Extreme Drought Research Articles

Vegetation Warming and Greenness Decline across Amazonia during the Extreme Drought of 2023

In 2023, most parts of the world experienced exceptional heat. In particular, anomalous warm temperatures and heatwave events were evidenced across South America during the second half of the year. The situation was particularly critical in the Amazon region in terms of not only hydrometeorological drought but also ecological and socioeconomic impacts. In this study, remote-sensing data collected from the Moderate Resolution Imaging Spectroradiometer (MODIS) were used to observe the changes in temperature and vegetation across Amazonia during the exceptional drought of 2023. This analysis was based on anomalies in the land surface temperature (LST) and vegetation indices: the enhanced vegetation index (EVI) and the normalized difference vegetation index (NDVI). The amplitude of the LST (AMP-LST), an indicator of the energy partitioning between the latent and sensible heat flux, and fire counts were also considered. The results show widespread and extreme warming across Amazonia during the austral spring in 2023, accompanied by a decline in vegetation greenness, water stress conditions across northern Amazonia, and an enhanced fire occurrence across central and northern Amazonia.

River morphological behavior between two barrages on the Euphrates: A case study

The Abbassia-Shammia stream is a meandering reach in Najaf Province downstream of the Euphrates. The geomorphological traits and process-based assessment of large rivers are rarely observed globally, particularly in less developed nations. The need for such evaluation arose due to climate change, hydraulic structure construction, and the possibility of extreme droughts and floods. The hydraulic and morphological properties of the Abbassia-Shammia reach were significantly altered owing to the installation of successive barrages and climatic change. This paper aims to assess the river morphological behavior downstream of the Euphrates near the Abbassia-Shammia reach for 32 km length through the bed change investigation process, i.e. river sedimentation and erosion. The morphological performance of the Euphrates reaches between two series of barrages, namely Abbassia and Shammia, was simulated using HEC RAS2D, a tool developed by the River Analysis System program of the Hydrologic Engineering Center. The research revealed that bed change levels ranged from 5.87 meters of sedimentation to 5.720 meters of erosion. Furthermore, the results showcased how effectively the HEC RAS2D model accurately captured the features of a Euphrates section between two barrages. The results of the study provide insights into the future behavior of channels. They can help to address the issues caused by the prevailing fluvial processes such as sedimentation and erosion.

A geographic information system and analytic hierarchy process drought risk analysis approach in arid south-western Zimbabwe: Prospects for informed resilience building

Climate change is increasing the vulnerability of communities to drought, with rural communities in developing countries being affected the most. The study assessed drought vulnerability in south western Zimbabwe based on the Analytic Hierarchy Process (AHP) supported by Geographic Information System (GIS) and remote sensing techniques. An empirical research design based on verifiable evidence of drought vulnerability was adopted. GIS and remote sensing data were used to execute the multi-criteria AHP for the determination of drought vulnerability. ArcMap 10.8 software was used for the analysis of drought influencing factors and carrying out the weighted overlay. Results indicate that almost the whole of south western Zimbabwe is prone to droughts with only 0.6 % of the area being comparatively better. It was also noted that the majority of the population are exposed to high and extreme risk of droughts as they are settled in extreme and high drought risk zones. The study recommends implementation of resilience building interventions from an informed dimension where specific resilience building initiatives are implemented in appropriate environments for high returns. This can sustain the communities in the face of increasing drought risk due to climate change in line with the aspirations of the universal sustainable development goals and the country's vision of attaining an upper middle-income society by 2030. A framework for creating drought resilience was developed to ensure that development stakeholders cooperate to build drought resilient communities in tropical regions with drought challenges like Zimbabwe and the rest of Southern Africa.

Long-term complementary scheduling model of hydro-wind-solar under extreme drought weather conditions using an improved time-varying hedging rule

The frequent occurrence of extreme drought weather poses serious challenges to the complementary scheduling of renewable energy, including uncertain production processes, ineffective scheduling rules, and complex model solving, which further reduces the reliability of the power grid. To address these issues, a long-term complementary scheduling model of hydro-wind-solar (LCMHWS) considering hedging rules is proposed. First, to fully eliminate the uncertainty in monthly variables, Monte Carlo simulation and K-means clustering are sequentially absorbed into the model to process historical sequences and provide deterministic scenarios in which variable characteristics are conformed as input factors. Second, an improved time-varying hedging rule with strong drought resistance capability is proposed to optimize the complementary process of hydro-wind-solar and maximize the objectives of power generation and final energy storage. Last, NSGAII and membership function are adopted to search for the optimal Pareto solution for the uncertain multi-objective model. LCMHWS is validated for 7 hydropower and nearby wind and solar plants on the Lancang River in China. The results indicate that, while meeting the guaranteed output of the system, LCMHWS can increase the power generation and final energy storage by 14 % and 3 % under extreme drought conditions, respectively, and also smoothed the output process of power grid.

Canopy cover and soil moisture influence forest understory plant responses to experimental summer drought.

Extreme droughts are globally increasing in frequency and severity. Most research on drought in forests focuses on the response of trees, while less is known about the impacts of drought on forest understory species and how these effects are moderated by the local environment. We assessed the impacts of a 45-day experimental summer drought on the performance of six boreal forest understory plants, using a transplant experiment with rainout shelters replicated across 25 sites. We recorded growth, vitality and reproduction immediately, 2 months, and 1 year after the simulated drought, and examined how differences in ambient soil moisture and canopy cover among sites influenced the effects of drought on the performance of each species. Drought negatively affected the growth and/or vitality of all species, but the effects were stronger and more persistent in the bryophytes than in the vascular plants. The two species associated with older forests, the moss Hylocomiastrum umbratum and the orchid Goodyera repens, suffered larger effects than the more generalist species included in the experiment. The drought reduced reproductive output in the moss Hylocomium splendens in the next growing season, but increased reproduction in the graminoid Luzula pilosa. Higher ambient soil moisture reduced some negative effects of drought on vascular plants. Both denser canopy cover and higher soil moisture alleviated drought effects on bryophytes, likely through alleviating cellular damage. Our experiment shows that boreal understory species can be adversely affected by drought and that effects might be stronger for bryophytes and species associated with older forests. Our results indicate that the effects of drought can vary over small spatial scales and that forest landscapes can be actively managed to alleviate drought effects on boreal forest biodiversity. For example, by managing the tree canopy and protecting hydrological networks.

Drought, water management, and agricultural livelihoods: Understanding human-ecological system management and livelihood strategies of farmer's in rural California

Mitigating impact between agricultural livelihoods and water conservation efforts in the face of significant drought requires a sophisticated understanding of policy efforts enacted to manage water supply and the logic of human livelihood decision-making. This case study extends literature on human-water decision-making in agricultural areas by using a political ecology framework to understand how and why farmers facing significant water shortages make livelihood decisions, and how such decisions are affected by broader socio-political contexts. Specifically, we focus on farmers' livelihood strategies in the Central San Joaquin Valley of California. Here, the effects of extreme and persistent drought have resulted in a resource management governance structure that forces farmer decision-making within the narrow bounds of the newly emerging California water policy. We argue that government public policy intervention has created a potential system of “big winners and big losers,” leading to three divergent strategies farmers adopt: Nimbility, Abandonment, and Policy Engagement. These findings raise questions about how policy interventions shape livelihood strategies of farmers in the Tulare Lake Basin and by extension other areas where public policy intervention is emerging to respond to decreased water supply resources.

Cultural and Spiritual Adaptations to Extreme Weather Events of Ethnic Farming Communities of the Three Watersheds Situated at Different Altitudinal Locations along Agno River Basin, Benguet and Pangasinan, Philippines

Ethnic farming communities in Agno River Basin face climate stressors that threaten their agricultural production. This paper investigated and assessed the cultural/spiritual adaptations to climate variabilities and extremes of ethnic farming communities in Agno River Basin, Philippines. How the presence of these cultural/spiritual practices moderate or mitigate the effects of climate variabilities and extremes were likewise investigated. The climate-related hazards considered in this study which are pronounced in the river basin are prolonged and extreme rainfall intensity, typhoons and extreme winds, drought, flood and occurrence of pests and diseases. These hazards are becoming more frequent and intense resulting to limited agricultural production. This paper considered only the sectors of agriculture/socioeconomic, water and health. The descriptive method employed in this study was based on the works of Oppenheimer et al (2014); Saroar, Routray and Leal Filho (2015) and Brooks and Adgers(undated). The data-gathering activities were household survey using pre-tested questionnaires, focused group discussions and key informant interviews. The ethnic affiliations of the farming communities were I-Karao, Ibaloi, Kankanaey and Kalanguya tribes. Secondary data on changing rainfall and erratic temperature characteristics were consistent with the general perception of the ethnic farming communities. Cultural/ spiritual traditions of Ethnic farming communities in the Agno River Basin form part of their adaptations to climate extremes and variabilities. The greatest number of rituals and activities (5) such as childless couples raising plant materials, burning of rice straws and Alay, Leppas, Maepdesan, and Ibkas or maboteng. are dedicated to ensuring a good harvest. Canyao, Libot, and Begnas are undertaken to prevent the occurrence of hazards. On the other hand, Ubob, Bayanihan, and Sakdo are adaptations to mitigate the impact of climate extremes and variabilities. Both Canyao and Leppas are also thanksgiving activities while Tagainep or dream interpretation serves as a coping mechanism.

Catchment-scale assessment of drought impact on environmental flow in the Indus Basin, Pakistan

Abstract. The impact of drought on environmental flow (EF) in 27 catchments of the Indus Basin is studied from 1980–2018 using indicators of hydrologic alterations (IHAs). The standardized precipitation evapotranspiration index (SPEI) was systematically propagated from one catchment to another using principal component analysis (PCA). Threshold regression is used to determine the severity of drought (scenario 1, drought severity that causes low flows) and the month (scenario 2, months where drought has resulted in low flows) that trigger low flows in the Indus Basin. The impact of drought on low EFs is quantified using range of variability analysis (RVA), which is an integrated component of the IHA used to study the hydrological alterations in environmental flow components (EFCs) by comparing the pre- and post-impact periods of human and/or climate interventions in EFCs. The hydrological alteration factor (HAF) is calculated for each catchment in the Indus Basin. The results show that most of the catchments were vulnerable to drought during the periods of 1984 to 1986, 1991/1992, 1997 to 2003, 2007 to 2008, 2012 to 2013, and 2017 to 2018. On a longer timescale (SPEI-12), drought is more severe in the lower Indus Basin (LIB) than in the upper Indus Basin (UIB). The IHA pointed out that drought significantly impacts the distribution of EFCs, particularly extremely low flow (ELF) and low flow (LF). The magnitude and frequency of the ELF and LF events increase as drought severity increases. The threshold regression provided useful insights, indicating that moderate drought can trigger ELF and LF at shorter timescales (SPEI-1 and SPEI-6) in the UIB and middle Indus Basin (MIB). Conversely, severe and extreme droughts trigger ELF and LF at longer timescales (SPEI-12) in the LIB. The threshold regression also divided the entire study period (1980–2018) into different time periods (scenario 2), which is useful for quantifying the impact of drought on low EFs using the SPEI coefficient. Higher SPEI coefficients are observed in the LIB, indicating high alterations in EF due to drought. HAF showed high alterations in EF in most of the catchments throughout the year except in August and September. Overall, this study provided useful insights for analysing the effects of drought on EF, especially during low flows.

Nitrogen deposition differentially regulates the sensitivity of gross primary productivity to extreme drought versus wetness.

Global hydroclimatic variability is increasing with more frequent extreme dry and wet years, severely destabilizing terrestrial ecosystem productivity. However, what regulates the consequence of precipitation extremes on productivity remains unclear. Based on a 9-year field manipulation experiment on the Qinghai-Tibetan Plateau, we found that the responses of gross primary productivity (GPP) to extreme drought and wetness were differentially regulated by nitrogen (N) deposition. Over increasing N deposition, extreme dry events reduced GPP more. Among the 12 biotic and abiotic factors examined, this was mostly explained by the increased plant canopy height and proportion of drought-sensitive species under N deposition, making photosynthesis more sensitive to hydraulic stress. While extreme wet events increased GPP, their effect did not shift over N deposition. These site observations were complemented by a global synthesis derived from the GOSIF GPP dataset, which showed that GPP sensitivity to extreme drought was larger in ecosystems with higher N deposition, but GPP sensitivity to extreme wetness did not change with N deposition. Our findings indicate that intensified hydroclimatic variability would lead to a greater loss of land carbon sinks in the context of increasing N deposition, due to that GPP losses during extreme dry years are more pronounced, yet without a synchronous increase in GPP gains during extreme wet years. The study implies that the conservation and management against climate extremes merit particular attention in ecosystems subject to N deposition.

Changes in productivity partitioning induced by precipitation extremes increase inaccuracy of grassland carbon estimation.

The fraction of net primary productivity (NPP) allocated to belowground organs (fBNPP) in grasslands is a critical parameter in global carbon cycle models; moreover, understanding the effect of precipitation changes on this parameter is vital to accurately estimating carbon sequestration in grassland ecosystems. However, how fBNPP responds to temporal precipitation changes along a gradient from extreme drought to extreme wetness, remains unclear, mainly due to the lack of long-term data of belowground net primary productivity (BNPP) and the fact that most precipitation experiments did not have a gradient from extreme drought to extreme wetness. Here, by conducting both a precipitation gradient experiment (100-500 mm) and a long-term observational study (34 years) in the Inner Mongolia grassland, we showed that fBNPP decreased linearly along the precipitation gradient from extreme drought to extreme wetness due to stronger responses in aboveground NPP to drought and wet conditions than those of BNPP. Our further meta-analysis in grasslands worldwide also indicated that fBNPP increased when precipitation decreased, and the vice versa. Such a consistent pattern of fBNPP response suggests that plants increase the belowground allocation with decreasing precipitation, while increase the aboveground allocation with increasing precipitation. Thus, the linearly decreasing response pattern in fBNPP should be incorporated into models that forecast carbon sequestration in grassland ecosystems; failure to do so will lead to underestimation of the carbon stock in drought years and overestimation of the carbon stock in wet years in grasslands.

Drought and wetness events encounter and cascade effect in the Yangtze River and Yellow River Basin

Under the background of global change, the multivariate attributes, multi-temporal and multi-watershed regional characteristics of extreme drought and flood disasters are significant. It is very important to identify the drought and wetness encounter law and spatial cascade effect in the source region-upper-middle-lower reaches of the basin. In this paper, the Yangtze River and Yellow River basins are taken as the research objects. Based on the standardized precipitation index (SPI) characterizing meteorological drought and wetness and the standardized runoff index (SRI) characterizing hydrological drought and wetness, the evolution law of extreme drought and flood events in the source region-upper-middle-lower reaches of the two basins is analyzed. On this basis, the correlation analysis and transfer function analysis are used to explore the response relationship and lag effect between the two in different partitions. A two-dimensional joint distribution model is constructed by Copula function to quantitatively analyze the joint probability of drought and wetness encounters of 9 combined events, and to deeply analyze the impact of different drought and wetness encounter scenarios. The results show that: from 1957 to 2020, the two basins showed a trend from drought to wet. The SPI-12 in the Yellow River Basin ranged from-1.57 to 1.32, and that in the Yangtze River Basin ranged from-1.24 to 1.11. The severity of drought and wetness in the Yellow River Basin was higher than that in the Yangtze River Basin; The correlation coefficients between SPI and SRI in the source-upper-middle-lower reaches of the Yellow River (Yangtze River) were 0.78 (0.76), 0.23 (0.73), 0.44 (0.55) and 0.23 (0.63), respectively. The correlation degree of meteorological-hydrological drought and wetness in the Yangtze River Basin was significantly higher than that in the Yellow River Basin. The average probability of synchronous combination events of drought and wetness in the two basins is greater than 51.43 %. The probability of drought in the Yellow River Basin is greater than that of flood, while the Yangtze River Basin is the opposite. In the same drought and wetness scenario, an average of 54.1% of the event pairs were aggravated by disasters, and more than 52 % of the events in the wetness-drought scenario had obvious drought mitigation effects. The research results can provide important support for improving the early warning and risk management of river basin disasters.

The paradox of success: Water resources closure in Axarquia (southern Spain)

Axarquia is a semi-arid region in southern Spain that in the past 25 years has experienced significant population growth, along with an economic boom driven by an increasing influx of tourists to Costa del Sol and the expansion of irrigated export-oriented subtropical crops. The combination of these factors has led to a chronic structural scarcity condition that has been intensified by the occurrence of a long and extreme drought. As a result, its only reservoir has reached historically low levels and the piezometric levels in its main aquifer have decreased significantly, suggesting that groundwater reserves are being overexploited. The water crisis is impacting citizens (urban supply), farmers (losses of yields and crops), and the environment (decreasing water reserves). The authorities have responded through supply-side measures such as incorporating reclaimed wastewater in the system and planning the deployment of desalination infrastructure in the region, but demand control and proper governance are required to guarantee sustainability. Consequently, in this case study we apply the European Environment Agency's DPSIR (driving forces, pressures, state, impact, and response model of intervention) framework to understand the basin closure process in Axarquia and assess the main actions that have been undertaken by public and private sector stakeholders to address the challenges faced by the region. Our results provide a valuable reference case to support the analysis of similar closure events, the early identification of potential crisis conditions, and the design of potential solutions in water scarce regions in the European Union, the Mediterranean, and elsewhere.

Greenhouse gas emissions in the Indian agriculture sector and mitigation by best management practices and smart farming technologies-a review.

The growing demand for agricultural products, driven by the Green Revolution, has led to a significant increase in food production. However, the demand is surpassing production, making food security a major concern, especially under climatic variation. The Indian agriculture sector is highly vulnerable to extreme rainfall, drought, pests, and diseases in the present climate change scenario. Nonetheless, the key agriculture sub-sectors such as livestock, rice cultivation, and biomass burning also significantly contribute to greenhouse gas (GHG) emissions, a driver of global climate change. Agriculture activities alone account for 10-12% of global GHG emissions. India is an agrarian economy and a hub for global food production, which is met by intensive agricultural inputs leading to the deterioration of natural resources. It further contributes to 14% of the country's total GHG emissions. Identifying the drivers and best mitigation strategies in the sector is thus crucial for rigorous GHG mitigation. Therefore, this review aims to identify and expound the key drivers of GHG emissions in Indian agriculture and present the best strategies available in the existing literature. This will help the scientific community, policymakers, and stakeholders to evaluate the current agricultural practices and uphold the best approach available. We also discussed the socio-economic, and environmental implications to understand the impacts that may arise from intensive agriculture. Finally, we examined the current national climate policies, areas for further research, and policy amendments to help bridge the knowledge gap among researchers, policymakers, and the public in the national interest toward GHG reduction goals.

Framework for mapping large-scale nature-based solutions for drought mitigation: Regional application in Flanders

Droughts are classified as the most expensive climate disasters as they leave long-term and chronic impacts on the ecosystem, agriculture, and human society. The intensity, frequency, and duration of drought events have increased in the past and are expected to continue rising at global, continental, and regional scales. Nature-based solutions (NBS) are highlighted as effective solutions to cope with the future impacts of these events. Despite this, there has been limited comprehensive research on the effectiveness of NBS for drought mitigation, and existing suitability mapping frameworks often overlook drought-specific criteria. To address this gap, a new framework is proposed to identify areas suitable for two drought-coping NBS types at a regional scale: detention basins and managed aquifer recharge. Two multi-criteria decision-making techniques (MCDM), i.e. Boolean logic and Analytic- Hierarchy Process (AHP), were used to map suitable large-scale NBS. The new framework accounts for unique criteria to specifically address drought conditions. By incorporating climate change scenarios for both surface and groundwater, recharge, and different groundwater characteristics, it identifies suitable and sustainable locations capable of managing extreme drought events. Executed through Boolean logic at a regional scale in Flanders (Belgium), the framework's strict approach yields significant potential areas for detention basins (298.7 km²) and managed aquifer recharge (867.5 km²). Incorporating AHP with the same criteria introduces a higher degree of flexibility for decision-makers. This approach shows a notable expansion across Flanders, varying with the level of suitability. The results underscore the highly suitable potential for detention basins (2552.2 km²) and managed aquifer recharge (2538.7 km²), emphasizing the adaptability and scalability of the framework for addressing drought in the region. The comparison between potential recharge volume due to detention basin and groundwater use in the region indicated that the detention basins could partially compensate for the high water demand. Therefore, creating a framework targeting drought is vital for the sustainable management of water scarcity scenarios.

SPATIOTEMPORAL VARIABILITY OF DROUGHT IN ROMANIA DURING 1901-2021 USING THE STANDARDIZED PRECIPITATION EVAPOTRANSPIRATION INDEX (SPEI)

Drought represents one of the most frequent climatic events with impact on the environment, economy and society. In this study, we analyse the drought characteristics in Romania during the period 1901-2021, using a meteorological drought index: the Standardized Precipitation Evapotranspiration Index (SPEI). To provide a clear image over time, we have divided the data into four time periods: 1901 – 1930, 1931 – 1960, 1960 – 1990, and 1991-2021. The results indicate that the period between 1901 to 1930 is characterized by moderate droughts, in contrast to the period between 1991-2021 when extreme droughts prevailed. Also, the SPEI3's spatial analysis indicates that Romania's eastern and southeastern parts are becoming drier. This study provides a clear image of climate change and indicates that the extreme drought events affected Romania in the previous decade.

Diverging growth trends and climate sensitivities of individual pine trees after the 1976 extreme drought

Summer droughts are affecting the productivity and functioning of central European forests, with potentially lasting consequences for species composition and carbon sequestration. Long-term recovery rates and individual growth responses that may diverge from species-specific and population-wide behaviour are, however, poorly understood. Here, we present 2052 pine (Pinus sylvestris) ring width series from 19 forest sites in south-west Germany to investigate growth responses of individual trees to the exceptionally hot and dry summer of 1976. This outstanding drought event presents a distinctive test case to examine long-term post-drought recovery dynamics. We have proposed a new classification approach to identify a distinct sub-population of trees, referred to as “temporarily affected trees”, with a prevalence ranging from 9 to 33 % across the forest stands. These trees exhibited an exceptionally prolonged growth suppression, lasting over a decade, indicating significantly lower resilience to the 1976 drought and a 50 % reduced capacity to recover to pre-drought states. Furthermore, shifts in resilience and recovery dynamics are accompanied by changing climate sensitivities, notably an increased response to maximum temperatures and summer droughts in post-1976 affected pines. Our findings underscore the likely interplay between individual factors and micro-site conditions that contribute to divergent tree responses to droughts. Assessing these factors at the individual tree level is recommended to advancing our understanding of forest responses to extreme drought events. By analyzing sub-population growth patterns, our study provides valuable insights into the impacts of summer droughts on central European forests in context of increasing drought events.

Effects of extreme drought and water scarcity on consumer behaviour – The impact of water consumption awareness and Consumers’ choices

Unsustainable changes to Earth’s ecosystems and human activities are intensifying global hydrographic pressure. This study explores the connection between extreme drought, water scarcity, and consumer behaviour, investigating the potential psychological impact of these two natural hazards on individuals’ consumption behaviour. Using an integrated model grounded in the theory of interpersonal behaviour, we surveyed through an online questionnaire 244 respondents in Portugal, a region regularly affected by extreme drought. The findings reveal that affect, perceived consequences, habits, and water scarcity positively influence the intention to engage in water-saving consumption behaviour. However, this intention does not translate into actual behaviour since no positive influence is verified. In contrast, both extreme drought and water scarcity have a positive impact on behaviour, reflecting the urgency to conserve and use water efficiently. These results have theoretical and practical implications for promoting water-saving actions.

Hyperspectral signals in the soil: Plant-soil hydraulic connection and disequilibrium as mechanisms of drought tolerance and rapid recovery.

Predicting soil water status remotely is appealing due to its low cost and large-scale application. During drought, plants can disconnect from the soil, causing disequilibrium between soil and plant water potentials at pre-dawn. The impact of this disequilibrium on plant drought response and recovery is not well understood, potentially complicating soil water status predictions from plant spectral reflectance. This study aimed to quantify drought-induced disequilibrium, evaluate plant responses and recovery, and determine the potential for predicting soil water status from plant spectral reflectance. Two species were tested: sweet corn (Zea mays), which disconnected from the soil during intense drought, and peanut (Arachis hypogaea), which did not. Sweet corn's hydraulic disconnection led to an extended 'hydrated' phase, but its recovery was slower than peanut's, which remained connected to the soil even at lower water potentials (-5 MPa). Leaf hyperspectral reflectance successfully predicted the soil water status of peanut consistently, but only until disequilibrium occurred in sweet corn. Our results reveal different hydraulic strategies for plants coping with extreme drought and provide the first example of using spectral reflectance to quantify rhizosphere water status, emphasizing the need for species-specific considerations in soil water status predictions from canopy reflectance.

Predicting drought stress under climate change in the Southern Central Highlands of Vietnam.

In the Southern Central Highlands of Vietnam, droughts occur more frequently, causing significant damage and impacting the region's socio-economic development. During the dry season, rivers, streams, and reservoirs often face limited water availability, exacerbated in recent years by increasing drought severity. Recognizing the escalating severity of droughts, the study offers a novel contribution by conducting a comprehensive analysis of surface water resource distribution in Lam Dong province, focusing on assessing water demand for agricultural production, a crucial factor in ensuring sustainable crop growth. Two scenarios, Current-2020 (SC1) and Climate Change-2025 (SC2), are simulated, with SC2 based on climate change and sea level rise scenarios provided by the Ministry of Natural Resources and Environment (MONRE). These scenarios are integrated into the MIKE-NAM and MIKE-HYDRO basin models, allowing for a thorough assessment of the water balance of Lam Dong province. Furthermore, the study utilizes the Keetch-Byram Drought Index (KBDI) to measure drought severity, revealing prevalent dry and moderately droughty conditions in highland districts with rainfall frequency ranging from 50 to 85%. Severe drought conditions occur with a rainfall frequency of 95%, indicating an increased frequency and geographic scope of severe droughts. Additionally, the study highlights that under abnormally dry conditions, water demand for the winter-spring crop is consistently met at 100%, decreasing to 85%, 80%, and less than 75% for moderate, severe, and extreme droughts, respectively. These findings offer insights into future drought conditions in the Lam Dong province and their potential impact on irrigation capacity, crucial for adaptation strategies.

Whole genome resequencing reveals the adaptability of native chickens to drought, tropical and frigid environments in Xinjiang

Chickens exhibit extensive genetic diversity and are distributed worldwide. Different chicken breeds have evolved to thrive in diverse environmental conditions. However, research on the genetic mechanisms underlying chicken adaptation to extreme environments, such as tropical, frigid and drought-prone regions, remains limited. In this study, we conducted whole-genome sequencing of 240 individuals from six native chicken breeds in Xinjiang, China, as well as 4 publicly available chicken breeds inhabiting regions with varying annual precipitations, temperatures, and altitudes. Our analysis revealed several genetic variants among the examined breeds. Furthermore, we investigated the genetic diversity and population structure of breeds residing in extreme drought and temperature environments by comparing them. Notably, native chicken breeds exhibited different genetic diversity and population structures. Moreover, we identified candidate genes associated with chicken adaptability to the environment, such as CORO2A, CTNNA3, AGMO, GRID2, BBOX1, COL3A1, INSR, SOX5, MAP2 and PLPPR1. Additionally, pathways such as lysosome, cysteine and methionine metabolism, glycosaminoglycan degradation, and Wnt signaling may be play crucial roles in regulating chicken adaptation to drought environments. Overall, these findings contribute to our understanding of the genetic mechanisms governing chicken adaptation to extreme environments, and also offer insights for enhancing the resilience of chicken breeds to different climatic conditions.