A significant upward shift in plant species optimum elevation during the 20th century

Spatial fingerprints of climate change on biotic communities are usually associated with changes in the distribution of species at their latitudinal or altitudinal extremes. By comparing the altitudinal distribution of 171 forest plant species between 1905 and 1985 and 1986 and 2005 along the entire elevation range (0 to 2600 meters above sea level) in west Europe, we show that climate warming has resulted in a significant upward shift in species optimum elevation averaging 29 meters per decade. The shift is larger for species restricted to mountain habitats and for grassy species, which are characterized by faster population turnover. Our study shows that climate change affects the spatial core of the distributional range of plant species, in addition to their distributional margins, as previously reported.     

Changes in climatic water balance drive downhill shifts in plant species' optimum elevations

Uphill shifts of species' distributions in response to historical warming are well documented, which leads to widespread expectations of continued uphill shifts under future warming. Conversely, downhill shifts are often considered anomalous and unrelated to climate change. By comparing the altitudinal distributions of 64 plant species between the 1930s and the present day within California, we show that climate changes have resulted in a significant downward shift in species' optimum elevations. This downhill shift is counter to what would be expected given 20th-century warming but is readily explained by species' niche tracking of regional changes in climatic water balance rather than temperature. Similar downhill shifts can be expected to occur where future climate change scenarios project increases in water availability that outpace evaporative demand.     

Complex species interactions and the dynamics of ecological systems: long-term experiments

Studies that combine experimental manipulations with long-term data collection reveal elaborate interactions among species that affect the structure and dynamics of ecosystems. Research programs in U.S. desert shrubland and pinyon-juniper woodland have shown that (i) complex dynamics of species populations reflect interactions with other organisms and fluctuating climate; (ii) genotype x environment interactions affect responses of species to environmental change; (iii) herbivore-resistance traits of dominant plant species and impacts of "keystone" animal species cascade through the system to affect many organisms and ecosystem processes; and (iv) some environmental perturbations can cause wholesale reorganization of ecosystems because they exceed the ecological tolerances of dominant or keystone species, whereas other changes may be buffered because of the compensatory dynamics of complementary species.     

Species interactions reverse grassland responses to changing climate

Predictions of ecological response to climate change are based largely on direct climatic effects on species. We show that, in a California grassland, species interactions strongly influence responses to changing climate, overturning direct climatic effects within 5 years. We manipulated the seasonality and intensity of rainfall over large, replicate plots in accordance with projections of leading climate models and examined responses across several trophic levels. Changes in seasonal water availability had pronounced effects on individual species, but as precipitation regimes were sustained across years, feedbacks and species interactions overrode autecological responses to water and reversed community trajectories. Conditions that sharply increased production and diversity through 2 years caused simplification of the food web and deep reductions in consumer abundance after 5 years. Changes in these natural grassland communities suggest a prominent role for species interactions in ecosystem response to climate change.     

IMPACTS OF CLIMATE CHANGE ON CROP PRODUCTION,PESTS AND PATHOGENS OF WHEAT AND RICE

● An overview of impacts of climate change on wheat and rice crops. ● A review on impacts of climate change on insect pests and fungal pathogens of wheat and rice. ● A selection of adaptation strategies to mitigate impacts of climate change on crop production and pest and disease management. Ongoing climate change is expected to have impacts on crops, insect pests, and plant pathogens and poses considerable threats to sustainable food security. Existing reviews have summarized impacts of a changing climate on agriculture, but the majority of these are presented from an ecological point of view, and scant information is available on specific species in agricultural applications. This paper provides an overview of impacts of climate change on two staple crops, wheat and rice. First, the direct effects of climate change on crop growth, yield formation, and geographic distribution of wheat and rice are reviewed. Then, the effects of climate change on pests and pathogens related with wheat and rice, and their interactions with the crops are summarized. Finally, potential management strategies to mitigate the direct impacts of climate change on crops, and the indirect impacts on crops through pests and pathogens are outlined. The present overview aims to aid agriculture practitioners and researchers who are interested in wheat and rice to better understand climate change related impacts on the target species.     

Transient floral change and rapid global warming at the Paleocene-Eocene boundary

Rapid global warming of 5 degrees to 10 degrees C during the Paleocene-Eocene Thermal Maximum (PETM) coincided with major turnover in vertebrate faunas, but previous studies have found little floral change. Plant fossils discovered in Wyoming, United States, show that PETM floras were a mixture of native and migrant lineages and that plant range shifts were large and rapid (occurring within 10,000 years). Floral composition and leaf shape and size suggest that climate warmed by approximately 5 degrees C during the PETM and that precipitation was low early in the event and increased later. Floral response to warming and/or increased atmospheric CO2 during the PETM was comparable in rate and magnitude to that seen in postglacial floras and to the predicted effects of anthropogenic carbon release and climate change on future vegetation.     

Global biodiversity scenarios for the year 2100

Scenarios of changes in biodiversity for the year 2100 can now be developed based on scenarios of changes in atmospheric carbon dioxide, climate, vegetation, and land use and the known sensitivity of biodiversity to these changes. This study identified a ranking of the importance of drivers of change, a ranking of the biomes with respect to expected changes, and the major sources of uncertainties. For terrestrial ecosystems, land-use change probably will have the largest effect, followed by climate change, nitrogen deposition, biotic exchange, and elevated carbon dioxide concentration. For freshwater ecosystems, biotic exchange is much more important. Mediterranean climate and grassland ecosystems likely will experience the greatest proportional change in biodiversity because of the substantial influence of all drivers of biodiversity change. Northern temperate ecosystems are estimated to experience the least biodiversity change because major land-use change has already occurred. Plausible changes in biodiversity in other biomes depend on interactions among the causes of biodiversity change. These interactions represent one of the largest uncertainties in projections of future biodiversity change.     

1987—2012年安西自然保护区生物多样性对气候变化的响应初探

生物多样性对气候变化的响应是研究区域生态环境演变的重要部分。为了分析甘肃安西极旱荒漠国家级自然保护区生物多样性对气候变化的响应趋势,笔者等选择保护区建区25年来温度和降水的变化情况及动植物资源的演变趋势,通过调查区域内动植物资源现状和总结区域25年以来年均温度和降水的变化趋势,与建区时保护区动植物资源概况进行对比。结果显示:保护区近25年来年均气温以升高趋势为主,21世纪初较20世纪80年代末升高0.989℃;年降水量整体上呈现下降趋势,21世纪初较20世纪80年代末减少3.3 mm。保护区荒漠植被出现群落面积减少、局部覆盖度下降、群落类型减少趋势;动物出现珍稀濒危数种减少、区系演变和动物种类数量减少的趋势。为掌握和应对气候变化对安西自然保护区生物多样性的影响提供了科学依据。     

新疆东部天山蝶类多样性及其垂直分布

2006-2008年研究了新疆东部天山蝶类多样性和垂直分布。结果表明:研究区域内共记录蝴蝶7科43属63种,占新疆已记录蝶类种数的24.80%,区系组成主要是古北种,占73%;其次是广布种,占27%,没有发现东洋种。其中蛱蝶科的物种数最多,为11属19种,蚬蝶科的物种数最少,只有1属1种。按海拔将生境分为5个垂直自然带,包括低山灌木草原带、山地森林草原带、亚高山草甸带、高山草甸带、垫状植被带。蝶类物种数和个体数排序为亚高山草甸带>山地森林草原带>低山灌木草原带>高山草甸带>垫状植被带。采用Shannon-Wiener指数和G-F指数对蝶类物种和科、属的多样性进行了分析评价,结果显示亚高山草甸带的蝶类多样性最为丰富,其次是山地森林草原带和低山灌木草原带,而高山草甸带和垫状植被带的蝶类多样性相对较低,物种和科、属多样性分析结果均一致。蝶类垂直分布明显,物种数和个体数随海拔变化的趋势类似,均为先增加后下降。蝶类区系成分随着海拔升高发生改变,广布种的比例逐渐降低,高山草甸带和垫状植被带只有古北种分布。研究结果显示,生境改变对蝴蝶群落影响明显,保护生境是保护蝴蝶生存的最主要措施。     

A map of local adaptation in Arabidopsis thaliana

Local adaptation is critical for species persistence in the face of rapid environmental change, but its genetic basis is not well understood. Growing the model plant Arabidopsis thaliana in field experiments in four sites across the species' native range, we identified candidate loci for local adaptation from a genome-wide association study of lifetime fitness in geographically diverse accessions. Fitness-associated loci exhibited both geographic and climatic signatures of local adaptation. Relative to genomic controls, high-fitness alleles were generally distributed closer to the site where they increased fitness, occupying specific and distinct climate spaces. Independent loci with different molecular functions contributed most strongly to fitness variation in each site. Independent local adaptation by distinct genetic mechanisms may facilitate a flexible evolutionary response to changing environment across a species range.     

The pace of shifting climate in marine and terrestrial ecosystems

Climate change challenges organisms to adapt or move to track changes in environments in space and time. We used two measures of thermal shifts from analyses of global temperatures over the past 50 years to describe the pace of climate change that species should track: the velocity of climate change (geographic shifts of isotherms over time) and the shift in seasonal timing of temperatures. Both measures are higher in the ocean than on land at some latitudes, despite slower ocean warming. These indices give a complex mosaic of predicted range shifts and phenology changes that deviate from simple poleward migration and earlier springs or later falls. They also emphasize potential conservation concerns, because areas of high marine biodiversity often have greater velocities of climate change and seasonal shifts.     

Climate-driven range expansion and morphological evolution in a marine gastropod

Little is known about the phenotypic consequences of global climate change, despite the excellent Pleistocene fossil record of many taxa. We used morphological measurements from extant and Pleistocene populations of a marine gastropod (Acanthinucella spirata) in conjunction with mitochondrial DNA sequence variation from living populations to determine how populations responded phenotypically to Pleistocene climatic changes. Northern populations show little sequence variation as compared to southern populations, a pattern consistent with a recent northward range expansion. These recently recolonized northern populations also contain shell morphologies that are absent in extant southern populations and throughout the Pleistocene fossil record. Thus, contrary to traditional expectations that morphological evolution should occur largely within Pleistocene refugia, our data show that geographical range shifts in response to climatic change can lead to significant morphological evolution.     

Frequent long-distance plant colonization in the changing Arctic

The ability of species to track their ecological niche after climate change is a major source of uncertainty in predicting their future distribution. By analyzing DNA fingerprinting (amplified fragment-length polymorphism) of nine plant species, we show that long-distance colonization of a remote arctic archipelago, Svalbard, has occurred repeatedly and from several source regions. Propagules are likely carried by wind and drifting sea ice. The genetic effect of restricted colonization was strongly correlated with the temperature requirements of the species, indicating that establishment limits distribution more than dispersal. Thus, it may be appropriate to assume unlimited dispersal when predicting long-term range shifts in the Arctic.     

CO2浓度和温度升高对川西亚高山红桦幼苗根系结构的影响

CO2浓度和温度升高对植物产生了深刻的影响,为从多角度对这种影响进行研究,该文利用封闭式生长室系统控制CO2浓度和温度,以红桦幼苗为材料,研究了CO2浓度升高、温度升高以及二者同时升高对川西亚高山红桦幼苗根系结构的影响。结果显示:①与对照相比,CO2浓度升高处理显著增加了红桦细根的生物量（最大增幅达152％）、根 幅（增幅为10％～22％）、0～10 cm土壤层根系总长度、5～10 cm层根夹角。②温度升高处理使红桦细根生物量2004年6、10月增加,8月减少,但只有0～5 cm土壤层与对照相比差异显著;根幅6、8、10月分别减少16％、7％、30％;5～15 cm土壤层根系总长度、0～10 cm土壤层根夹角显著(P0.05)减少。③二者同时升高处理使红桦各层细根生物量８月增加最多,0～5 cm、5～10 cm、10～15 cm土壤层分别比对照增加237％、51％、107％;根系总长度减少,但0～10 cm土壤层根夹角增加。表明CO2浓度和温度升高均改变了红桦根系结构, 且对浅层根系结构影响较大,这是红桦对气候变化的一种有利适应。      

氮磷添加和干旱对高寒草甸优势植物叶片化学计量的影响

    目的   全球变化背景下，土壤氮和磷有效性及含水量发生显著变化，进而对植物生长和生理过程产生影响。但是，目前同时考虑土壤氮、磷和水分三因素交互作用对植物生长和生理性状的研究还很少，特别是对高寒草甸植物的研究。本研究旨在揭示氮富集、磷富集、干旱及其交互作用对高寒草甸优势植物生长、叶片氮磷含量及其化学计量的影响，为高寒草甸生态系统管理提供科学依据。    方法   基于川西北高寒草甸氮添加（10 g/（m 2 ·a））、磷添加（10 g/（m 2·a））与干旱（减雨50%）控制实验，通过测定垂穗披碱草、发草和草玉梅地上生物量、叶片氮含量（N）、磷（P）含量以及N:P比例，分析不同处理及其交互作用对3种植物生物量和叶片养分性状的影响。    结果   对于植物生长，氮添加均显著增加3种植物地上生物量，但是磷添加和干旱及不同处理之间的交互作用对植物生物量没有显著影响。对于叶片养分，氮添加显著增加3种植物叶片氮含量和N:P比例，磷添加也增加植物叶片磷含量但降低叶片N:P比例。干旱增加垂穗披碱草与发草的叶片氮含量，对叶片磷含量和N:P比例影响不显著。氮添加与干旱处理之间的交互作用显著增加垂穗披碱草与发草叶片氮含量和N:P比。氮添加与磷添加之间的交互作用对3种植物叶片养分性状没有影响。    结论   本研究表明高寒草甸植物生长和养分性状对养分富集、干旱及其交互作的响应格局存在很大差异。氮输入主要影响植物生长，而氮磷养分和干旱及它们之间复杂的交互作用均改变植物养分和化学计量平衡。这些结果指示出未来需要深入研究高寒草甸植物生理过程对全球变化交互作用的响应机理。      

Direct and indirect effects of resource quality on food web structure

The diversity and complexity of food webs (the networks of feeding relationships within an ecological community) are considered to be important factors determining ecosystem function and stability. However, the biological processes driving these factors are poorly understood. Resource quality affects species interactions by limiting energy transfer to consumers and their predators, affecting life history and morphological traits. We show that differences in plant traits affect the structure of an entire food web through a series of direct and indirect effects. Three trophic levels of consumers were influenced by plant quality, as shown by quantitative herbivore-parasitoid-secondary parasitoid food webs. We conclude, on the basis of our data, that changes in the food web are dependent on both trait- and density-mediated interactions among species.     

Climate Change During the Last Deglaciation in Antarctica

Greenland ice core records provide clear evidence of rapid changes in climate in a variety of climate indicators. In this work, rapid climate change events in the Northern and Southern hemispheres are compared on the basis of an examination of changes in atmospheric circulation developed from two ice cores. High-resolution glaciochemical series, covering the period 10,000 to 16,000 years ago, from a central Greenland ice core and a new site in east Antarctica display similar variability. These findings suggest that rapid climate change events occur more frequently in Antarctica than previously demonstrated.     

Potential magnitude of future vegetation change in eastern north america: comparisons with the past

Increases in atmospheric trace gas concentrations could warm the global average temperature 1.5 degrees to 4.5 degrees C by the end of the next century. Application of climate-pollen response surfaces to three climate model simulations of doubled preindustrial atmospheric CO(2) levels shows that the change in the equilibrium distribution of natural vegetation over eastern North America over the next 200 to 500 years could be larger than the overall change during the past 7,000 to 10,000 years and equivalent to the change that took place over the 1,000- to 3,000-year period of most rapid deglaciation. Some plant ranges and abundance maxima could shift as much as 500 to 1000 km during the next 200 to 500 years; such changes would have dramatic impacts on silvicultural and natural ecosystems. Although unprecedented vegetation change is likely if climate changes as predicted, forecasting the exact timing and patterns of change will be difficult.     

镰芒针茅、博洛特绢蒿草地群落年际动态

【目的】研究长时期自然放牧条件下草地植物群落特征的变化。【方法】采用定位连续测定方法,分析测定1985~2001年分布于新疆天山北坡以镰芒针茅(Stipa caucsica)、博洛特绢蒿(Seriphidium borotalense)群落的种类组成、数量特征。【结果】在连续测定的17 a间,草地植物群落的种类组成与结构没有发生变化,而草地植物群落的数量特征始终处于动态变化过程;1985~1995年时段内,草地群落的高度、盖度和地上生物产量波动幅度不大,与自然降水量波动规律保持基本一致,影响草地基本数量特征的变化,降水量是主因,放牧干扰是次因;1996年~2001年时段内,草地基本数量特征波动较大。【结论】在1985~2001年期间,研究区草地群落植物种类组成与结构没有发生变化,群落优势种和主要伴生种在群落中的序位稳定,始终保持着群落原有的结构与功能。     

植物与其它有机体的化学作用—潜在的有害生物控制途径

植物与其它有机体种间存在着通过次生物质为媒介的化学作用，这些化学作用在农业生态系统中则表现为植物对有害生物的化学防御。面对动物取食、微生物侵染和其它植物竞争，植物能合成释放特定的次生物质抵御侵害。而且，植物这种对有害生物的化学防御机制常常是在侵害条件下诱导产生的。当前的研究显示，作物/害虫/天敌三营养食物链也有自然的种间化学作用关系操纵，作物和杂草种间除了有相互抑制的化感作用外，还存在着通过次生物质进行的信息传递关系。揭示并充分利用植物这种内在的化学防御机制不仅能拓宽认识植物与其它有机体种间关系的视野，而且能开拓植物保护的新途径。