Climate change rapidly warms and acidifies Australian estuaries

Differential tolerance of species alters the seasonal response of marine epifauna to extreme warming

Marine heatwaves are occurring with greater frequency and magnitude worldwide and can significantly alter community structure and ecosystem function. Predicting changes in community structure in extreme temperatures requires an understanding of variation among species in their thermal tolerance, and how potential acclimatization to recent temperatures influences survival. To address this, we determined the tolerance to extreme temperatures in a crustacean epifaunal assemblage that inhabits macroalgae in the southeast Australian ocean warming hotspot. Amphipods were the most abundant group and the thermal tolerance of the most abundant species (two in winter and four in summer) was tested to determine their thermal limits and probability of survival in near-future extreme temperatures. Survival, measured as time to immobilization, was compared across species, sexes, life stage and body size. The greatest variation in tolerance to extreme temperatures was among species (not body sizes or life stages), indicating that heatwaves could shift the composition of the macroalgal associated epifaunal assemblage. Comparison of recent thermal history (between 18 °C to 22 °C) revealed greater thermal tolerance of warm acclimatized individuals. Our results indicate that the impacts of a marine heatwave will depend on local species composition and their timing relative to recent climate conditions.

Assessing Ecological Vulnerability under Climate Change and Anthropogenic Influence in the Yangtze River Estuarine Island-Chongming Island, China

Understanding and assessing ecological vulnerability for estuarine islands are important for maintaining estuarine island ecosystem services and its sustainable development. However, due to its complex fresh water-sea-land interaction mechanism and multiple stressors from both climate change and anthropogenic influence, a comprehensive evaluation of ecological vulnerability for estuarine islands has been limited. Therefore, taking the typical estuary island of Chongming Island as an example, we developed a comprehensive evaluation system of ecological vulnerability for an estuarine island ecosystem based on the pressure-state-response (PSR) conceptual model, and explored the spatial and temporal distribution of ecological vulnerability in 2005 and 2015. The results indicated that the main pressures of Chongming Island from saltwater intrusion intensity and land use intensity were mainly distributed in northern coastal areas and eastern areas of wetland; the ecological vulnerability index (EV) of Chongming Island showed a slight decrease from 2005 to 2015; and three categories of towns based on ecological vulnerability assessment for an eco-island planning and environmental management were identified. Our study provides an effective evaluation system of ecological vulnerability for estuarine islands, which could be helpful for planners and decision makers in improving eco-island planning and environmental management.

Microbiomes of an oyster are shaped by metabolism and environment

Microbiomes can both influence and be influenced by metabolism, but this relationship remains unexplored for invertebrates. We examined the relationship between microbiome and metabolism in response to climate change using oysters as a model marine invertebrate. Oysters form economies and ecosystems across the globe, yet are vulnerable to climate change. Nine genetic lineages of the oyster Saccostrea glomerata were exposed to ambient and elevated temperature and PCO2 treatments. The metabolic rate (MR) and metabolic by-products of extracellular pH and CO2 were measured. The oyster-associated bacterial community in haemolymph was characterised using 16 s rRNA gene sequencing. We found a significant negative relationship between MR and bacterial richness. Bacterial community composition was also significantly influenced by MR, extracellular CO2 and extracellular pH. The effects of extracellular CO2 depended on genotype, and the effects of extracellular pH depended on CO2 and temperature treatments. Changes in MR aligned with a shift in the relative abundance of 152 Amplicon Sequencing Variants (ASVs), with 113 negatively correlated with MR. Some spirochaete ASVs showed positive relationships with MR. We have identified a clear relationship between host metabolism and the microbiome in oysters. Altering this relationship will likely have consequences for the 12 billion USD oyster economy.

Comparative embryo/larval sensitivity of Australian marine bivalves to ten metals: A disjunct between physiology and phylogeny

Metal contamination within the urbanized coastal zon is one threat linked to a decline in the abundance, distribution and/or species diversity of wild marine bivalve populations. This study determined the 48-h embryo/larval sensitivity (no-effect concentration (NEC) and median-effect concentration (EC50)) of ten marine bivalve species (nine endemic to Australia) to aluminium (Al), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), nickel (Ni) and zinc (Zn), key metal contaminants impacting urbanized coastal zones in south-eastern Australia, in natural seawater (20-22 °C, 30‰ salinity, pH 7.8-7.9, 1.2 mg/L dissolved organic carbon). For all metals, except Fe, the order of sensitivity was oysters > mussels ≥ scallops ≥ cockles ≥ clams, where the economically-important oysters, Magallana gigas and Saccostrea glomerata, were 2.6 (Al) to 4.2 (Cd) times more sensitive than the least sensitive clam species. For all bivalve species, the order of metal sensitivity was Cu > Pb > Zn = Ni > Co > Cd > Al > Cr(VI) > Mn ≥ Fe(III), where Cu was eight times more toxic than Zn or Ni, 28 times more toxic than Cd, 220 times more toxic than Cr(VI) and 570 times more toxic than Fe(III). Iron, unlike the other nine soluble metals, occurred as particulate Fe(III) oxyhydroxide, where EC50 values decreased with increasing exposure time as the larval (D-veliger) stage. There was no significant (p > 0.05) effect of embryo/larval mass, or surface area/volume, on metal sensitivity. Further, there was no significant (p > 0.05) relationship between metal sensitivity and phylogeny (genetic distance). Divalent metal sensitivity was positively related (r2 = 0.87) to cell surface metal-binding affinity. The current Australian marine water quality guideline for Ni is not protective of the ten bivalve species (NECs were 2-6-fold below the guideline), while the guideline for Zn is not protective of oysters.

Biotic habitats as refugia under ocean acidification

Habitat-forming organisms have an important role in ameliorating stressful conditions and may be of particular relevance under a changing climate. Increasing CO₂ emissions are driving a range of environmental changes, and one of the key concerns is the rapid acceleration of ocean acidification and associated reduction in pH. Such changes in seawater chemistry are anticipated to have direct negative effects on calcifying organisms, which could, in turn, have negative ecological, economic and human health impacts. However, these calcifying organisms do not exist in isolation, but rather are part of complex ecosystems. Here, we use a qualitative narrative synthesis framework to explore (i) how habitat-forming organisms can act to restrict environmental stress, both now and in the future; (ii) the ways their capacity to do so is modified by local context; and (iii) their potential to buffer the effects of future change through physiological processes and how this can be influenced by management adopted. Specifically, we highlight examples that consider the ability of macroalgae and seagrasses to alter water carbonate chemistry, influence resident organisms under current conditions and their capacity to do so under future conditions, while also recognizing the potential role of other habitats such as adjacent mangroves and saltmarshes. Importantly, we note that the outcome of interactions between these functional groups will be context dependent, influenced by the local abiotic and biotic characteristics. This dependence provides local managers with opportunities to create conditions that enhance the likelihood of successful amelioration. Where individuals and populations are managed effectively, habitat formers could provide local refugia for resident organisms of ecological and economic importance under an acidifying ocean.

Contemporary Oyster Reef Restoration: Responding to a Changing World

Globally, there is growing interest in restoring previously widespread oyster reefs to reinstate key ecosystem services such as shoreline protection, fisheries productivity and water filtration. Yet, since peak expiration of oysters in the 1800s, significant and ongoing environmental change has occurred. Estuaries and coasts are undergoing some of the highest rates of urbanization, warming and ocean acidification on the planet, necessitating novel approaches to restoration. Here, we review key design considerations for oyster reef restoration projects that maximize the probability that they will meet biological and socio-economic goals not only under present-day conditions, but into the future. This includes selection of sites, and where required, substrates and oyster species and genotypes for seeding, not only on the basis of their present and future suitability in supporting oyster survival, growth and reproduction, but also based on their match to specific goals of ecosystem service delivery. Based on this review, we provide a road map of design considerations to maximize the success of future restoration projects.

Microbiome response differs among selected lines of Sydney rock oysters to ocean warming and acidification

Oyster microbiomes are integral to healthy function and can be altered by climate change conditions. Genetic variation among oysters is known to influence the response of oysters to climate change and may ameliorate any adverse effects on oyster microbiome; however, this remains unstudied. Nine full-sibling selected breeding lines of the Sydney rock oyster (Saccostrea glomerata) were exposed to predicted warming (ambient = 24°C, elevated = 28°C) and ocean acidification (ambient pCO2 = 400, elevated pCO2 = 1000 µatm) for 4 weeks. The haemolymph bacterial microbiome was characterized using 16S rRNA (V3-V4) gene sequencing and varied among oyster lines in the control (ambient pCO2, 24°C) treatment. Microbiomes were also altered by climate change dependent on oyster lines. Bacterial α-diversity increased in response to elevated pCO2 in two selected lines, while bacterial β-diversity was significantly altered by combinations of elevated pCO2 and temperature in four selected lines. Climate change treatments caused shifts in the abundance of multiple amplicon sequence variants driving change in the microbiome of some selected lines. We show that oyster genetic background may influence the Sydney rock oyster haemolymph microbiome under climate change and that future assisted evolution breeding programs to enhance resilience should consider the oyster microbiome.

Energetic lipid responses of larval oysters to ocean acidification

Climate change will increase energetic demands on marine invertebrate larvae and make planktonic food more unpredictable. This study determined the impact of ocean acidification on larval energetics of the oysters Saccostrea glomerata and Crassostrea gigas. Larvae of both oysters were reared until the 9-day-old, umbonate stage under orthogonal combinations of ambient and elevated p CO ₂ (340 and 856 μatm) and food was limited. Elevated p CO ₂ reduced the survival, size and larval energetics, larvae of C. gigas being more resilient than S. glomerata. When larvae were fed, elevated p CO ₂ reduced lipid levels across all lipid classes. When larvae were unfed elevated p CO ₂ resulted in increased lipid levels and mortality. Ocean acidification and food will interact to limit larval energetics. Larvae of S. glomerata will be more impacted than C. gigas and this is of concern given their aquacultural status and ecological function.

Coast-wide evidence of low pH amelioration by seagrass ecosystems

Global-scale ocean acidification has spurred interest in the capacity of seagrass ecosystems to increase seawater pH within crucial shoreline habitats through photosynthetic activity. However, the dynamic variability of the coastal carbonate system has impeded generalization into whether seagrass aerobic metabolism ameliorates low pH on physiologically and ecologically relevant timescales. Here we present results of the most extensive study to date of pH modulation by seagrasses, spanning seven meadows (Zostera marina) and 1000 km of U.S. west coast over 6 years. Amelioration by seagrass ecosystems compared to non-vegetated areas occurred 65% of the time (mean increase 0.07 ± 0.008 SE). Events of continuous elevation in pH within seagrass ecosystems, indicating amelioration of low pH, were longer and of greater magnitude than opposing cases of reduced pH or exacerbation. Sustained elevations in pH of >0.1, comparable to a 30% decrease in [H⁺ ], were not restricted only to daylight hours but instead persisted for up to 21 days. Maximal pH elevations occurred in spring and summer during the seagrass growth season, with a tendency for stronger effects in higher latitude meadows. These results indicate that seagrass meadows can locally alleviate low pH conditions for extended periods of time with important implications for the conservation and management of coastal ecosystems.

Multiple Evidence for Climate Patterns Influencing Ecosystem Productivity across Spatial Gradients in the Venice Lagoon

Effects of climatic changes in transitional ecosystems are often not linear, with some areas likely experiencing faster or more intense responses, which something important to consider in the perspective of climate forecasting. In this study of the Venice lagoon, time series of the past decade were used, and primary productivity was estimated from hourly oxygen data using a published model. Temporal and spatial patterns of water temperature, salinity and productivity time series were identified by applying clustering analysis. Phytoplankton and nutrient data from long-term surveys were correlated to primary productivity model outputs. pmax, the maximum oxygen production rate in a given day, was found to positively correlate with plankton variables measured in surveys. Clustering analysis showed the occurrence of summer heatwaves in 2008, 2013, 2015 and 2018 and three warm prolonged summers (2012, 2017, 2019) coincided with lower summer pmax values. Spatial effects in terms of temperature were found with segregation between confined and open areas, although the patterns varied from year to year. Production and respiration differences showed that the lagoon, despite seasonality, was overall heterotrophic, with internal water bodies having greater values of heterotrophy. Warm, dry years with high salinity had lower degrees of summer autotrophy.

Climate change alters the haemolymph microbiome of oysters

The wellbeing of marine organisms is connected to their microbiome. Oysters are a vital food source and provide ecological services, yet little is known about how climate change such as ocean acidification and warming will affect their microbiome. We exposed the Sydney rock oyster, Saccostrea glomerata, to orthogonal combinations of temperature (24, 28 °C) and pCO₂ (400 and 1000 μatm) for eight weeks and used amplicon sequencing of the 16S rRNA (V3-V4) gene to characterise the bacterial community in haemolymph. Overall, elevated pCO₂ and temperature interacted to alter the microbiome of oysters, with a clear partitioning of treatments in CAP ordinations. Elevated pCO₂ was the strongest driver of species diversity and richness and elevated temperature also increased species richness. Climate change, both ocean acidification and warming, will alter the microbiome of S. glomerata which may increase the susceptibility of oysters to disease.

Advancing the Science of Environmental Flow Management for Protection of Temporarily Closed Estuaries and Coastal Lagoons

The science needed to inform management of environmental flows to temporarily closed estuaries and coastal lagoons is decades behind the state of knowledge for rivers and large embayments. These globally ubiquitous small systems, which are often seasonally closed to the ocean’s influence, are under particular threat associated with hydrologic alteration because of changes in atershed land use, water use practices, and climate change. Managing environmental flows in these systems is complicated by their tight coupling with watershed processes, variable states because of intermittently closing mouths, and reliance on regional scale sediment transport and littoral processes. Here we synthesize our current understanding of ecohydrology in temporarily closed estuaries (TCEs) and coastal lagoons and propose a prioritized research agenda aimed at advancing understanding of ecological responses to altered flow regimes in TCEs. Key research needs include agreeing on a consistent typology, improving models that couple watershed and ocean forcing at appropriate spatial and temporal scales, quantifying stress–response relationships associated with hydrologic alteration, improving tools to establish desired conditions that account for climate change and consider cultural/indigenous objectives, improving tools to measure ecosystem function and social/cultural values, and developing monitoring and adaptive management programs that can inform environmental flow management in consideration of other stressors and across different habitat types. Coordinated global efforts to address the identified research gaps can help guide management actions aimed at reducing or mitigating potential impacts of hydrologic alteration and climate change through informed management of freshwater inflows.

Effects of marine heatwave conditions across the metamorphic transition to the juvenile sea urchin (Heliocidaris erythrogramma)

For short development species, like the sea urchin Heliocidaris erythrogramma, the entire planktonic duration can be impacted by marine heatwaves (MHW). Developmental thermal tolerance of this species through metamorphosis was investigated over a broad range (7.6-28.0 °C), including temperatures across its distribution and MHW conditions. In controls (19.5-21.0 °C), 80% of individuals developed to metamorphosis at day 5, doubling to 10 days at 14.0 °C. The thermal range (14.4-21.2 °C) of metamorphosis on day 7 reflected the realised thermal niche with 25.9 °C the upper temperature for success (T₄₀). By day 10, juvenile tolerance narrowed to the local range (16.2-19.0 °C), similar to levels tolerated by adults, indicating negative carryover effects across the metamorphic transition. Without phenotypic adjustment or adaptation, regional warming will be detrimental, although populations may be sustained by thermotolerant offspring. Our results show the importance of the metamorphic transition in understanding the cumulative sensitivity of species to MHW.

Variability of Currents and Water Column Structure in a Temperate Estuarine System (Sado Estuary, Portugal)

The circulation in estuaries promotes the transport of organisms, nutrients, oxygen and sediments. Simultaneously, the mixture of fresh and salt water leads to variations of the physicochemical and biological components of the region. Therefore, it is important to further understand the hydrodynamic patterns of an estuary as one of the bases to understand the whole dynamic of these systems, ecologically important regions that must be preserved. However, little is known about the hydrodynamics of some estuarine systems. In order to bridge the knowledge gap about the Sado estuary, sampling was conducted with the purpose of evaluating some circulation patterns of the estuary and classifying it according to the stratification of the water column. The campaigns were conducted to collect monthly data on the intensity and direction of the currents, and on the temperature and salinity of the water column, between September 2018 and September 2019. The data indicated that water circulation in the Sado estuary, occurred through the two main navigation channels (North and South), according to the tidal regime. Both the temperature and the salinity were homogeneous along the water column, revealing little stratification. The analysis suggests possible hydrodynamic changes of the estuary in the past years.

Effects of reduced pH on an estuarine penaeid shrimp (Metapenaeus macleayi)

Acid sulfate soils are a major problem in modified coastal floodplains and are thought to have substantial impacts on estuarine species. In New South Wales, Australia, acid sulfate soils occur in every estuary and are thought to impact important fisheries species, such as Eastern School Prawn (Metapenaeus macleayi). These fisheries have experienced declining productivity over the last ten years and increasing occurrence of catchment-derived stressors in estuaries contribute to this problem. We evaluated the effect of pH 4-7.5 on School Prawn survival at two salinities (27 and 14.5), pH 5, 6 and 7.5 on the predation escape response (PER) speed at two salinities (27 and 14.5), and pH 4 and 7.5 on respiration rates. While mortality appeared to be greater in the high salinity treatment, there was no significant relationship between proportional survival and pH for either salinity treatment. Respiration was significantly slower under acidic conditions and the average PER was almost twice as fast at pH 7.5 compared to pH 5 (p < 0.05), indicating prawns may fall prey to predation more easily in acidic conditions. These findings confirm the hypothesised impacts of acidic water on penaeid prawns. Given that the conditions simulated in these experiments reflect those encountered in estuaries, acidic runoff may be contributing to bottlenecks for estuarine species and impacting fisheries productivity.

Developing in a warming intertidal, negative carry over effects of heatwave conditions in development to the pentameral starfish in Parvulastra exigua

Ocean warming and increasing incidence of marine heat waves (MHW) are having far-reaching impacts on coastal ecosystems. The small intertidal asterinid starfish, Parvulastra exigua, in south-eastern Australia, occurs in a global warming hotspot. Development occurs in the intertidal as this species lays eggs and has benthic larvae. The impact of temperature on development to the juvenile was determined over a broad temperature range (12-28 °C) encompassing temperatures experienced during the breeding season (16-20 °C) and cool (- 4 °C) and warm (+10 °C) extremes with the higher temperatures (24-28 °C) simulating a MHW. As the larva to juvenile transition involves major body reorganisation, we determined the impact of temperature on metamorphosis and formation of the normal five-armed juvenile. Development was faster at the higher temperatures 24-28 °C, but survival decreased from 1 to 5 days post fertilisation (dpf). Mortality was evident from day 15 at 22 °C and no larvae survived to 20 dpf at 28 °C. Thermal tolerance decreased over developmental time and the thermal optimum for 95% survival to the 20 day old juvenile spanned from 12 to 20.0 °C with the lethal temperature for 50% survival being 23.5 °C (5.5 °C above ambient). Juveniles reared in 26 °C were smaller, suggesting application of the temperature size rule. Increased temperature (22-26 °C) perturbed pentamery with three, four, six and no-armed juveniles present, contrasting with the low level of non-pentamerous individuals (<3%) in the cooler cultures and in nature (five populations surveyed). Despite the high thermal tolerance in premetamorphic stages, negative carry over effects were evident in the juveniles. This shows the importance of considering the whole of development in climate warming studies. As sea surface temperatures increase and heatwaves become more prevalent, habitat warming will be detrimental to P. exigua populations.

Thermal tolerance in the amphipod Sunamphitoe parmerong from a global warming hotspot, acclimatory carryover effects within generation

The thermal response of the amphipod Sunamphitoe parmerong was contrasted between unacclimated 'wild' and acclimated populations. Brooding females were allocated to 17 °C or 23 °C treatments and their progeny developed to adulthood at the same temperature. Tolerance to acute thermal challenge (26-36 °C) was determined. The 17 °C and 23 °C acclimated S. parmerong had a 0.45 and 0.64 risk of death compared to the unacclimated individuals. The upper lethal temperature (LT₅₀) was 27.4 °C for the unacclimated group and 29.6 °C and 30.4 °C for the 17 °C and 23 °C acclimated groups, respectively. Acclimation shifted their LT₅₀ by 2.2 °C and 3 °C, respectively. The wild population exhibited high variability in thermal tolerance, potentially due to their environmental history and greater diversity of genotypes. After acclimation S. parmerong had decreased variability in thermal tolerance and that of the 23 °C group shifted by 1 °C compared with the 17 °C group. These results indicate developmental phenotypic plasticity or differential survival of resilient progeny as potential mechanisms to facilitate persistence in a warming ocean.

Heatwaves alter survival of the Sydney rock oyster, Saccostrea glomerata

Heatwaves are an increasing threat to organisms across the globe. Marine and atmospheric heatwaves are predicted to impact sessile intertidal marine organisms, especially when exposed at low tide and unable to seek refuge. The study aimed to determine whether a simulated atmospheric heatwave will alter the survival of selectively bred families of Sydney rock oysters (Saccostrea glomerata), and whether survival is dependent on morphological and physiological traits. The survival of S. glomerata families to a simulated atmospheric heatwave varied from 25 to 60% and was not correlated with morphology or physiology. Survival may depend on the presence of genotypes that translate into molecular defenses such as heat-shock proteins and inhibitor of apoptosis proteins that provide oysters with resilience. Understanding the responses among families of oysters to heatwaves is critical if we are to restore the ecological services of oyster reefs and sustain oyster aquaculture.

Ten Principles to Determine Environmental Flow Requirements for Temporarily Closed Estuaries

Temporarily closed estuaries require seasonal opening to tidal flows to maintain normalecological processes. Each estuary has specific environmental flow (EFlow) requirements basedon the relationship between freshwater inflow, coastal dynamics, rate of sandbar formation,and the open/closed state of the mouth. Key abiotic processes and ecosystem services linkedto mouth state were highlighted. We reviewed completed EFlow requirement studies for temporarilyclosed estuaries in South Africa and found that the formulation of these requirements shouldconsider the timing and magnitude of flows in relation to the morphology of an estuary, its mouthstructure, catchment size, and climate. We identified ten key principles that could be adapted tosimilar systems in equivalent climatic settings. Principle 1 recognizes that each estuary is unique interms of its EFlow requirements because size, scale, and sensitivity of core elements to freshwaterinflow are specific for each system; EFlows cannot be extrapolated from one estuary to another.Principle 2 highlights the importance of baseflows in keeping an estuary mouth open because a smallreduction in flow can cause the mouth to close and alter essential ecological processes. Principle 3outlines the role of floods in resetting natural processes by flushing out large volumes of sedimentand establishing the equilibrium between erosion and sedimentation. Principle 4 emphasizes the needfor open mouth conditions to allow regular tidal flushing that maintains water quality throughreducing retention times and preventing the onset of eutrophic conditions. Principle 5 advisesartificial breaching to be practiced with caution because execution at low water levels encouragessedimentation that reduces the scouring eect of flushing. Principle 6 holds that elevated inflowvolumes from wastewater treatment works or agricultural return flows can increase the frequency ofmouth opening and cause ecological instability. Principle 7 states that water released from dams tosupply the environmental flow cannot mimic the natural flow regime. Principle 8 specifies the needfor short- and long-term data to increase the confidence levels of EFlow assessments, with data tobe collected during the open and closed mouth states. Principle 9 advocates the implementation ofa monitoring program to track the achievement of EFlow objectives as part of a strategic adaptivemanagement cycle. Finally, Principle 10 recommends the adoption of a holistic catchment-to-coastmanagement approach underpinned by collaboration with regulatory authorities and stakeholdersacross a range of sectors. These principles can be used to guide the formulation and managementof EFlows, an essential strategy that links the maintenance of estuarine ecological integrity withsocial well-being.

Resilience to the interactive effects of climate change and discard stress in the commercially important blue swimmer crab (Portunus armatus)

Globally, millions of people depend on nutritional benefits from seafood consumption, but few studies have tested for effects of near-future climate change on seafood health and quality. Quantitative assessments of the interactive effects of climate change and discarding of fisheries resources are also lacking, despite ~10% of global catches being discarded annually. Utilising the harvested blue swimmer crab (Portunus armatus), we experimentally tested the effects of near-future temperature and salinity treatments under simulated capture and discarding on a suite of health and nutritional quality parameters. We show that nutritional quality (protein, lipids, moisture content and fatty acid composition) was not significantly affected by near-future climate change. Further, stress biomarkers (catalase and glutathione S-transferases activity and glycogen content) did not differ significantly among treatments following simulated capture and discarding. These results support the inherent resilience of P. armatus to short-term environmental change, and indicate that negative physiological responses associated with discarding may not be exacerbated in a future ocean. We suggest that harvested estuarine species, and thus the industries and food security they underpin, may be resilient to the future effects of climate change due to their adaptation to naturally variable habitats.