Average July Temperature Research Articles

First Report of Leaf Blight Caused by Alternaria brassicicola on Orychophragmus violaceus in China

Orychophragmus violaceus (February orchid) is an annual or perennial cruciferous herbaceous plant that is widely cultivated and used as an ornamental plant or as a green manure in China. In September 2017, a new leaf blight disease was observed on O. violaceus plants with 80 to 100% disease incidence in a field located in Huanghua County, Cangzhou City, Hebei Province, in northern China. Symptoms on affected leaves began as pinpoint spots that enlarged to form irregular to circular black spots with an obvious wheel striatum, approximately 12 mm in diameter, after 14 days. After 7 days lesions became necrotic and occupied 30 to 70% of the leaf surface. Approximately 5- × 5-mm pieces from the margin of necrotic leaves were surface disinfested with 75% ethanol and 10% sodium hypochlorite, rinsed three times with sterile distilled water, and placed onto potato dextrose agar (PDA). After 2 days of incubation at 25°C in the dark, newly grown-out mycelia were transferred onto fresh PDA and purified by the single-spore method. On PDA, olive-green mycelium developed after 2 days of incubation at 25°C, turned dark green, and covered the Petri dish 10 days later. Primary conidiophores were mostly simple with a single conidiogenous site. Conidia formed long, branched chains 12 to 125 μm in length. The youngest conidia in a chain were ovoid, 8.7 to 26.1 × 4.4 to 6.2 μm. Older conidia were larger, ellipsoid to ovoid with dimensions 25.8 to 35.2 × 10.9 to 11.8 μm. Conidia had 0 to 8 transverse septa, usually without longitudinal septa. A very small conidial beak or no beak was observed on each conidium. On the basis of these morphological characteristics the fungus was identified as Alternaria brassicicola (Wiltshire 1947). For molecular identification, the translation elongation factor-1α (TEF-1α) and internal transcribed spacer (ITS) region of ribosomal RNA were amplified and sequenced from four isolates (GS1-1, GS1-2, HH2-1, and HH3-1) (Carbone and Kohn 1999, White et al. 1990). Partial TEF-1α gene sequences (EF1-986R/EF1-728F) and ITS (ITS1/ITS2) of isolates GS1-1, GS1-2, HH2-1, and HH3-1 were generated (GenBank accession nos. MH424919, MK249721, MK249722, MK249723; MH424918, MK249724, MK257127, MK257128). BLASTn analysis revealed 100% sequence identity to A. brassicicola (KT895946, KF889266, JX213350, KF889266; MH102059, MF462311, MF462313, JF439458). Pathogenicity testing with four single-conidium isolates (GS1-1, GS1-2, HH2-1, HH3-1) were conducted by inoculating leaves with a conidial suspension of the individual isolates (diluted with distilled water, approximately 1 × 10⁶ conidia/ml) on 20 plants at the three-leaf stage and placing them in a humidity chamber at 25°C for 24 h. The 20 plants at the three-leaf stage were mock inoculated with distilled water as a control. Initial symptoms developed after 3 days and the typical symptoms 5 days after inoculation with A. brassicicola and were similar to those observed in the field. The pathogen was reisolated and confirmed to be A. brassicicola, completing Koch’s postulates. No symptoms were observed on control leaves. To our knowledge, this is the first report of A. brassicicola causing leaf blight on O. violaceus in northern China. The summer in Hebei Province is hot and wet with an average temperature and precipitation in July of 26°C and 627 mm, respectively. Because of the suitable climatic conditions for leaf blight, strategies for managing A. brassicicola on O. violaceus in this region should be developed.

Using Neural Network Classifier Approach for Statistically Forecasting Extreme Corn Yield Losses in Eastern United States

This paper presents a statistical method for forecasting extreme corn yield losses caused by weather extremes. A neural network classifier approach is tested over the Eastern United States (time series of 35 years) to detect extreme yield losses for corn from weather‐related information. We first developed a methodology to rank a series of climate‐based predictors according to the accuracy with which they classify extreme from nonextreme yield losses. The classification methodology is adapted in order to be trained with a limited number of extreme cases. Using four weather predictors—the average temperature in July and August, and the SPEI (Standardized Precipitation‐Evapotranspiration Index) in June and July—71% of the extreme cases are well classified by this statistical model. Furthermore, the neural network output represents a good yield severity index and can provide an early quantitative warning for extreme yield anomalies.

THE COMPARATIVE ANALYSIS OF INCIDENCE AND MORTALITY OF THE POPULATION LIVING IN VARIOUS CLIMATIC ZONES OF RUSSIA

The article presents a comparative analysis of health indices of the population living in different (second and third) climatic zones of Russia. The selection of the climatic belts is based on the climate of each zone: average January temperature, average July temperature, especially the winter period, which affects the heat transfer processes in a person and the subjective, the perception of comfort climate. In identifying the role of climatic factors in shaping the health of the population, a comparative analysis of areas with different climatic parameters at similar levels of socio-economic indices: per capita income, unemployment rate, number of physicians, persons with higher and incomplete higher education, ethnic composition. Under similar socio-economic conditions in the regions, the role of climate is obviously shown to be in shaping the health of the population. The health of the population was assessed in terms of the morbidity and mortality rate in selected population groups. The morbidity rate was analyzed in age groups, not characteristic for migration (children aged 15-17 years and older). Children not exposed to occupational factors as adult population residing permanently in the region. The incidence of an older population living in the third climatic zone (Novosibirsk region), as in all diseases, and for individual disease groups exceeded the performance of the corresponding age groups of the second climatic zone (Penza region). Higher levels of the mortality rate of the population of the Novosibirsk region, compared to the same figures for the population of the Penza region, are formed at the age of 50 years and older in the following causes of death: cerebrovascular diseases, endocrine diseases, alcoholism, trauma, poisoning, and other external influence.

Responses of an oyster host (Crassostrea virginica) and its protozoan parasite (Perkinsus marinus) to increasing air temperature.

BackgroundChanges in climate are predicted to influence parasite and pathogen infection patterns in terrestrial and marine environments. Increases in temperature in particular may greatly alter biological processes, such as host-parasite interactions. For example, parasites could differentially benefit from increased reproduction and transmission or hosts could benefit from elevated immune responses that may mediate or even eliminate infections. In the southeastern United States, the Eastern oyster, Crassostrea virginica, is infected by the lethal protozoan parasite, Perkinsus marinus. Under field conditions, intertidal (air-exposed) oysters have been found to have significantly higher P. marinus infection intensity and marginally higher infection prevalence than subtidal (submerged) oysters. During summer, air temperatures are much warmer than water and this exposure of intertidal oysters to higher temperatures is a suggested mechanism for increased infection intensity.MethodsWe simulated intertidal exposure using controlled laboratory experiments to determine how host traits (survival and immune response) and parasite infection intensity will respond to elevated air temperature ranging from 27 °C to 53 °C during emersion at low tide. In Georgia, where our work was conducted, the average summer water temperature is 29 °C and the average maximum high air temperature in July is 33 °C (though oysters have been shown to survive at much higher air temperatures).ResultsHost survival declined as temperature increased, with a definitive drop-off between 39–43 °C. Negative effects of air temperature on host immune response (phagocytic activity) were detectable only at extremely high temperatures (47–50 °C) when hosts were suffering acute mortality. Parasite infection intensity peaked at 35 °C.DiscussionOur results suggest that an increase in average summer air temperature to 35 °C or higher could affect oyster survival directly through temperature-related impacts in the short-term and indirectly through increased P. marinus infection intensity over the long-term.

Summer Climatic Moisture Balances for Yukon Xerophytic Grassland Slopes and Their Late-Wisconsinan Counterparts: Are Present-Day Grasslands Beringian Relicts?

Summer climatic moisture balances (precipitation vs. potential evapotranspiration) for topographic slopes favored by present-day xerophytic boreal grasslands (SSW aspects with 61% – 65% gradients) in southwest Yukon were compared to their unglaciated late-Wisconsinan (14 000 – 12 000 cal yr BP) Beringian counterparts. The purpose was to determine whether present-day grasslands are ecologically plausible Beringian relicts or analogues. The Beringian climate was represented by meteorological stations with average July temperatures 4˚C colder than those of present-day grassland areas; all were from Arctic locations. The most commonly occupied grassland slopes received maximum local solar radiation and likely represented the warmest topographic positions in the landscape. Their summer evapotranspiration demands exceeded the 200 mm moisture supply by 189 mm. The same slopes had late-Wisconsinan summer moisture balances of −57 to −101 mm because of colder and shorter growing seasons. Moisture balances for late-Wisconsinan SSW slopes were similar to those of present-day WNW – NW aspects, which do not support grasslands. Differences in moisture deficits indicated present-day xerophytic grasslands were improbable Beringian in situ relicts or analogues. Alternatively, it was hypothesized that present-day Calamagrostis purpurascens communities developed during the Holocene Thermal Maximum (11 000 – 9000 cal yr BP), whereas Hesperostipa comata communities formed less than 3000 years ago after postglacial migration of the species from central North America.

Detecting treeline dynamics in response to climate warming using forest stand maps and Landsat data in a temperate forest

BackgroundTreeline dynamics have inevitable impacts on the forest treeline structure and composition. The present research sought to estimate treeline movement and structural shifts in response to recent warming in Cehennemdere, Turkey. After implementing an atmospheric correction, the geo-shifting of images was performed to match images together for a per pixel trend analysis. We developed a new approach based on the NDVI, LST (land surface temperature) data, air temperature data, and forest stand maps for a 43-year period. The forest treeline border was mapped on the forest stand maps for 1970, 1992, 2002, and 2013 to identify shifts in the treeline altitudes, and then profile statistics were calculated for each period. Twenty sample plots (10 × 10 pixels) were selected to estimate the NDVI and LST shifts across the forest timberline using per-pixel trend analysis and non-parametric Spearman’s correlation analysis. In addition, the spatial and temporal shifts in treeline tree species were computed within the selected plots for four time periods on the forest stand maps to determine the pioneer tree species.ResultsA statistically significant increasing trend in all climate variables was observed, with the highest slope in the monthly average mean July temperature (tau = 0.62, ρ < 0.00). The resultant forest stand maps showed a geographical expansion of the treeline in both the highest altitudes (22 m–45 m) and the lowest altitudes (20 m–105 m) from 1970 to 2013. The per pixel trend analysis indicated an increasing trend in the NDVI and LST values within the selected plots. Moreover, increases in the LST were highly correlated with increases in the NDVI between 1984 and 2017 (r = 0.75, ρ < 0.05). Cedrus libani and Juniperus communis spp. were two pioneer tree species that expanded and grew consistently on open lands, primarily on rocks and soil-covered areas, from 1970 to 2013.ConclusionThe present study illustrated that forest treeline dynamics and treeline structural changes can be detected using two data sources. Additionally, the results will have a significant contribution to and implication for treeline movement studies and forest landscape change investigations attempting to project climate change impacts on tree species in response to climate warming. The results will assist forest managers in establishing some developmental adaptation strategies for forest treeline ecotones.

Exploring an efficient habitat index for predicting population and abundance of migratory birds in Poyang Lake Wetland, South China

Poyang Lake wetland is an important wintering habitat of migratory birds with a complexity of coupled nature and human systems. Reported studies suggested that habitat indices were mostly developed based on single-class factors and scale-dependent. Therefore the indices might not be sufficient and applicable to predict regional changes for population and abundance of migratory birds (PMB and AMB) in Poyang Lake wetland at watershed and basin scales. In order to explore an efficient habitat index for predicting PMB and AMB, an integrated and scale-independent habitat index was proposed by integration of landscape and environmental temperature variables at basin and watershed scales. The landscape index and environmental temperature index based on single-class dominant factors, were also evaluated by weighted additive method. Multi-source data, including multi-spatial and temporal remote sensing images and field survey data, was used in this study. Results indicated that the average 10-night temperature in July (TN-Jul.) had dominant influence on PMB and the environmental temperature index was a better predictor for predicting PMB; AMB was influenced by both landscape and temperature variables and the proposed integrated habitat index was better for prediction of AMB in Poyang Lake wetland. The proposed integrated habitat index is a supplement of the single-class habitat index, which provides a more scientific technique for the study of biodiversity.

Case Study of an Epidemiological Approach Dissecting Historical Soybean Sclerotinia Stem Rot Observations and Identifying Environmental Predictors of Epidemics and Yield Loss.

Sclerotinia sclerotiorum is a significant threat to soybean production worldwide. In this study, an epidemiological approach was used to examine 11 years of historical data from a soybean management performance trial in order to advance our understanding of Sclerotinia stem rot (SSR) development and to identify environmental predictors of SSR epidemics and associated yield losses. Recursive partitioning analysis suggested that average air temperature and total precipitation in July were the most significant variables associated with disease severity. High levels of SSR disease severity index were observed when the average temperature in July was below 19.5°C and total precipitation in July was moderate, between 20 and 108.5 mm. A biphasic sigmoidal curve accurately described the relationship between SSR disease severity index (DSI) and yield, with a DSI threshold of 22, below which minimal yield loss was observed. A 10% increase in the DSI, from 22.0 to 24.2, led to an 11% decrease in yield, from 3,308.14 to 2,951.29 kg/ha. Also, a yield threshold (3,353 kg/ha) that was higher than the annual U.S. average soybean yield (3,039.7 kg/ha) was suggested as an expected yield under low or no SSR pressure in the U.S. Midwest. These thresholds can allow soybean stakeholders to assess the value of disease control and establish an SSR baseline for cost-effective management to protect yields. Because S. sclerotiorum has more than 400 plant host species, and because having quantitative information concerning crop losses is crucial for decision making, this study shows the usefulness of historical data on SSR and, hence, can serve as a model in other SSR pathosystems (canola, dry bean, potato, pea, and so on).

Radiation-and-temperature resources of the steppe zone in Ukraine under the climate change conditions in the period of up to 2050

Indices of the radiation-and-temperature regime in the Steppe zone of Ukraine in the period of 1986 through 2005, as compared to the expected changes in these indices, calculated in accordance with the two climate change scenarios, RCP4.5 and RCP8.5, for the period of up to 2050, are under consideration in the paper. RCP4.5 is a scenario of stabilization of greenhouse gas emissions into the atmosphere, while RCP8.5 is the one of very high greenhouse gas emissions. To characterize the radiation and thermal resources in the Steppe zone of Ukraine in the period of 1986 through 2005 (the basic period), and the change in the period of 2021 through 2050 calculations of average long-term values for the first group of environmental factors were performed: the duration of daytime, the total daily solar radiation, the intensity of photosynthetically active radiation (PAR), the accumulated PAR, the radiation balance of the vegetation cover, and the temperature regime. The following principal agro-climatic characteristics of the temperature regime were considered: dates of stable rise of the air temperature above 0, 5, 10, 15 °C in spring and autumn, duration of the period with air temperatures above 0, 5, 10, 15 °C, the accumulated positive air temperatures for the period with air temperatures above 0, 5, 10, 15 °C, the average air temperature in January and July, and the amplitude.&#x0D; It is pointed out that in the period of up to 2050, according to the calculations in both scenarios, increased indices of the radiation-and-temperature regime will be observed. The values of the radiation regime parameters will predominantly increase in late summer and early autumn. As a result of the inflow of increased accumulated solar radiation, the accumulated temperatures in the period with air temperatures above 5 °C will also rise. The expected increase in the accumulated temperatures will nevertheless not exceed 200 °C. A rise in the total temperature will contribute to better heat supply for the crops.

Method of Determining Characteristic Values of Average and Maximum Wind Pressure from the Carpathians Zoning Trans Carpathian Region

Based on observations of climate parameters in 1955-2005, respectively 9 weather stations using 8 directions between the initial eight weather stations and Playa ultimate meteorological station by the average and maximum characteristic values of wind pressure in July and January to the highest peak of the Carpathians - Hoverla. For 4 directions between the initial weather stations altitude coefficients and formulas using parameters atmospheric pressure, the average outdoor temperature (in January and July) calculated comparative characteristic values of summer and winter average and maximum wind pressure for 9 peaks of the Carpathians.

Exploring the clinical characters of Shugan Jieyu capsule through text mining

In this paper,the potential climate factors affecting the Pairs polyphylla var. yunnanensis distribution in China at rational scales were selected from related literatures, using the sampling point geographic information from of P. polyphylla var. yunnanensis, combine the maximum entropy model (MaxEnt) with spatial analyst function of ArcGIS software, to study the climate suitability of P. polyphylla var. yunnanensis cultivating region in China and the leading climate factors. The results showed that, average rainfall in August, average rainfall in October, coefficient of variation of seasonal precipitation, the average temperature of the dry season, isothermal characteristic, average temperature in July were the leading climate factors affecting the potential distribution of P. polyphylla var. yunnanensis cultivating region in China, with their cumulative contribution rate reached 97.2% of all candidate climate factors. Existence probability of the region to be predicted of P. polyphylla var. yunnanensis through the constructed model, the climate unsuitable region, low, medium and high region of P. polyphylla var. yunnanensis in China were clarified and the threshold of climatic factors were gave and clarified the climate characteristics of the cultivating region in each climatic suitability division. The results of research can provide reference for production layout and introduction of P. polyphylla var. yunnanensis.

Fertilizer Management and Environmental Factors Drive N2O and NO3 Losses in Corn: A Meta‐Analysis

Core Ideas Systematic review and meta‐analysis demonstrate key factors for reducing agricultural N losses. Nitrification inhibitors and side‐dress fertilizer N each reduce N2O losses by ∼30%. Temperature controls N2O emissions and precipitation controls NO3 leaching losses. Higher levels of soil carbon reduce NO3 losses, but increase N2O emissions. Lack of simultaneous data for N2Oand NO3 impedes understanding of tradeoffs and synergies. Effective management of nitrogen (N) in agricultural landscapes must account for how nitrate (NO3) leaching and nitrous oxide (N2O) emissions respond to local field‐scale management and to broader environmental drivers such as climate and soil. We assembled a comprehensive database of fertilizer management studies with data on N2O (417 observations, 27 studies) and NO3 (388 observations, 25 studies) losses associated with 4R fertilizer N management in North American corn‐cropping systems. Only one study measured both losses, and studies of N2O and NO3 differed by location, time period, and management practices. Meta‐analysis of side‐by‐side comparisons found significant yield‐scaled N2O emission reductions when SUPERU replaced urea or UAN, and when urea replaced anhydrous ammonia. Hierarchical regression models found near‐equivalent magnitude effects on N2O emissions of 1°C rise in average July temperature (+), increase in soil C by 10 g kg–1 (+), nitrification inhibitors (–), side‐dressed fertilizer timing (–), broadcast fertilizer (–), and 100 kg N ha–1 decrease in fertilizer rate (–). Average NO3 leaching response to 100 kg N ha–1 reduction in fertilizer rate (–) were comparable to effects of 100 mm less annual precipitation (–), 10 g kg–1 more soil C (–), or replacing continuous corn with corn‐soybean rotations (–). The large effects of climate and soil, and the potential for opposite reactions to some management changes, indicate that more simultaneous measurements of N2O and NO3 losses are needed to understand their joint responses to management and environmental factors, and how these shape tradeoffs or synergies in pathways of N loss.

Meteorological factors affecting scrub typhus occurrence: a retrospective study of Yamagata Prefecture, Japan, 1984-2014.

Climate change, by its influence on the ecology of vectors might affect the occurrence of vector-borne diseases. This study examines the effects of meteorological factors in Japan on the occurrence of scrub typhus, a mite-borne zoonosis caused by Orientia tsutsugamushi. Using negative binomial regression, we analysed the relationships between meteorological factors (including temperature, rainfall, snowfall) and spring-early summer cases of scrub typhus in Yamagata Prefecture, Japan, during 1984-2014. The average temperature in July and August of the previous year, cumulative rainfall in September of the previous year, snowfall throughout the winter, and maximum depth of snow cover in January and February were positively correlated with the number of scrub typhus cases. By contrast, cumulative rainfall in July of the previous year showed a negative relationship to the number of cases. These associations can be explained by the life-cycle of Leptotrombidium pallidum, a predominant vector of spring-early summer cases of scrub typhus in northern Japan. Our findings show that several meteorological factors are useful to estimate the number of scrub typhus cases before the endemic period. They are applicable to establish an early warning system for scrub typhus in northern Japan.

Morpho-Physiological Variation of White Spruce Seedlings from Various Seed Sources and Implications for Deployment under Climate Change.

Because of changes in climatic conditions, tree seeds originating from breeding programs may no longer be suited to sites where they are currently sent. As a consequence, new seed zones may have to be delineated. Assisted migration consists of transferring seed sources that match the future climatic conditions to which they are currently adapted. It represents a strategy that could be used to mitigate the potential negative consequences of climate change on forest productivity. Decisions with regard to the choice of the most appropriate seed sources have to rely on appropriate knowledge of morpho-physiological responses of trees. To meet this goal, white spruce (Picea glauca [Moench] Voss) seedlings from eight seed orchards were evaluated during two years in a forest nursery, and at the end of the first growing season on three plantation sites located in different bioclimatic domains in Quebec. The morpho-physiological responses obtained at the end of the second growing season (2+0) in the nursery made it possible to cluster the orchards into three distinct groups. Modeling growth curves of these different groups showed that the height growth of seedlings from the second-generation and southern first-generation seed orchards was significantly higher than that of those from other orchards, by at least 6%. A multiple regression model with three climatic variables (average growing season temperature, average July temperature, length of the growing season) showed that the final height of seedlings (2+0) from the first-generation seed orchards was significantly related to the local climatic conditions at the orchard sites of origin where parental trees from surrounding natural populations were sampled to provide grafts for orchard establishment. Seedling height growth was significantly affected by both seed source origins and planting sites, but the relative ranking of the different seed sources was maintained regardless of reforestation site. This knowledge could be used, in conjunction with transfer models, to refine operational seed transfer rules and select the most suitable sites in an assisted migration strategy.

Climatic conditions and human mortality: spatial and regional variation in the United States.

Previous research on climatic conditions and human mortality in the United States has three gaps: largely ignoring social conditions, lack of nationwide focus, and overlooking potential spatial variations. Our goal is to understand whether climatic conditions contribute to mortality after considering social conditions and to investigate whether spatial non-stationarity exists in these factors. Applying geographically weighted regression to a unique nationwide county-level dataset, we found that (1) net of other factors, average July temperatures are positively (detrimentally) associated with mortality while January temperatures mainly have a curvilinear relationship, (2) the mortality-climatic condition associations are spatially non-stationary, (3) the relationships between social conditions (e.g., social capital) and mortality are stable geographically, and (4) without a spatial approach to understanding the environment-mortality relationship, important spatial variations are overlooked. Our findings suggest that a universal approach to coping with the relationships between rapid climate changes and health may not be appropriate and effective.

Effects of temperature variability on community structure in a natural microbial food web

Climate change research has demonstrated that changing temperatures will have an effect on community-level dynamics by altering species survival rates, shifting species distributions, and ultimately, creating mismatches in community interactions. However, most of this work has focused on increasing temperature, and still little is known about how the variation in temperature extremes will affect community dynamics. We used the model aquatic community held within the leaves of the carnivorous plant, Sarracenia purpurea, to test how food web dynamics will be affected by high temperature variation. We tested the community response of the first (bacterial density), second (protist diversity and composition), and third trophic level (predator mortality), and measured community respiration. We collected early and late successional stage inquiline communities from S.purpurea from two North American and two European sites with similar average July temperature. We then created a common garden experiment in which replicates of these communities underwent either high or normal daily temperature variation, with the average temperature equal among treatments. We found an impact of temperature variation on the first two, but not on the third trophic level. For bacteria in the high-variation treatment, density experienced an initial boost in growth but then decreased quickly through time. For protists in the high-variation treatment, alpha-diversity decreased faster than in the normal-variation treatment, beta-diversity increased only in the European sites, and protist community composition tended to diverge more in the late successional stage. The mortality of the predatory mosquito larvae was unaffected by temperature variation. Community respiration was lower in the high-variation treatment, indicating a lower ecosystem functioning. Our results highlight clear impacts of temperature variation. A more mechanistic understanding of the effects that temperature, and especially temperature variation, will have on community dynamics is still greatly needed.

Climatic thresholds shape northern high‐latitude fire regimes and imply vulnerability to future climate change

Boreal forests and arctic tundra cover 33% of global land area and store an estimated 50% of total soil carbon. Because wildfire is a key driver of terrestrial carbon cycling, increasing fire activity in these ecosystems would likely have global implications. To anticipate potential spatiotemporal variability in fire‐regime shifts, we modeled the spatially explicit 30‐yr probability of fire occurrence as a function of climate and landscape features (i.e. vegetation and topography) across Alaska. Boosted regression tree (BRT) models captured the spatial distribution of fire across boreal forest and tundra ecoregions (AUC from 0.63–0.78 and Pearson correlations between predicted and observed data from 0.54–0.71), highlighting summer temperature and annual moisture availability as the most influential controls of historical fire regimes. Modeled fire–climate relationships revealed distinct thresholds to fire occurrence, with a nonlinear increase in the probability of fire above an average July temperature of 13.4°C and below an annual moisture availability (i.e. P‐PET) of approximately 150 mm. To anticipate potential fire‐regime responses to 21st‐century climate change, we informed our BRTs with Coupled Model Intercomparison Project Phase 5 climate projections under the RCP 6.0 scenario. Based on these projected climatic changes alone (i.e. not accounting for potential changes in vegetation), our results suggest an increasing probability of wildfire in Alaskan boreal forest and tundra ecosystems, but of varying magnitude across space and throughout the 21st century. Regions with historically low flammability, including tundra and the forest–tundra boundary, are particularly vulnerable to climatically induced changes in fire activity, with up to a fourfold increase in the 30‐yr probability of fire occurrence by 2100. Our results underscore the climatic potential for novel fire regimes to develop in these ecosystems, relative to the past 6000–35 000 yr, and spatial variability in the vulnerability of wildfire regimes and associated ecological processes to 21st‐century climate change.

Effects of future climate change on climatic suitability of flue-cured tobacco plantation in Yunnan, China.

The climatic suitability distribution of flue-cured tobacco planting in Yunnan will be profoundly affected by climate change. According to three key factors influencing climatic suitability of flue-cured tobacco planting in Yunnan, namely, average temperature in July, sunshine duration from July to August, precipitation from April to September, the variations of climatic suitability distribution of flue-cured tobacco planting in Yunnan respectively in 1986-2005, 2021-2040 and 2041-2060 under RCP4.5 and RCP8.5 climate scenarios were investigated by using the climatic simulation data in 1981-2060 and the meteorological observation data during 1986-2005. The results showed that climatic suitability region would expand northward and eastward and plantable area of flue-cured tobacco would gradually increase. The increment of plantable area was more in 2041-2060 than in 2021-2040, and under RCP8.5 scenario than under RCP4.5 scenario. The optimum climatic area and sub-suitable climatic area were expanded considerably, while the suitable climatic area was not much changed. In the future, the north-central Yunnan such as Kunming, Qujing, Dali, Chuxiong, Lijiang would have a big increase in both the optimum climatic area and the cultivable area, meanwhile, the southern Yunnan including Wenshan, Honghe, Puer and Xishuangbanna would have a big decrease in both the optimum climatic area and the cultivable area.

Retrospective analysis of weather conditions in environs of Myronivka Institute of Wheat

Introduction. Variation of weather conditions in cropping seasons (as a result of global climate change) significantly effects on formation of yield components for any crops, including winter wheat.Aim. To conduct retrospective analysis of weather conditions in environs of the V.M. Remeslo Myronivka Institute of Wheat of NAAS in order to correct long-term programs on bread winter wheat breeding in consideration of climate changes.Methods. The coefficient of deviation essentiality of hydrothermal regime elements relative to multi-annual average means according to Ped D.A. method was used to study weather conditions monthly during 30 years (1981- 2010).Results. Environs of Myronivka Institute of Wheat are characterized by favorable climate conditions for growing bread winter wheat. Average annual air temperature is7°C. July is the hottest month of the year; January is the coldest one with average temperature +20.1°C in July and-4.7°C in January. Average July temperatures varied within +17.2…+24.1°C, and in January they did within -1.7…-15.4°C.In 30 years (1981-2010) there is observed increasing average air temperatures, especially in the 2001-2010 (min8.0°Cand max9.9°C).The years 1985, 1987, 1989, 1990, 2000, 2002, 2007-2010 appear to be rare by coefficient of deviation essentiality for air temperature relative to multi-annual average mean. When analyzing air temperature in the 30-year period (1981-2010), it is possible to assert its increasing with each next decade. That is, based on this coefficient upward, the number of months with conditions close to rare increased from 4.2 to 10%.Coefficient of deviation essentiality of precipitation monthly in 30 years studied (1981-2010) was various. In March 1991, April 1984, 1988, 1991-1994, May 1981, 1983, 1986, 1998, June 1986, July 1989, 1992, and 1994 rainfalls were insufficient. Resulted from observations in 1981-2010 there is a tendency to increasing frequency of sharp fluctuations in rainfall with each next decade. The share of months with conditions being close to rare increased from 3.3 to 10%.Conclusions. According to the analysis of weather conditions over the 30-year period (1981-2010), during spring and summer growing seasons of winter wheat there were observed significant deviations in air temperature and rainfall by months from multi-year average indices. Coefficient of deviation essentiality confirmed a tendency to increase the percentage of months with conditions close to the rare for rainfall from 3.3 to 10% and for temperatures from 4.2 to 10%.

Piñon pine (Pinus edulis Engelm.) growth responses to climate and substrate in southern Utah, U.S.A.

Pinon pines (Pinus edulis Engelm.) are a widely distributed species across the western United States (U.S.) providing habitat for wildlife species in addition to forest products for humans. Thus, understanding factors that promote the productivity of this species is important to predict future responses to environmental change. We examined pinon pine growth from tree-ring records and evaluated whether growth responses to climate may be explained by local site characteristics such as geologic substrate from the late 1900s through the early 2000s. Cluster analysis revealed two distinct clusters that differed in their growth response (i.e., tree-ring width) to July temperature of the current growing season (cluster 1, r = −0.45; cluster 2, r = −0.31). Clusters 1 and 2 displayed synchronous growth throughout the early to mid-twentieth century but growth patterns diverged in the 1970s. Ring widths in cluster 1, which were most sensitive to average July temperature, showed a downward trend in the 1970s through the 2000s. By contrast, cluster 2 growth showed positive growth responses during the 1980s followed by growth declines during the multi-year drought of the 1990s. There was evidence that these growth patterns may be partially explained by geologic substrate (i.e., shale, sandstone, alluvial fan). Pearson’s r values of tree growth over time were strongly negative on shales and sandstones (r = −0.30, P = 0.009; r = −0.34, P = 0.003), whereas those on alluvial fans were not significant (r = 0.13, P = 0.23). Reported values of soil available water capacity on the shale and sandstone substrates are low relative to the alluvial fans, which may partially explain the differential growth responses. Our findings suggest that consideration of increasing summer temperatures on low availability water capacity geologic substrates may be important in predicting future pinon pine growth declines.