Search Results (24)

Rostov Oblast is one of the key grain-producing regions in Russia, accounting for 6% of the total grain production. However, it faces an increasing risk of climate aridization, which requires an accurate scientific assessment to ensure the food security of the country. The present study analyzes the spatial and temporal dynamics of climate aridification in the Rostov region for the period 1951–2054. This analysis is based on ERA5 reanalysis data and CMIP6 forecast models (MPI-ESM1-2-HR, CanESM5, BCC-CSM2-MR). The analysis indicates that the annual mean temperature in the region has increased by 2–3 °C since the 1950s, reaching 12 °C in 2023. At the same time, precipitation shows significant interannual variability with no detectable long-term trend. Spatial analysis reveals a stable meridional temperature gradient and zonality of precipitation distribution. The southeastern parts of the region are characterized by the highest degree of aridification. Projection models indicate further warming (+1.5–3 °C by 2054) and increasing contrasts between western (wetter) and eastern (drier) areas. Projections derived from the CMIP6 models indicate an intensification of aridification, accompanied by a decrease in the De Martonne index of 15–25% by the year 2054. The area of territories with arid climates is expected to increase from 30% to 40%. The most vulnerable regions will be in the southeast part of Rostov Oblast, where the De Martonne index values are predicted to decrease to less than 10. The potential increase in temperature and evapotranspiration, coupled with spatial differentiation, could pose significant risks to the sustainability of the agro-industrial complex, particularly in the southeastern part of the region. Full article

This article explores the impacts of climate change on the rural and natural landscapes in the region of Eastern Macedonia and Thrace, northeastern Greece. The spatial distributions of the bioclimatic de Martonne Index and the phytoclimatic Emberger Index were calculated at a very high resolution (~500 m) for present conditions (1970–2000), two future time periods (2030–2060; 2070–2100), and two greenhouse gas concentration scenarios (RCP4.5; RCP8.5). The results show significant bioclimatic changes, especially in the Rhodope Mountain range and along almost the whole length of the Greek–Bulgarian border, where forests of high ecosystem value are located, together with the rural areas along the Evros river valley, as well as in the coastal zone of the Aegean Sea. The article describes the processes of bioclimatic changes that can significantly modify the study area’s landscapes. The study area reveals a shift toward xerothermic environments over time, with significant bioclimatic changes projected under the extreme RCP8.5 scenario. By 2100, de Martonne projections indicate that around 40% of agricultural areas in the eastern, southern, and western regions will face Mediterranean and semi-humid conditions, requiring supplemental irrigation for sustainability. The Emberger Index predicts that approximately 42% of natural and agricultural landscapes will experience sub-humid conditions with mild or cool winters. In comparison, 5% will face drier humid/sub-humid, warm winter conditions. These foreseen futures propose initial interpretations for key landscape conservation, natural capital, and ecosystem services management. Full article

Based on long-term observations of the water discharge (WD) from 1878 to 2018, the main trends and patterns of its change in the basin of one of the largest rivers in the east of the East European Plain, the Vyatka River, were revealed using a set of standard statistical procedures and a graphical analysis of the WD probability curves. Three main phases of the annual river WD were identified, corresponding to the periods 1878–1929, 1930–1977, and 1978–2018. The first and third periods were characterized by increased WD (by 22–23%) relative to the medium period, and the differences in the average annual WD characteristics between these periods were statistically significant. It is also noteworthy that the difference in the average annual WD between the first and last periods of increased WD was very small and statistically insignificant. A gradual increase in the share of the so-called normal annual WD and a decrease in the abnormal (including extreme) annual WD were noted from 1878–1929 to 1978–2018 in the predominantly northern half of the river basin. At the same time, in the predominantly southern half of the basin, according to the analysis of only the periods 1930–1977 and 1978–2018, the so-called normal and abnormal WD remained almost unchanged; only a slight increase in positive anomalies of the WD was noted. Increased intra-annual variability in the WD was characteristic of the period of its reduced average annual value. Between the three identified periods, a gradual reduction in the water runoff coefficient was observed during the warm (mainly summer) season in the Vyatka River basin. The specified long-term variability in the water discharge of the Vyatka River was chiefly due to long-term changes in climatic factors, primarily the ratio of the air temperature and precipitation, expressed as the De Martonne aridity index. The duration of the principal cycle of these changes was 82 years. An additional contribution could also have been made by the widespread reduction in cropland in the study region in recent decades. The obtained results can be preliminarily considered representative of the entire southern sector of the boreal forest zone (taiga zone) of the east of the East European Plain. Full article

Environmental conditions can control the structure and composition of plant communities by changing the direction and intensity of plant–plant interactions. In extreme arid regions, accompanied by water and soil nutrient limitation, positive shrub–herb interactions may vary along an aridity gradient, leading to changes in the ecological consequences of shrub encroachment. We investigated the vegetation and soil within 60 shrub patches and their paired interspaces at 20 sites from the northeast to southwest desert steppe of Inner Mongolia, China, encroached by the Caragana microphylla shrub. The results show that aridity, soil organic matter (SOM), and soil total phosphorus (TP) were the main factors driving shrub–herb interactions. The positive shrub–herb interaction first increased and then decreased with increasing aridity (in the range of De Martonne Index (DMI) 0.54 to 1.85). The DMI indirectly affected shrub–herb interaction through TP, and the facilitation of shrubs on herbs coverage and biomass increased with the increase in TP. The SOM can directly affect the shrub–herbs interaction, and the facilitation of shrubs on herb diversity decreases with the increase in SOM. Our results indicate that the shrub–herb interaction changes along the environmental stress gradient; in general, shrubs have a positive effect on herbaceous communities along the aridity gradient. This study underscores the positive effects of shrubs on vegetation restoration in desert steppes, and changing environmental conditions by increasing precipitation, increasing TP content, and reducing SOM content can enhance the facilitation of shrub on herbs to accelerate the ecological restoration of degraded desert steppe. Full article

Drought poses a significant risk in many parts of the world, especially in regions reliant on agriculture. Evaluating this risk is an essential step in preventing and reducing its impact. In this context, we assess the drought intensity at six sites in Constanța County (Romania) using the de Martonne aridity index. The risk of aridity and vulnerability to drought were evaluated by the Drought Hazard Index (DHI) and Drought Risk Index (DRI), computed based on the Standardized Precipitation Index (SPI). The de Martonne index indicates a variation between the slightly arid and semi-arid climates for Adamclisi station, with periodic changes from semi-arid to arid. At Cernavodă station, we notice a passage from an arid period towards a moderately humid one (in 2005), followed by a movement in the opposite direction to the limit of the arid zone (in 2011), and a return inside the “limits” of the semi-arid to moderately arid climate. A similar variation for 2000–2018 is noticed at Medgidia, Hârșova, and Mangalia. DRI classifies two stations in the low risk to drought category and one in the moderate risk to drought class. The other two locations experience a high or very high risk of drought. The drought intensities varied in the intervals 0.503–1.109 at Constanța, 0.473–1.363 at Mangalia, 0.511–1.493 at Adamclisi, 0.438–1.602 at Hârșova, 0.307–1.687 at Medgidia, and 0.463–1.307 at Cernavodă, and the prolonged drought periods were over 99 months at all stations. Full article

Bioclimate alteration unquestionably poses a current but also a potential future threat to natural and agricultural ecosystems and their services. In this scope, the present and future bioclimatic footprint of the Central European territory is investigated and presented. For the first time, an ultrahigh spatial resolution (<250 m) of the de Martonne index is analyzed over the entire area, as well as for individual countries (Austria, Switzerland, Czech Republic, Hungary and Slovakia). The research is performed for the reference period (1981–2010) and for three time series (2011–2040; 2041–2070; 2071–2100) under two emissions scenarios (SSP370 and SSP585) for the determination of the potential short-term and distant future bioclimatic change trends. Projection results reveal higher xerothermic trends over the lowland agricultural areas mostly in 2071–2100 and under the extreme SSP585, with the classes’ spatial distributions going from 0.0% to 2.3% for the semi-dry class and from 0.0% to 30.1% for the presiding Mediterranean class. Additionally, more than half of the territory’s agricultural surface area (53.4%) is foreseen to be depending on supplementary irrigation by 2100. Overall, more intense dry thermal conditions are expected to impact the agricultural areas of the Czech Republic, Slovakia and Hungary with the latter emerging as particularly vulnerable. Full article

The changing climate is closely related to changes in the bioclimate. This research deals with the present bioclimate and its projected evolution over the entirety of the natural and agricultural lands of south-eastern Europe and individual countries (Bulgaria, Greece, Kosovo, N. Macedonia, Romania, and Serbia). For this purpose, an ultrahigh spatial resolution of the de Martonne bioclimatic index pattern was elaborated and analysed for the first time. The survey is performed over the reference period (1981–2010) and future time frames (2011–2040; 2041–2070; 2071–2100) under SSP370 and SSP585 emission scenarios. On a territorial level, both natural and agricultural areas appear as highly impacted by the future changes of bioclimate; the highest xerothermic trend is expected to influence the latter areas, mostly in 2071–2100 and under the higher emission scenario. The natural areas will face an expansion in the semidry class from 0.9% (of the total area) during the reference period to 5.6% during 2071–2100 under the RCP8.5 scenario as the dominant extremely humid class falls from 53.5% to 32.9% for the same periods and scenario. On the other hand, agricultural areas will face a more intense xerothermic alteration going from 4.9% to 17.7% for the semidry class and from 41.1% to 23.5% for the dominant very humid class for the same periods and scenario. This study presents the spatial statistics per country for the selected scenarios and periods to provide information for stakeholders. This study’s results highlight the necessity for intensifying adaptation plans and actions aiming at the feasibility of agricultural practices and the conservation of natural areas. Full article

Drought is a major problem in the world and has become more severe in recent decades, especially in arid and semi-arid regions. In this study, a Google Earth Engine (GEE) app has been implemented to monitor spatiotemporal drought conditions over different climatic regions. The app allows every user to perform analysis over a region and for a period of their choice, benefiting from the huge GEE dataset of free and open data as well as from its fast cloud-based computation. The app implements the scaled drought condition index (SDCI), which is a combination of three indices: the vegetation condition index (VCI), temperature condition index (TCI), and precipitation condition index (PCI), derived or calculated from satellite imagery data through the Google Earth Engine platform. The De Martonne climate classification index has been used to derive the climate region; within each region the indices have been computed separately. The test case area is over Iran, which shows a territory with high climate variability, where drought has been explored for a period of 11 years (from 2010 to 2021) allowing us to cover a reasonable time series with the data available in the Google Earth Engine. The developed tool allowed the singling-out of drought events over each climate, offering both the spatial and temporal representation of the phenomenon and confirming results found in local and global reports. Full article

In this study, the present bioclimatic conditions and the estimated changes of the bioclimate over natural and agricultural areas of the Adriatic territory (Albania, Bosnia and Herzegovina, Croatia, Italy, Montenegro, and Slovenia) are analysed and presented. For this purpose, a survey on De Martonne’s bioclimate categories’ spatial distribution over the entire examined area and individual countries is conducted for the reference period (1981–2010) and for three more future time periods (2011–2040; 2041–2070; 2071–2100) under two emissions scenarios (ssp370/RCP7 and ssp585/RCP8.5). The very high spatial resolution (~300 m) results demonstrate that the potential future alterations of the Adriatic territory’s bioclimate indicate the probable acceleration of the trend towards warmer and dryer conditions by 2100 under the RCP8.5 scenario, with the Italian region’s agricultural areas mainly being influenced. Moreover, as the studied scenarios project, the bioclimatic impact will affect natural and agricultural areas. For the agricultural areas, the semi-dry class (the most xerothermic in the study area) will expand from 4.9% (reference period) to 17.7% according to the RCP8.5 scenario for the period 2071–2100. When over the natural areas, the related variation of the same class is from 0.9% to 5.6%. In general, the western part of the Adriatic coastline is more vulnerable to climate results than the eastern one. Full article

Aridity conditions in semi-arid lands with warm climates are key variables that must be assessed to properly manage water and plan to minimise the threat of desertification. This study analyses the spatial distribution of aridity in Extremadura, southwestern Spain, using the De Martonne aridity index (I_DM), considering a historical reference period (1971–2005) and three-time intervals: 2006–2035 (near future), 2036–2065 (mid-century) and 2066–2095 (end of the century). Projections were computed using a set of ten global climate model (GCM) and regional climate model (RCM) combinations under two representative concentration pathways (RCPs), RCP4.5, an intermediate anthropogenic radiative forcing scenario, and RCP8.5, a fossil-intensive emission scenario. Progressive strengthening of aridity conditions over Extremadura was evident until the end of the century, mainly under the RCP8.5 scenario. From the predominance of the Mediterranean aridity class in the south of the region during the reference period, semi-arid conditions will soon spread across this zone, occupying most of it during mid-century and later. In the north of Extremadura, less arid conditions will be reduced to the highest elevations, increasing the Mediterranean and semi-arid categories, particularly under the RCP8.5 scenario. Consequently, the projected increase in aridity conditions in Extremadura will make this region more vulnerable to climate change. Policies devoted to adapting to the expected conditions and controlling aridity in vulnerable areas will be necessary to mitigate the negative impacts, with significant environmental and socio-economic implications in the region. Full article

Aridity is a key determinant of agriculture worldwide due to rising temperatures, rainfall variability, and drought frequency and intensity, amongst other factors. The De Martonne aridity index is particularly useful to evaluate the spatial and temporal variations in aridity in agricultural regions for characterising the climate of these areas and evaluating their susceptibility to climate change. From the mean precipitation and maximum–minimum daily temperature values recorded at 108 weather stations over 32 years (1989–2020) in Extremadura (southwest Spain), spatial analysis of aridity was performed at different grapevine growth stages. The present study aimed to (1) determine the mean aridity conditions in Extremadura according to year and growth stage and (2) assess aridity in six grapevine-growing areas of Ribera del Guadiana de Extremadura (Spain) protected designation of origin (PDO). To visualise aridity patterns, maps were generated using a geographic information system and a multivariate regression geostatistical algorithm (ordinary kriging). The climate of Extremadura is primarily Mediterranean at the annual scale, and aridity widely varies from extremely humid at the dormancy stage to arid at the berry development and ripening stages. This variation shapes the conditions of the studied grapevine-growing region. Furthermore, large differences were noted amongst the sub-areas of the Rivera del Guadiana PDO at the initial and final grapevine growth stages, requiring differential crop management. In addition, analysis according to growth stage allowed us to identify the most vulnerable areas and periods to climate change and potential grapevine-growing areas highly suitable for this climate. Full article

The Mediterranean vegetation belt on the eastern Adriatic covers an area of nearly 15,000 km². It is comprised of forest stands that can be divided into three vegetation zones based on the presence of certain plant species within each: sub-Mediterranean, eu-Mediterranean, and steno-Mediterranean. The dominant ecological factors result in the domination of specific tree species within the floral composition between these vegetation zones. The aim of this study was to collect climate data from 38 weather stations over a 30-year period to compare climate data and bioclimate properties in the area of these three vegetation zones. The results confirmed statistically significant differences between the main climatic elements and most bioclimatic indices between the vegetation zones. Cooler and more humid conditions were found in the sub-Mediterranean zone, warmer and somewhat drier conditions in the eu-Mediterranean zone, and particularly pronounced warm and dry conditions in the steno-Mediterranean zone. However, the analysis of the main components for researching climate parameters showed that the mean annual air temperature, average minimum air temperature of the coldest month of the year and continentality index, length of the dry season, and de Martonne aridity index contribute the most to the grouping of vegetation in forest stands in the Mediterranean vegetation belt of the eastern Adriatic. Full article

The recent climate change scenarios show significant increases in temperature and extreme drought events in Southern and Eastern Europe by the end of the 21st century, which will have a serious impact on forest growth and adaptation, and important consequences for forest management. The system of provenance regions, according to the OECD Scheme and EU Directive, was thought to encourage the use of the local seed sources, under the concept ‘local is the best’. However, climate is changing faster than some species or populations can adapt or migrate, which raises some uncertainties with respect to the future performance of local populations. In Romania, as in other countries, the delimitation of provenance regions is based on geographical, ecological and vegetation criteria. The aim of this study is to evaluate: (1) the climate change that has occurred at the level of the provenance regions; (2) which regions will be most vulnerable to climate change; (3) which forest types will be the most vulnerable in a certain region; and (4) changes in the climatic envelope of forest species. Several climatic parameters and an ecoclimatic indices have been calculated and analyzed at the level of provenance regions, subregions and ecological sectors (forest types) in Romania, during the period 1951–2020. The results highlight a general shift towards warmer and drier conditions in the last 30 years, the mean annual temperature increasing with 0.3–1.1 °C across the provenance subregions. The De Martonne aridity index for the vegetation season shows that 86% of the ecological sectors fell into the arid and semiarid categories, which indicates a very high degree of vulnerability for forest species. On the Lang rainfall index, forest steppe climatic conditions occurred in all pure or mixed pedunculate oak forests, thermophile oak species, meadow forests, poplar and willow, Turkey oak and Hungarian oak forests. The Ellenberg coefficient highlights that the warming process is more evident along the altitude and the degree of vulnerability increase at lower altitude or at the edge of species distribution. The climate envelopes of many forest species have already shifted to another ecosystem’s climate. This paper presents the importance of re-delineation the provenance regions for the production and deployment of forest reproductive materials according to the climate change occurred in the last decades, as a fundamental tool for an adaptive forest management. Full article

In water resources management, modeling water balance factors is necessary to control dams, agriculture, irrigation, and also to provide water supply for drinking and industries. Generally, conceptual and physical models present challenges to find more hydro-climatic parameters, which show good performance in the assessment of runoff in different climatic regions. Accordingly, a dynamic and reliable model is proposed to estimate inter-annual rainfall-runoff in five climatic regions of northern Algeria. This is a new improvement of Ol’Dekop’s equation, which models the residual values obtained between real and predicted data using artificial neuron networks (ANN_s), namely by ANN₁ and ANN₂ sub-models. In this work, a set of climatic and geographical variables, obtained from 16 basins, which are inter-annual rainfall (IAR), watershed area (S), and watercourse (WC), were used as input data in the first model. Further, the ANN₁ output results and De Martonne index (I) were classified, and were then processed by ANN₂ to further increase reliability, and make the model more dynamic and unaffected by the climatic characteristic of the area. The final model proved the best performance in the entire region compared to a set of parametric and non-parametric water balance models used in this study, where the R²_Adj obtained from each test gave values between 0.9103 and 0.9923. Full article

Urbanization and climate change are two inevitable megatrends of this century. Knowledge about the growth responses of urban trees to climate is of utmost importance towards future management of green infrastructure with the aim of a sustainable provision of the environmental ecosystem services. Using tree-ring records, this study analyzed growth response to climate by stem diameter at breast height (DBH) of 1178 trees in seven large cities worldwide, including Aesculus hippocastanum L. in Munich; Platanus × hispanica Münchh. in Paris; Quercus nigra L. in Houston; Quercus robur L. in Cape Town; Robinia pseudoacacia L. in Santiago de Chile, Munich, and Würzburg; and Tilia cordata Mill. in Berlin, Munich, and Würzburg. Climate was characterized following the de Martonne aridity index (DMI). Overall, trees showed an 8.3% lower DBH under arid than humid climate at the age of 100. Drought-tolerant tree species were overall not affected by climate. However, R. pseudoacacia showed a lower diameter when growing in semi-dry than humid climate. In contrast, drought-sensitive tree species were negatively affected by arid climate. Moreover, the effect of drought years on annual diameter increment was assessed. P. × hispanica and R. pseudoacacia appeared as the most drought-resistant species. The highest sensitivity to drought was detected in T. cordata and Q. robur. A. hippocastanum and Q. nigra showed a lower diameter growth during drought events, followed by a fast recovery. This study’s findings may contribute to a better understanding of urban tree growth reactions to climate, aiming for sustainable planning and management of urban trees. Full article