Temperature In May Research Articles

Fluctuating selection driven by global and local climatic conditions leads to stasis in breeding time in a migratory bird.

The origin of natural selection is linked to environmental heterogeneity, which influences variation in relative fitness among phenotypes. However, individuals in wild populations are exposed to a plethora of biotic and abiotic environmental factors. Surprisingly, the relative influence of multiple environmental conditions on the relative fitness of phenotypes has rarely been tested in wild populations. Identifying the main selection agent(s) is crucial when the target phenotype is tightly linked to reproduction and when temporal variation in selection is expected to affect evolutionary responses. By using individual-based data from a 29-year study of a short-lived migratory songbird, the pied flycatcher (Ficedula hypoleuca), we studied the relative influence of 28 temperature- and precipitation-based factors at local and global scales on selection on breeding time (egg laying) at the phenotypic level. Selection, estimated using the number of recruits as a proxy for fitness, penalized late breeders. Minimum temperatures in April and May were the environmental drivers that best explained selection on laying date. In particular, there was negative directional selection on laying date mediated by minimum temperature in April, being strongest in cold years. In addition, nonlinear selection on laying date was influenced by minimum temperatures in May, with selection on laying date changing from null to negative as the breeding season progressed. The intensity of selection on late breeders increased when minimum temperatures in May were highest. Our results illustrate the complex influence of environmental factors on selection on laying date in wild bird populations. Despite minimum temperature in April being the only variable that changed over time, its increase did not induce a shift in laying date in the population. In this songbird population, stabilizing selection has led to a three-decade stasis in breeding time. We suggest that variation in the effects of multiple climatic variables on selection may constrain phenotypic change.

Temperature Control of Spring CO2 Fluxes at a Coniferous Forest and a Peat Bog in Central Siberia

Climate change impacts the characteristics of the vegetation carbon-uptake process in the northern Eurasian terrestrial ecosystem. However, the currently available direct CO2 flux measurement datasets, particularly for central Siberia, are insufficient for understanding the current condition in the northern Eurasian carbon cycle. Here, we report daily and seasonal interannual variations in CO2 fluxes and associated abiotic factors measured using eddy covariance in a coniferous forest and a bog near Zotino, Krasnoyarsk Krai, Russia, for April to early June, 2013–2017. Despite the snow not being completely melted, both ecosystems became weak net CO2 sinks if the air temperature was warm enough for photosynthesis. The forest became a net CO2 sink 7–16 days earlier than the bog. After the surface soil temperature exceeded ~1 °C, the ecosystems became persistent net CO2 sinks. Net ecosystem productivity was highest in 2015 for both ecosystems because of the anomalously high air temperature in May compared with other years. Our findings demonstrate that long-term monitoring of flux measurements at the site level, particularly during winter and its transition to spring, is essential for understanding the responses of the northern Eurasian ecosystem to spring warming.

Changes in the body size of black-veined white, Aporia crataegi (Lepidoptera: Pieridae), recorded in a natural population in response to different spring weather conditions and at different phases of an outbreak

Changes in body size in response to environmental factors (especially temperature) is one of the crucial traits studied in connection with insect adaptation to climate change. However, current data on the strength and direction of temperature-size responses in Lepidoptera are inconsistent and the reasons for this are unclear. This study investigates the relationship between the adult size of Aporia crataegi L. (Lepidoptera: Pieridae) and spring weather conditions (temperature and rainfall) at different phases in its outbreak cycle (low population density or high abundance). The forewing area of A. crataegi, a univoltine and irruptive Lepidopteran species, was used as a proxy for overall body size. It was found that temperature in the last month before imago emergence (May) and temperature in the larval growth period following overwintering (April) had differing effects on imago size. The fact that the wing size of both male and female A. crataegi increased following higher temperatures in May corresponds with the converse temperature-size rule and is consistent with the predictions of life history theory for univoltine species. Conversely, while imago size decreased following higher temperatures in April, increased rainfall had a slightly positive effect on imago size. The wings of A. crataegi at the peak of abundance were larger than when sampled during periods of low population density, contradicting available data on changes in the body weight of A. crataegi recorded during outbreaks.

Temperature and Precipitation Diversely Control Seasonal and Annual Dynamics of Litterfall in a Temperate Mixed Mature Forest, Revealed by Long‐Term Data Analysis

AbstractLitterfall is a good indicator of overall forest functions in forest ecosystems. Globally, forest litterfall has been extensively investigated, however, there is a lack of long‐term data analysis to show the various litterfall components in relation to environmental factors on the monthly and yearly scales. Here, monthly (May–October) and annual (1981–2018) litterfall including leaves, twigs, bark, reproductive, and miscellaneous fractions were collected in a mixed mature Pinus koraiensis forest on Changbai Mountain in Northeast, China, across 30 years. Based on these long‐term litterfall data, we analyzed the seasonal and annual variations in different litterfall fractions and the internal/external drivers. We observed that both the leaf and total litterfall exhibited a strong, similar seasonal pattern, with the highest levels between September and October, and the annual litterfall had an “S‐shaped” increasing pattern from 1981 to 2018. The other litterfall fractions showed distinct monthly and yearly fluctuations across the 30 years. Mean monthly evapotranspiration and temperature (minimum and maximum) were the best predictors for monthly litterfall. By contrast, the models that best predicted the annual litterfall production included mean annual precipitation and mean monthly precipitation and temperature in May and October. Our study, using a unique dataset of detailed long‐term litterfall dynamics, has potentially major significance for enhancing our understanding of the role of climatic factors controlling forest litterfall amount and seasonality in temperate mixed mature forests. This insight is of paramount importance for modeling and estimating soil carbon sequestration and nutrient cycling of temperate forests under climate change.

Approaching of May maximum surface air temperature to characteristic summer season for Baghdad city

Seasonal variability is the complex non-linear response of the physical climate system. There are two types of natural variability: those external and internal to the climate system. In any given season, natural variability may cause the climate to be different than its long-term average. This study examines with the seasonal variation of the maximum temperatures during the summer season. In addition, the maximum temperatures in May become close to the characteristics of the summer season. The monthly data for maximum temperature of May, June and July were used from Iraqi Meteorological Organization and Seismology (IMOS) for 47 years from 1970 to 2017 for Baghdad city. This period was long enough to estimate the range of approaching maximum temperature (Tmax) May to summer. Results revealed a significant Tmax for Baghdad during the second period (1992–2017) and ?shown similar behavior of Tmax in May to June and July; on the contrary that first period (1970–1991). In second period, two phases have been found out, positive phase and negative phase. The positive phase were happened in 1995, 1999, and 2006, and the negative phase was four cases (1992, 2004, 2013, and 2016), while a few cases recorded in first period. The amplitudes of monthly variability had same distance of leaner correlation especially in 1999 and 2013 that represent coherent wave with summer seasons. The variance difference for Tmax between May and June approximately was 2°C for second study’s period, while exceed this range in first period. This variance change to 7.5°C when found difference between July and May.

Warming of water temperature in spring and nutrient release from sediment in a shallow eutrophic lake

AbstractWe investigated whether recent springtime water temperature increases in a shallow eutrophic lake affected bottom sediment temperature and fluxes of ammonia (NH4+) and phosphate (PO43−) from the sediment. We conducted a lake-wide survey of Lake Kasumigaura, Japan, and analyzed the relationship between water temperature increases in spring and NH4+ and PO43− release fluxes. We also developed a numerical model to analyze how water temperature increase affects sediment temperature. Water temperature in May increased during 2010–2019 at a rate of 1.8–3.2 °C decade−1. The numerical simulation results showed that the water temperature increase was accompanied by a sediment temperature increase from a minimum of 18.3 °C in 2011 to a maximum of 21.6 °C in 2015. Despite the substantial difference in the observed sediment temperature (2.9 °C), no significant differences in NH4+ and PO43− fluxes in May between 2013/2014 and 2015 were found. These results suggest that both water and sediment temperatures are increasing in Lake Kasumigaura in spring, but it is unclear whether this warming has affected NH4+ and PO43− releases from the sediment. However, because a nonlinear response to sediment temperature was observed, future springtime warming may accelerate NH4+ and PO43− releases.

A Tree-Ring-Based Assessment of Pinus armandii Adaptability to Climate Using Two Statistical Methods in Mt. Yao, Central China during 1961–2016

Assessing the characteristics and limiting factors of tree growth is of practical significance for environmental studies and climatic reconstruction, especially in climate transition zones. In this study, four sites of Pinus armandii Franeh are investigated to understand regional climate-tree growth response in Mt. Yao, central China. Based on the high similarity of four residual chronologies and high correlations between chronologies and climatic factors, we analyzed the correlations of regional residual chronology with monthly climatic factors and the self-calibrating Palmer Drought Severity Index (scPDSI) from 1961–2016. The results indicate that the hydrothermal combination of prior August and current May and the scPDSI in May are main limiting factors of regional tree growth in Mt. Yao. The results of stepwise regression models also show that temperature and scPDSI in May are the main limiting factors of tree growth, but the limiting effect of scPDSI is more than temperature in this month. Through the analysis of the number of tree growth years corresponding to high temperature and high scPDSI, it was further confirmed that scPDSI in May is the main limiting factor on the growth of P. armandii in Mt. Yao. However, the influence of scPDSI in May has weakened, while temperature in May has increasingly significant influence on tree growth. The above findings will help improve our understanding of forest dynamics in central China under global climate change.

Influence of Climate Warming on Grapevine (Vitis vinifera L.) Phenology in Conditions of Central Europe (Slovakia).

The impact of warming on the phenology of grapevine (Vitis vinifera L.) in conditions of central Europe was evaluated at the locality of Dolné Plachtince in the Slovakian wine region. In Welschriesling and Pinot Blanc model varieties, the onset of phenophases as defined in the BBCH scale over the period of 1985 to 2018 was observed. Based on the data obtained, the influence of the average and average maximum temperature and GDD on the onset of phenophases was evaluated. The results observed indicate earlier budburst by five to seven days, earlier beginning of flowering by 7 to 10 days, earlier berry softening by 18 days, and harvest dates advanced by 8 to 10 days on average. In both varieties, the highest influence of the average monthly temperature in March on budburst, the highest influence of the average monthly temperature and the average maximum temperature in May on the beginning of flowering, and the highest statistically significant influence of the average maximum temperature in June on the softening of berries was found. Warming observed in moderate climate conditions of northern wine regions in central Europe (Slovakia) has not yet caused changes in the grapevine phenology stable enough to require serious adaptation measures.

Продуктивність ячменю ярого залежно від погодних умов і рівня інтенсифікації технології вирощування

Goal. To assess weather conditions and establish the patterns of their impact on the yield of spring barley for different energy saturation technologies for its cultivation in the Northern part of the Right Bank Forest-Steppe of Ukraine. Methods. Field — to carry out long-term experiment in 4 repetitions; measuring and weighing — to account for crop yields; comparative — to calculate the dependence of crop yields on weather factors; statistical and correlation. Results. The tendencies of change of weather conditions for 1999–2018 were analyzed and the regularities of their influence on the yield of spring barley in the conditions of the Northern part of the Right-Bank Forest-Steppe were established. According to the results of 20-year experimental data based on correlation regression analysis, mathematical models were created that reproduce the dependence of spring barley yield, which was grown by technologies of different intensity, on the complex weather conditions of the growing season. The greatest dependence of crop productivity on the conditions of April moistening and the temperature regime of May is shown. Conclusions. In the Northern part of the Right-Bank Forest-Steppe there is a significant fluctuation of weather conditions, namely: an increase in temperature and a decrease in rainfall during the growing season and their instability over the years. Analysis of correlations between spring barley yield and weather conditions under different cultivation technologies shows that the conditions of April moisture and temperature in May had the greatest influence on crop formation.

Spatial Variation and Temporal Instability in the Growth/Climate Relationship of White Birch (Betula platyphylla Suk) in the Changbai Mountain, China

Tree growth in mountain ecosystems is affected by complex environments, and its relationship with climatic and environmental factors varying with elevation. In order to examine the spatial variation and temporal stability of the growth/climate relationship of Betula platyphylla (BP), the dendrochronological method was used to analyze the radial growth/climate relationship between 1946 and 2016 of the BP trees along an altitudinal gradient in the Changbai Mountain of northeast China. Our results showed that the mean sensitivity of BP was higher than that of other species studied in Changbai Mountain. The growth/climate relationship of BP trees varies with altitude, and this conclusion has reached a consensus from the study of tree growth response to climate change. More specifically, at low altitudes (550–995 m a.s.l.), the radial growth of BP is mainly affected by spring precipitation and temperature in May and October of the current year. However, at high-altitude areas (1210–1425 m a.s.l.), it is mainly affected by the temperature in September of the previous year and May of the current year. Furthermore, the growth/climate relationship of BP trees showed temporal instability. After 1970, the rise in temperature inhibited the growth of BP at low altitudes and promoted the growth of BP trees at high altitudes. In the context of continued warming in the future, the white birch stands in Changbai Mountain will move to higher altitudes.

Spatial and temporal variation of sea surface temperature and chlorophyll-a on the mackerel fish (Scomberomorus commerson) distribution using aqua modis satellite in naukerjerai district, merauke regency

Remote sensing is a technique that can be applied for observing oceanographic paramaters such as content of sea surface temperature and chlorophyll-a. The study aims to analyze the parameters of Sea Surface Temperature and Chlorophyll-a by using Aqua Modis Satellite to see the spatial and temporal distribution of the two paramaters on the distribution of CPUE of Mackerel (Scomberomorus commerson).Conducted for 2 months from May-June 2019 this study was held in the waters area of Naukenjerai District, Merauke Regency. The results showed the concentration of sea surface temperature in May was warmer in the range of 26.56 – 28.42 °C compared to June, where the temperature was cooler in the range of 25.43 – 26.94 °C. Meanwhile the concentration of chlorophyll-a in May was seen to be low around 0.3-1.73 mg/m3 which compared to June the concentration was relatively high around 1.45-2.36 mg/m3. The highest distribution of CPUE of Mackerel was found in June, which was 89 kg and the lowest CPUE Mackerel in May was around 22 kg. Therefore in June there is a great potential for capturing Mackerel.

Climate effects on the growth of Pinus latteri and Pinus kesiya at the Intakin Silvicultural Research Station, Chiang Mai Province, Thailand

Abstract. Naumthong M, Palakit K, Duangsathaporn K, Prasomsin P, Lumyai P. 2021. Climate effects on the growth of Pinus latteri and Pinus kesiya at the Intakin Silvicultural Research Station, Chiang Mai Province, Thailand. Biodiversitas 22: 2512-2519. Relationship between the growth of two pine species, Pinus latteri and Pinus kesiya, and past climatic factors are studied. Standard dendrochronological techniques were used on 40 core samples obtained from 20 trees from each species to cross-date tree-ring width and determine the growth patterns of each species. Over a period spanning from 1980-2019 (P. latteri) and 1984-2019 (P. kesiya), the calculated mean ring-width values were 0.596 and 0.430 cm per year, respectively. An analysis of the relationship between tree-ring width of P. latteri and climatic data indicated a positive correlation with the relative humidity in April. However, a negative correlation was observed with the temperature in April and August. The factors limiting the growth of P. latteri the most were the temperature in August (r2=0.228; P<0.01). The index constructed for P. kesiya indicated a positive correlation with extreme minimum relative humidity in December and extreme maximum temperature in March. The factors limiting the growth of P. kesiya with a significant correlation, were the relative humidity in April (r2=0.173) and temperature in May (r2=0.184). These results can be used to plan the management of forest plantations and to select suitable areas for the cultivation of pine trees in Thailand

Fifty-year dynamics of the Lena River islands (Russia): Spatio-temporal pattern of large periglacial anabranching river and influence of climate change

The Lena, a large river that drains the northern coldest region of the Northern Hemisphere, is deeply influenced by the continuous permafrost and degradation of the frozen ground has been shown to be the main cause of the marked increase in water discharge. The first objective of this study conducted on the middle Lena was to analyze the island dynamics for the last 50 years (1967 to 2017). Several morphological parameters were surveyed using a GIS on seven series of aerial photographs and satellite images of a 100 km-long reach: island size, eroded and deposited areas, position and morphology of the islands. This approach enabled the identification of evolutionary models. Our second objective was to evaluate the potential impact of ongoing climate change. We analyzed morphological parameters with respect to two main factors: efficient discharge (bar-full, bankfull and flood discharges) and water temperature. A potential erosion index (PEI) was calculated by coupling the duration of discharge exceeding the bar-full level and water temperature.The results identified several morphological changes that occurred at the end of the 20th century: an increase in the number of islands, greater eroded surfaces and accelerated migration of islands. Comparing the dynamics of islands with and without permafrost is a good indicator of their sensitivity to climate change. A major change was observed concerning the erosion and migration of islands with and without permafrost. This evolution seems to be linked both with the duration of the discharge that exceeds the bar-full level and with the number of flood peaks. The water temperature in May and August have a major influence on permafrost islands that become increasingly destabilized. Thus, as large rivers are assumed to slowly react to climate change, the recent changes in the Lena River prove that the global change deeply impacts periglacial rivers.

Effect of Gear Type on Vibrio spp. Levels in Farm-Raised Oysters (Crassostrea virginica) after Routine Handling and Resubmersion

During routine handling, cultured oysters are removed from the water and exposed to elevated temperatures, causing growth of Vibrio vulnificus and Vibrio parahaemolyticus within them. Farmers can resubmerse oysters in the water, allowing elevated Vibrio spp. levels to return to ambient levels within the oysters. Previous resubmersion research is limited to one aquaculture gear type during studies performed from June to September. This study aims to expand knowledge about the recovery times needed for elevated Vibrio levels in handled oysters from two common gear types (the adjustable longline system and the OysterGro system) during early and midsummer periods. Oysters held in both gear types were subjected to being tumbled and refrigerated or desiccated and then resubmersed into water in May and July 2018 and 2019. Vibrio spp. levels were measured before and after the treatments, and 3, 7, and 14 days after resubmersion, and were compared with levels in submersed oysters. All samples were tested for V. vulnificus, total V. parahaemolyticus, and pathogenic V. parahaemolyticus (tdh+/trh+). Water temperatures in May were significantly lower (∼5°C; P ≤ 0.009) than in July, corresponding to lower V. vulnificus levels (-0.67 log MPN/g) and higher tdh+/trh+ levels (+0.56 to 0.63 log MPN/g) in control oysters. The average Vibrio spp. levels in control oysters from each trial did not differ between the gear types (P ≥ 0.08). Elevated V. vulnificus levels recovered to ambient levels after 7 days in May and 3 days in July, regardless of gear or handling. For V. parahaemolyticus, the desiccated oysters required 14 days to recover in May and 7 days in July, whereas the tumbled and refrigerated oysters required 14 days or more in both months. This study had limited replication in each month, but the data suggest that the resubmersion times differ between the gear types, treatment types, and months. Future studies with more replications are needed to determine whether these trends continue.

Long-Term Analysis of the Variability of Agronomic Characters in the VIR Oat Germplasm Collection in Central Black Soil Region of Russia

Climate change has become a significant factor in crop production in the 21st century for many countries. To turn losses into profit, adaptation measures are needed, which are based on the analysis and forecast of economically valuable characteristics of crops. The field trial data were analyzed for 764 oat accessions from the global germplasm collection by the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) in 2001–2019 and the cultivar ‘Gorizont’ in 1990–2019 in Yekaterinino Experiment Station of VIR (Tambov Province, Russia, 52°59′ N, 40°50′ E). A progressive shortening of the growing season and a yield increase were observed during the study both in the mean values for the tested accessions and in the cv. ‘Gorizont’. Grain yield variability of cv. ‘Gorizont’ across the years was also associated with 1000 grain weight variations. The models predict a further reduction in the growing season by 2.4 days/10 years, mainly caused by an increase in temperatures above 15 °C, and an increase in yield by 47.6 g/m2/10 years, mainly caused by an increase in the temperature in May. ANOVA demonstrated that the highest yields in Tambov Province were produced by accessions from Ulyanovsk Province, Ukraine, Moscow Province, Norway, Germany, and Poland.

Provenance-specific climate sensitivity of Pinus massoniana – a multi-environmental trial in subtropical China

Climate change is causing changes in tree species performance and distribution, impacting breeding programme effectiveness. Our aim was to analyse the effects of provenance and climatic factorson the annual ring density of Masson pine (Pinus massoniana Lamb.) at different experimental sites and potential breeding strategies that may be developed in response to future climate change. The study trees represented provenances originating from the western, east-central, northern, and southern regions of P. massoniana distribution in China. The wood density differed significantly among provenances. A multisite variance analysis test showed that the type B correlation coefficients for ring density at the two sites studied were less than 0.8, indicating an interaction effect of genotype by environment (G×E) on tree ring density. Climatic factors directly affected the wood density properties. At Chun’an (CA), the maximum latewood density (MXD) and minimum earlywood density (MND) were positively correlated with absolute maximum temperatures in August and May of the current growing season, respectively. At Taizi Mountain (TZS), MXD was significantly positively correlated with absolute maximum temperature in September ofthe current year and significantly negatively correlated with precipitation in June. MND was significantly positively correlated with absolute maximum temperature in May of the current year and significantly negatively correlated with precipitation in April. The climatic effects on P. massoniana wood density differed among seed-source origins. This study showed that ring density characteristics differed significantly among provenances, and provenance selection could promote wood density. MXD and MND exhibited significant genotype-by-environment interaction effects, and significant correlations were found between ring density and temperature, and precipitation conditions. These findings suggest that climatic factors and site conditionsin addition to genetics could be strong drivers of wood density variation, and/or that wood density is a highly plastic trait.

Improving the representation of high-latitude vegetation distribution in dynamic global vegetation models

Abstract. Vegetation is an important component in global ecosystems, affecting the physical, hydrological and biogeochemical properties of the land surface. Accordingly, the way vegetation is parameterized strongly influences predictions of future climate by Earth system models. To capture future spatial and temporal changes in vegetation cover and its feedbacks to the climate system, dynamic global vegetation models (DGVMs) are included as important components of land surface models. Variation in the predicted vegetation cover from DGVMs therefore has large impacts on modelled radiative and non-radiative properties, especially over high-latitude regions. DGVMs are mostly evaluated by remotely sensed products and less often by other vegetation products or by in situ field observations. In this study, we evaluate the performance of three methods for spatial representation of present-day vegetation cover with respect to prediction of plant functional type (PFT) profiles – one based upon distribution models (DMs), one that uses a remote sensing (RS) dataset and a DGVM (CLM4.5BGCDV; Community Land Model 4.5 Bio-Geo-Chemical cycles and Dynamical Vegetation). While DGVMs predict PFT profiles based on physiological and ecological processes, a DM relies on statistical correlations between a set of predictors and the modelled target, and the RS dataset is based on classification of spectral reflectance patterns of satellite images. PFT profiles obtained from an independently collected field-based vegetation dataset from Norway were used for the evaluation. We found that RS-based PFT profiles matched the reference dataset best, closely followed by DM, whereas predictions from DGVMs often deviated strongly from the reference. DGVM predictions overestimated the area covered by boreal needleleaf evergreen trees and bare ground at the expense of boreal broadleaf deciduous trees and shrubs. Based on environmental predictors identified by DM as important, three new environmental variables (e.g. minimum temperature in May, snow water equivalent in October and precipitation seasonality) were selected as the threshold for the establishment of these high-latitude PFTs. We performed a series of sensitivity experiments to investigate if these thresholds improve the performance of the DGVM method. Based on our results, we suggest implementation of one of these novel PFT-specific thresholds (i.e. precipitation seasonality) in the DGVM method. The results highlight the potential of using PFT-specific thresholds obtained by DM in development of DGVMs in broader regions. Also, we emphasize the potential of establishing DMs as a reliable method for providing PFT distributions for evaluation of DGVMs alongside RS.

升温突变对川西道孚林线川西云杉和鳞皮冷杉生长的影响

高山林线作为理想的全球气候变化监测器，是研究植被与气候变化关系的重要场所。利用川西道孚县高山林线川西云杉（Picea likiangensis var.balfouriana）和鳞皮冷杉（Abies squamata）的年轮宽度资料，基于树木年代学的方法，构建差值年表并通过升温突变前后（1995年前后）年轮指数与气候要素的相关分析，探讨了该区林线主要针叶树种的年轮响应变化，为研究青藏高原地区树木与气候响应关系提供研究基础。结果表明：（1）年尺度上，1995年气温突变前后川西云杉和鳞皮冷杉年轮指数和生长弹性时间变化趋势均不显著，没有发生显著的响应分歧现象。（2）月尺度上，升温突变前川西云杉年轮指数与前一年11月月均最高温、5-7月月均温、6月月均最高温、7月月均最低温呈显著正相关；鳞皮冷杉则与前一年11月月均温、11月月均最高温和12月月均温呈显著正相关；表明升温突变前林线树木生长分别受夏季和冬季温度控制；升温突变后川西云杉年轮指数与前一年11月月均温呈显著负相关，和当年2月降水量及7月月均最低温呈显著正相关；而鳞皮冷杉则与当年5月月均温和5月月均最低温呈显著负相关，与5月降水的正相关性达到最大；表明升温突变后林线川西云杉生长依然受夏季温度控制，而鳞皮冷杉生长则受到春季干旱胁迫的影响。未来气候若随着升温出现干暖化，则林线鳞皮冷杉可能会发生明显的响应分歧现象。;Alpine tree line is the key area to study the relationship between vegetation and climate change. Used the tree ring width data of Picea likiangensis var. balfouriana and Abies squamata at tree line in Dafu, Sichuan, China, based on the method of dendrochronology, the residual chronologies was devoloped. Through the correlation analysis between tree ring index and climatic factors before and after abrupt warming (1995), we anaylazed the changes in the tree ring response of the main coniferous tree species at tree line. The results show that:(1) on the annual scale, the temporal trend of tree ring index and tree resilience of P. likiangensis var. balfouriana and A. squamata before and after abrupt warming was not significant, and there was no obvious divergence phenomenon. (2) On the monthly scale, tree ring index of P. likiangensis var. balfouriana before abrupt warming was significantly positively correlated with the average maximum temperature in December of the previous year, the monthly average temperature from May to July, the average maximum temperature in June, and the average minimum temperature in July; tree ring index of A. squamata was significantly positively correlated with the average temperature in November, the maximum temperature in November, and the average temperature in December of the previous year. Both indicated that tree growth at tree line before abrupt warming was controlled by summer and winter temperature. After abrupt warming, tree ring index of P. likiangensis var. balfouriana was significantly negatively correlated with the average tempreture in November of the previous year, and was significantly positively correlated with the precipitation in February and the average minimum temperature in July; while the A. squamata was significantly negatively correlated with the average temperature in May and the average minimum temperature in May. The correlation coefficient between fir growth and the precipitation in May reached the maximum. All indicated that the growth of P. likiangensis var. balfouriana was still controlled by summer temperature, while the growth of A. squamata was affected by spring drought stress after abrupt warming. If it becomes dry with continuous warming in the future, divergence phenomena of A. squamata maybe appear.

Amaranthaceae pollen grains as indicator of climate change in Lublin (Poland)

Previous studies have demonstrated that plants are a very good indicator of global environmental variations. The responses of many plant species to climate change are confirmed by aerobiological research. This paper presents an analysis of many parameters of pollen seasons in the Amaranthaceae family based on measurements of pollen concentrations in atmospheric air. Pollen samples were collected with the volumetric method at a sampling site in Lublin (Poland) in 2001–2019. The obtained data were verified using statistical analyses. Moreover, the presence of pollenkitt on the pollen grain surface was examined in fresh anthers using scanning electron and light microscopes, since there are some difficulties in identification of Amaranthaceae pollen grains deposited on microscopic slides in aerobiological analysis.The pollen season in Amaranthaceae began on average on June 23 and ended on October 5, i.e. it lasted 105 days. The peak value and annual pollen sum were characterized by the highest variability in the study years in comparison with other season characteristics. The annual pollen sum was in the range from 183 to 725. Maximum concentrations were most often recorded in the second half of August, which is associated with the greatest risk of development of pollen allergy symptoms in sensitive subjects during this period. The results obtained in the 19-year study revealed that the pollen seasons began 14 days earlier. Similarly, the end of the season was accelerated by 24 days. The response of these plants to climate change also include the reduced pollen production by representatives of this family, which was manifested by a decrease in the annual sum of daily airborne pollen concentrations, on average by 35%, and a reduction in the maximum pollen concentration, on average by more than 60%. We found that temperature in May and June had an effect on pollen release, and relative air humidity in May influenced pollen concentrations. We noted significant similarities in the pollen release rate during the last 8 years of the study. The scanning electron microscopy examinations showed that the pollen grain surface in the representative of this family was covered completely or partially with pollenkitt. Hence, the apertures characteristic for pollen in this family were poorly visible. The presence of pollenkitt on the surface of these polyaperturate pollen grains may play an important role in preventing water loss during pollen migration in the air. Our research has demonstrated the response of plants flowering in summer to climate change. The results not only have practical importance for public health in the aspect of allergy risk but can also help to assess environmental changes.

Reasons of time shifting of animals’ seasonal events in the Central Forest Biosphere Reserve

The paper considers dynamics of phenological phenomena of animals in the south taiga Central Forest biosphere reserve. As initial data we used materials of meteorological and phenological observations made under the program of maintaining the nature chronicle on the basis of the meteorological post Forest reserve in the Roshydromet network. Of the 46 meteorological series only ten (22%) show significant long-term changes over the period 19902019: an increase in the average annual air temperature, temperature in May, August, September and November; a decrease of total precipitation in September and an increase in December; a positive displacement of occurrence dates of maximum temperature less than 0C and the final formation of ice on the pond, a negative shift of the phenological summer beginning dates. The authors prove that there has been a shift of time when winter comes or an increase in the duration of the frost-free period on the reserve territory over a 30-year period. For the spring phenodates of the considered animal species, there is a negative long-term linear trend in the variability of phenological phenomena towards an earlier start of events. Such signs as the first meeting of the small tortoiseshell, the first bites of the biting mosquito, the first appearance of the grass frog and the viviparous lizard are recommended to be used as indicators of the climate change. The shift of insect and amphibian phenodates is associated with a shortening of the cold season in the reserve climate system. A significant change of lizards phenological phenomenon time is caused by abiotic as well as by biotic (forage) factors.