Climatic Buffering Research Articles

A maritime location reduced palynofloral turnover and extirpation across the end Cretaceous boundary interval on the west coast of Canada

A well-preserved suite of ∼163 spore-pollen taxa from a recently discovered K/Pg interval within the maritime Oyster Bay Formation, Vancouver Island, British Columbia, Canada, reveals a pattern of floral turnover across the boundary event with local extirpations of ∼15 % of Cretaceous taxa. Along the margin of the eastern North Pacific, a shift occurred in near-coastal vegetation composition from uppermost Cretaceous diverse fern and bryophyte-dominated communities to Danian conifer-dominated forests with a fern understory. The ‘fern spore spike’ common in other K/Pg records was not detected within the sandstone to mudstone sequence. Spore-pollen assemblages preserved herein align with those of the Continental Margin floristic province. Palm pollen is noteworthy in the studied sections including Arecipites spp. (aff. Arecaceae), Spinizonocolpites spp. (aff. Nypa) and Pandaniidites typicus (aff. Pandanus) suggesting a warm, frost-free, sub-tropical climate prevailed across the K/Pg interval. The presence of numerous endemic spore-pollen taxa is indicative of geographic isolation from the North American Western Interior. Maritime climate buffering along the west coast of North America contributed to microrefugia permitting greater stability in terrestrial plant communities than in continental regions.

Species richness responds to buffer effectiveness and competitive priorities in simulations of alpine microrefugia

AbstractAimMicrorefugia on alpine slopes may allow species to persist in a warming climate. How plant species richness could respond to of the effectiveness of climatic buffering, defined as the difference in climate change in a microrefugium in comparison to that of an open alpine slope as mediated by competitive priority effects, is explored.LocationAlpine habitat anywhere.TaxonVascular plants.MethodsA simple spatially explicit model of plant species with adaptations across a climatic gradient simulates reproduction, dispersal, and mortality through climatic change. The effectiveness of microrefugia in buffering climate change and levels of competitive priority effects are included as factors that alter demographic rates in an experimental framework. Spatial patterns of microrefugia and differences in dispersal are also simulated. Differences in mean species richness were analysed.ResultsThe number of species conserved, relative to an instantaneous equilibrium calculation with the same climatic change, decreases with inclusion of a period of change (transient vs. instantaneous, equilibrium change) and further with competitive priority effects. In these simulations, the number of species conserved does not simply increase with buffer effectiveness, as hypothesized, but instead is bimodal.Main ConclusionsThe dip in number of species conserved in the middle range of buffer effectiveness occurs because barriers develop. These are temporal ecological traps, wherein species adapted to the middle of a climatic gradient become extinct, because their colonization of microrefugia is blocked by an extinction debt of resident species. The inertia that allows these demographic consequences is increased by competitive priorities. The highest levels of buffering and resulting inertia will not be ubiquitous but the bimodal pattern indicates that assessments of the role of microrefugia need to recognize the temporal species‐environment and species‐species interactions that will change the number of species conserved versus extinctions.

Consumer isoscapes reveal heterogeneous food webs in deep-sea submarine canyons and adjacent slopes

The deep sea is the largest biome on earth, but one of the least studied despite its critical role in global carbon cycling and climate buffering. Deep-sea organisms largely rely on particulate organic matter from the surface ocean for energy – these organisms in turn play critical roles in energy transport, transformation, storage, and sequestration of carbon. Within the deep sea, submarine canyons are amongst the most complex and dynamic environments in our oceans, where varied morphology, powerful currents, and variable nutrient conditions influence the distribution of species and transport of organic material throughout the water column and the seafloor. Significant habitat heterogeneity provides ideal substrates for cold-water corals, making submarine canyons of interest to conservation and management. However, how these and other topographic features in the deep ocean influence energy flow and trophic pathways is poorly known. Thus, submarine canyons serve as model systems to track variability in organic material flux and consequential utilization and assimilation by the benthos. In this study, we used an extensive stable isotope dataset to examine food-web structure in Baltimore and Norfolk submarine canyons and compared them to their adjacent slopes located along the U.S. Atlantic margin. Linear models were used to construct geospatially-explicit consumer isoscapes that predicted variation in carbon and nitrogen isotopes across the canyon-slope seascape, providing a predictive map from which to test hypotheses on the distribution and flow of energy resources, relevant to understanding whole community function. Communities were composed of isotopically diverse feeding groups with photosynthetically-derived organic carbon providing the basal food resource. Canyon communities were distinct from the slope, with canyon consumers significantly 13C-depleted, indicating a greater supply and/or utilization of fresh organic matter compared to the slope. Isoscapes for benthic and suspension feeders were distinct, possibly due to the consumption of different quality organic matter sources (fresh = suspension feeders, old = benthic feeders), each with distinct isotope composition. To our knowledge, our modeled isoscapes represent the first spatially extensive isotopic maps of deep-sea consumers, providing insights into regional-scale variation in stable carbon and nitrogen isotopes for different consumer groups. They provide a baseline for tracking climate-change induced fluctuations in the quality and availability of surface primary production and the consequential impact to benthic communities, which play critical roles in carbon cycling in our world’s oceans.

Assisted migration in a warmer and drier climate: less climate buffering capacity, less facilitation and more fires at temperate latitudes?

Assisted tree migration has been proposed as a conceptual solution to mitigate lags in biotic responses to anthropogenic climate change. The rationale behind this concept is that tree species currently growing under warmer and drier climates will be more resistant and resilient to the new climatic conditions than tree species naturally growing in currently wetter and colder climates. However, we hypothesize that, by being more stress‐tolerant to warmer and drier conditions, translocated species should exhibit different functional attributes, which could induce important ecological and societal costs and overcome the desired benefits of maintaining wood production and other ecosystem services. We used principal component analysis (PCA) to analyze variation in seven traits of 106 tree and tall shrub species from contrasting latitudinal distributions in western North America and Europe to predict the potential functional changes of forest ecosystems due to the translocation of tree species from low to high latitudes. We show that species from both continents differed primarily by their position on the leaf economy spectrum (LES) and their size traits. Even though, in Europe, differences in LES were significantly correlated to species southern latitudinal positions, in both continents differences in size traits were significantly correlated to latitude. These results suggest that assisted migration by translocating more conservative species of shorter stature in currently cooler climates should decrease the buffering capacity of forest canopies, decrease facilitation for understory species, and increase wildfire risks, whose effects have the potential to accelerate climate warming through negative atmospheric feedback processes. As an alternative solution to assisted migration that may accelerate rather than mitigate climate change, we recommend that foresters gradually diversify the vertical structure and layering of the existing forest canopy to maintain a sustainable water cycle and energy balance between the soil, the tree and the atmosphere without increasing the wildfire risk.

Applying climate change refugia to forest management and old-growth restoration.

Recent studies highlight the potential of climate change refugia (CCR) to support the persistence of biodiversity in regions that may otherwise become unsuitable with climate change. However, a key challenge in using CCR for climate resilient management lies in how CCR may intersect with existing forest management strategies, and subsequently influence how landscapes buffer species from negative impacts of warming climate. We address this challenge in temperate coastal forests of the Pacific Northwestern United States, where declines in the extent of late-successional forests have prompted efforts to restore old-growth forest structure. One common approach for doing so involves selectively thinning forest stands to enhance structural complexity. However, dense canopy is a key forest feature moderating understory microclimate and potentially buffering organisms from climate change impacts, raising the possibility that approaches for managing forests for old-growth structure may reduce the extent and number of CCR. We used remotely sensed vegetation indices to identify CCR in an experimental forest with control and thinned (restoration) treatments, and explored the influence of biophysical variables on buffering capacity. We found that remotely sensed vegetation indices commonly used to identify CCR were associated with understory temperature and plant community composition, and thus captured aspects of landscape buffering that might instill climate resilience and be of interest to management. We then examined the interaction between current restoration strategies and CCR, and found that selective thinning for promoting old-growth structure had only very minor, if any, effects on climatic buffering. In all, our study demonstrates that forest management approaches aimed at restoring old-growth structure through targeted thinning do not greatly decrease buffering capacity, despite a known link between dense canopy and CCR. More broadly, this study illustrates the value of using remote sensing approaches to identify CCR, facilitating the integration of climate change adaptation with other forest management approaches.

Positive classroom climate buffers against increases in loneliness arising from shyness, rejection sensitivity and emotional reactivity.

Loneliness is detrimental to well-being, particularly during the transition into and early years of adolescence when peer relations are ascendant. Shy and emotionally sensitive youth, who often spend considerable time alone, have known vulnerabilities to loneliness. Studies of young children suggest that a supportive classroom context may mitigate adjustment risks, reducing victimization and improving a sense of belonging. Herein we extend this work to older students, testing the hypothesis that a positive classroom climate protects temperamentally vulnerable children (i.e., those who are shy, emotionally reactive, or sensitive to rejection) from escalating levels of loneliness across the course of a school year. A community sample of 540 (277 boys, 263 girls) Lithuanian students in grades 5-7 (10-14 years old) completed identical surveys twice, 4-5 months apart. Self-reports assessed shyness, emotional reactivity, and rejection sensitivity, as well as perceived positive classroom climate and loneliness. Path analyses indicated that longitudinal associations from shyness, emotional reactivity, and rejection sensitivity to increased loneliness were mitigated by positive classroom climate. In each case, temperamental vulnerability anticipated greater loneliness for youth reporting low but not high positive classroom climate. The results held after accounting for several potential confounding variables. The findings have practical implications, suggesting that scholars and practitioners redouble efforts to improve classroom support, particularly for temperamentally vulnerable children who are at elevated risk for solitude, loneliness, and attendant mental health challenges.

Effects of shade tree species on soil biogeochemistry and coffee bean quality in plantation coffee

Shade trees are used in many coffee production systems across the globe. Beyond the benefits on biodiversity conservation, climate buffering, carbon sequestration and pathogen regulation, shade trees can impact the soil nutrient status via, for instance, litter inputs and nitrogen fixation. Since soil nutrients affect coffee quality and taste, there is also a potential indirect effect of shade tree species on coffee quality. Yet, in spite of the potentially large impact of shade tree species, quantitative data on the effects of shade trees on (i) soil biogeochemistry and (ii) the associated coffee bean quality remain scarce. To what extent four widely used shade trees species (Acacia abyssinica L., Albizia gummifera L., Cordia africana L. and Croton macrostachyus L.) in a plantation coffee agroforestry system impact soil biogeochemistry, and how this in turn affects coffee quality, measured as cupping scores and bean size. A significant negative impact of N-fixing shade tree species on soil pH and base cation concentrations was found. Plant-available and total phosphorus was enhanced by the presence of Albizia gummifera L. Thus, the present findings demonstrate that careful selection and integration of shade tree species such as Acacia abyssinica L. and Albizia gummifera L. into coffee production systems is a good practice for sustaining soil chemical properties in coffee agroecosystem. Despite the impacts on soil chemical characteristics, the shade tree species had no effect on coffee cup quality but did affect the bean mass. In this particular study, an attempt was made to quantify the impacts of widely used shade tree species on soil biogeochemistry and the subsequent effect on coffee bean quality in a plantation agroforestry system over the course of one season in southwest Ethiopia. However, it might be feasible to accommodate both relatively sparse time-series experimental data consisting of coffee farms from plantations and smallholders, which needs to be the goal of future research to accurately examine the impacts on the outcome variables.

Staying connected: assessing the capacity of landscapes to retain biodiversity in a changing climate

ContextManagement for positive biodiversity outcomes under a changing climate requires a shift of perspective relative to traditional conservation. Here we develop a repeatable indicator for measuring the capacity of landscapes to retain biodiversity under a range of plausible climate futures, as a function of the condition and spatial configuration of native habitat.MethodsThe Spatial Resilience Index extends an existing approach to assessing the potential for biodiversity associated with any location in a region to access suitable habitat in the surrounding landscape under climate change, incorporating multiple dispersal rates integrated over time and an optimised spatial structure. Derivation of the indicator is demonstrated for an Australian case study, covering the entire State of New South Wales, drawing on existing spatial datasets and models.ResultsMapping of the Spatial Resilience Index across New South Wales suggests that different regions, and locations within these regions, vary markedly in their expected capacity to retain biodiversity, depending on the direct rate of climate change, the degree of climatic buffering (or reduction of climate velocity) afforded by landscape heterogeneity, and the degree of anthropogenic impacts on the connectedness of habitat in the landscape. The developed approach accounts for the interplay between these processes by treating them within a unified framework.ConclusionsThe index highlights areas which can potentially benefit from adaptive management (e.g. habitat restoration) to enhance capacity to retain biodiversity under climate change, and offers an objective means of monitoring any resulting change in this capacity over time.

Accounting for snowpack and time-varying lags in statistical models of stream temperature

Water temperature plays a primary role in driving ecological processes in streams due to its direct impact on biogeochemical cycles and the physiological processes of stream fauna, such as growth, development, and the timing of life history events. Streams influenced by snowpack melt are generally cooler in the summer and demonstrate less sensitivity to climate variability in what is commonly referred to as “climate buffering”. Despite the substantial influence of snowpack on stream temperature and expected changes in snowpack accumulation and melt timing with climate change, methods for representing snowpack in statistical models for stream temperature have not been well explored. In this investigation, we quantified the extent of stream temperature buffering in free-flowing streams across a geographically diverse region in the Pacific Northwest USA. We demonstrated that statistical models of daily mean stream temperature can be improved by explicitly accounting for temporal variability in a small number of climate covariates believed to be mechanistically related to stream temperature. Our novel statistical approach included as predictors combinations and interactions between the following variables: (1) air temperature, (2) lagged air temperature (where the lag duration varied according to its relationship with flow on a given day at that site), (3) flow, (4) snowpack in the upstream catchment, and (5) day of year. We found that sites with substantial snow influence were associated with increased air temperature buffering during the warm season and longer air temperature lags (>30 days during spring high flows and ∼ 10 days during late summer low flows) compared to sites where precipitation predominantly fell as rain (<6 days year-round). By accounting for snowpack and temporal variation in lagged heat transfer processes, our models were able to accurately predict seasonal patterns and interannual variability in stream temperature in validation data from years not used in model fits using publicly available data sources (average RMPSE ∼ 0.80).

Integration of landscape-level remote sensing and tree-level ecophysiology reveals drought refugia for a rare endemic, bigcone Douglas-fir

For forest species, areas buffered from the rapidly increasing climate stressors and patterns of disturbance — i.e., climate change refugia — are important targets for conservation and protection. Here, we present a novel field survey and remote sensing approach to identification of fine-scalefunctional drought refugiafor bigcone Douglas-fir (Pseudotsuga macrocarpa)-dominated forests. This rare species has been exposed to climate change-exacerbated drought conditions over the past two decades; yet, little is known about its responses to recent drought and how these drought responses vary across local environmental gradients and interact with recent record wildfire seasons. We combined a remote sensing analysis of vegetation condition with field surveys and physiological measurements to better understand bigcone Douglas-fir responses to recent climate trends. We also identified 444 stands exhibiting relatively low response and high resilience to drought — i.e., potential drought refugia. We found that low elevation stands and those in south-facing aspects generally experienced greater levels of seasonal and interannual drought stress. This trend was more pronounced for stands that experienced fire (2007 Zaca Fire) prior to the drought, suggesting that wildfire can increase the importance of topographic mediation of climate conditions in bigcone Douglas-fir forests. Elevation and aspect also interacted to affect physiological acclimation to seasonal drought conditions, with low elevation north-facing sites in particular experiencing a favorable combination of greater climate buffering and greater drought resilience, suggesting that these sites may be important refugia for bigcone Douglas-fir at low elevations. Furthermore, we found that the relationships between topography and drought response were weaker in more coastal sites, possibly due to maritime climate buffering in these sites. Altogether, these results illustrate how topographic mediation of regional drought conditions is critical for the persistence of this rare species in drought and fire-prone landscapes, and offer important insights for the conservation and restoration of this iconic species.

Survival in the understorey: Testing direct and indirect effects of microclimatological changes on Ixodes ricinus

The distribution of ticks in the Ixodes ricinus species complex is partly driven by climate, with temperature and relative humidity affecting survival. These variables are driven by macroclimate, but vary locally due to microclimate buffering. This buffering has been suggested to be one of the driving forces behind variation in tick survival and density in time and space. In order to understand the role of the herb layer with respect to this variation, we deployed I. ricinus within an existing experimental setup studying the response of forest understorey to micrometeorological changes. This allowed for the analysis of both direct effects of warming on tick survival in controlled field conditions, as well as indirect effects through changes in herb layer biomass. Herb layer biomass estimates were observed to be higher in plots that had been experimentally warmed, with a trend towards higher survival in these warmed plots. This marginal increase in survival rate may be due to increased microclimate buffering. Comparing our results to literature implies that canopy and shrub layer vegetation have a larger effect on climate buffering, and therefore also on tick survival. Since the herb layer biomass is expected to increase due to global warming and increased frequency of disturbance-induced canopy gaps, survival in forested habitats may increase in the future. This would increase the difference in survival compared to that in open habitats.

Emerging spatial prioritization for biodiversity conservation indicated by climate change velocity

Anthropogenic climate change is challenging biodiversity conservation worldwide. Climate change metrics derived from future climate predictions help to assess potential impacts of climate change on biodiversity. Here we calculated future climate change velocities across biogeographical regions of terrestrial Europe and the Natura 2000 protected area network, the largest protected area network on Earth. We applied climate projections for the year 2070, considering two emission scenarios, six global climate models and a fine spatial resolution. Areas with very high climate change velocity were identified as climate change hotspots, while areas with very low velocity were recognized as coldspots. We further revealed where and to what extent climate change hotspots and coldspots coincide with Natura 2000 sites. We found that climate change velocities are projected highest in the Continental and Boreal regions, and lowest in the Mediterranean and Anatolian regions. However, the Alpine region will likely contain largest areal proportions of climate change hotspots, while areal proportions of coldspots are projected largest in the Mediterranean region. High mountain regions such as the Alps show a high proportion of Natura 2000 sites that coincide with climate change hotspots. Both, hotspots and coldspots, are geographically associated with areas of topographic diversity. Low topographical diversity indicates high climate change exposure. The impact of hotspots increases with spatial isolation. Oceanic climate buffers climate change exposure in contrast to continental climate. However, continental regions of Europe tend to exhibit less spatial isolation. We recommend conservation action in climate change hotspots and coldspots to simultaneously protect the most climate-exposed biodiversity as well as climate change refugia. Climate change hotspots and coldspots overlapping with Natura 2000 sites should be considered priority conservation sites because new protected areas are hard to realize in densely populated landscapes of Europe. This study directs European conservation management and policy towards meeting international conservation goals in a climate-smart way.

Buffering Climate Change with Nature

Abstract It is increasingly evident that climate sustainability depends not only on societal actions and responses, but also on ecosystem functioning and responses. The capacity of global ecosystems to provide services such as sequestering carbon and regulating hydrology is being strongly reduced both by climate change itself and by unprecedented rates of ecosystem degradation. These services rely on functional aspects of ecosystems that are causally linked—the same ecosystem components that efficiently sequester and store carbon also regulate hydrology by sequestering and storing water. This means that climate change adaptation and mitigation must involve not only preparing for a future with temperature and precipitation anomalies, but also actively minimizing climate hazards and risks by conserving and managing ecosystems and their fundamental supporting and regulating ecosystem services. We summarize general climate–nature feedback processes relating to carbon and water cycling on a broad global scale before focusing on Norway to exemplify the crucial role of ecosystem regulatory services for both carbon sequestration and hydrological processes and the common neglect of this ecosystem–climate link in policy and landscape management. We argue that a key instrument for both climate change mitigation and adaptation policy is to take advantage of the climate buffering and regulative abilities of a well-functioning natural ecosystem. This will enable shared benefits to nature, climate, and human well-being. To meet the global climate and nature crises, we must capitalize on the importance of nature for buffering climate change effects, combat short-term perspectives and the discounting of future costs, and maintain or even strengthen whole-ecosystem functioning at the landscape level. Significance Statement Natural ecosystems such as forests, wetlands, and heaths are key for the cycling and storage of water and carbon. Preserving these systems is essential for climate mitigation and adaptation and will also secure biodiversity and associated ecosystem services. Systematic failure to recognize the links between nature and human well-being underlies the current trend of accelerating loss of nature and thereby nature’s ability to buffer climate changes and their impacts. Society needs a new perspective on spatial planning that values nature as a sink and store of carbon and a regulator of hydrological processes, as well as for its biodiversity. We need policies that fully encompass the role of nature in preventing climate-induced disasters, along with many other benefits for human well-being.

Coordinated Implementation of Climate-Smart Practices in Coffee Farming Increases Benefits at Farm, Landscape and Global Scale

Coffee is a major commodity crop that shapes large shares of tropical landscapes. However, the sustainability of these landscapes is threatened by climate change. Whilst adopting climate-smart (CS) practices clearly offers direct benefits to local farmers, their greater benefits at landscape and global scales has not been studied for specific commodity crops so far. Our research uniquely outlines how local adoption of CS-practices in coffee-farming systems provides local, landscape and global benefits. We review literature on CS agriculture, CS landscapes, and coffee farming to firstly identify the different CS-practices applicable to coffee farming systems, and then group these into functional groups that represent the main functional trait targeted by different practices within coffee-farming systems. This allows identifying benefits provided at local, landscape and global scales. The seven functional groups identified are: soil characteristics; water management; crop and genetic diversity; climate buffer and adjustment; crop nutrient management; structural elements and natural habitats; and system functioning. Benefits offered at landscape and global scales (non-exhaustively) include improved water quality, biodiversity conservation and habitat connectivity, as well as stabilized regional climate patterns. Our review shows that regulating services are especially pronounced, although the extent of benefits provided depend on landscape coordination. We discuss considerations for managing possible conflicts, coordinating actions, financing and accommodating lead time. Local farmers, policy-makers and global donors must unite to improve uptake of CS coffee-production practices in a coordinated way, to thereby augment and safeguard coffee-farming's socio-ecological system along with associated local, landscape and global benefits.

High-resolution analysis of observed thermal growing season variability over northern Europe

Strong historical and predicted future warming over high-latitudes prompt significant effects on agricultural and forest ecosystems. Thus, there is an urgent need for spatially-detailed information of current thermal growing season (GS) conditions and their past changes. Here, we deployed a large network of weather stations, high-resolution geospatial environmental data and semi-parametric regression to model the spatial variation in multiple GS variables (i.e. beginning, end, length, degree day sum [GDDS, base temperature + 5 °C]) and their intra-annual variability and temporal trends in respect to geographical location, topography, water and forest cover, and urban land use variables over northern Europe. Our analyses revealed substantial spatial variability in average GS conditions (1990–2019) and consistent temporal trends (1950–2019). We showed that there have been significant changes in thermal GS towards earlier beginnings (on average 15 days over the study period), increased length (23 days) and GDDS (287 °C days). By using a spatial interpolation of weather station data to a regular grid we predicted current GS conditions at high resolution (100 m × 100 m) and with high accuracy (correlation ≥ 0.92 between observed and predicted mean GS values), whereas spatial variation in temporal trends and interannual variability were more demanding to predict. The spatial variation in GS variables was mostly driven by latitudinal and elevational gradients, albeit they were constrained by local scale variables. The proximity of sea and lakes, and high forest cover suppressed temporal trends and inter-annual variability potentially indicating local climate buffering. The produced high-resolution datasets showcased the diversity in thermal GS conditions and impacts of climate change over northern Europe. They are valuable in various forest management and ecosystem applications, and in adaptation to climate change.

Displacement Induced by Climate Change Adaptation: The Case of ‘Climate Buffer’ Infrastructure

Climate buffer infrastructure is on the rise as a promising ‘green’ climate adaptation strategy. More often than not, such infrastructure building is legitimized as an urgent technical intervention—while less attention is paid to the distribution of costs and benefits among the affected population. However, as this article shows, adaptation interventions may directly or indirectly result in the relocation or even eviction of households or communities, thereby increasing vulnerabilities for some while intending to reduce long-term climate vulnerabilities for all. We argue that this raises serious, if underappreciated, ethical issues that need to be more explicitly addressed in adaptation policy making. We illustrate our conceptual argument with the help of three examples of infrastructural ‘climate buffers’: Space for the River projects in the Netherlands, the Diamer–Bhasha dam in Pakistan and the coastal protection plan in Jakarta, Indonesia.

OCBIL theory: a new science for old ecosystems

Abstract This paper is an introduction to the special issue of the Biological Journal of the Linnean Society entitled OCBIL theory: a new science for old ecosystems. Firstly, we elaborate on the origins and development of OCBIL theory, which argues that landscape age, climatic buffering and soil fertility are key environmental dimensions shaping ecological and evolutionary processes across different scales. We then consider the 21 contributions made in this special issue in terms of cutting edge advances in the Southern Hemisphere that test, explore and apply aspects of OCBIL theory at the end of its first decade of formal publication. More attempts at refutation are urged, as untested aspects remain controversial. Lastly, a concluding discussion is offered on promising new lines of enquiry to develop the theory further and ensure its global application to pressing conservation issues facing biological and cultural diversity. Although OCBILs are absent or rare in much of the postglacial and periglacial Northern Hemisphere, we demonstrate, in south-west Europe and North America, starting with California, that they are likely to be found, thus extending the implications and applications of OCBIL theory in new directions. We also propose that, in many ways, Noongar Aboriginal cosmology from south-west Australia has developed sophisticated insights about ancient uplands that are precursors to key ideas in OCBIL theory.

Biodiversity arks in the Anthropocene

The Anthropocene proposal suggested that the Earth may have entered a new geological epoch, in which human activity and climate change are influencing the environment at global scale. Arrival of the Anthropocene is bringing an unprecedented challenge to the biodiversity that is essential to humans, and enhancing many benefits of nature to human being. However, biodiversity loss is aggravating in the rhythm of inevitable change in the Anthropocene, and the adaptation of biodiversity to the anthropogenic disturbance seems unable to keep pace with the human activity and climate change. Therefore, re-examination of the assumptions and practices upon the current conservation endeavor are needed. We suggested that biodiversity conservation should be paid more attention to the response from biodiversity to the human activity and climate change in the Anthropocene. Thus, the concept of biodiversity arks in the Anthropocene is proposed, that is, biodiversity arks in the Anthropocene are the areas where vulnerable biodiversity is sheltered to alleviate human activity and buffered from climate change under the anthropogenic disturbance. The concept should be implemented for biodiversity conservation to fill gaps between our knowledge and build on successful conservation and sustainability in the Anthropocene. It will be certainly important to conservation policy instruction and management under climate change, especially the implementation of climate buffering zones preserving biodiversity in the face of warming climate.

The value of climate responses of individual trees to detect areas of climate-change refugia, a tree-ring study in the Brazilian seasonally dry tropical forests

Forests worldwide are facing increasingly frequent climate extremes due to global warming. The negative effects of climate change on tropical forests have been extensively reported by both permanent plots and tree-ring studies that targeted forest's responses to climate. While they focus mostly on community and population levels, the effects of landscape heterogeneity on trees’ sensitivity to climate is often not accounted for, overlooking the diverse responses of individual trees to climate variation. We tested the hypotheses that trees may differ in sensitivity to climate and that some microenvironmental conditions may exert the role of climate-change refugia. We built the first tree-ring chronology of Amburana cearensis trees sampled across a Seasonally Dry Tropical Forest (SDTF) in Brazil. We ensure a robust tree-ring dating using dendrochronological methods and 14C dating of trees inhabiting various conditions characterized here through the seasonality of the local Normalized Difference Vegetation Index. At the population level, the standard tree-ring chronology suggests that tree growth depends on rainfall and temperature, leading to a common conclusion that drier and warmer conditions would impact interannual tree growth in the tropics. However, the cluster analyses revealed groups of individual trees with distinct growth sensitivities to climate. The most sensitive trees were the individuals located in the highly seasonal vegetation of the epikarst, in contrast to the complacent trees (non-sensitive to regular interannual climate variability) inhabiting the less-seasonal vegetation in the deep soil epikarst and valley. Based on these groups of trees, we built two mean chronologies and assessed their climate-growth relationships. In accordance with the individual analysis, the tree-ring chronology of complacent trees showed no association with wet season precipitation and only moderate association with temperature. The areas supporting these complacent trees of A. cearensis in the less seasonal vegetation correspond to a quarter of the entire sampling site. The climate buffering capacity of these refugia may only be compromised in years of climate extremes when all sampled trees share low growth rates during years with anomalous low rainfall and high temperature. Assessing individual’s climate sensitivity is therefore paramount for a comprehensive understanding of the heterogeneous responses of tropical forests to climate change. The hidden individual tree responses in the population can help identify priority areas of management in a rapidly changing environment.

The climate adaptation potential of the rural-urban fringe

As global warming continues, cities need to adapt to the changing climate including aggravating floods and increased heat stress. Urban and landscape planners build such climate-proof city through the development ofgreen open spaces, who serve as climate buffers. At the rural-urban fringe (RUF) the green open spaces, and farmland in particular, are changing rapidly: reallocation to built-up land uses and creation of private open spaces such as gardens and horse pastures. This paper studies how these developments at the RUF affect the floods and heat stress in the nearby city. Moreover, it explores the potential of green open spaces at the RUF to alleviate climate impacts at the local as well as the metropolitan scale. The research employs research by design (RbD) on a case study: the Brussels’ RUF, and the watershed of the Vogelzang in particular. Via maps, sections and other design instruments, this paper unravels the complexity of climate adaptation in Brussels and highlights the interlinkage between the city center and the south-western RUF. Due to its’ geographical location, the watershed of the Vogelzang is of climate-strategic importance to manage floods, droughts and heat stress in the urban conglomeration. Following that analysis the paper explores how the watershed of the Vogelzang water can be climate-proofed. The RbD builds on a new master-plan for the area that proposes to develop an alternative food network in the area. The paper provides insights into the Brussels’ situation but equally feeds back into the debate about sustainable planning at the RUF. Firstly, it highlights the potential of the RUF’s green open spaces to contribute to climate adaption at the local as well as the metropolitan scale. Hence, the challenge of planning for urban climate adaptation exceeds the limitations of the urban conglomeration and planners must incorporate the RUF within the vision on local climate adaptation. Secondly, this paper illustrates how the farmland at the RUF has great potential to sustainably develop the area, including the creation of climate buffers.