Minimum Winter Temperature Research Articles

Changes in the Seasonally Frozen Ground Over the Eastern Qinghai-Tibet Plateau in the Past 60 Years

The Qinghai-Tibet Plateau (QTP) has the largest extent of high altitude permafrost at the middle and low latitudes in northern hemisphere and is surrounded by dozens of seasonally frozen ground. Rising air temperatures have resulted in frozen ground degradation over QTP since the last century. Based on the daily frozen soil depth, annual mean daily minimum air temperatures and annual mean air temperatures obtained from 19in-situobservations over QTP, the changes in the thickness, temporal and spatial distributions of frozen ground, as well as the associated attributions, are analyzed for the period of 1960-2019. The results show that the maximum depth of frost penetration, the beginning time of soil freezing and the ending time of soil thawing have changed considerably. On average, the maximum depth of frost penetration (MDFP) has reduced by 0.14 similar to 1.71 m at most stations. The annual frozen period has decreased by about 40 days. The changes in seasonal freezing of soils appear to be attributed to the rising of minimum air temperatures in winter, especially at the higher elevations range from 4500 to 5000 m.

Reducing air pollution increases the local diurnal temperature range: A case study of Lanzhou, China

AbstractLanzhou is one of the largest heavy industry cities in northwestern China. The city has carried out massive air pollution‐control programmes since 2012. As a result, the concentrations of air pollutants in Lanzhou have decreased. In order to examine the effects of air pollution‐control programmes on air temperature, the differences in air temperatures between Lanzhou and Yuzhong (a small county adjacent to Lanzhou) and their change between 2009–2011 (P1) and 2013–2015 (P2) were calculated. The results showed that the maximum (minimum) temperature difference significantly increased (decreased) by 0.32°C (0.40°C) in winter (summer) between P1 and P2, indicating an increase (decrease) of the maximum (minimum) temperature in winter (summer) in Lanzhou caused by the reduction in air pollution. Therefore, the diurnal temperature range in Lanzhou increased by 0.50°C in summer and 0.22°C in winter during P2 compared with P1. The increase in the maximum temperature in winter and the decrease in the minimum temperature in summer are supported by a decrease in mean air temperature at night and by an increase of mean air temperature in daytime in winter and summer during P2 compared with P1. The increase in temperature in daytime may be ascribed to more absorption of solar radiation at the surface. The decrease in temperature at night in summer is caused by increasing light rainfall. The decrease in temperature at night during winter may be related to more loss of surface heat through long wave radiation.

Integrated Population Modeling for White‐Tailed Deer in Saskatchewan, Canada

ABSTRACTMonitoring annual change and long‐term trends in population structure and abundance of white‐tailed deer (Odocoileus virginianus) is an important but challenging component of their management. Many monitoring programs consist of count‐based indices of relative abundance along with a variety of population structure information. Analyzed separately these data can be difficult to interpret because of observation error in the data collection process, missing data, and the lack of an explicit biological model to connect the data streams while accounting for their relative imprecision. We used a Bayesian age‐structured integrated population model to integrate data from a fall spotlight survey that produced a count‐based index of relative abundance and a volunteer staff and citizen classification survey that generated a fall recruitment index. Both surveys took place from 2003–2018 in the parkland ecoregion of southeast Saskatchewan, Canada. Our approach modeled demographic processes for age‐specific (0.5‐, 1.5‐, ≥2.5‐year‐old classes) populations and was fit to count and recruitment data via models that allowed for error in the respective observation processes. The Bayesian framework accommodated missing data and allowed aggregation of transects to act as samples from the larger management unit population. The approach provides managers with continuous time series of estimated relative abundance, recruitment rates, and apparent survival rates with full propagation of uncertainty and sharing of information among transects. We used this model to demonstrate winter severity effects on recruitment rates via an interaction between winter snow depth and minimum temperatures. In years with colder than average temperatures and above average snow depth, recruitment was depressed, whereas the negative effect of snow depth reversed in years with above average temperatures. This and other covariate information can be incorporated into the model to test relationships and provide predictions of future population change prior to setting of hunting seasons. Likewise, post hoc analysis of model output allows other hypothesis tests, such as determining the statistical support for whether population status has crossed a management trigger threshold. © 2020 The Wildlife Society.

Ocean warming is the key filter for successful colonization of the migrant octocoral Melithaea erythraea (Ehrenberg, 1834) in the Eastern Mediterranean Sea.

Climate, which sets broad limits for migrating species, is considered a key filter to species migration between contrasting marine environments. The Southeast Mediterranean Sea (SEMS) is one of the regions where ocean temperatures are rising the fastest under recent climate change. Also, it is the most vulnerable marine region to species introductions. Here, we explore the factors which enabled the colonization of the endemic Red Sea octocoral Melithaea erythraea (Ehrenberg, 1834) along the SEMS coast, using sclerite oxygen and carbon stable isotope composition (δ18OSC and δ13CSC), morphology, and crystallography. The unique conditions presented by the SEMS include a greater temperature range (∼15 °C) and ultra-oligotrophy, and these are reflected by the lower δ13CSCvalues. This is indicative of a larger metabolic carbon intake during calcification, as well as an increase in crystal size, a decrease of octocoral wart density and thickness of the migrating octocoral sclerites compared to the Red Sea samples. This suggests increased stress conditions, affecting sclerite deposition of the SEMS migrating octocoral. The δ18Osc range of the migrating M. erythraea indicates a preference for warm water sclerite deposition, similar to the native depositional temperature range of 21–28 °C. These findings are associated with the observed increase of minimum temperatures in winter for this region, at a rate of 0.35 ± 0.27 °C decade−1 over the last 30 years, and thus the region is becoming more hospitable to the Indo-Pacific M. erythraea. This study shows a clear case study of “tropicalization” of the Mediterranean Sea due to recent warming.

Mapping temperature and precipitation extremes under changing climate (on the example of The Ural region, Russia)

The paper presents a series of maps of extreme climatic characteristics for the Ural region and their changes under climate warming observed in last decades. We calculate threshold, absolute and percentile-based indices with the use of daily temperature and precipitation dataset of 99 weather stations of Roshydromet. Extreme climatic characteristics were averaged by moving 30-year periods from 1951 to 2010 for temperature and from 1966 to 2015 for precipitation. The regression-based interpolation was used for mapping climatic extremes taking into consideration the influence of topography. Elevation and general curvature of the terrain are considered as independent variables. In addition, the changes of extreme characteristics between the 30-year periods were estimated. As a result, a series of maps of temperature and precipitation extremes for the Ural region has been created. The maps present not only spatial distribution of the climatic extremes, but also regional features of their changes under climate warming. In general, the revealed changes in extremes in the Ural region correspond to the trends observed on the most of the territory of Russia. There is a substantial decrease of the number of extremely cold days in winter, and the minimum winter temperature has a strong positive trend (up to 1-5°C/30 years). The maximum temperature in summer has a positive trend in most of the territory, but the increase rate does not exceed 2°C between 1951–1980 and 1981–2010. The precipitation extremes also increased up to 0.5-1.5 mm when comparing 1966–1995 and 1985–2015 periods.

Impact of training system on ‘Blanc Du Bois’ vegetative growth, yield components and fruit composition

‘Blanc Du Bois’ (Vitisspp.) is the most widely grown Pierce’s disease tolerant white grapevine cultivar in Texas. As an interspecific hybrid, its growth habit is seimi-drooping, and 'Blanc Du Bois' is characterized as vigorous. This study evaluated the impact of training system (Mid-Wire Cordon with VSP, Mid-Wire Cane with VSP and Smart-Dyson, High-Wire Quadralateral, and Watson) on 'Blanc Du Bois' growth, yield components, and fruit composition at two locations in Texas. The first site was located in the Rio Grande Valley where the mean extreme minimum winter temperature is -1.1 to 1.7° C (USDA Cold Hardiness Zone 10a). As a result of climate and site conditions, vine size, determined by dormant pruning weight, was very large averaging from 3.71 to 5.56 kg per vine across training systems over a three-year period. At this site, the horizontally divided systems, High-Wire Quadrilateral and Watson were the highest yielding averaging 10.66 and 7.49 kg per vine, respectively, as a result of more shoots per vine, and higher fruitfulness. The Mid-Wire Cordon and Mid-Wire Cane Pruned Training Systems had lower yields in two out of three years, but fruit maturity indices soluble solids and pH reflected more advanced maturity at harvest. At the second site, located in the Central Gulf Coast of Texas (USDA Cold Hardiness Zone 8b), vines were less vigorous with pruning weights averaging 1.66 to 1.83 kg per vine across training systems over three years. Consistent differences in yield components, vine size, and fruit composition were not observed, and all the three training systems under study had acceptable growth and fruiting characteristics. The results of this research suggest that 'Blanc Du Bois’ vigor potential and growth habit makes it well-suited for horizontally divided canopy training systems, particularly on vigorous sites.

THE ANALYSIS OF SOIL TEMPERATURES IN DIFFERENT DEPTHS USING SPEARMAN’S RHO AND MANN-KENDALL CORRELATION TESTS: THE CASE STUDY OF NIGDE CENTER IN TURKEY

This research was conducted to determine soil temperatures in different soil depths in located Turkey’s Anatolia Region in Center of Nigde Province. In the study, the maximum, minimum and average soil temperature values of 10 cm, 50 cm and 100 cm depths observed between 1970-2019 were examined. All soil temperature data were evaluated monthly within the scope of the study. In the study, Mann-Kendall, Sperman's Rho correlation test and Sen's slope method were used. According to the research result; The average of maximum soil temperatures in 10 cm depth was calculated as 6,8 0C in winter months and 20,7 0C in spring months. The average minimum soil temperature was calculated as 0,3 0C in winter and 5,0 0C in spring Months in long periods Generally, it was observed that there was an increasingly significant trend at maximum temperatures of 10 cm depth. According to the Mann-Kendal facility, a significant increase trend was observed in minimum soil temperatures in spring, winter and Summer months except for the months of autumn. Considering the average maximum temperature values in 50 cm; It was calculated as 6,6 °C in winter and 13,6 °C in spring months. The minimum soil temperature average was calculated as 3,5 0C in winter and 8,3 0C in spring months in long period (50 year, 600 months). In general, it was observed that there was an increasingly significant trend at maximum temperatures of 50 cm soil depth. According to Mann-Kendall and Sperman Rho test, a significant increase trend was observed in minimum soil temperatures in all seasons except for autumn months. According to the average maximum temperature values in 100 cm depth; It was calculated as 9,2 0C in winter and 11,5 0C in spring. The minimum soil temperature average was calculated as 7,1 0C in winter and 8.7 0C in spring months. It has been observed that there is a significant increase trend in the increasing of maximum and minimum soil temperatures of 100 cm soil depth.

Geographic variation in body size of five Australian marsupials supports Bergmann’s thermoregulation hypothesis

Abstract Despite a large body of research, little agreement has been reached on the ultimate driver(s) of geographic variation in body size (mass and/or length). Here we use skull length measurements (as a surrogate for body mass) from five Australian marsupial species to test the primary hypotheses of geographic variation in body size (relating to ambient temperature, productivity, and seasonality). We used a revised articulation of Bergmann’s rule, wherein evidence for thermoregulation (heat dissipation or heat conservation) is considered supportive of Bergmann’s rule. We modeled the skull lengths of four Petaurid glider species and the common brushtail possum (Trichosurus vulpecula) as a function of indices of ambient temperature, productivity, and seasonality. The skull length of Petaurus ariel, P. notatus, and the squirrel glider (P. norfolcensis), increased with increasing winter minimum temperature, while that of T. vulpecula decreased with increasing summer maximum temperature. The skull length of P. ariel decreased with indices of productivity, falsifying the productivity hypothesis. Only P. ariel met the hypothesis of seasonality, as skull length increased with increasing seasonality. Thermoregulation was the most consistently supported driver of geographic variation in body size, as we found evidence of either heat conservation or heat dissipation in four of the five species examined. We found the geographic range of the individual species and the climate space in which the species occurred was integral to understanding the species’ responses to climate variables. Future studies should use specimens that are representative of a species’ entire geographic range, encompass a variety of climatic regions, and use consistent methodologies and terminology when testing drivers of geographic variation in body size.

Minimum Winter Temperature as a Limiting Factor of the Potential Spread of Agrilus planipennis, an Alien Pest of Ash Trees, in Europe.

The emerald ash borer, EAB (Agrilus planipennis) is a devastating alien pest of ash trees. It is spreading in European Russia and Ukraine and will appear in other European countries. Our aim was to determine the regions of Europe where the winter temperature drops low enough to prevent A. planipennis establishment. We calculated the minimum daily air temperature from 2003–2019 for each grid square (0.5° × 0.5°) in East Asia, North America and Europe and determined the minimum daily temperature in the grid squares where A. planipennis was recorded. Temperatures of −30 to −33 °C occur in the northern portions of the pest range on all continents. No established population has been recorded in localities where temperatures below −34 °C occur. This temperature is close to the absolute supercooling point of A. planipennis larva (−35.3 °C). It is unlikely that low temperatures could prevent the spread of A. planipennis in northern Western Europe (Sweden, Norway, Finland, etc.), since the temperature in this area did not fall to −34 °C from 2003–2019. However, such temperatures are not rare in eastern European Russia (Kostroma, Vologda, Orenburg regions, etc.), where Fraxinus pennsylvanica and F. excelsior occur. These regions could potentially become refuges for these ash species.

Tree-ring record of winter temperature from Humla, Karnali, in central Himalaya: a 229 years-long perspective for recent warming trend

ABSTRACT Tree rings are widely used to reconstruct past climates in regions where observational records of climate are short. In this study, we developed a 294 years-long (1718–2011 CE) ring-width chronology of the Himalayan Silver fir (Abies spectabilis (D.Don, Spach)) from Humla district in western Nepal to reconstruct winter minimum temperature for the remote region of central Himalaya where instrumental records are limited to past three or four decades. Ring-width chronology of the Himalayan Silver fir showed strongest and significant positive correlation with minimum winter temperature prior to the growing season. Based on this relationship, we reconstructed the winter season (previous October–current February) minimum temperature for western Nepal covering the period of 1780–2008 CE. Our reconstruction showed that winter minimum temperature is continuously increasing since the early twentieth century with unprecedented rapid warming in the latter half. The cold episodes in the reconstruction coincided with the major volcanic eruptions in the Northern Hemisphere and tropical regions. The spectral analysis using Multi-Taper Method revealed that the winter temperature in the north-western Himalaya has short- to medium-term periodicities of 2–3, 5.8–6.2, 7.9–8.2, 39–46 and 56–73 years, which suggest possible teleconnections with ENSO (El-Nino Southern Oscillation) and AMO (Atlantic Multidecadal Oscillation).

Modelling temperature and fish biomass data to predict annual Scottish farmed salmon, Salmo salar L., losses: Development of an early warning tool

Losses due to mortality are a serious economic drain on Scottish salmon aquaculture and are a limitation to its sustainable growth. Understanding the changes in losses, and associated drivers, are required to identify risks to sustainable aquaculture. Data on losses were obtained from two open source data sets: monthly losses of biomass 2003−2018 and losses of salmon over production cycles (numbers input minus output harvest) 2002–2016. Monthly loss rates increased, accelerating after 2010, while losses per production cycle displayed no trend. Two modelling frameworks were investigated to produce an early warning tool for managers about potential increases in losses. Both linear regression and beta regression showed that monthly losses related to biomass and minimum winter air temperatures with high precision and low bias. These relationships apply at both the national and regional levels where the beta regression best fit model explain 82 % and 69 % of variation in mortality, some regional differences apply, particularly for the Northern Isles. The lack of trend in losses per production cycle may have been due to shorter production cycles as more salmon were harvested earlier, and possibly increasing losses of larger salmon (which affects biomass but not numbers lost). In the long-term, the models predict that milder winters and increased biomass will be associated with increased mortality, which will need to be managed. In the short-term, given relatively little year-to-year variation in biomass, minimum winter temperature is a powerful early warning of the likely extent of losses in the Scottish salmon farming industry.

Three‐spined stickleback armour predicted by body size, minimum winter temperature and pH

AbstractSimilar phenotypes evolve under equivalent environmental conditions through parallel evolution. Because they have repeatedly invaded and adapted to new freshwater environments, the three‐spined stickleback (Gasterosteus aculeatus) offers a powerful system for understanding the agents of selection in nature that drive parallel evolution. Here, we examine the ecological and environmental variables responsible for morphological variation in three‐spined stickleback populations across its European range. We collected fish from 85 populations, encompassing much of the European latitudinal range of the species and including lowland rivers and lakes, coastal lagoons and moorland ponds. We measured biotic and environmental variables at all sites along with morphological traits for 2,358 individuals. Using an information theory approach, we identified body size, minimum average winter temperature and pH as primary predictors of stickleback armour evolution, challenging current hypotheses for stickleback morphological diversification and demonstrating the fundamental role played by body size and scaling in mediating responses to selection. Stickleback lateral plate phenotype represents a potentially powerful tool for monitoring change in climate variables across the northern temperate region.

Multi-year population dynamics of a specialist trawling bat at streams with contrasting disturbance

Abstract Habitat degradation leads to homogenization of biological communities, often due to the dominance of generalist species over specialists. Yet data as to how life history attributes of specialists vary with such perturbations remain sparse. We compared long-term population dynamics of a specialist trawling bat, the large-footed myotis (Myotis macropus), between two forested catchments. One forest stream was nutrient-enriched from dairy farming in its headwaters and a portion of its surrounding catchment was harvested for timber during the study, while the other was located in primarily undisturbed forest. We caught and banded bats annually at their roosts over 14 years and banded 529 individuals with a 45% recapture rate. The maximum time to recapture was nine years and there was no evidence for transiency in our populations. Mark-recapture analyses allowed for investigation of the dependence of survival on time, sex, and age at marking. Our study spanned extreme El Niño and La Niña weather events, but we found little variation in survival, although recruitment was lower during drought. Mean minimum winter temperature (positive) and rainfall (positive) had weak influences on survival. Survival of adults (~0.70) and population size of adult females was similar between the two sites, suggesting that neither timber harvesting with retained riparian buffers nor eutrophication from farming influenced survival. Survival of adult males and females was similar, but survival of juveniles was less than half that of adults, probably due to a combination of mortality and dispersal. Survival was three times lower immediately after one of the timber bridges used as a roost fully collapsed. Specializing on aquatic habitats buffered M. macropus from most extreme weather, but there was also evidence for possible mortality and recovery after an intense rainfall and flooding event immediately prior to the study. More frequent intense rainfall predicted with global warming may reduce the species’ resilience over time.

On the contribution of internal climate variability to European future climate trends

Large historical and future ensemble simulations from the Max-Planck Institute and the Canadian Earth System Models and from CMIP5 have been analysed to investigate the uncertainty due to internal variability in multi-decadal temperature and precipitation trends over Europe. Internal variability dominates the uncertainties in temperature and precipitation trends in all seasons at 30-year time scales. Locally, seasonal 30-year temperature trends deviate up to ±3 °C from the ensemble mean trend. Thus, in the entire of Europe, local seasonal temperature changes until year 2050 from below −1 °C up to more than 4 °C are possible according to the model results. Up to 30% of all ensemble members show negative temperature trends until year 2050 in winter, up to 10% of the members in summer. Uncertainties of 30-year precipitation trends due to internal variability exceed the trends almost everywhere in Europe. Only in few European regions more than 75% of the members agree on the sign of the change until year 2050. In southern Sweden, minimum and maximum winter (summer) temperature trends in the next 30 years differ with up to 7 °C (5 °C) between individual members of the large model ensembles. Large positive temperature trends are linked to positive (negative) precipitation trends in winter (summer) in southern Sweden. This variability is attributed to the variability in large scale atmospheric circulation trends, mainly due to internal atmospheric variability. We find only weak linkages between the variability of temperature trends and the dominant decadal to multi-decadal climate modes. This indicates that there is limited potential to predict the multi-decadal variability in climate trends. The main findings from our study are robust across the large ensembles from the different models used in this study but at the local scale, the results depend also on the choice of the model.

Historical Trends in Air Temperature, Precipitation, and Runoff of a Plateau Inland River Watershed in North China

Understanding historical trends in temperature, precipitation, and runoff is important but incomplete for developing adaptive measures to climate change to sustain fragile ecosystems in cold and arid regions, including the Balagaer River watershed on the Mongolian Plateau of northeast China. The objective of this study was to detect such trends in this watershed from 1959 to 2017. The detection was accomplished using a Mann-Kendall sudden change approach at annual and seasonal time scales. The results indicated that the abrupt changes in temperature preceded that in either runoff or precipitation; these abrupt changes occurred between 1970 and 2004. Significant (α = 0.05) warming trends were found at the minimum temperatures in spring (0.041 °C a−1), summer (0.037 °C a−1), fall (0.027 °C a−1), and winter (0.031 °C a−1). In contrast, significant decreasing trends were found in the precipitation (−1.27 mm a−1) and runoff (−0.069 mm a−1) in the summer. Marginally increasing trends were found in the precipitation in spring (0.18 mm a−1) and fall (0.032 mm a−1), whereas an insignificant decreasing trend was found in the runoffs in these two seasons. Both precipitation and runoff in the wet season exhibited a significant decreasing trend, whereas in the dry season, they exhibited a marginally increasing trend. Sudden changes in spring runoff and sudden rises in temperature are the main causes of sudden changes in basin rainfall.

Environmental Determinants of Aedes albopictus Abundance at a Northern Limit of Its Range in the United States.

.Aedes albopictus is a vector of arboviruses with high rates of morbidity and mortality. The northern limit of Ae. albopictus in the northeastern United States runs through New York state (NYS) and Connecticut. We present a landscape-level analysis of mosquito abundance measured by daily counts of Ae. albopictus from 338 trap sites in 12 counties during May–September 2017. During the study period, the mean number of Ae. albopictus caught per day of trapping across all sites was 3.21. We constructed four sets of negative binomial generalized linear models to evaluate how trapping methodology, land cover, as well as temperature and precipitation at multiple time intervals influenced Ae. albopictus abundance. Biogents-Sentinel (BGS) traps were 2.78 times as efficient as gravid traps and 1.49 times as efficient as CO2-baited CDC light traps. Greater proportions of low- and medium-intensity development and low proportions of deciduous cover around the trap site were positively associated with increased abundance, as were minimum winter temperature and March precipitation. The cumulative precipitation within a 28-day time window before the date of collection had a nonlinear relationship with abundance, such that greater cumulative precipitation was associated with increased abundance until approximately 70 mm, above which there was a decrease in abundance. We concluded that populations are established in Nassau, Suffolk, and New York City counties in NYS; north of these counties, the species is undergoing population invasion and establishment. We recommend that mosquito surveillance programs monitoring the northward invasion of Ae. albopictus place BGS traps at sites chosen with respect to land cover.

Recent climate changes in the northwestern Qaidam Basin inferred from geothermal gradients

Temperature perturbations under the ground surface are a direct thermal response to temperature changes on the ground surface. Thus, borehole temperature measurements can be used to reconstruct the temperature history of the ground surface using borehole Paleothermometry. In this study, we use seven borehole temperature profiles to reconstruct the ground surface temperature variation for the past 514 years in the Qaidam Basin, northwestern China. Borehole transient temperature measurements from seven sites in the northwestern Qaidam Basin were separated from the geothermal gradients and analyzed using the functional space inversion method to determine the ground surface temperature variation history of the region. All of the temperature profiles show the effects of recent climatic disturbances. The inversion reveals that during the last 514 years, the ground surface temperature has increased by an average of 1.2 °C (−0.11 to 2.21 °C). Clear signs of a cold period between 1500 and 1900 A.D. were found, which corresponds to the Little Ice Age. The coldest period occurred between 1780 and 1790 A.D. with a ground surface temperature of 5.4 °C. The reconstructed ground surface temperature shows an increasing trend during the 19th and the 20th centuries, but the temperature began to decrease in the late twentieth century. However, during the past 514 years, the highest temperature occurred in the 1990s. This reconstructed ground surface temperature variation history is verified by the simulated annual surface air temperature computed using EdGCM, while the cooling trend is confirmed by reconstructions of the winter half-year minimum temperatures from tree rings on the northeastern Tibetan Plateau.

Assessing the impact of projected climate change on the future of grape growth and wine production in the Niagara Peninsula (Canada)

ABSTRACTThe impacts of projected climate change on several key climatic indicators for grape growth and wine production are assessed for the Niagara Peninsula (Canada). Global Climate Model outputs are evaluated and ranked for the study region to create selective ensembles of seasonal climate change projections. Statistical downscaling is performed to create local, daily, climate change scenarios. Average growing season temperature and the number of growing degree days have been increasing over time (1981–2010) and are projected to increase further under climate change (2011–2100). There were trends in total accumulated growing season precipitation or in the number of days with total precipitation greater than 10 mm, but slight increases were still projected under climate change. Minimum winter temperatures were warming over time and the number of days with temperatures below −20°C were decreasing, with both these trends projected to continue. There were no statistically significant trends associated with maximum summer temperatures or the number of days with temperatures above 30°C, but both were projected to increase considerably in the future. A warmer, wetter climate in the region is expected to lengthen growing seasons, increase growth potential, diminish risk of winter freeze damage, while increasing summer heat stress.

Geographical Range Extension of the Spotfin burrfish, Chilomycterus reticulatus (L. 1758), in the Canary Islands: A Response to Ocean Warming?

In recent decades, numerous marine species have changed their distribution ranges due to ocean warming. The Spotfin burrfish, Chilomycterus reticulatus, is a reef fish with a global distribution along tropical, subtropical and warm-temperate areas of the Pacific, Indian and Atlantic oceans. In this work, we analyzed the presence of this species, between 1990 and 2019, at two islands of the Canarian Archipelago under varying oceanographic conditions: El Hierro (the westernmost island, under more tropical conditions) and Gran Canaria (a central-east island, under more cooler conditions). We expected that, under increased ocean temperatures in recent decades, the number of sightings has increased in Gran Canaria relative to El Hierro. We compiled information from different sources, including interviews and local citizenship databases. A total of 534 sightings were reported: 38.58% from El Hierro and 61.43% from Gran Canaria. The number of sightings on Gran Canaria has significantly increased through time, at a rate of 0.1 sightings per year; at El Hierro, however, the number of sightings has not significantly changed over time. Sea Surface Temperature has linearly increased in both El Hierro and Gran Canaria islands over the last three decades. Positive Sea Surface Temperature anomalies, particularly in 1998 and 2010, including high winter minimum temperatures, provide an ideal oceanographic context to favour the arrival of new individuals and, consequently, the increase in the number of sightings in Gran Canaria. Still, potential donor areas of fish recruits remain unknown.

Application of the Principal Component Analysis (PCA) Method to Assess the Impact of Meteorological Elements on Concentrations of Particulate Matter (PM10): A Case Study of the Mountain Valley (the Sącz Basin, Poland)

The aim of this study was to determine, by use PCA analysis, the impact of meteorological elements on the PM10 concentration on the example of the mountain valley. Daily values of selected meteorological elements, measured during a ten-year period in the spring, summer, autumn and winter, obtained from the meteorological station in Nowy Sącz, were adopted as variables explaining PM10 concentration. The level of PM10 was significantly affected by the maximum, minimum and average temperature in autumn, winter and spring. In summer the average and maximum temperature was significant. In winter, the first principle component mainly consisted of the combination of the average and maximum wind speed. The second principal component in spring, summer and autumn was the combination of the wind speed (average and maximum), but in winter humidity and atmospheric pressure seemed to be significant. The third principal component, in terms of strength of impact, was humidity in spring, the combination of humidity and minimum temperature in summer, and precipitation in autumn. In winter, the highest PM10 concentrations were observed during the non-directional, anticyclonic wedge conditions. Three principal components were distinguished in this situation: temperature (average, maximum and minimum); the combination of humidity and wind speed and precipitation.