Decrease In Annual Precipitation Research Articles

The impact of precipitation changes on the safety of railway operations in China under the background of climate change

Global climate change has intensified the water cycle, leading to frequent extreme precipitation events, posing a significant threat to railway infrastructure and safety operations. Based on the analysis of past and future precipitation changes in China, this study investigates the impact of climate change on railway safety operations. The study reveals the following findings: (1) Under the influence of the intensified East Asian summer monsoon and the northward shift of the subtropical high during the 2017–2021 compared to the 2012–2016, precipitation has significantly decreased (120 mm) in the regions south of the Yangtze River and South China, while it has increased (60 mm) in the regions from the eastern of Northwest China to the middle and lower reaches of Yangtze River; The operational precipitation risk has decreased for Urumqi, Lanzhou, Qinghai-Tibet Group, Xi’an, and Wuhan railway bureaus (abbreviated as Bureau), while it has increased for Nanchang, Chengdu, Zhengzhou, Shanghai, and Shenyang Bureaus. Particularly noteworthy is that despite a decrease in total annual precipitation for Nanchang bureau (15.3 mm/a), the frequency of intense precipitation events has increased, leading to an increased operational precipitation risk. (2) During the 21st century, under high (SSP5-8.5), medium (SSP2-4.5), and low (SSP1-2.6) forcing scenarios, all projections indicate that most of the China will experience an increasing trend in precipitation, with significant increases in precipitation observed in the regions south of the Yangtze Rive, South and Southwest China. The higher the greenhouse gas emissions, the more pronounced the increasing trend in precipitation. (3) Compared to the 20th century, under high (SSP5-8.5), medium (SSP2-4.5), and low (SSP1-2.6) forcing scenarios, all projections indicate that the total annual precipitation hours, railway inspection, speed limit, and closure risk hours have all increased on a national scale during the 21st century. The operational precipitation risk for railways has also increased. The higher the alert level for railway precipitation (precipitation < inspection < speed limit < closure), the higher the proportion of risk hours compared to the 20th century. By the late 21st century, the railway inspection, speed limit, and closure risk hours have increased by 175%, 463%, and 647%, respectively, compared to the 20th century.

Analysing the Evidence of the Effects of Climate Change, Air Pollutants, and Occupational Factors in the Appearance of Cataracts

Cataracts are ocular conditions characterized by the opacification of the natural lens within the eye, which develops gradually over time and can affect one or both eyes. This condition commonly results from age-related changes in the lens, but can also arise from various factors. Cataract surgeries are expensive, particularly in states such as Spain, where they receive full support from the Spanish social welfare system. Despite a significant body of research on cataracts, few studies address the social and environmental factors triggering their development or consider the spatiotemporal evolution of their impacts. We analysed the incidence of cataracts in a southern region of Spain, differentiating between senile cataracts (those over 60 years old) and early cataracts (those between 15 and 59 years old). Twenty-one socio-economic, climate, and air pollution variables were statistically analysed using bivariate correlation, cluster analysis, and Geographic Information Systems. Eleven years of observation show a decadal increase in annually averaged maximum temperature and a decrease in annual precipitation, partially explaining the rising incidence of operable cataracts in the following year (r = 0.77 and −0.84, respectively; p < 0.05). Furthermore, early cataracts responded spatially to % agricultural employment (r = 0.85; p < 0.05) and moderately to maximum temperatures, insolation, and various constituents.

The Spatio-Temporal Dynamics of Water Resources (Rainfall and Snow) in the Sierra Nevada Mountain Range (Southern Spain)

This paper describes the use of a unique spatio-temporally resolved precipitation and temperature dataset to assess the spatio-temporal dynamics of water resources over a period of almost seven decades across the Sierra Nevada mountain range, which is the most southern Alpine environment in Europe. The altitude and geographical location of this isolated alpine environment makes it a good detector of climate change. The data were generated by applying geostatistical co-kriging to significant instrumental precipitation and temperature (minimum, maximum and mean) datasets. The correlation between precipitation and altitude was not particularly high and the statistical analysis yielded some surprising results in the form of mean annual precipitation maps and yearly precipitation time series. These results confirm the importance of orographic precipitation in the Sierra Nevada mountain range and show a decrease in mean annual precipitation of 33 mm per decade. Seasonality, however, has remained constant throughout the period of the study. The results show that previous studies have overestimated the altitudinal precipitation gradient in the Sierra Nevada and reveal its complex spatial variability. In addition, the results show a clear correspondence between the mean annual precipitation and the NAO index and, to a much lesser extent, the WeMO index. With respect to temperature, there is a high correlation between minimum temperature and altitude (coefficient of correlation = −0.84) and between maximum temperature and altitude (coefficient of correlation = −0.9). Thus, our spatial temperature maps were very similar to topographic maps, but the temporal trend was complex, with negative (decreasing) and positive (increasing) trends. A dynamic model of snowfall can be obtained by using the degree-day methodology. These results should be considered when checking the local performance of climatological models.

Impact of urban dynamics and climate change on forest areas the Maamora forest in the city of Kenitra, Morocco

Studies have focused on the issue of drought on one hand, and urban dynamics on the other, as prominent topics in physical geography for the former, which specializes in climate change, and human geography for the latter, which concerns field sciences. This research is part of a series of studies and specifically relates to a wetland area in the western plain, specifically Maamora Forest in the city of Kenitra. This research addresses three main axes: the first axis relates to human factors contributing to the reduction and deterioration of Maamora Forest over the past three decades and analyzes their impact on the forest. This is done by determining the development and dynamics of cork oak through remote sensing data, manifested in the analysis of aerial images from three different periods (1975, 1995, and 2022), complemented by field research throughout the period between 2022 and 2023. The second axis focuses on studying climatic data for the studied area, extending from 1987 to 2019. It highlights the manifestations of climate change, such as a decrease in annual precipitation and an increase in temperatures, and their impacts on the overall forest and specifically on cork oak trees. This is done using the LANG equation. The results indicate that the region has experienced four dry periods, accounting for 87.5% of the total 28 years, which range from 1987/1988 to 1995/1994, 1997/1998 to 2010/2011, 2012/2013 to 2014/2015, and 2016/2017 to 2018/2019. In contrast, the percentage of semi-humid and extremely dry years only accounted for 6.25% each, with an average duration of two years. The third axis relates to monitoring the effects of climate change on the forestry sector, specifically the Maamora Forest, through the use of modern techniques such as remote sensing and spectral plant and water indicators. It aims to understand the role of these technologies in spatial monitoring of factors and phenomena that negatively impact forest areas in general, and the Maamora Forest in particular.

Yield stability of winter wheat in intercrop makes better adaptation to climate conditions

Global climate change is a main issue today. Negative effects, such as gradual warming, annual precipitation decrease and frequences of extreme meteorological events have also felt in Hungary. These effects significally tested the adaptive capacity of our cultivated plants. In our country two-thirds of the arable land is occupied by cereals. In most cases there is no crop rotation, pre-crop effect remains unused. Intercrop is a special kind of plant association, where two or more crops growing simultaneously on the same field. It can be increases resilience against pest and pesticides, provides better utilization of growth resources, and weed suppression. In mixture mitigate the effects of climate. Our experiments were made in 2020/2021 with 3 winter wheat varieties (GK Szilárd, Celulle, GK Csillag) and a winter pea variety (Aviron) in 4 repeats, on 10 square meter random layout plots in Szeged-Öthalom. We set 3 different seed density in every variety in every combination. Higher seed density of wheat makes higher yield regardless of pea, except of GK Csillag at 75% seed density of wheat and pea. Increasing pea ratio in mixture, wheat yield decreased. In contrast GK Szilárd and Cellule, their 75% and 100% mixture with 75% Aviron achieved higher wheat yield. Pure stands have shown better values than the combined ones, vice versa for GK Csillag: every seed density with 50% of Aviron gaves the highest wheat yield. Wheat and pea yield together gives the yield advantage what intercrop provides.

Impacts of climate change and human activities on sediment load in Longchuan River Basin, China

Study regionLongchuan River Basin in the Hengduan mountain region, China. Study focusWith the decrease in annual precipitation, the sediment yield on the slope and sediment delivery ratio (SDR) in the river channel, both play a critical role in runoff and sediment load change. However, the response mechanism of SDR to climate change and human activities remains unclear. The RUSLE model was used to calculate the sediment yield on the slope, and the SDR is quantified by the ratio of sediment load in the channel to the sediment yield on the slope.New hydrological insights for the region: Under climate change, the reduced annual rainfall caused a significant decrease in annual runoff and sediment load in the Longchuan River Basin (LRB), since 2003. The RUSLE model was used to calculate the sediment yield on the slope in LRB, and the sediment delivery ratio (SDR) was calculated by the ratio of sediment load to sediment yield. We found a new approach relevant to the relationship of SDR with annual runoff and sediment yield, which can indicate the response mechanism of SDR to climate change. In anthropogenic activities, reservoir interception is the main reason for the sediment load reduction, instead of the land use and land cover change. With a large reservoir built in the LRB, the average SDR is reduced by 83.04 % and the average trap efficiency of the reservoir is 0.96, which was calculated by the Brune equation. This study provides a feasible method to evaluate the effect of different factors on the runoff and sediment load change in the basin.

Unveiling the future of relict Mediterranean mountain peatlands by integrating the potential response of ecological indicators with environmental suitability assessments

Mediterranean mountain peatlands are unique ecosystems because of their distinct hydrology and environmental conditions, as well as being home to a vast array of rare and endemic species. Due to anthropogenic activities and ongoing climate change, mountain peatlands are one of the most endangered ecosystems in Mediterranean areas. Climate scenarios for the western Mediterranean area estimate a sharp decrease in annual precipitation and an upsurge in temperature, which may disrupt the structure and functioning of ground-water-dependent ecosystems. To predict how the environmental suitability of Mediterranean mountain peatlands would be impacted by climate-induced changes, a microscale climatic model was used to downscale 2 m hourly air temperature to a high spatial resolution of 100 m in protected area of North Portugal. The environmental suitability was assessed based on bioclimatic indices associated with mountain peatland indicator species. Climate change projections envisage a decline in the environmental suitability of Mediterranean mountain peatlands and their indicator species, which could compromise this relict ecosystem probability of occurrence. Specifically, environmental suitability was considered highly sensitive to increases in temperature, namely when coupled with decreases in precipitation, resulting in significant reshaping of potential evaporation, evapotranspiration, and soil water content of the areas where peatlands actually occur. Also, the importance of microclimatic information for detecting change in ecosystems that are more vulnerable to climate change and in defining the best management options and conservation priorities is highlighted. Considering their vital role in the conservation of biodiversity and provider of ecosystem services, actions to mitigate and restore Mediterranean mountain peatlands are urgent.

Stable isotopes contain substantial additive information about terrestrial carbon and water cycling

Stable isotope ratios of H (δ 2 H), O (δ 18O), and C (δ 13C) are linked to key biogeochemical processes of the water and carbon cycles; however, the degree to which isotope-associated processes are reflected in macroscale ecosystem flux observations remains unquantified. Here through formal information assessment, new measurements of δ 13C of net ecosystem exchange (NEE) as well as δ 2H and δ 18O of latent heat (LH) fluxes across the United States National Ecological Observation Network (NEON) are used to determine conditions under which isotope measurements are informative of environmental exchanges. We find all three isotopic datasets individually contain comparable amounts of information about NEE and LH fluxes as wind speed observations. Such information from isotope measurements, however, is largely unique. Generally, δ 13C provides more information about LH as aridity increases or mean annual precipitation decreases. δ 2H provides more information about LH as temperatures or mean annual precipitation decreases, and also provides more information about NEE as temperatures decrease. Overall, we show that the stable isotope datasets collected by NEON contribute non-trivial amounts of new information about bulk environmental fluxes useful for interpreting biogeochemical and ecohydrological processes at landscape scales. However, the utility of this new information varies with environmental conditions at continental scales. This study provides an approach for quantifying the value adding non-traditional sensing approaches to environmental monitoring sites and the patterns identified here are expected to aid in modeling and data interpretation efforts focused on constraining carbon and water cycles’ mechanisms.

Long-Term Monitoring of Tree Population Dynamics in Desert Ecosystems: Integrating Field and Satellite Data

Arid environments are characterized by rare rain events that are highly variable, as a result of which plant populations often exhibit episodic recruitment and mortality dynamics. However, direct records and observations of such events are rare because of the slow development of woody species. In this study, we described how a decrease in annual precipitation affected acacia tree population dynamics in two hydrological regime types: small wadis and salt flats. This study combines 15 years of continuous, yearly field monitoring of individual acacia trees and data from a historical Corona satellite image, which has extended the time scope of the research. Results indicate that the annual mortality of acacia trees in small wadis reflects the cumulative effective rain events in the preceding five years, whereas the population on the salt flats was not affected by annual rainfall fluctuations. Moreover, in small wadis, rain events of less than 8 mm did not increase acacia tree survival rates. The mortality pattern and dynamics of each plot was unique, suggesting unsynchronized mortality and recruitment episodes on a regional scale. Mortality in all plots was documented both in “old” trees (i.e., recognized in 1968) and “new” trees (not recognized in 1968), but varied highly between plots. More than 50% of the dead trees recorded at the sites had died during the previous dry period (2000–2010). Combining field monitoring and historical satellite image data provided a unique database of acacia population dynamics. This record revealed the response of the acacia population to climate fluctuations and a period of episodic mortality.

Natural revegetation has dominated annual runoff reduction since the Grain for Green Program began in the Jing River Basin, Northwest China

The Grain for Green Program (GFGP) has successfully increased the vegetation cover in northern China over the last two decades through large-scale natural and artificial revegetation approaches. Unfortunately, an obvious runoff reduction has been observed in many basins, especially on the semiarid Loess Plateau. Past studies generally attributed this runoff reduction to the artificial revegetation of the GFGP, i.e., the land cover type change from cropland to forest, since there was no significant annual precipitation decrease. Such cognition has led to widespread concern about the hydrological effects of the GFGP. In fact, in addition to artificial revegetation, natural revegetation relies on natural processes of vegetation succession without land cover type changes directed by humans. Therefore, it is necessary to separate and quantify the contributions of natural and artificial revegetation to runoff reduction to assess the GFGP and optimize revegetation in the future. In this study, the contributions of natural and artificial revegetation to annual runoff change after the implementation of the GFGP were quantified in fifteen subbasins of the Jing River Basin in the central Loess Plateau. The mean annual runoff of the Jing River Basin decreased by 11.8 mm after the GFGP, although the climate (precipitation and potential evapotranspiration) inversely increased the mean annual runoff by 6.6 mm. This is due to that the direct effect of climate change was much less than the ecohydrological effect of revegetation on runoff reduction, i.e., the revegetation caused the mean annual runoff reduction of 18.4 mm. Natural revegetation (50.5% of basin area) was the dominant reason for runoff reduction rather than artificial revegetation (9% of basin area). The natural revegetated area with vegetation quality improvement, i.e., an NDVI increase without land cover type change, contributed to a runoff reduction of 15.5 mm, accounting for 131.1% of the total runoff reduction after the GFGP, and the grassland of natural revegetation was the main vegetation type, with runoff reductions of 9.8 mm. However, artificial revegetation by area increase and quality improvement, i.e., NDVI increase, contributed to a runoff reduction of 8.4 mm, accounting for 49.6% of the total runoff reduction. These results demonstrated that the GFGP needs to be properly adjusted, i.e., natural revegetated areas should be opened in a timely manner and properly utilized, and improving vegetation quality improvement rather than increasing vegetation area would be a priority management measure in artificial revegetated areas.

Characteristics and Projection of Rainfall Erosivity Distribution in the Hengduan Mountains

This study examines the spatiotemporal variations of rainfall erosivity in the Hengduan Mountains, known for their rugged terrain and high potential for soil erosion risks, over the past 30 years. Additionally, it investigates the changing trends of rainfall erosivity between 2025 and 2040 under the Sustainable Development Pathway 2–4.5 (SSP2–4.5), using four Global Climate Models (GCMs) based on the Coupled Model Intercomparison Project phase 6 (CMIP6). The results indicate: (1) The annual distribution of rainfall erosivity in the Hengduan Mountains exhibited significant seasonal variations, ranking in the order of summer > autumn > spring > winter on a seasonal scale. (2) Over the past 30 years, there has been a slight decrease in annual precipitation and a corresponding slight increase in rainfall erosivity. Periodic extreme values occur every 6–8 years. (3) Spatially, rainfall erosivity demonstrates a decreasing gradient from southeast to northwest. There is a significant positive correlation between rainfall erosivity and precipitation, while a significant negative correlation exists with elevation in the vertical direction. Furthermore, the northeastern part of the Hengduan Mountains exhibits an increasing trend of rainfall erosivity, while the southern region experiences a decreasing trend. (4) Considering the joint driving forces of increased precipitation and erosive rainfall events, rainfall erosivity is expected to significantly increase in the future, posing a more severe risk of soil erosion in this region.

The impact of global changes in near-term climate forcers on East Africa’s climate

Climate change and air pollution are two interconnected daunting environmental challenges of the twenty-first century. Globally, stringent public health and environmental policies are set to mitigate the emissions of near-term climate forcers (NTCFs) because they double as air pollutants. While the global climate impact of NTCF mitigation has been investigated using coarse resolution climate models, the fine scale regional climate impacts over East Africa are not fully known. This study presents the first 2021–2055 downscaled model results of two future scenarios which both have increasing greenhouse gas emissions but with weak (SSP3-7.0) versus strong (SSP3-7.0_lowNTCF) levels of air quality control. NTCF mitigation is defined here as SSP3-7.0_lowNTCF–SSP3-7.0. The results reveal that NTCF mitigation could cause an increase in annual mean surface temperature ranging from 0.005 to 0.01 °C decade−1 over parts of Kenya, Ethiopia and Somalia. It could also cause an increase in annual mean precipitation ranging from 0.1 to 1 mm month−1 decade−1 over parts of Uganda, Kenya, Tanzania, South Sudan and Ethiopia. Majority of the precipitation increase is projected to occur during the MAM season. On the other hand, Zambia, Malawi and southern Tanzania could also experience a decrease in annual mean precipitation by up to 0.5 mm month−1 decade−1. Majority of this decrease is projected to occur during the DJF season. These findings suggest that pursuing NTCF mitigation alone while ignoring greenhouse gas emissions will cause additional climate change over East Africa. Mitigating both of them concurrently would be a better policy option.

"Cold deficiency" and degradation of permafrost soils as a factor of transformation of hunting activity among the Yakuts

One of the most important global problems of the XXI century is climate change. Every year, in some parts of the world, a decrease in annual precipitation and temperature is recorded, in others, on the contrary, an increase. These fluctuations can cause droughts, floods and degradation of permafrost soils. Further climate change may cause irreparable damage to traditional farming methods and adversely affect housing conditions in many regions of the globe. Thus, climate change can complicate and disrupt the established order of life and activity of the population of the Republic of Sakha (Yakutia). This paper highlights a problem that has not been specifically studied before, and which concerns all hunters of the republic, the impact of climate change on hunting activities. The work is based on field materials collected by Vilyuysky and Tattinsky districts. Field materials were collected by audio, photo and video recording, in-depth interviewing and included observation during field work in the Vilyuysky and Tattinsky districts of the Republic of Sakha (Yakutia). In earlier scientific works research was conducted separately on the topic of the impact of climate change on the daily life and economic activities of the Yakuts, in this work hunting activity was considered. Hunters who participated in the research adapt to the changing climate in various ways: they increase the range of hunting area, equip trips over longer distances than before, learn to re-read changes in weather conditions, manufacture and use various devices for hunting and storage. The main conclusions of the research are that climatic changes directly or indirectly affect hunting activities in the studied areas: ordinary amateur hunters note that the habitat of animals is changing, roads are being destroyed, the soil of hunting grounds is degrading, there is a danger of the spread of various diseases.

Contribution of non-point source pollution that migrated with underground runoff process based on the SWAT model and a digital filter algorithm.

Non-point source (NPS) pollution has always been the focus of research worldwide, and understanding the migration process is the basis for effective control of NPS pollution. In this study, the SWAT model and digital filtering algorithm were combined to explore the contribution of NPS pollution that migrated with underground runoff (UR) process to the Xiangxi River watershed. The results showed that the surface runoff (SR) was the main migration process of NPS pollution, while the contribution of NPS pollution that migrated with the UR process only accounted for 30.9%. With the decrease in annual precipitation among the three selected hydrological years, the proportion of NPS pollution that migrated with the UR process for TN decreased, whereas the proportion for TP increased. The contribution of NPS pollution migrated with UR process varied remarkably during different months. Although the maximum total load and the load of NPS pollution that migrated with the UR process for TN and TP all appeared in the wet season, due to the hysteresis effect, the load of NPS pollution that migrated with the UR process for TP appeared 1month later than the total load of NPS pollution. With an increase in precipitation from the dry season to the wet season, the proportion of NPS pollution that migrated with the UR process for TN and TP decreased gradually, and the degree of decrease in NPS pollution that migrated with the UR process for TP was more evident than that for TN. Besides, being affected by topography, land use, and other factors, the proportion of NPS pollution that migrated with the UR process for TN decreased from 80% in upstream areas to 9% in downstream areas, while that for TP reached a maximum of 20% in downstream areas. Based on the research results, the contribution of soil and groundwater cumulative nitrogen and phosphorus should be considered, and different managements and control measures for different migration routes should be adopted in controlling pollution.

Influence of climate change and pesticide use practices on the ecological risks of pesticides in a protected Mediterranean wetland: A Bayesian network approach

Pollution by agricultural pesticides is one of the most important pressures affecting Mediterranean coastal wetlands. Pesticide risks are expected to be influenced by climate change, which will result in an increase of temperatures and a decrease in annual precipitation. On the other hand, pesticide dosages are expected to change given the increase in pest resistance and the implementation of environmental policies like the European ´Farm-to-Fork` strategy, which aims for a 50 % reduction in pesticide usage by 2030. The influence of climate change and pesticide use practices on the ecological risks of pesticides needs to be evaluated making use of realistic environmental scenarios. This study investigates how different climate change and pesticide use practices affect the ecological risks of pesticides in the Albufera Natural Park (Valencia, Spain), a protected Mediterranean coastal wetland. We performed a probabilistic risk assessment for nine pesticides applied in rice production using three climatic scenarios (for the years 2008, 2050 and 2100), three pesticide dosage regimes (the recommended dose, and 50 % increase and 50 % decrease), and their combinations. The scenarios were used to simulate pesticide exposure concentrations in the water column of the rice paddies using the RICEWQ model. Pesticide effects were characterized using acute and chronic Species Sensitivity Distributions built with toxicity data for aquatic organisms. Risk quotients were calculated as probability distributions making use of Bayesian networks. Our results show that future climate projections will influence exposure concentrations for some of the studied pesticides, yielding higher dissipation and lower exposure in scenarios dominated by an increase of temperatures, and higher exposure peaks in scenarios where heavy precipitation events occur right after pesticide application. Our case study shows that pesticides such as azoxystrobin, difenoconazole and MCPA are posing unacceptable ecological risks for aquatic organisms, and that the implementation of the ´Farm-to-Fork` strategy is crucial to reduce them.

Quercus insignis seedling response to climatic transfer distance in the face of climate change

Rising temperatures are causing increased tree mortality at lower elevations and upward migrations in montane tree communities. To reduce the risk of extinction from climate change, managed translocation or assisted migration could serve to support the management of endangered species, but is currently a controversial strategy with very limited information available from experimental field studies in the tropics. We examined the effect of climatic transfer distance (CTD; the climatic difference between the site of seed origin and the site of plantation) on the establishment of Quercus insignis, an endangered oak with a distribution restricted to cloud forests. If the natural population (seed origin) occurs at its optimum climate, a decline in seedling transplant performance is expected to occur with greater CTD. Enrichment plantings were established in three sites near the seed origin area (at 1400 m a.s.l.), and in five sites from an elevation similar to the seed source up to high elevations (1365 to 2531 m a.s.l.) in Mexico. We examined the effect of CTD on seedling survival and Relative Growth Rate (RGR) over a period of four years. In the provenance area, a 1.4 °C increase and a 25–30 % annual precipitation decrease were estimated to have occurred during the study period (2018–2021), relative to the reference climate (1960–1990) in which the population in the provenance area developed. We found no significant evidence to support lower seedling survival with greater CTD. High survival occurred in sites with a warmer temperature at present (up to 80 % survival), but also in colder sites at higher elevation (up to 90 %), revealing the high tolerance of Q. insignis to a wide range of climatic conditions. The RGR showed the expected decrease with greater CTD of the Aridity Index, reflecting the importance of the balance between temperature and water availability. These findings support the potential of Q. insignis enrichment plantings, both near the seed origin area and at higher elevation (currently 2–3 °C colder than in the provenance area) to compensate for the expected temperature increase. However, the projected reduction in precipitation and cloud immersion within the cloud forest belt associated with climate change, could act to limit growth and lead to lower establishment success.

Projected changes in precipitation characteristics over the Drakensberg Mountain Range

AbstractThis study examines the potential impacts of climate change on the characteristics of precipitation over the Drakensberg Mountain Range (DMR) at different global warming levels (GWLs: 1.5, 2.0, 2.5 and 3.0°C) under the Representative Concentration Pathway 8.5 (RCP8.5) scenario, using dynamical and statistical downscaled datasets. The dynamical datasets consist of 19 multi‐model simulations datasets from the Coordinated Regional Climate Downscaling Experiment (CORDEX), whereas the statistical downscaled datasets comprise 19 multi‐model simulations from the National Aeronautics and Space Administration (NASA) Earth Exchange (NEX) Global Daily Downscaled Projections (NEX‐GDDP, hereafter NEX). The capacity of the CORDEX and NEX datasets to represent past characteristics of extreme precipitation over the DMR was evaluated against eight observation datasets. The precipitation characteristics were represented by eight precipitation indices. Both CORDEX and NEX realistically capture the characteristics of extreme precipitation over the Drakensberg and, in most cases, their biases lie within the observation uncertainty. However, NEX performs better than CORDEX in reproducing most of the precipitation characteristics, except in simulating the threshold of extreme rainfall. The ensemble means of CORDEX and NEX agree on a future increase in the intensity of normal precipitation, in the frequency and intensity of extreme precipitation, as well as an increase in widespread extreme events, with a decrease in the number of precipitation days and continuous wet days. However, they disagree on the projected changes of annual precipitation, for which CORDEX projects an increase over most parts of the DMR, whereas NEX indicates a decrease. The self‐organizing‐map analysis, which reveals diversity in the projection patterns hidden in the ensemble means, shows the most probable combinations of projected changes in the annual precipitation and extreme precipitation events (in terms of intensity and frequency): (a) increase in both annual precipitation and extreme precipitation events; (b) decrease in both annual precipitation and extreme precipitation events; (c) decrease in annual precipitation but increase in extreme precipitation events. The results of this study can thus provide a basis for developing climate change adaptation and mitigating strategies over the DMR.

The Northward Range Shifting of Agapanthiola Leucaspis Under the Climate Change

Agapanthiola leucaspis is a steppe transpalearctic cerambycid species, widely distributed from the Pannonian lowland in Europe to the Mongolian plateau in Asia. In Ukraine, the species was previously known from the Pontic Plains and the Crimean Peninsula. However, in the last decade, a number of new localities of A. leucaspis have been discovered far outside the original range. We previously hypothesized a possible link between the northward spread of A. leucaspis and the current climate change. In this paper, we tested this hypothesis using computer simulations with GIS technologies. Our primary objective was to determine the critical value of key climatic factors that could potentially trigger the northward and montane range expansion of A. leucaspis. We collected all available data, including our own materials, scientific collections, published scientific papers, and citizen science data on the distribution of A. leucaspis in Ukraine and neighboring countries. These data were separated by the time of records before 2000 and after 2000 according to the change of the current understanding of climatic norm of 1950-2000 due to global warming. As a result, we determined the ecological valency of A. leucaspis in relation to climatic factors and built a model of its original range. Further simulations were associated with a +2.0°C change in global temperature parameters in 0.5°C increments and a 30% increase and decrease in precipitation in 10% increments. Resultantly, we found that the amount of precipitation and the seasonality of temperatures, especially in winter, are crucial factors for the observed fluctuation of A. leucaspis range. An increase in average temperatures eliminates the winter frosts which are limiting factor for the spread of A. leucaspis to the north. The decrease in average annual precipitation increases the probability of the species survival in areas where this was previously impossible. We have shown that to expand the current range of A. leucaspis, it is enough to warm the climate in the annual average by +0.5°C and reduce the amount of precipitation by 10%. A warmer and drier climate is the main abiotic factor for the expansion of A. leucaspis into higher latitudes and mountains.

Downward Trends in Streamflow and Sediment Yield Associated with Soil and Water Conservation in the Tingjiang River Watershed, Southeast China

Soil erosion is one of the most serious environment problems in China. Soil and water conservation (SWC) measures play an important role in reducing streamflow and sediment yields. A nested watershed approach, together with the Mann–Kendall trend test, double mass curve, and path analysis were used to quantitatively explore hydrological effects of SWC measures in the Tingjiang River Watershed. Results showed the annual streamflow and sediment yields tended toward a remarkable downward trend since the implementation of SWC measures during 1982–2014, indicating that SWC measures produced significant hydrological effects. The contribution of precipitation to annual streamflow increased from 71% to 79% from the periods 1982–2000 to 2000–2014, indicating decreases in annual precipitation after 2003 and stronger impacts on streamflow than that of SWC measures. However, the contribution of SWC measures to sediment yields increased from 11% to 64% from 1982 to 2014 and gradually dominated contributions to the sediment yields in the watershed. An ecological threshold was established at which the proportion of the cumulative afforestation area due to SWC reaches 10% of the whole watershed, and the remarkable improvements of hydrological effects in the watershed can be observed. These findings could be used to evaluate performance of SWC measures in watersheds.

Soil Erosion under Future Climate Change Scenarios in a Semi-Arid Region

The Mediterranean Region is presumed to be one of the locations where climate change will have the most effect. This impacts natural resources and increases the extent and severity of natural disasters, in general, and soil water erosion in particular. The focus of this research was to assess how climate change might affect the rate of soil erosion in a watershed in the High Atlas of Morocco. For this purpose, high-resolution precipitation and temperature data (12.5 × 12.5 km) were collected from EURO-CORDEX regional climate model (RCM) simulations for the baseline period, 1976–2005, and future periods, 2030–2060 and 2061–2090. In addition, three maps were created for slopes, land cover, and geology, while the observed erosion process in the catchment was determined following field observations. The erosion potential model (EPM) was then used to assess the impacts of precipitation and temperature variations on the soil erosion rate. Until the end of the 21st century, the results showed a decrease in annual precipitation of −32% and −46% under RCP 4.5 for the periods 2030–2060 and 2061–2090, respectively, −28% and −56% under RCP 8.5 for the same periods, respectively, and a large increase in temperature of +2.8 °C and +4.1 °C for the RCP 4.5 scenario, and +3.1 °C and +5.2 °C for the RCP 8.5 scenario for the periods 2030–2060 and 2061–2090, respectively. The aforementioned changes are anticipated to significantly increase the soil erosion potential rate, by +97.11 m3/km2/year by 2060, and +76.06 m3/km2/year by 2090, under the RCP 4.5 scenario. The RCP 8.5 predicts a rise of +124.64 m3/km2/year for the period 2030–2060, but a drop of −123.82 m3/km2/year for the period 2060–2090.