气候变化对鸟类影响的研究进展

气候变化对生物多样性的影响已成为热点问题.本文以鸟类为研究对象,根据鸟类受气候变化影响的最新研究成果,综述了气候变化对鸟类的分布、物候和种群等方面的影响.结果表明,在气候变化影响下,鸟类分布向高纬度或高海拔区移动,速度比以往加快,繁殖地和非繁殖地的分布移动变化并不相同,并且多数分布范围缩小,物候期发生复杂变化,种群数量下降明显.文章还讨论了该领域主要的预测和评估方法,以及进化适应等生物因素对气候变化预测结果的影响,除了以往单一的相关性模型外,目前应用最多的是集成模型,而未来最具发展潜力的是机理模型.进化适应方面的研究近来取得新进展,证实了生物个体积极应对气候变化影响的事实,从而对人为模型预测的准确性带来挑战.文章最后进行了总结和展望,结合国外研究经验和我国实际情况,提出一些建议:由于气候变化的影响及其研究是长期性的,从而对鸟类的历史监测数据提出很高的要求,当前我国急需建立一套长期、全面和可靠的鸟类数据监测系统;此外,人们需要综合评估现有各种预测模型的可靠性,在此基础上探索新的研究方法.     

The impact of global climate change on tropical forest biodiversity in Amazonia

Aim To model long‐term trends in plant species distributions in response to predicted changes in global climate. Location Amazonia. Methods The impacts of expected global climate change on the potential and realized distributions of a representative sample of 69 individual Angiosperm species in Amazonia were simulated from 1990 to 2095. The climate trend followed the HADCM2GSa1 scenario, which assumes an annual 1% increase of atmospheric CO₂ content with effects mitigated by sulphate forcing. Potential distributions of species in one‐degree grid cells were modelled using a suitability index and rectilinear envelope based on bioclimate variables. Realized distributions were additionally limited by spatial contiguity with, and proximity to, known record sites. A size‐structured population model was simulated for each cell in the realized distributions to allow for lags in response to climate change, but dispersal was not included. Results In the resulting simulations, 43% of all species became non‐viable by 2095 because their potential distributions had changed drastically, but there was little change in the realized distributions of most species, owing to delays in population responses. Widely distributed species with high tolerance to environmental variation exhibited the least response to climate change, and species with narrow ranges and short generation times the greatest. Climate changed most in north‐east Amazonia while the best remaining conditions for lowland moist forest species were in western Amazonia. Main conclusions To maintain the greatest resilience of Amazonian biodiversity to climate change as modelled by HADCM2GSa1, highest priority should be given to strengthening and extending protected areas in western Amazonia that encompass lowland and montane forests.     

The integration of biodiversity and climate change: A contextual assessment of the carbon farming initiative

Summary The Carbon Farming Initiative (CFI) allows the creation of tradable Australian Carbon Credit Units (ACCUs) derived from across the ecosystem sector via project‐level baseline and credit activities: it is the first national offset scheme in the world to broadly include farming and forestry projects. Because these activities have the potential to produce both biodiversity and climate change benefits, a crucial outcome is for widespread uptake of the policy. However, the design, complexity and cost of the CFI project development process, and low prices as a result of ACCUs trading in the voluntary market, will all likely militate against this. This article shows how international politics and policy surrounding the Kyoto Protocol have influenced the design of the CFI, with its potential to proliferate complex and narrow methodologies and counter‐productive approaches to integrity standards such as permanence. The article shows that despite the pressing need to integrate biodiversity and climate change considerations as equally important challenges, their global integration remains poorly articulated. Biodiversity considerations are also not integrated into the CFI but, rather, are dealt with indirectly through safeguard measures that avoid perverse incentives and unintended harm, and as an optional co‐benefit via the development of an index. This article suggests that we need to move past the shackles of Kyoto towards streamlined and standardized approaches such as risk‐based assessments and the use of regional baselines. Using regionally specific baselines such as for avoided deforestation would allow landholders to opt‐in to regional‐scale mitigation opportunities. Activities that Australia accounts for, such as reforestation and deforestation, should also be able to opt‐in for coverage under the Clean Energy Act (and out of the voluntary carbon market) to obtain a secure price.     

Projected range contractions of montane biodiversity under global warming

Mountains, especially in the tropics, harbour a unique and large portion of the world''s biodiversity. Their geographical isolation, limited range size and unique environmental adaptations make montane species potentially the most threatened under impeding climate change. Here, we provide a global baseline assessment of geographical range contractions and extinction risk of high-elevation specialists in a future warmer world. We consider three dispersal scenarios for simulated species and for the world''s 1009 montane bird species. Under constrained vertical dispersal (VD), species with narrow vertical distributions are strongly impacted; at least a third of montane bird diversity is severely threatened. In a scenario of unconstrained VD, the location and structure of mountain systems emerge as a strong driver of extinction risk. Even unconstrained lateral movements offer little improvement to the fate of montane species in the Afrotropics, Australasia and Nearctic. Our results demonstrate the particular roles that the geography of species richness, the spatial structure of lateral and particularly vertical range extents and the specific geography of mountain systems have in determining the vulnerability of montane biodiversity to climate change. Our findings confirm the outstanding levels of biotic perturbation and extinction risk that mountain systems are likely to experience under global warming and highlight the need for additional knowledge on species'' vertical distributions, dispersal and adaptive capacities.     

Hierarchical regulation of pelagic invertebrates in lakes of the northern Great Plains: a novel model for interdecadal effects of future climate change on lakes

Endorheic lakes of the northern Great Plains encompass a wide range of environmental parameters (e.g., salinity, pH, DOC, Ca, nutrients, depth) that vary 1000‐fold among sites and through the past 2000 years due to variation in basin hydrology and evaporative forcing. However, while many environmental parameters are known to individually influence zooplankton diversity and taxonomic composition, relatively little is known of the hierarchical relationships among potential controls or of how regulatory mechanisms may change in response to climate variation on diverse scales. To address these issues, we surveyed 70 lakes within a 100 000 km² prairie region to simulate the magnitude of environmental change expected to occur over 100–1000 years and to quantify the unique and interactive effects of diverse environmental parameters in regulating pelagic invertebrate community structure at that scale. Multivariate analyses showed that salinity was the principal correlate of changes in invertebrate composition among lakes, with a sequential loss of taxa between salinities of 4 and 50 g total dissolved solids L^?1 until one to two species predominated in highly saline systems. In contrast, changes in the concentrations of Ca²⁺ and other mineral nutrients exerted secondary controls of invertebrate assemblages independent of salinity, whereas lake depth provided a tertiary regulatory mechanism structuring species composition. In contrast to these large‐scale hierarchical patterns, seasonal surveys (May, July, September) of a subset of 21 lakes in each of 2003–2005 revealed that annual meteorological variation had no measurable effect on pelagic invertebrates, despite large differences in temperature, precipitation, and evaporation arising from regional droughts. Together these findings show that pelagic invertebrate communities in saline lakes are resilient to interannual variability in climate, but suggest that lakes of the northern Great Plains may provide a sensitive model to forecast centennial effects of future climate change.     

From global change to a butterfly flapping: biophysics and behaviour affect tropical climate change impacts

Difficulty in characterizing the relationship between climatic variability and climate change vulnerability arises when we consider the multiple scales at which this variation occurs, be it temporal (from minute to annual) or spatial (from centimetres to kilometres). We studied populations of a single widely distributed butterfly species, Chlosyne lacinia, to examine the physiological, morphological, thermoregulatory and biophysical underpinnings of adaptation to tropical and temperate climates. Microclimatic and morphological data along with a biophysical model documented the importance of solar radiation in predicting butterfly body temperature. We also integrated the biophysics with a physiologically based insect fitness model to quantify the influence of solar radiation, morphology and behaviour on warming impact projections. While warming is projected to have some detrimental impacts on tropical ectotherms, fitness impacts in this study are not as negative as models that assume body and air temperature equivalence would suggest. We additionally show that behavioural thermoregulation can diminish direct warming impacts, though indirect thermoregulatory consequences could further complicate predictions. With these results, at multiple spatial and temporal scales, we show the importance of biophysics and behaviour for studying biodiversity consequences of global climate change, and stress that tropical climate change impacts are likely to be context-dependent.     

Assessing effects of forecasted climate change on the diversity and distribution of European higher plants for 2050

The rapidly increasing atmospheric concentrations of greenhouse gases may lead to significant changes in regional and seasonal climate patterns. Such changes can strongly influence the diversity and distribution of species and, therefore, affect ecosystems and biodiversity. To assess these changes we developed a model, called euromove. The model uses climate data from 1990 to 2050 as compiled from the image 2 model, and determines climate envelopes for about 1400 plant species by multiple logistic regression analysis. The climate envelopes were applied to the projected climate to obtain predictions about plant diversity and distributions by 2050. For each European grid cell, euromove calculates which species would still occur in forecasted future climate conditions and which not. The results show major changes in biodiversity by 2050. On average, 32% of the European plant species that were present in a cell in 1990 would disappear from that cell. The area, in which 32% or more of the 1990 species will disappear, takes up 44% of the modelled European area. Individual responses of the plant species to the forecasted climate change were diverse. In reviewing possible future trends, we found that plant species, in general, would find their current climate envelopes further northeast by 2050, shifting ranges that were comparable with those ranges in other studies.     

Impact of climate change on risk of incursion of Crimean-Congo haemorrhagic fever virus in livestock in Europe through migratory birds

Aims: To predict the risk of incursion of Crimean‐Congo haemorrhagic fever virus (CCHFV) in livestock in Europe introduced through immature Hyalomma marginatum ticks on migratory birds under current conditions and in the decade 2075–2084 under a climate‐change scenario. Methods and Results: A spatial risk map of Europe comprising 14 282 grid cells (25 × 25 km) was constructed using three data sources: (i) ranges and abundances of four species of bird which migrate from sub‐Saharan Africa to Europe each spring, namely Willow warbler (Phylloscopus trochilus), Northern wheatear (Oenanthe oenanthe), Tree pipit (Anthus trivialis) and Common quail (Coturnix coturnix); (ii) UK Met Office HadRM3 spring temperatures for prediction of moulting success of immature H. marginatum ticks and (iii) livestock densities. On average, the number of grid cells in Europe predicted to have at least one CCHFV incursion in livestock in spring was 1·04 per year for the decade 2005–2014 and 1·03 per year for the decade 2075–2084. In general with the assumed climate‐change scenario, the risk increased in northern Europe but decreased in central and southern Europe, although there is considerable local variation in the trends. Conclusions: The absolute risk of incursion of CCHFV in livestock through ticks introduced by four abundant species of migratory bird (totalling 120 million individual birds) is very low. Climate change has opposing effects, increasing the success of the moult of the nymphal ticks into adults but decreasing the projected abundance of birds by 34% in this model. Significance and Impact of the Study: For Europe, climate change is not predicted to increase the overall risk of incursion of CCHFV in livestock through infected ticks introduced by these four migratory bird species.     

Global variation in thermal tolerances and vulnerability of endotherms to climate change

The relationships among species'' physiological capacities and the geographical variation of ambient climate are of key importance to understanding the distribution of life on the Earth. Furthermore, predictions of how species will respond to climate change will profit from the explicit consideration of their physiological tolerances. The climatic variability hypothesis, which predicts that climatic tolerances are broader in more variable climates, provides an analytical framework for studying these relationships between physiology and biogeography. However, direct empirical support for the hypothesis is mostly lacking for endotherms, and few studies have tried to integrate physiological data into assessments of species'' climatic vulnerability at the global scale. Here, we test the climatic variability hypothesis for endotherms, with a comprehensive dataset on thermal tolerances derived from physiological experiments, and use these data to assess the vulnerability of species to projected climate change. We find the expected relationship between thermal tolerance and ambient climatic variability in birds, but not in mammals—a contrast possibly resulting from different adaptation strategies to ambient climate via behaviour, morphology or physiology. We show that currently most of the species are experiencing ambient temperatures well within their tolerance limits and that in the future many species may be able to tolerate projected temperature increases across significant proportions of their distributions. However, our findings also underline the high vulnerability of tropical regions to changes in temperature and other threats of anthropogenic global changes. Our study demonstrates that a better understanding of the interplay among species'' physiology and the geography of climate change will advance assessments of species'' vulnerability to climate change.     

Climate change vulnerability of forest biodiversity: climate and competition tracking of demographic rates

Forest responses to climate change will depend on demographic impacts in the context of competition. Current models used to predict species responses, termed climate envelope models (CEMs), are controversial, because (i) calibration and prediction are based on correlations in space (CIS) between species abundance and climate, rather than responses to climate change over time (COT), and (ii) they omit competition. To determine the relative importance of COT, CIS, and competition for light, we applied a longitudinal analysis of 27 000 individual trees over 6–18 years subjected to experimental and natural variation in risk factors. Sensitivities and climate and resource tracking identify which species are vulnerable to these risk factors and in what ways. Results show that responses to COT differ from those predicted based on CIS. The most important impact is the effect of spring temperature on fecundity, rather than any input variable on growth or survival. Of secondary importance is growing season moisture. Species in the genera Pinus, Ulmus, Magnolia, and Fagus are particularly vulnerable to climate variation. However, the effect of competition on growth and mortality risk exceeds the effects of climate variation in space or time for most species. Because sensitivities to COT and competition are larger than CIS, current models miss the most important effects. By directly comparing sensitivity to climate in time and space, together with competition, the approach identifies which species are sensitive to climate change and why, including the heretofore overlooked impact on fecundity.     

Climate change affects populations of northern birds in boreal protected areas

Human land-use effects on species populations are minimized in protected areas and population changes can thus be more directly linked with changes in climate. In this study, bird population changes in 96 protected areas in Finland were compared using quantitative bird census data, between two time slices, 1981-1999 and 2000-2009, with the mean time span being 14 years. Bird species were categorized by distribution pattern and migratory strategy. Our results showed that northern bird species had declined by 21 per cent and southern species increased by 29 per cent in boreal protected areas during the study period, alongside a clear rise (0.7-0.8 °C) in mean temperatures. Distribution pattern was the main factor, with migratory strategy interacting in explaining population changes in boreal birds. Migration strategy interacted with distribution pattern so that, among northern birds, densities of both migratory and resident species declined, whereas among southern birds they both increased. The observed decline of northern species and increase in southern species are in line with the predictions of range shifts of these species groups under a warming climate, and suggest that the population dynamics of birds are already changing in natural boreal habitats in association with changing climate.     

An inventory of the possible effects of climatic change on western palearctic migratory birds

This paper presents an assessment of the possible effects of future climatic change on migratory birds. The assessment is based on two approaches: firstly an inventory is made of the environmental factors that may change which directly affect migratory birds. These factors include physical (temperature, hydrology, ocean and air streaming patterns) as well as biological (floral and faunal composition of ecosystems) and landuse aspects of the environment.Secondly, these possible changes were related to the annual cycles of migratory birds in order to estimate the problems that different groups of migratory birds have to cope with at various stages in their annual cycle. It is concluded that many migratory bird species will be influenced by climatic change, leading to adaptations in the birds annual cycle. The biggest problems may arise for those birds which depend on wetlands, because many of these wetlands may dessicate.     

The impacts of climate change on the annual cycles of birds

Organisms living today are descended from ancestors that experienced considerable climate change in the past. However, they are currently presented with many new, man-made challenges, including rapid climate change. Migration and reproduction of many avian species are controlled by endogenous mechanisms that have been under intense selection over time to ensure that arrival to and departure from breeding grounds is synchronized with moderate temperatures, peak food availability and availability of nesting sites. The timing of egg laying is determined, usually by both endogenous clocks and local factors, so that food availability is near optimal for raising young. Climate change is causing mismatches in food supplies, snow cover and other factors that could severely impact successful migration and reproduction of avian populations unless they are able to adjust to new conditions. Resident (non-migratory) birds also face challenges if precipitation and/or temperature patterns vary in ways that result in mismatches of food and breeding. Predictions that many existing climates will disappear and novel climates will appear in the future suggest that communities will be dramatically restructured by extinctions and changes in range distributions. Species that persist into future climates may be able to do so in part owing to the genetic heritage passed down from ancestors who survived climate changes in the past.     

Evolution in action: climate change,biodiversity dynamics and emerging infectious disease

Climatological variation and ecological perturbation have been pervasive drivers of faunal assembly, structure and diversification for parasites and pathogens through recurrent events of geographical and host colonization at varying spatial and temporal scales of Earth history. Episodic shifts in climate and environmental settings, in conjunction with ecological mechanisms and host switching, are often critical determinants of parasite diversification, a view counter to more than a century of coevolutionary thinking about the nature of complex host–parasite assemblages. Parasites are resource specialists with restricted host ranges, yet shifts onto relatively unrelated hosts are common during phylogenetic diversification of parasite lineages and directly observable in real time. The emerging Stockholm Paradigm resolves this paradox: Ecological Fitting (EF)—phenotypic flexibility and phylogenetic conservatism in traits related to resource use, most notably host preference—provides many opportunities for rapid host switching in changing environments, without the evolution of novel host-utilization capabilities. Host shifts via EF fuel the expansion phase of the Oscillation Hypothesis of host range and speciation and, more generally, the generation of novel combinations of interacting species within the Geographic Mosaic Theory of Coevolution. In synergy, an environmental dynamic of Taxon Pulses establishes an episodic context for host and geographical colonization.     

Validation of species–climate impact models under climate change

Increasing concern over the implications of climate change for biodiversity has led to the use of species–climate envelope models to project species extinction risk under climate‐change scenarios. However, recent studies have demonstrated significant variability in model predictions and there remains a pressing need to validate models and to reduce uncertainties. Model validation is problematic as predictions are made for events that have not yet occurred. Resubstituition and data partitioning of present‐day data sets are, therefore, commonly used to test the predictive performance of models. However, these approaches suffer from the problems of spatial and temporal autocorrelation in the calibration and validation sets. Using observed distribution shifts among 116 British breeding‐bird species over the past ～20 years, we are able to provide a first independent validation of four envelope modelling techniques under climate change. Results showed good to fair predictive performance on independent validation, although rules used to assess model performance are difficult to interpret in a decision‐planning context. We also showed that measures of performance on nonindependent data provided optimistic estimates of models' predictive ability on independent data. Artificial neural networks and generalized additive models provided generally more accurate predictions of species range shifts than generalized linear models or classification tree analysis. Data for independent model validation and replication of this study are rare and we argue that perfect validation may not in fact be conceptually possible. We also note that usefulness of models is contingent on both the questions being asked and the techniques used. Implementations of species–climate envelope models for testing hypotheses and predicting future events may prove wrong, while being potentially useful if put into appropriate context.     

The ability of climate envelope models to predict the effect of climate change on species distributions

Climate envelope models (CEMs) have been used to predict the distribution of species under current, past, and future climatic conditions by inferring a species' environmental requirements from localities where it is currently known to occur. CEMs can be evaluated for their ability to predict current species distributions but it is unclear whether models that are successful in predicting current distributions are equally successful in predicting distributions under different climates (i.e. different regions or time periods). We evaluated the ability of CEMs to predict species distributions under different climates by comparing their predictions with those obtained with a mechanistic model (MM). In an MM the distribution of a species is modeled based on knowledge of a species' physiology. The potential distributions of 100 plant species were modeled with an MM for current conditions, a past climate reconstruction (21 000 years before present) and a future climate projection (double preindustrial CO₂ conditions). Point localities extracted from the currently suitable area according to the MM were used to predict current, future, and past distributions with four CEMs covering a broad range of statistical approaches: Bioclim (percentile distributions), Domain (distance metric), GAM (general additive modeling), and Maxent (maximum entropy). Domain performed very poorly, strongly underestimating range sizes for past or future conditions. Maxent and GAM performed as well under current climates as under past and future climates. Bioclim slightly underestimated range sizes but the predicted ranges overlapped more with the ranges predicted with the MM than those predicted with GAM did. Ranges predicted with Maxent overlapped most with those produced with the MMs, but compared with the ranges predicted with GAM they were more variable and sometimes much too large. Our results suggest that some CEMs can indeed be used to predict species distributions under climate change, but individual modeling approaches should be validated for this purpose, and model choice could be made dependent on the purpose of a particular study.     

Implications of climate change for North American wood warblers (Parulidae)

Since 1912, Neotropical–Nearctic migrant birds may now have up to 20 fewer days to travel between Southern Illinois, where spring is arriving later, and Northern Minnesota, where spring is arriving earlier, to exploit optimal habitat conditions (expanding leaves and caterpillar activity) for refueling and breeding. As case studies of the effect of climate change on bird migration, I analyzed two long‐term data sets of arrival times for eight species of northern breeding migratory wood warblers (Parulidae) gathered over a 100 year period in east‐central Illinois (IL, USA) and a 40 year period in western Minnesota (MN, USA). Six (IL) and seven (MN) of the wood warbler species showed no significant tendency to migrate earlier in response to earlier springs in their breeding range. These results suggest that climate change may force many species of long‐distance migratory songbirds to become uncoupled in the spring from their food resources that are driven by temperature.     

Variable effects of climate change on six species of North American birds

Many recent studies have shown that birds are advancing their laying date in response to long-term increases in spring temperatures. These studies have been conducted primarily in Europe and at local scales. If climate change is a large-scale phenomenon, then we should see responses at larger scales and in other regions. We examined the effects of long-term temperature change on the laying dates and clutch sizes of six ecologically diverse species of North American birds using 50 years of nest record data. As predicted, laying dates for most (four of six) species were earlier when spring temperatures were warmer. Over the long-term, laying dates advanced over time for two species (red-winged blackbirds, Agelaius phoeniceus and eastern bluebirds, Sialia sialis). Laying date of song sparrows (Melospiza melodia) also advanced with increasing temperature when the analysis was restricted to eastern populations. Neither laying date nor clutch sizes changed significantly over time in the remaining species (American coot, Fulica americana, killdeer, Charadrius vociferous, and American robin, Turdus migratorius), an unsurprising result given the lack of increase in temperatures over time at nest locations of these species. This study indicates that the relationship between climate change and breeding in birds is variable within and among species. In large-scale analyses of North American birds, four of seven species have shown advances in laying dates with increasing temperature (including song sparrows in the east). These variable responses within and among species highlight the need for more detailed studies across large spatial scales.     

The legacy of past climate and landscape change on species' current experienced climate and elevation ranges across latitude: a multispecies study utilizing mammals in western North America

Aim Elevation and climate ranges across latitude experienced by 21 wide‐ranging mammal species in western North America were summarized to examine two questions: (1) do populations in the northern and southern portions of a species’ range experience different climates or are environments selected to remain similar to climates at the core of ranges; and (2) how do species’ elevational ranges, experienced temperature seasonality and temperature ranges change across latitude? Given the larger effects of climate oscillations in the north vs. the south, a predicted outcome is for species to conserve climate niches across latitude and to show reduced climate and elevation ranges in the north. An alternative outcome is latitudinal niche diversification and increased climate variation in the north. Location Western North America. Methods The questions above were examined using a combination of species occurrence data bases, climate data bases, simple summaries of means and standard deviations and by testing summaries against random distributions across latitude for 21 mammal species from a variety of orders. Results The results showed that: (i) most species conserve their niche strongly or weakly given overall temperature gradients from north to south; (ii) seasonality experienced by species is relatively static until the highest latitudes despite directional trends across the region; and (iii) the elevation range and temperature variation that species experience decreases from south to north. Main conclusions Populations at range edges appear to partition environments to remain closer to temperature values similar to those at the core of the range. In addition, seasonality is not a likely explanatory factor of genetic diversity in latitudinal gradients. The data are instead more consistent with predictions that a combination of higher gene‐flow, increasing environmental instability and decreasing elevation gradients in the north compared to the south may lead to negative correlations between latitude and species’ climate variation. The results corroborate risks faced by northern mammal populations to global climate changes.