a complex landscape syndrome that includes borer infestations and fire impacts among other factors, rather than solely hydraulic failure. Messmate Stringybark has suffered widespread but patchy stand collapse. There is no obvious common pattern of collapsed sites with respect to topography or local water availability (e.g., swamps and ridges equally affected), although northern range-edge sites are heavily affected. Brown Stringybark is less affected but has notable collapse sites. We hope these studies establish a springboard for future investigations and more widespread sampling of MLR stringybark forests. Further investigations should include regional surveys of stringybark sites to record spatial and temporal patterns of tree mortality combined with multi- or hyperspectral analysis of remotely sensed imagery and visual inspection of dieback from very high resolution aerial images and ground-truthing. Our findings confirm the susceptibility of stringybark forests in the MLR to ecosystem collapse and highlight the urgent need to understand the causes and aetiology of the observed dieback.

Dolines are depressions in karst landscapes that are of high value for conservation, providing habitats and supporting species not found in the surrounding landscape. This is due to their high microhabitat diversity and ability to decouple microclimate from regional climate changes, making them potential refugia for biodiversity. Nevertheless, local anthropogenic disturbances have had considerable impact on the species composition and vegetation structure of many dolines. Here we investigate the conservation value of dolines in three European karst areas, where different levels and types of anthropogenic disturbances have been shaping the vegetation for centuries, using the number of plant species that are cool-adapted, moist-adapted and of high conservation importance (i.e. vulnerable species) as indicators. We found that anthropogenic disturbances generally have a negative impact, reducing the number of vulnerable species supported by dolines. However, more cool-adapted and moist-adapted species were found in some dolines planted with non-native Picea abies than in less disturbed dolines, indicating that anthropogenic disturbances can also have positive consequences for biodiversity. We conclude that anthropogenic disturbances alter the capacity of dolines to support vulnerable species, and that this will impact survival of species in landscapes under global warming. In this context, the effects of various disturbances on species composition and diversity need to carefully considered to determine the best conservation and/or management options.

Refugia can facilitate the persistence of biodiversity under changing environmental conditions, such as anthropogenic climate change, and therefore constitute the best chance of survival for many coral species in the wild. Despite an increasing amount of literature, the concept of coral reef refugia remains poorly defined; so that climate change refugia have been confused with other phenomena, including temporal refuges, pristine habitats and physiological processes such as adaptation and acclimatization. We propose six criteria that determine the capacity of refugia to facilitate species persistence, including long-term buffering, protection from multiple climatic stressors, accessibility, microclimatic heterogeneity, size, and low exposure to non-climate disturbances. Any effective, high-capacity coral reef refugium should be characterized by long-term buffering of environmental conditions (for several decades) and multi-stressor buffering (provision of suitable environmental conditions with respect to climatic change, particularly ocean warming and acidification). Although not always essential, the remaining criteria are important for quantifying the capacity of potential refugia.

Aim: Refugia under past climates have been important in structuring current patterns in diversity, while refugia under anthropogenic climate change will likely be important in retaining this diversity and shaping new patterns. However, few studies have examined the congruence of past, present and future refugia, or the spatiotemporal connectivity of these refugia. Our aim was to test the extent of overlap of refugia under Last Glacial Maximum (LGM), present (2015) and likely future climates (2100), for Tasmania's palaeoendemic flora. We then aimed to identify areas of high spatiotemporal refugia connectivity, as priority areas for conservation and management. Location: Tasmania, Australia. Methods: We developed and applied a new community-level approach to identifying refugia, based on generalized dissimilarity modelling of compositional turnover and a set of reference sites with known biodiversity value. Using these projections of palaeoendemic plant refugia for past, present and future climates, we developed and applied a second approach to quantify the level of connectivity of these refugia over space and time. Results: Although there was large overlap (85%) between current and future climates in the distribution of the highest value palaeoendemic refugia, the small congruence of these areas with refugia at the LGM resulted in only a small area ( c. km 2 ) of persistent high value refugia over all three time periods. Despite this, our spatiotemporal analysis identified several areas of high connectivity in refugial environments for Tasmania's palaeoendemic flora over time. Main conclusions: The community-level approaches we demonstrate here to quantify refugia and their spatiotemporal connectivity have the potential to advance our understanding of biodiversity dynamics, particularly for taxonomic groups that are species-rich, poorly studied or comprised of many rare species, where species-level approaches are less suitable.

This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited., Extreme heat events will become more frequent under anthropogenic climate change, especially in Mediterranean ecosystems. Microhabitats can considerably moderate (buffer) the effects of extreme weather events and hence facilitate the persistence of some components of the biodiversity. We investigate the microclimatic moderation provided by two important microhabitats (cavities formed by the leaves of the grass-tree Xanthorrhoea semiplana F.Muell., Xanthorrhoeaceae; and inside the leaf-litter) during the summer of 2015/16 on the Fleurieu Peninsula of South Australia. We placed microsensors inside and outside these microhabitats, as well as above the ground below the forest canopy. Grass-tree and leaf-litter microhabitats significantly buffered against high temperatures and low relative humidity, compared to ground-below-canopy sensors. There was no significant difference between grass-tree and leaf-litter temperatures: in both microhabitats, daily temperature variation was reduced, day temperatures were 1–5°C cooler, night temperatures were 0.5–3°C warmer, and maximum temperatures were up to 14.4°C lower, compared to ground-below-canopy sensors. Grass-tree and leaf-litter microhabitats moderated heat increase at an average rate of 0.24°C temperature per 1°C increase of ambient temperature in the ground-below-canopy microhabitat. The average daily variation in temperature was determined by the type (grass-tree and leaf-litter versus ground-below-canopy) of microhabitat (explaining 67%), the amount of canopy cover and the area of the vegetation fragment (together explaining almost 10% of the variation). Greater canopy cover increased the amount of microclimatic moderation provided, especially in the leaf-litter. Our study highlights the importance of microhabitats in moderating macroclimatic conditions. However, this moderating effect is currently not considered in species distribution modelling under anthropogenic climate change nor in the management of vegetation. This shortcoming will have to be addressed to obtain realistic forecasts of future species distributions and to achieve effective management of biodiversity.

Background and aims: Dolines are small- to large-sized bowl-shaped depressions of karst surfaces. They may constitute important microrefugia, as thermal inversion often maintains cooler conditions within them. This study aimed to identify the effects of large- (macroclimate) and small-scale (slope aspect and vegetation type) environmental factors on cool-adapted plants in karst dolines of East-Central Europe. We also evaluated the potential of these dolines to be microrefugia that mitigate the effects of climate change on cool-adapted plants in both forest and grassland ecosystems. • Methods: We compared surveys of plant species composition that were made between 2007 and 2015 in 21 dolines distributed across four mountain ranges (sites) in Hungary and Romania. We examined the effects of environmental factors on the distribution and number of cool-adapted plants on three scales: (1) regional (all sites); (2) within sites and; (3) within dolines. Generalized linear models and non-parametric tests were used for the analyses. • Key Results: Macroclimate, vegetation type and aspect were all significant predictors of the diversity of cool-adapted plants. More cool-adapted plants were recorded in the coolest site, with only few found in the warmest site. At the warmest site, the distribution of cool-adapted plants was restricted to the deepest parts of dolines. Within sites of intermediate temperature and humidity, the effect of vegetation type and aspect on the diversity of cool-adapted plants was often significant, with more taxa being found in grasslands (versus forests) and on north-facing slopes (versus south-facing slopes). • Conclusions: There is large variation in the number and spatial distribution of cool-adapted plants in karst dolines, which is related to large- and small-scale environmental factors. Both macro- and microrefugia are therefore likely to play important roles in facilitating the persistence of cool-adapted plants under global warming. Refereed/Peer-reviewed

Background and Aims: Low-altitude mountains constitute important centres of diversity in landscapes with little topographic variation, such as the Southwest Australian Floristic Region (SWAFR). They also provide unique climatic and edaphic conditions that may allow them to function as refugia. We investigate whether the Porongurups (altitude 655 m) in the SWAFR will provide a refugium for the endemic Ornduffia calthifolia and O. marchantii under forecast climate change. Methods: We used species distribution modelling based on WorldClim climatic data, 30-m elevation data and a 2-m-resolution LiDAR-derived digital elevation model (DEM) to predict current and future distributions of the Ornduffia species at local and regional scales based on 605 field-based abundance estimates. Future distributions were forecast using RCP2.6 and RCP4.5 projections. To determine whether local edaphic and biotic factors impact these forecasts, we tested whether soil depth and vegetation height were significant predictors of abundance using generalized additive models (GAMs). Key Results: Species distribution modelling revealed the importance of elevation and topographic variables at the local scale for determining distributions of both species, which also preferred shadier locations and higher slopes. However, O. calthifolia occurred at higher (cooler) elevations with rugged, concave topography, while O. marchantii occurred in disturbed sites at lower locations with less rugged, convex topography. Under future climates both species are likely to severely contract under the milder RCP2.6 projection (approx. 2 °C of global warming), but are unlikely to persist if warming is more severe (RCP4.5). GAMs showed that soil depth and vegetation height are important predictors of O. calthifolia and O. marchantii distributions, respectively. Conclusions: The Porongurups constitute an important refugium for O. calthifolia and O. marchantii, but limits to this capacity may be reached if global warming exceeds 2 °C. This capacity is moderated at local scales by biotic and edaphic factors. Refereed/Peer-reviewed

IntroductionRefugia are habitats that components of biodiversityretreat to, persist in and can potentially expand fromunder changing environmental conditions (Keppelet al., 2012), facilitating the survival of organisms dur-ing extreme climatic changes (Me´dail & Diadema,2009). They may thus maintain favourable climatic con-ditions now absent in the surrounding landscape. Thisis enabled by higher local heterogeneity of micro-climates and the decoupling of local from regionalclimates (Dobrowski, 2011; Keppel et al., 2012).Because refugia potentially safeguard the persistenceof components of biodiversity over millennia, they mayact as safe havens under projected anthropogenic cli-mate change (Me´dail & Diadema, 2009; Keppel et al.,2012). This capacity makes them critical components inclimate change management. As a result, the identifica-tion and protection of refugia has increased in priorityin conservation planning (Noss, 2001; Game et al.,2011). However, refugia are currently loosely definedand their study is often based on ad hoc, descriptivedata sources (Ashcroft, 2010). We therefore clarify theconcept of refugia and related terms. We then argue foran increased focus on understanding how refugia willrespond to climate change. In the context of rapidanthropogenic climate change, we suggest that thisfocus will lead to prioritization of conservation actionstowards those habitats offering the greatest potential assafe havens for biodiversity.What are refugia and what are not?Despite an exponential increase in the use of the termsrefugia and refuges in literature (Fig. 1), refugia are stillconfused with refuges, remnants and reserves. Most cur-rent uses of refugia are to places providing environmen-tal conditions not available in the surroundinglandscapeoverlongperiodsoftime(e.g.,Ashcroft,2010;Dobrowski,2011),withanincreasinginterestinidentify-ing future refugia under projected anthropogenic cli-matechange.However,thetermisalsousedtorefertoavariety of other concepts. For example, in Global ChangeBiology refugia have recently been used to refer totemporary shelter from predation or disturbance (e.g.,Ledger et al., 2011) and to remnant patches of suitablehabitat (e.g., Rittenhouse et al., 2010). The term refugiahas also been used in reference to reserves (see Fig. 1).While thetermrefugiahas onlyrecently beeneffectivelydefined (see Keppel et al., 2012), use of the other threeR-terms has long been widely established. We thereforeadvocatethecorrectuseoftherelevantjargon.Refuges are places that through structures or pro-cesses provide shelter from disturbances, predation,herbivory or competition. They are therefore defined aslocations providing spatial and/or temporal protectionor advantages in biotic interactions over ecological timeperiods (i.e., within the life span of the relevant organ-ism). Remnants are patches of suitable habitats for spe-cies intolerant of changed or modified landscapes thatprevail in landscapes highly modified by human popu-lations and resource exploitation. Reserves are areaslegally or customarily protected from particular anthro-pogenic activities and may vary in size from remnantsto portions of large ‘intact’ landscapes or so-calledwilderness areas.Refugia and anthropogenic climate changeWhile refuges, remnants and reserves continue toreceive considerable research attention, refugia are anarea of rapid recent growth (Fig. 1). The ability of refu-gia to locally mitigate the effects of regional climatechange is increasingly considered important for climatechange adaptation planning (Ashcroft, 2010; Gameet al., 2011). This is because they are potential safehavens for biota and may offer the only hope for in-situpersistence of poorly dispersed species. Protecting suchclimate change refugia could allow some species to

Aim Granite outcrops may be able to act as refugia for species during adverse climate change, owing to their topographic complexity. We assessed this hypothesis by examining phylogeographical patterns in a common, geographically widespread granite endemic, Stypandra glauca (Hemerocallidaceae). Location Granite outcrops of the Southwest Australian Floristic Region, Western Australia. Main conclusions The levels of divergence and low diversity revealed in S. glauca support a scenario of prolonged isolation and persistence on granite outcrops may result from the maintenance of a larger effective population size in southern regions, which retained more mesic climates during drier glacial periods. Although the climatic conditions differ between outcrops in this study, our results indicate that outcrops in both regions have harboured S. glauca throughout climatic changes, accentuating the value of these habitats to biodiversity conservation under future changing climate. Methods Twenty-four tetraploid individuals of the granite endemic Stypandraglauca were sampled from each of 12 granite outcrops: 7 from a mesic environment and 5 from the semi-arid region. Phylogenetic reconstruction and divergence-dating was achieved using Bayesian and parsimony analyses of chloroplast haplotypes from 90 individuals. Nuclear diversity and population differentiation were analysed across all individuals using 10 microsatellite loci. Results Stypandra glauca exhibited high (chloroplast) or moderate (nuclear)levels of divergence among, and low diversity within, outcrops. Haplotype diversity was high in both sampling regions, and each haplotype was unique to one outcrop. There was little correlation between geographical and genetic distance.Both nuclear and chloroplast diversity were higher in southern (mesic)outcrops than in northern (semi-arid) outcrops, although the level of chloroplast divergence among outcrops was similar for both climatic regions. Refereed/Peer-reviewed

Identification of refugia is an increasingly important adaptation strategy in conservation planning under rapid anthropogenic climate change. Granite outcrops (GOs) provide extraordinary diversity, including a wide range of taxa, vegetation types and habitats in the Southwest Australian Floristic Region (SWAFR). However, poor characterization of GOs limits the capacity of conservation planning for refugia under climate change. A novel means for the rapid identification of potential refugia is presented, based on the assessment of local-scale environment and vegetation structure in a wider region. This approach was tested on GOs across the SWAFR. Airborne discrete return Light Detection And Ranging (LiDAR) data and Red Green and Blue (RGB) imagery were acquired. Vertical vegetation profiles were used to derive 54 structural classes. Structural vegetation types were described in three areas for supervised classification of a further 13 GOs across the region. Habitat descriptions based on 494 vegetation plots on and around these GOs were used to quantify relationships between environmental variables, ground cover and canopy height. The vegetation surrounding GOs is strongly related to structural vegetation types (Kappa = 0.8) and to its spatial context. Water gaining sites around GOs are characterized by taller and denser vegetation in all areas. The strong relationship between rainfall, soil-depth, and vegetation structure (R2 of 0.8-0.9) allowed comparisons of vegetation structure between current and future climate. Significant shifts in vegetation structural types were predicted and mapped for future climates. Water gaining areas below granite outcrops were identified as important putative refugia. A reduction in rainfall may be offset by the occurrence of deeper soil elsewhere on the outcrop. However, climate change interactions with fire and water table declines may render our conclusions conservative. The LiDAR-based mapping approach presented enables the integration of site-based biotic assessment with structural vegetation types for the rapid delineation and prioritization of key refugia. Refereed/Peer-reviewed

Identifying refugia is a critical component of effective conservation of biodiversity under anthropogenic climate change. However, despite a surge in conceptual and practical interest, identifying refugia remains a significant challenge across diverse continental landscapes. We provide an overview of the key properties of refugia that promote species' persistence under climate change, including their capacity to (i) buffer species from climate change; (ii) sustain long-term population viability and evolutionary processes; (iii) minimize the potential for deleterious species interactions, provided that the refugia are (iv) available and accessible to species under threat. Further, we classify refugia in terms of the environmental and biotic stressors that they provide protection from (i.e. thermal, hydric, cyclonic, pyric and biotic refugia), but ideally refugia should provide protection from a multitude of stressors. Our systematic characterization of refugia facilitates the identification of refugia in the Australian landscape. Challenges remain, however, specifically with respect to how to assess the quality of refugia at the level of individual species and whole species assemblages. It is essential that these challenges are overcome before refugia can live up to their acclaim as useful targets for conservation and management in the context of climate change. Refereed/Peer-reviewed

Refugia are habitats that populations can retreat to as prevailing climates become inhospitable, and potentially expand from should climates again become favourable [1]. They therefore potentially facilitate the long-term persistence of populations, despite changes in the regional climate. The importance of refugia for the survival of populations under anthropogenic climate change is increasingly recognised [1,2]. As a result, they are now considered keys to conservation planning under climate change [3,4].