Limited potential for adaptation to climate change in a broadly distributed marine crustacean

The extent to which acclimation and genetic adaptation might buffer natural populations against climate change is largely unknown. Most models predicting biological responses to environmental change assume that species' climatic envelopes are homogeneous both in space and time. Although recent discussions have questioned this assumption, few empirical studies have characterized intraspecific patterns of genetic variation in traits directly related to environmental tolerance limits. We test the extent of such variation in the broadly distributed tidepool copepod Tigriopus californicus using laboratory rearing and selection experiments to quantify thermal tolerance and scope for adaptation in eight populations spanning more than 17° of latitude. Tigriopus californicus exhibit striking local adaptation to temperature, with less than 1 per cent of the total quantitative variance for thermal tolerance partitioned within populations. Moreover, heat-tolerant phenotypes observed in low-latitude populations cannot be achieved in high-latitude populations, either through acclimation or 10 generations of strong selection. Finally, in four populations there was no increase in thermal tolerance between generations 5 and 10 of selection, suggesting that standing variation had already been depleted. Thus, plasticity and adaptation appear to have limited capacity to buffer these isolated populations against further increases in temperature. Our results suggest that models assuming a uniform climatic envelope may greatly underestimate extinction risk in species with strong local adaptation.     

Pathogen adaptation to seasonal forcing and climate change

Many diverse infectious diseases exhibit seasonal dynamics. Seasonality in disease incidence has been attributed to seasonal changes in pathogen transmission rates, resulting from fluctuations in extrinsic climate factors. Multi-strain infectious diseases with strain-specific seasonal signatures, such as cholera, indicate that a range of seasonal patterns in transmission rates is possible in identical environments. We therefore consider pathogens capable of evolving their 'seasonal phenotype', a trait that determines the sensitivity of their transmission rates to environmental variability. We introduce a theoretical framework, based on adaptive dynamics, for predicting the evolution of disease dynamics in seasonal environments. Changes in the seasonality of environmental factors are one important avenue for the effects of climate change on disease. This model also provides a framework for examining these effects on pathogen evolution and associated disease dynamics. An application of this approach gives an explanation for the recent cholera strain replacement in Bangladesh, based on changes in monsoon rainfall patterns.     

The short history of research in a marine climate change hotspot: from anecdote to adaptation in south-east Australia

Climate change is not being felt equally around the world. Regions where warming is most rapid will be among those to experience impacts first, will need to develop early responses to these impacts and can provide a guide for management elsewhere. We describe the research history in one such global marine hotspot—south-east Australia—where a number of contentions about the value of hotspots as natural laboratories have been supported, including (1) early reporting of changes (2) early documentation of impacts, and (3) earlier development and promotion of adaptation options. We illustrate a transition from single discipline impacts-focused research to an inter-disciplinary systems view of adaptation research. This transition occurred against a background of change in the political position around climate change and was facilitated by four preconditioning factors. These were: (1) early observations of rapid oceanic change that coincided with (2) biological change which together provided a focus for action, (3) the strong marine orientation and history of management in the region, and (4) the presence of well developed networks. Three case studies collectively show the critical role of inter-disciplinary engagement and stakeholder participation in supporting industry and government adaptation planning.     

气候变化下旱区农业生态系统的可持续性

农业生产是将自然资源不断转化为农产品的过程.简单的说就是将阳光、空气、水和土壤等无机资源转化为可以供人类消费的有机产物.农业生态系统必须对全球气候变化、市场竞争、自然环境的恶化、经济等政策法规和人民的需求等因素做出灵活的应对策略,同时还要保证自然生态系统的稳定性.在发展中国家,有超过20 亿的人口每天收入低于2 美元,他们收入中绝大部分都用于解决温饱.这些人大部分生活在干旱、半干旱地区,并以农业生产作为生活的主要来源.由于这些地区水资源匮乏、土壤贫瘠,粮食安全问题一直是该地区人类生存的关键.中澳两国都把干旱、半干旱地区的农牧业发展作为研究的重点.两国的专家都致力于恢复和维护干旱半干旱地区脆弱的农业生态系统.气候变化正在使农业生态系统可持续发展面临严峻挑战.因此,迫切需要农学,生态学,环境学,社会经济学等多学科的共同发展和融合解决这一问题.     

Plant communities on infertile soils are less sensitive to climate change

Background and Aims Much evidence suggests that plant communities on infertile soils are relatively insensitive to increased water deficit caused by increasing temperature and/or decreasing precipitation. However, a multi-decadal study of community change in the western USA does not support this conclusion. This paper tests explanations related to macroclimatic differences, overstorey effects on microclimate, variation in soil texture and plant functional traits.Methods A re-analysis was undertaken of the changes in the multi-decadal study, which concerned forest understorey communities on infertile (serpentine) and fertile soils in an aridifying climate (southern Oregan) from 1949–1951 to 2007–2008. Macroclimatic variables, overstorey cover and soil texture were used as new covariates. As an alternative measure of climate-related change, the community mean value of specific leaf area was used, a functional trait measuring drought tolerance. We investigated whether these revised analyses supported the prediction of lesser sensitivity to climate change in understorey communities on infertile serpentine soils.Key Results Overstorey cover, but not macroclimate or soil texture, was a significant covariate of community change over time. It strongly buffered understorey temperatures, was correlated with less change and averaged >50 % lower on serpentine soils, thereby counteracting the lower climate sensitivity of understorey herbs on these soils. Community mean specific leaf area showed the predicted pattern of less change over time in serpentine than non-serpentine communities.Conclusions Based on the current balance of evidence, plant communities on infertile serpentine soils are less sensitive to changes in the climatic water balance than communities on more fertile soils. However, this advantage may in some cases be lessened by their sparser overstorey cover.     

Antarctic nematode communities: observed and predicted responses to climate change

The rapidly changing climate in Antarctica is impacting the ecosystems. Since records began, climate changes have varied considerably throughout Antarctica with both positive and negative trends in temperatures and precipitation observed locally. However, over the course of this century a more directional increase in both temperature and precipitation is expected to occur throughout Antarctica. The soil communities of Antarctica are considered simple with most organisms existing at the edge of their physiological capabilities. Therefore, Antarctic soil communities are expected to be particularly sensitive to climate changes. However, a review of the current literature reveals that studies investigating the impact of climate change on soil communities, and in particular nematode communities, in Antarctica are very limited. Of the few studies focusing on Antarctic nematode communities, long-term monitoring has shown that nematode communities respond to changes in local climate trends as well as extreme (or pulse) events. These results are supported by in situ experiments, which show that nematode communities respond to both temperature and soil moisture manipulations. We conclude that the predicted climate changes are likely to exert a strong influence on nematode communities throughout Antarctica and will generally lead to increasing abundance, species richness, and food web complexity, although the opposite may occur locally. The degree to which local communities respond will depend on current conditions, i.e., average temperatures, soil moisture availability, vegetation or more importantly the lack thereof, and the local species pool in combination with the potential for new species to colonize.     

Incorporating climate change adaptation into national conservation assessments

The Convention on Biological Diversity requires that member nations establish protected area networks that are representative of the country's biodiversity. The identification of priority sites to achieve outstanding representation targets is typically accomplished through formal conservation assessments. However, representation in conservation assessments or gap analyses has largely been interpreted based on a static view of biodiversity. In a rapidly changing climate, the speed of changes in biodiversity distribution and abundance is causing us to rethink the viability of this approach. Here we describe three explicit strategies for climate change adaptation as part of national conservation assessments: conserving the geophysical stage, identifying and protecting climate refugia, and promoting cross‐environment connectivity. We demonstrate how these three approaches were integrated into a national terrestrial conservation assessment for Papua New Guinea, one of the most biodiverse countries on earth. Protected areas identified based on representing geophysical diversity were able to capture over 90% of the diversity in vegetation communities, suggesting they could help protect representative biodiversity regardless of changes in the distribution of species and communities. By including climate change refugia as part of the national conservation assessment, it was possible to substantially reduce the amount of environmental change expected to be experienced within protected areas, without increasing the overall cost of the protected area network. Explicitly considering environmental heterogeneity between adjacent areas resulted in protected area networks with over 40% more internal environmental connectivity. These three climate change adaptation strategies represent defensible ways to guide national conservation priority given the uncertainty that currently exists in our ability to predict climate changes and their impacts. Importantly, they are also consistent with data and expertise typically available during national conservation assessments, including in developing nations. This means that in the vast majority of countries, these strategies could be implemented immediately.     

Temperature adaptation of soil bacterial communities along an Antarctic climate gradient: predicting responses to climate warming

Soil microorganisms, the central drivers of terrestrial Antarctic ecosystems, are being confronted with increasing temperatures as parts of the continent experience considerable warming. Here we determined short‐term temperature dependencies of Antarctic soil bacterial community growth rates, using the leucine incorporation technique, in order to predict future changes in temperature sensitivity of resident soil bacterial communities. Soil samples were collected along a climate gradient consisting of locations on the Antarctic Peninsula (Anchorage Island, 67 °34′S, 68 °08′W), Signy Island (60 °43′S, 45 °38′W) and the Falkland Islands (51 °76′S 59 °03′W). At each location, experimental plots were subjected to warming by open top chambers (OTCs) and paired with control plots on vegetated and fell‐field habitats. The bacterial communities were adapted to the mean annual temperature of their environment, as shown by a significant correlation between the mean annual soil temperature and the minimum temperature for bacterial growth (T_min). Every 1 °C rise in soil temperature was estimated to increase T_min by 0.24–0.38 °C. The optimum temperature for bacterial growth varied less and did not have as clear a relationship with soil temperature. Temperature sensitivity, indicated by Q₁₀ values, increased with mean annual soil temperature, suggesting that bacterial communities from colder regions were less temperature sensitive than those from the warmer regions. The OTC warming (generally <1 °C temperature increases) over 3 years had no effects on temperature relationship of the soil bacterial community. We estimate that the predicted temperature increase of 2.6 °C for the Antarctic Peninsula would increase T_min by 0.6–1 °C and Q₁₀ (0–10 °C) by 0.5 units.     

Vulnerability of mires under climate change: implications for nature conservation and climate change adaptation

Wetlands in general and mires in particular belong to the most important terrestrial carbon stocks globally. Mires (i.e. bogs, transition bogs and fens) are assumed to be especially vulnerable to climate change because they depend on specific, namely cool and humid, climatic conditions. In this paper, we use distribution data of the nine mire types to be found in Austria and habitat distribution models for four IPCC scenarios to evaluate climate change induced risks for mire ecosystems within the 21st century. We found that climatic factors substantially contribute to explain the current distribution of all nine Austrian mire ecosystem types. Summer temperature proved to be the most important predictor for the majority of mire ecosystems. Precipitation—mostly spring and summer precipitation sums—was influential for some mire ecosystem types which depend partly or entirely on ground water supply (e.g. fens). We found severe climate change induced risks for all mire ecosystems, with rain-fed bog ecosystems being most threatened. Differences between scenarios are moderate for the mid-21st century, but become more pronounced towards the end of the 21st century, with near total loss of climate space projected for some ecosystem types (bogs, quagmires) under severe climate change. Our results imply that even under minimum expected, i.e. inevitable climate change, climatic risks for mires in Austria will be considerable. Nevertheless, the pronounced differences in projected habitat loss between moderate and severe climate change scenarios indicate that limiting future warming will likely contribute to enhance long-term survival of mire ecosystems, and to reduce future greenhouse gas emissions from decomposing peat. Effectively stopping and reversing the deterioration of mire ecosystems caused by conventional threats can be regarded as a contribution to climate change mitigation. Because hydrologically intact mires are more resilient to climatic changes, this would also maintain the nature conservation value of mires, and help to reduce the severe climatic risks to which most Austrian mire ecosystems may be exposed in the 2nd half of the 21st century according to IPCC scenarios.     

Potential response to climate change of a semi-arid coastal ecosystem in eastern Mediterranean

Eastern Mediterranean gulfs, adjacent to small semi-arid watersheds are particularly susceptible to climate changes. In this study, an analysis was performed for air temperature and rainfall during 1955–2010 over a coastal ecosystem in NE Aegean, and potential effects of recent changes on the physical setting and ecological status of the marine system were studied. A trend toward drier conditions was revealed, and in order to assess possible effects on the surrounding basin, a watershed model was applied. In addition, the hydrology and ecology of the marine ecosystem were studied using a water budget model along with available field data. Based on local climatological data, dryness may lead to a decrease of one to two orders of magnitude in the amount of runoff during a dry annual cycle, resulting to a fivefold increase in the residence time of the marine system. High residence time associated with terrestrial nutrient inputs and strong stratification result to phytoplankton blooms during winter, including harmful algal blooms. Integrated approaches, modeling both the hydrology and ecology of watersheds and adjacent water bodies, are essential toward forecasting, understanding and management of potential alterations in functioning of coastal ecosystems due to recent climate changes.     

Footprints of climate change in the Arctic marine ecosystem

In this article, we review evidence of how climate change has already resulted in clearly discernable changes in marine Arctic ecosystems. After defining the term ‘footprint’ and evaluating the availability of reliable baseline information we review the published literature to synthesize the footprints of climate change impacts in marine Arctic ecosystems reported as of mid‐2009. We found a total of 51 reports of documented changes in Arctic marine biota in response to climate change. Among the responses evaluated were range shifts and changes in abundance, growth/condition, behaviour/phenology and community/regime shifts. Most reports concerned marine mammals, particularly polar bears, and fish. The number of well‐documented changes in planktonic and benthic systems was surprisingly low. Evident losses of endemic species in the Arctic Ocean, and in ice algae production and associated community remained difficult to evaluate due to the lack of quantitative reports of its abundance and distribution. Very few footprints of climate change were reported in the literature from regions such as the wide Siberian shelf and the central Arctic Ocean due to the limited research effort made in these ecosystems. Despite the alarming nature of warming and its strong potential effects in the Arctic Ocean the research effort evaluating the impacts of climate change in this region is rather limited.     

Quorum quenching in cultivable bacteria from dense marine coastal microbial communities

Acylhomoserine lactone (AHLs)-mediated quorum-sensing (QS) processes seem to be common in the marine environment and among marine pathogenic bacteria, but no data are available on the prevalence of bacteria capable of interfering with QS in the sea, a process that has been generally termed 'quorum quenching' (QQ). One hundred and sixty-six strains isolated from different marine dense microbial communities were screened for their ability to interfere with AHL activity. Twenty-four strains (14.4%) were able to eliminate or significantly reduce N-hexanoyl-l-homoserine lactone activity as detected by the biosensor strain Chromobacterium violaceum CV026, a much higher percentage than that reported for soil isolates, which reinforces the ecological role of QS and QQ in the marine environment. Among these, 15 strains were also able to inhibit N-decanoyl-l-homoserine lactone activity and all of them were confirmed to enzymatically inactivate the AHL signals by HPLC-MS. Active isolates belonged to nine different genera of prevalently or exclusively marine origin, including members of the Alpha- and Gammaproteobacteria (8), Actinobacteria (2), Firmicutes (4) and Bacteroidetes (1). Whether the high frequency and diversity of cultivable bacteria with QQ activity found in near-shore marine isolates reflects their prevalence among pelagic marine bacterial communities deserves further investigation in order to understand the ecological importance of AHL-mediated QS and QQ processes in the marine environment.     

Threats to mangroves from climate change and adaptation options: A review

Mangrove ecosystems are threatened by climate change. We review the state of knowledge of mangrove vulnerability and responses to predicted climate change and consider adaptation options. Based on available evidence, of all the climate change outcomes, relative sea-level rise may be the greatest threat to mangroves. Most mangrove sediment surface elevations are not keeping pace with sea-level rise, although longer term studies from a larger number of regions are needed. Rising sea-level will have the greatest impact on mangroves experiencing net lowering in sediment elevation, where there is limited area for landward migration. The Pacific Islands mangroves have been demonstrated to be at high risk of substantial reductions. There is less certainty over other climate change outcomes and mangrove responses. More research is needed on assessment methods and standard indicators of change in response to effects from climate change, while regional monitoring networks are needed to observe these responses to enable educated adaptation. Adaptation measures can offset anticipated mangrove losses and improve resistance and resilience to climate change. Coastal planning can adapt to facilitate mangrove migration with sea-level rise. Management of activities within the catchment that affect long-term trends in the mangrove sediment elevation, better management of other stressors on mangroves, rehabilitation of degraded mangrove areas, and increases in systems of strategically designed protected area networks that include mangroves and functionally linked ecosystems through representation, replication and refugia, are additional adaptation options.     

Keeping up with a warming world; assessing the rate of adaptation to climate change

The pivotal question in the debate on the ecological effects of climate change is whether species will be able to adapt fast enough to keep up with their changing environment. If we establish the maximal rate of adaptation, this will set an upper limit to the rate at which temperatures can increase without loss of biodiversity.The rate of adaptation will primarily be set by the rate of microevolution since (i) phenotypic plasticity alone is not sufficient as reaction norms will no longer be adaptive and hence microevolution on the reaction norm is needed, (ii) learning will be favourable to the individual but cannot be passed on to the next generations, (iii) maternal effects may play a role but, as with other forms of phenotypic plasticity, the response of offspring to the maternal cues will no longer be adaptive in a changing environment, and (iv) adaptation via immigration of individuals with genotypes adapted to warmer environments also involves microevolution as these genotypes are better adapted in terms of temperature, but not in terms of, for instance, photoperiod.Long-term studies on wild populations with individually known animals play an essential role in detecting and understanding the temporal trends in life-history traits, and to estimate the heritability of, and selection pressures on, life-history traits. However, additional measurements on other trophic levels and on the mechanisms underlying phenotypic plasticity are needed to predict the rate of microevolution, especially under changing conditions.Using this knowledge on heritability of, and selection on, life-history traits, in combination with climate scenarios, we will be able to predict the rate of adaptation for different climate scenarios. The final step is to use ecoevolutionary dynamical models to make the link to population viability and from there to biodiversity loss for those scenarios where the rate of adaptation is insufficient.     

Determining vulnerability of stream communities to climate change at the landscape scale

1. As the climate changes, species are expected to shift to higher latitudes and altitudes where suitable habitat is available if dispersal is not constrained by geographic barriers. We analyse patterns of turnover in freshwater macroinvertebrate assemblages to identify which communities are most likely to be at risk from climate change, and the location of geographic barriers that could impede such adaptive range shifts. 2. We analysed macroinvertebrate data from standard biological assessments at the family level, from surveys of all coastal basins of New South Wales, Australia, covering a latitudinal gradient of more than 1000 km. We used variance partitioning to separate the variation in composition explained by climate, among‐site distance, human disturbance and other stream factors. 3. Montane stream assemblages showed high turnover in response to climatic variation. Turnover in coastal‐fringe streams was least affected by climate, but strongly correlated with distance and stream variables. Significant shifts in assemblage composition occurred between habitats within catchments and across catchment boundaries. 4. Montane stream assemblages are most vulnerable to climate change because their distribution is most responsive to climatic factors, and elevated sites are isolated from one another, reducing the scope for altitudinal migration. Dispersal limitations in coastal‐fringe assemblages will also increase their vulnerability to habitat loss from sea‐level rise. For all stream classes, the separation of many neighbouring catchment assemblages, owing to either limited dispersal or the lack of suitable habitat, is likely to constrain adaptive range shifts. This would lead to an overall reduction in beta diversity among reaches and subsequently to a reduction in landscape‐level gamma diversity.     

Modelling marine ecosystem response to climate change and trawling in the North Sea

The marine ecosystem response to climate change and demersal trawling was investigated using the coupled hydrodynamic-biogeochemical water column model GOTM-ERSEM-BFM for three contrasting sites in the North Sea. Climate change forcing was derived from the HadRM3-PPE-UK regional climate model for the UK for the period 1950–2100 using historical emissions and a medium emissions scenario (SRESA1B). Effects of demersal trawling were implemented as an additional mortality on benthic fauna, and changes in the benthic–pelagic nutrient and carbon fluxes. The main impacts of climate change were (i) a temperature-driven increase in pelagic metabolic rates and nutrient cycling, (ii) an increase in primary production fuelled by recycled nutrients, (iii) a decrease in benthic biomass due to increased benthic metabolic rates and decreased food supply as a result of the increased pelagic cycling, and (iv) a decrease in near-bed oxygen concentrations. The main impacts of trawling were (i) reduced benthic biomass due to the increased mortality, and (ii) the increased benthic–pelagic nutrient fluxes, with these effects counteracting each other, and relatively small changes in other variables. One important consequence was a large decrease in the de-nitrification flux predicted at the two summer-stratified sites because less benthic nitrate was available. The effects of trawling scaled linearly with fishing effort, with greatest sensitivity to fishing in summer compared to fishing in winter. The impacts of climate change and trawling were additive, suggesting little or no non-linear interactions between these disturbances.     

Predicting adaptation of phenology in response to climate change, an insect herbivore example

Climate change has led to an advance in phenology in many species. Synchrony in phenology between different species within a food chain may be disrupted if an increase in temperature affects the phenology of the different species differently, as is the case in the winter moth egg hatch–oak bud burst system. Operophtera brumata (winter moth) egg hatch date has advanced more than Quercus robur (pedunculate oak) bud burst date over the past two decades. Disrupted synchrony will lead to selection, and a response in phenology to this selection may lead to species genetically adapting to their changing environment. However, a prerequisite for such genetic change is that there is sufficient genetic variation and severe enough fitness consequences. So far, examples of observed genetic change have been few. Using a half-sib design, we demonstrate here that O. brumata egg-hatching reaction norm is heritable, and that genetic variation exists. Fitness consequences of even a few days difference between egg hatch and tree bud opening are severe, as we experimentally determined. Estimates of genetic variation and of fitness were then combined with a climate scenario to predict the rate and the amount of change in the eggs' response to temperature. We predict a rapid response to selection, leading to a restoration of synchrony of egg hatch with Q. robur bud opening. This study shows that in this case there is a clear potential to adapt – rapidly – to environmental change. The current observed asynchrony is therefore not due to a lack of genetic variation and at present it is unclear what is constraining O. brumata to adapt. This kind of model may be particularly useful in gaining insight in the predicted amount and rate of change due to environmental changes, given a certain genetic variation and selection pressure.