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The amplified “greenhouse effect” associated with increasing concentrations of greenhouse gases has increased atmospheric temperature by 1°C since industrialization (around 1750), and it is ... anticipated to cause an additional 2°C increase by mid-century. Increased biospheric warming is also projected to modify the amount and distribution of annual precipitation and increase the occurrence of both drought and heat waves. The ecological consequences of climate change will vary substantially among ecoregions because of regional differences in antecedent environmental conditions; the rate and magnitude of change in the primary climate change drivers, including elevated carbon dioxide (CO₂), warming and precipitation modification; and nonadditive effects among climate drivers. Elevated atmospheric CO₂ will directly stimulate plant growth and reduce negative effects of drying in a warmer climate by increasing plant water use efficiency; however, the CO₂ effect is mediated by environmental conditions, especially soil water availability. Warming and drying are anticipated to reduce soil water availability, net primary productivity, and other ecosystem processes in the southern Great Plains, the Southwest, and northern Mexico, but warmer and generally wetter conditions will likely enhance these processes in the northern Plains and southern Canada. The Northwest will warm considerably, but annual precipitation is projected to change little despite a large decrease in summer precipitation. Reduced winter snowpack and earlier snowmelt will affect hydrology and riparian systems in the Northwest. Specific consequences of climate change will be numerous and varied and include modifications to forage quantity and quality and livestock production systems, soil C content, fire regimes, livestock metabolism, and plant community composition and species distributions, including range contraction and expansion of invasive species. Recent trends and model projections indicate continued directional change and increasing variability in climate that will substantially affect the provision of ecosystem services on North American rangelands. more

为揭示亚热带森林对未来全球变暖的生理响应特征,本研究以杉木为研究对象,利用开顶式增温方式模拟气候变暖,研究其对叶片和细根丙二醛含量、活性氧代谢、渗透调节物质含量以及抗氧化酶活性的影响.研究结果显示:(1)增温显著增加杉木叶片和细根的丙二醛含量,且叶片丙二醛含量显著高于细根,说明增温加剧了杉木叶片和细根氧化损伤,且叶片氧化损伤程度高于细根;(2)增温后,杉木叶片脯氨酸和可溶性蛋白含量降低,细根脯氨酸和可溶性蛋白含量则增加;(3)增温显著提高了杉木叶片过氧化物酶活性,对杉木细根抗氧化酶活性无显著影响;(4)增温后,杉木叶片和细根活性氧含量未发生显著变化,杉木叶片活性氧含量显著高于细根.综合分析表明,尽管增温增加了杉木叶片和细根的氧化损伤,但杉木可以通过提高抗氧化保护酶活性(叶片)和积累较多的渗透调节物质(细根)来维持体内活性氧代谢平衡.可见,杉木地上和地下部分器官间的相互合作与协调使杉木能有效地适应高温环境.

Although high atmospheric temperatures suppress anthocyanin accumulation in most plant species, we show that high temperatures accelerate anthocyanin pigmentation in flower tepals of Asiatic hybrid ... lilies (Lilium spp.). After incubation at high temperatures (35 °C) for two days, anthocyanin color became deeper in the most of tepal parts of two Asiatic hybrid lily cultivars, although the basal parts of ‘Montreux’ tepals and top parts of 'Toronto' outer tepals were whitened. Environmental stimuli often affect the expression of R2R3-MYB positive regulators that control anthocyanin biosynthesis. Although their expression is often suppressed by hot temperatures in other species, the expression of lily MYB12 in tepals was upregulated by high temperatures. MicroRNA828 (miR828), which suppresses the action of MYB12 post-transcriptionally, exhibited reduced accumulation levels under high temperature, indicating that miR828 regulation is involved in MYB12 upregulation. In addition, transcription levels of MYB12, estimated by unspliced MYB12 transcript accumulation, were also activated by high temperatures. Thus, both suppressed miR828 accumulation and increased MYB12 transcription are likely to be involved in MYB12 activation at high temperatures. In the whitened basal parts of ‘Montreux’ tepals at 35 °C, expression of bHLH2 was severely suppressed while that of MYB12 was not affected. The present results demonstrate that plants display diverse responses to hot climatic conditions and shed new light on anthocyanin regulation under various environmental conditions. more

Abstract We present phenological data for two time periods (1985–1987 and 2014–2016) on major tree species (Shorea robusta, Pinus roxburghii, Myrica esculenta, Quercus leucotrichophora, Rhododendron ... arboreum, Quercus floribunda, and Machilus duthiei) occurring along an altitudinal gradient of 300–2,200 m asl of Himalayan forests (a data-deficient region identified by the IPCC, 2007), and show that bud break and leafing in trees has advanced at 0.20 days/year, which is associated with a significant (P < 0.001) increase in atmospheric temperature (0.038°C/year) over the years in the study area. Also, the leaf drop period has advanced correspondingly (0.40 days/year); hence, the length of season (LOS) did not increase in these trees. This finding is contrary to the report of increase in LOS due to climatic warming from temperate latitudes of the world and satellite-based studies in Himalayan region. Arguably, phenomena such as bud break and leafing may not be captured by remote sensing, which is critical for determining the impact of climate change on the forest vegetation of the eco-sensitive Himalayan region. We suggest that this phenological earliness may alter forest structure and functioning and associated ecosystem services of these forests in the long run. more

Global warming is expected to cause significant changes in the distribution of species worldwide, altering ecosystem function and services. These impacts can be exacerbated by synergism with other ... global change drivers, such as biological invasions. Furcraea foetida (Asparagaceae) is a CAM species native to Central America and northern South America that is currently invading coastal ecosystems in the Atlantic Forest biome in Brazil. The species propagates clonally by bulbils, forming dense clusters that exclude native species. We addressed whether warming may favor or impair development of F. foetida bulbils based on functional traits and assessed whether plant cover of native species influenced F. foetida establishment in a rocky shore ecosystem. We used open-top chambers during summer and autumn, which increased air temperature during daylight hours by 0.4 °C relative to ambient conditions. This shortterm warming effect increased the leaf length of bulbils but had no effect on number of leaves, dry mass, specific leaf area, leaf dry matter content (LDMC), or photosynthetic efficiency of photosystem II (Fv/Fm). However, an increase in vegetation cover decreased LDMC and helped maintain high Fv/Fm, having an indirect positive effect on F. foetida establishment that suggests a facilitation interaction in this extreme environment. Even though the manipulated temperature did not reach IPCC (Intergovernmental Panel on Climate Change) forecasts for 2100, our data show that even small, short-term changes in temperature affected plant performance. Thus, we suggest that F. foetida may be favored in a scenario of climate change, increasing its negative effects on biodiversity of coastal ecosystems. more

Se analizan los procesos naturales y antrópicos que intervienen en la dinámica del paisaje de la Sierra del Aramo, en especial la dinámica de laderas y el calentamiento atmosférico, así como el ... despoblamiento y los cambios de usos del suelo en los medios de montaña. La metodología ha combinado el trabajo de campo, la fotointerpretación de imágenes aéreas, el análisis de datos climáticos, fuentes demográficas y agrarias. El despoblamiento y el abandono de las actividades tradicionales explican la disminución de los pastizales. No obstante, la intensidad de los aludes de nieve actuales interfiere en buena medida en la recuperación de los bosques. En efecto, 3,7 km2 de la Sierra del Aramo se hallan deforestados por la recurrencia de tales avalanchas. Se muestra, por tanto, la relevancia de los aludes de nieve en la dinámica del paisaje de las montañas medias en las latitudes templadas. more

基于IPCC对未来大气增温的预测,采用开顶式生长室（OTC）增温技术,以不增温为对照,研究滇西北高原典型湿地纳帕海湖滨带优势植物水葱和黑三棱在大气增温2.0和3.5 ℃处理下种子的繁殖特征.结果表明： 大气增温对植物结实率影响显著,但存在种间差异.其中,增温对水葱的结实率有促进作用;黑三棱结实率在增温2.0 ℃处理下显著下降,但在增温3.5 ... ℃处理下又恢复到对照水平.增温促进了2种植物穗的生长,在增温2.0、3.5 ℃处理下水葱的穗长分别增加82.9%、89.0%,小穗数分别增加133.3%、150.0%,每株穗生物量分别增加了10.1%、89.6%,每株穗生物量占总生物量的比例分别增加79.5%、409.3%;在增温2.0、3.5 ℃处理下,黑三棱穗长分别增加66.1%、95.2%,每株穗生物量占总生物量的比例分别增加878.8%、1052.6%.增温显著增加了水葱和黑三棱每穗种子产量,在增温2.0、3.5 ℃处理下,水葱每穗种子产量分别增加33.7%、58.3%,黑三棱每穗种子产量分别显著增加3.4%、69.5%.在增温2.0、3.5 ℃处理下水葱种子长分别增加5.4%、6.9%,种子长宽比分别增大9.1%、5.3%;而增温对黑三棱的种子形态无显著影响.最高温和最低温是影响2种植物种子繁殖的主要温度因子.温度增高引起的生长季提前、营养生长期延长以及有机物积累量增加,为植物繁殖扩散提供了充足的物质和能量积累,可能是2种植物在增温条件下繁殖能力提高的原因. more

The atmospheric vertical structure and changed characteristics of boundary layer parameters, as well as their relations with sea ice and temperature changes in the center of Arctic Ocean（80°–88°N） ... are presented by adopting GPS sounding data obtained by the 4th–6th Arctic expeditions of China and NCEP（National Centre for Environmental Prediction） reanalysis data. Obvious differences are observed regarding the tropopause, boundary layer height, temperature inversion, and vertical structure of wind speed and direction in the center Arctic Ocean in the summer of 2012, 2010, and 2014. These differences can be explained by the relations between temperature and changes in sea ice extent in September from 1979 to 2014. In September 2012, the Arctic sea ice extent decreased by 44% an with obvious warming process. In September 2010 and 2014, it decreased by 22.6% and 17% with an obvious cooling process, respectively. A comparison of the two processes shows that sea ice change has a significant influence on the structure of the atmospheric boundary layer. In the recent 30 years, the temperature changes of 1000 and 850 h Pa in the center of the Arctic Ocean have displayed an obvious warming trend and negative correlation with sea ice extent. These changes indicate that the continuous reduction of Arctic sea ice will continue the warming of the troposphere middle layer. more

Rumex nepalensis , one of several plant species distributed across wide elevation gradient in Himalayas, was studied for difference in seed traits, phenology and photosynthetic characteristics in ... four populations from 800 m (sub-tropical population: SP), 1300 m (sub-temperate population: STP), 2200 m (temperate population: TP) and 4000 m (alpine population: AP) elevations above mean sea level. Seeds of AP were larger in size and germinated faster at 15 °C than at 25 °C compared to those from lower elevations. Seed raised four populations of the species studied under ex situ conditions of greenhouse showed that AP emerged late but was able to complete its post flowering phenophases much earlier, such that its life cycle was reduced by 14 days compared to SP. Ex-situ and in situ studies in the native habitat for all populations showed AP and SP to differed significantly in most of the photosynthetic traits, thus indicating the two populations to be genetically different. Further studies are required to understand how different genotypes of R. nepalensis would respond to atmospheric warming. more

Physiological measurements were used to investigate the dependence of photosynthesis on light, temperature, and intercellular carbon dioxide (CO 2 ) levels in the C 4 marsh grass Spartina ... alterniflora . Functional relationships between these environmental variables and S. alterniflora physiological responses were then used to improve C 4 -leaf photosynthesis models. Field studies were conducted in monocultures of S. alterniflora in Virginia, USA. On average, S. alterniflora exhibited lower light saturation values (~1000 μmol m −2  s −1 ) than observed in other C 4 plants. Maximum carbon assimilation rates and stomatal conductance to water vapor diffusion were 36 μmol (CO 2 ) m −2  s −1 and 200 mmol (H 2 O) m −2  s −1 , respectively. Analysis of assimilation-intercellular CO 2 and light response relationships were used to determine Arrhenius-type temperature functions for maximum rate of carboxylation ( V cmax ), phosphoenolpyruvate carboxylase activity ( V pmax ), and maximum electron transport rate ( J max ). Maximum V cmax values of 105 μmol m −2  s −1 were observed at the leaf temperature of 311 K. Optimum V pmax values (80.6 μmol m −2  s −1 ) were observed at the foliage temperature of 308 K. The observed V pmax values were lower than those in other C 4 plants, whereas V cmax values were higher, and more representative of C 3 plants. Optimum J max values reached 138 μmol (electrons) m −2  s −1 at the foliage temperature of 305 K. In addition, the estimated CO 2 compensation points were in the range of C 3 or C 3 –C 4 intermediate plants, not those typical of C 4 plants. The present results indicate the possibility of a C 3 –C 4 intermediate or C 4 -like photosynthetic mechanism rather than the expected C 4 -biochemical pathway in S. alterniflora under field conditions. In a scenario of atmospheric warming and increased atmospheric CO 2 concentrations, S. alterniflora will likely respond positively to both changes. Such responses will result in increased S. alterniflora productivity, which is uncharacteristic of C 4 plants. more