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1.
Solomon Z. Dobrowski John Abatzoglou Alan K. Swanson Jonathan A. Greenberg Alison R. Mynsberge Zachary A. Holden Michael K. Schwartz 《Global Change Biology》2013,19(1):241-251
Rapid climate change has the potential to affect economic, social, and biological systems. A concern for species conservation is whether or not the rate of on‐going climate change will exceed the rate at which species can adapt or move to suitable environments. Here we assess the climate velocity (both climate displacement rate and direction) for minimum temperature, actual evapotranspiration, and climatic water deficit (deficit) over the contiguous US during the 20th century (1916–2005). Vectors for these variables demonstrate a complex mosaic of patterns that vary spatially and temporally and are dependent on the spatial resolution of input climate data. Velocities for variables that characterize the climatic water balance were similar in magnitude to that derived from temperature, but frequently differed in direction resulting in the divergence of climate vectors through time. Our results strain expectations of poleward and upslope migration over the past century due to warming. Instead, they suggest that a more full understanding of changes in multiple climatic factors, in addition to temperature, may help explain unexpected or conflicting observational evidence of climate‐driven species range shifts during the 20th century. 相似文献
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Zak Ratajczak Amber C. Churchill Laura M. Ladwig Jeff H. Taylor Scott L. Collins 《植被学杂志》2019,30(4):687-697
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Andreja Sušnik 《Biological Rhythm Research》2019,50(2):280-286
Agrometeorological department of Meteorological Office at Slovenian Environment Agency (ARSO) is a key provider of agrometeorological service in Slovenia. Its major priority is to manage agrometeorological and phenological networks including providing guidelines for observers and maintenance of databases. Agrometeorological and phenological data are foundation for several tools and analyses which have been developed during the past decades for agricultural decision purposes. Recently, focus is on the crop water balance modelling with irrigation forecasts, drought monitoring, climate change impact scenarios and many others. After year 2006 special work emphasis is on coordination of Drought Management Center for South-eastern Europe hosted by ARSO. A set of information, tools and publications, bulletins is free available at the webpage and servers of ARSO with the aim to make smarter weather/climate related decisions in agriculture. 相似文献
4.
Interactions between rainfall, deforestation and fires during recent years in the Brazilian Amazonia 总被引:1,自引:0,他引:1
Aragão LE Malhi Y Barbier N Lima A Shimabukuro Y Anderson L Saatchi S 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2008,363(1498):1779-1785
Understanding the interplay between climate and land-use dynamics is a fundamental concern for assessing the vulnerability of Amazonia to climate change. In this study, we analyse satellite-derived monthly and annual time series of rainfall, fires and deforestation to explicitly quantify the seasonal patterns and relationships between these three variables, with a particular focus on the Amazonian drought of 2005. Our results demonstrate a marked seasonality with one peak per year for all variables analysed, except deforestation. For the annual cycle, we found correlations above 90% with a time lag between variables. Deforestation and fires reach the highest values three and six months, respectively, after the peak of the rainy season. The cumulative number of hot pixels was linearly related to the size of the area deforested annually from 1998 to 2004 (r2=0.84, p=0.004). During the 2005 drought, the number of hot pixels increased 43% in relation to the expected value for a similar deforested area (approx. 19000km2). We demonstrated that anthropogenic forcing, such as land-use change, is decisive in determining the seasonality and annual patterns of fire occurrence. Moreover, droughts can significantly increase the number of fires in the region even with decreased deforestation rates. We may expect that the ongoing deforestation, currently based on slash and burn procedures, and the use of fires for land management in Amazonia will intensify the impact of droughts associated with natural climate variability or human-induced climate change and, therefore, a large area of forest edge will be under increased risk of fires. 相似文献
5.
随着全球气候变化和水循环的改变,降水不均和持续干旱等极端天气事件的频度和强度增加,对水资源,尤其是人口和社会经济密度高的城市的水资源带来很大的影响和压力。为了探究我国干旱天气的变化趋势、区域特征、及其对城市水资源压力的影响,采用全国917个气象站点1951—2014年的逐日降水量数据集,分析了我国水资源及干旱的变化趋势和空间分布特征,并以我国289个主要地级市为研究对象,构建了气候变化情境下的城市基于区域降水禀赋的水资源压力评估方法,预测并展望了不同时段和不同代表性浓度路径(RCPs)情景下的未来城市水资源压力的情况。结果显示,我国极端干旱情况整体是随着全球气候变化增加的,年最长连续无降水天数变化速度的平均值为2.3d/100a,但是具有区域性,具体表现为南部地区干旱减缓而北部地区干旱严重。我国城市水资源压力受水资源禀赋的影响,呈现北方高而南方低的分布,除此之外水资源消耗大的大城市资源压力也比较大。随着气候变化,近期我国整体城市水资源压力相对现阶段增加了2%左右,具体水资源压力上升的城市有170个,水资源压力减少的城市有110个,剩下的9个城市水资源压力受气候变化的影响比较小。在低应对的RCP8.5情景下的城市水资源压力远远高于在RCP2.6情景,这说明减缓气候变化工作对降低我国城市水资源压力有积极作用;城市水资源压力的变化并不是均匀的,呈现南部减少而北部增加的变化趋势,我国华北地区城市的水资源压力最大,随着气候的变化,该地区的水资源压力也在随着时间不断增加,需要政府积极行动,提出有针对性和前瞻性的水资源规划方案,并依据方案采取措施,以应对气候变化造成的城市干旱增加。 相似文献
6.
Polly C. Buotte Samuel Levis Beverly E. Law Tara W. Hudiburg David E. Rupp Jeffery J. Kent 《Global Change Biology》2019,25(1):290-303
Recent prolonged droughts and catastrophic wildfires in the western United States have raised concerns about the potential for forest mortality to impact forest structure, forest ecosystem services, and the economic vitality of communities in the coming decades. We used the Community Land Model (CLM) to determine forest vulnerability to mortality from drought and fire by the year 2049. We modified CLM to represent 13 major forest types in the western United States and ran simulations at a 4‐km grid resolution, driven with climate projections from two general circulation models under one emissions scenario (RCP 8.5). We developed metrics of vulnerability to short‐term extreme and prolonged drought based on annual allocation to stem growth and net primary productivity. We calculated fire vulnerability based on changes in simulated future area burned relative to historical area burned. Simulated historical drought vulnerability was medium to high in areas with observations of recent drought‐related mortality. Comparisons of observed and simulated historical area burned indicate simulated future fire vulnerability could be underestimated by 3% in the Sierra Nevada and overestimated by 3% in the Rocky Mountains. Projections show that water‐limited forests in the Rocky Mountains, Southwest, and Great Basin regions will be the most vulnerable to future drought‐related mortality, and vulnerability to future fire will be highest in the Sierra Nevada and portions of the Rocky Mountains. High carbon‐density forests in the Pacific coast and western Cascades regions are projected to be the least vulnerable to either drought or fire. Importantly, differences in climate projections lead to only 1% of the domain with conflicting low and high vulnerability to fire and no area with conflicting drought vulnerability. Our drought vulnerability metrics could be incorporated as probabilistic mortality rates in earth system models, enabling more robust estimates of the feedbacks between the land and atmosphere over the 21st century. 相似文献
7.
Helen R. Sofaer Joseph J. Barsugli Catherine S. Jarnevich John T. Abatzoglou Marian K. Talbert Brian W. Miller Jeffrey T. Morisette 《Global Change Biology》2017,23(7):2537-2553
Identifying the climatic drivers of an ecological system is a key step in assessing its vulnerability to climate change. The climatic dimensions to which a species or system is most sensitive – such as means or extremes – can guide methodological decisions for projections of ecological impacts and vulnerabilities. However, scientific workflows for combining climate projections with ecological models have received little explicit attention. We review Global Climate Model (GCM) performance along different dimensions of change and compare frameworks for integrating GCM output into ecological models. In systems sensitive to climatological means, it is straightforward to base ecological impact assessments on mean projected changes from several GCMs. Ecological systems sensitive to climatic extremes may benefit from what we term the ‘model space’ approach: a comparison of ecological projections based on simulated climate from historical and future time periods. This approach leverages the experimental framework used in climate modeling, in which historical climate simulations serve as controls for future projections. Moreover, it can capture projected changes in the intensity and frequency of climatic extremes, rather than assuming that future means will determine future extremes. Given the recent emphasis on the ecological impacts of climatic extremes, the strategies we describe will be applicable across species and systems. We also highlight practical considerations for the selection of climate models and data products, emphasizing that the spatial resolution of the climate change signal is generally coarser than the grid cell size of downscaled climate model output. Our review illustrates how an understanding of how climate model outputs are derived and downscaled can improve the selection and application of climatic data used in ecological modeling. 相似文献
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9.
Jennifer R. Gremer John B. Bradford Seth M. Munson Michael C. Duniway 《Global Change Biology》2015,21(11):4049-4062
Climate change predictions include warming and drying trends, which are expected to be particularly pronounced in the southwestern United States. In this region, grassland dynamics are tightly linked to available moisture, yet it has proven difficult to resolve what aspects of climate drive vegetation change. In part, this is because it is unclear how heterogeneity in soils affects plant responses to climate. Here, we combine climate and soil properties with a mechanistic soil water model to explain temporal fluctuations in perennial grass cover, quantify where and the degree to which incorporating soil water dynamics enhances our ability to understand temporal patterns, and explore the potential consequences of climate change by assessing future trajectories of important climate and soil water variables. Our analyses focused on long‐term (20–56 years) perennial grass dynamics across the Colorado Plateau, Sonoran, and Chihuahuan Desert regions. Our results suggest that climate variability has negative effects on grass cover, and that precipitation subsidies that extend growing seasons are beneficial. Soil water metrics, including the number of dry days and availability of water from deeper (>30 cm) soil layers, explained additional grass cover variability. While individual climate variables were ranked as more important in explaining grass cover, collectively soil water accounted for 40–60% of the total explained variance. Soil water conditions were more useful for understanding the responses of C3 than C4 grass species. Projections of water balance variables under climate change indicate that conditions that currently support perennial grasses will be less common in the future, and these altered conditions will be more pronounced in the Chihuahuan Desert and Colorado Plateau. We conclude that incorporating multiple aspects of climate and accounting for soil variability can improve our ability to understand patterns, identify areas of vulnerability, and predict the future of desert grasslands. 相似文献
10.
Anderson L. Vargas Thamires Brazil Jayme M. Santangelo Reinaldo L. Bozelli 《Freshwater Biology》2024,69(5):635-644
- Resting eggs are commonly produced by zooplankton inhabiting permanent and temporary lakes. Although resting eggs are acknowledged to survive varying harsh conditions, the effects of desiccation on the viability and hatching patterns of resting eggs are not fully understood and might be context-dependent.
- This study simulated one long-term (1 year) dry-out episode in wet sediments originating from permanent and temporary lakes and compared hatching patterns through ex situ experiments.
- The abundance and species richness of hatchlings decreased in dry sediments compared to wet sediments. Hatchling composition differed between wet and dry sediments of each lake category, whereas community variability did not differ between wet and dry sediments of temporary lakes.
- Overall, there was no difference in the ability of rotifers and crustaceans to cope with desiccation, since all species decreased hatchling numbers after desiccation. Artemia was the only taxon that benefited from drying sediments.
- Long-term desiccation may affect the contribution of resting egg banks to future active populations in the water column, even in temporary habitats which presumably select for drought-resistant resting eggs. The ecological roles played by resting egg banks may be weakening because droughts are becoming more common worldwide, even in former permanent aquatic habitats.
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Marengo JA Nobre CA Tomasella J Cardoso MF Oyama MD 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2008,363(1498):1773-1778
In 2005, southwestern Amazonia experienced the effects of an intense drought that affected life and biodiversity. Several major tributaries as well as parts of the main river itself contained only a fraction of their normal volumes of water, and lakes were drying up. The consequences for local people, animals and the forest itself are impossible to estimate now, but they are likely to be serious. The analyses indicate that the drought was manifested as weak peak river season during autumn to winter as a consequence of a weak summertime season in southwestern Amazonia; the winter season was also accompanied by rainfall that sometimes reached 25% of the climatic value, being anomalously warm and dry and helping in the propagation of fires. Analyses of climatic and hydrological records in Amazonia suggest a broad consensus that the 2005 drought was linked not to El Niño as with most previous droughts in the Amazon, but to warming sea surface temperatures in the tropical North Atlantic Ocean. 相似文献
13.
Margaret Friedel Grant E. Allan Angus Duguid 《Ecological Management & Restoration》2014,15(2):128-132
Ecologists have long been concerned that contemporary fire regimes of central Australia have poor consequences for some plant species, vegetation communities and the native animals they support. Fire frequency, size and intensity (the ‘fire regime’) have all been implicated in the decline of native biota and in vegetation changes that potentially constitute ecological drift. However, not all perceived declines and changes are quantified or proven. The fire regimes themselves defy quantification and are arguably unknowable. We examine the relationships between fire, vegetation and the physical landscape and consider the adequacy of available knowledge for guiding fire management. Devising targeted ‘fire management regimes’, which take into account vegetation type and management objectives such as pastoral production, conservation and cultural observance, and which actively use fire to achieve those objectives, is a more realistic goal than controlling unquantifiable fire regimes in spatially diverse landscapes. 相似文献
14.
M. REICHSTEIN P. CIAIS D. PAPALE R. VALENTINI S. RUNNING N. VIOVY W. CRAMER A. GRANIER J. OGE V. ALLARD M. AUBINET Chr. BERNHOFER N. BUCHMANN A. CARRARA T. GRÜNWALD M. HEIMANN B. HEINESCH A. KNOHL W. KUTSCH D. LOUSTAU G. MANCA G. MATTEUCCI F. MIGLIETTA J.M. OURCIVAL K. PILEGAARD J. PUMPANEN S. RAMBAL S. SCHAPHOFF G. SEUFERT J.‐F. SOUSSANA M.‐J. SANZ T. VESALA M. ZHAO 《Global Change Biology》2007,13(3):634-651
The European CARBOEUROPE/FLUXNET monitoring sites, spatial remote sensing observations via the EOS‐MODIS sensor and ecosystem modelling provide independent and complementary views on the effect of the 2003 heatwave on the European biosphere's productivity and carbon balance. In our analysis, these data streams consistently demonstrate a strong negative anomaly of the primary productivity during the summer of 2003. FLUXNET eddy‐covariance data indicate that the drop in productivity was not primarily caused by high temperatures (‘heat stress’) but rather by limitation of water (drought stress) and that, contrary to the classical expectation about a heat wave, not only gross primary productivity but also ecosystem respiration declined by up to more than to 80 gC m−2 month−1. Anomalies of carbon and water fluxes were strongly correlated. While there are large between‐site differences in water‐use efficiency (WUE, 1–6 kg C kg−1 H2O) here defined as gross carbon uptake divided by evapotranspiration (WUE=GPP/ET), the year‐to‐year changes in WUE were small (<1 g kg−1) and quite similar for most sites (i.e. WUE decreased during the year of the heatwave). Remote sensing data from MODIS and AVHRR both indicate a strong negative anomaly of the fraction of absorbed photosynthetically active radiation in summer 2003, at more than five standard deviations of the previous years. The spatial differentiation of this anomaly follows climatic and land‐use patterns: Largest anomalies occur in the centre of the meteorological anomaly (central Western Europe) and in areas dominated by crops or grassland. A preliminary model intercomparison along a gradient from data‐oriented models to process‐oriented models indicates that all approaches are similarly describing the spatial pattern of ecosystem sensitivity to the climatic 2003 event with major exceptions in the Alps and parts of Eastern Europe, but differed with respect to their interannual variability. 相似文献
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Deterministic or rule-based succession is expected under homogeneous biotic and abiotic starting conditions. Effects of extreme climatic events such as drought, however, may alter these assembly rules by adding stochastic elements. We monitored the succession of species composition of 30 twin grassland communities with identical biotic and abiotic starting conditions in an initially sown diversity gradient between 1 and 16 species over 13 years. The stochasticity of succession, measured as the synchrony in the development of the species compositions of the twin plots, was strongly altered by the extreme warm and dry summer of 2003. Moreover, it was independent from past and present plant diversity and neighbourhood species compositions. Extreme climatic events can induce stochastic effects in community development and therefore impair predictability even under homogeneous abiotic conditions. Stochastic events may result in lasting shifts of community composition, as well as adverse and unforeseeable effects on the stability of ecological services. 相似文献
17.
Episodic tree mortality can be caused by various reasons. This study describes climate-driven tree mortality and tree growth in the Black Forest mountain range in Germany. It is based on a 68-year consistent data series describing the annual mortality of all trees growing in a forest area of almost 250 thousand ha. The study excludes mortality caused by storm, snow and ice, and fire. The sequence of the remaining mortality, the so-called “desiccated trees,” is analyzed and compared with the sequence of the climatic water balance during the growing season and the annual radial growth of Norway spruce in the Black Forest. The annual radial growth series covers 121 years and the climatic water balance series 140 years. These unique time series enable a quantitative assessment of multidecadal drought and heat impacts on growth and mortality of forest trees on a regional spatial scale. Data compiled here suggest that the mortality of desiccated trees in the Black Forest during the last 68 years is driven by the climatic water balance. Decreasing climatic water balance coincided with an increase in tree mortality and growth decline. Consecutive hot and dry summers enhance mortality and growth decline as a consequence of drought legacies lasting several years. The sensitivity of tree growth and mortality to changes in the climatic water balance increases with the decreasing trend of the climatic water balance. The findings identify the climatic water balance as the main driver of mortality and growth variation during the 68-year observation period on a landscape-scale including a variety of different sites. They suggest that bark beetle population dynamics modify mortality rates. They as well provide evidence that the mortality during the last 140 years never was as high as in the most recent years. 相似文献
18.
Summary The mixed oak woodland on the island of Clairinsh has been left unmanaged as part of the Loch Lomond National Nature Reserve. Until 1913 the woodlands had been treated as coppice-with-standards. Between 1961 and 1986 changes in the structure and composition of the stand were recorded by means of two transects, within which individual trees and shrubs were charted and measured. Most of the stand remained closed, increasing in basal area, but decreasing in density. However, a limited number of canopy gaps formed, part-icularly as a result of the 1968 hurricane. Of the individuals present in 1961, 30% died by 1986, mortality being particularly high in smaller individuals and in birch. Recruitment was mainly confined to rowan, holly and hazel in the closed woodland, and to birch and rowan in the gaps. The changes are discussed in relation to natural processes and the history of management. 相似文献
19.
Impacts of climate change on fire activity and fire management in the circumboreal forest 总被引:5,自引:0,他引:5
MIKE FLANNIGAN BRIAN STOCKS† MERRITT TURETSKY‡ MIKE WOTTON 《Global Change Biology》2009,15(3):549-560
Forest fires are a significant and natural element of the circumboreal forest. Fire activity is strongly linked to weather, and increased fire activity due to climate change is anticipated or arguably has already occurred. Recent studies suggest a doubling of area burned along with a 50% increase in fire occurrence in parts of the circumboreal by the end of this century. Fire management agencies' ability to cope with these increases in fire activity is limited, as these organizations operate with a narrow margin between success and failure; a disproportionate number of fires may escape initial attack under a warmer climate, resulting in an increase in area burned that will be much greater than the corresponding increase in fire weather severity. There may be only a decade or two before increased fire activity means fire management agencies cannot maintain their current levels of effectiveness. 相似文献
20.
青藏高原黄河上游河岸带是典型的生态脆弱区, 然而近年来气候变暖加剧了该地极端旱涝事件的频繁发生, 高原河岸带生态脆弱区植被是否能够应对极端旱涝事件的干扰成为流域生态环境管理工作所关注的重点问题。为了研究黄河上游河岸林中主要树种对极端旱涝的响应, 该研究选取青海省同德县和兴海县3处河岸林中的47株甘蒙柽柳(Tamarix austromongolica), 分别从树干面向邻近山体一侧及与之垂直的一侧分别获取1根树轮样本, 分析其历史生长。通过对比两个方向上的生长速率判断甘蒙柽柳是否受到地质灾害影响从而将其划分为受伤组和对照组, 分析两组甘蒙柽柳在过去63年中径流极值年的抵抗力状况及两个方向的生长差异。研究发现, 甘蒙柽柳对干旱和洪涝均有着很强的抵抗力, 河岸带多样化的水分来源有助于甘蒙柽柳在极端干旱环境中较好地生长; 但洪涝伴随泥石流等地质灾害的频发使甘蒙柽柳面向山体侧面受到严重的生长抑制, 表现出显著的方向性差异, 从而影响甘蒙柽柳的形态。较长的创伤恢复期带来的遗留效应可能造成甘蒙柽柳对外界干扰的较高敏感性。研究黄河上游甘蒙柽柳生长对极端旱涝的响应, 将有助于评估生态脆弱区生态弹性过程, 同时为高原河岸带生态建设和恢复提供科学依据。 相似文献