Reduced Water Availability Research Articles

CLIMATE CHANGE AND WATER CRISIS, CONSEQUENCES ON AGRICULTURE AND HYDROLOGICAL JUSTICE: CASE STUDY OF PAKISTAN

Hydrologic justice is necessary in the current time of climate change deteriorating effects. This thesis examines the impacts of climate change on Pakistan's hydrological system and agriculture sector and evaluates the government and stakeholder response to such impacts, with a focus on the water crisis and its implications for hydrological justice. The study uses qualitative research methods to analyse the data collected from various sources, including interviews, and observation. The findings of the research indicate that climate change has led to a reduction in water availability, which has had a significant impact on Pakistan's agriculture sector, particularly small-scale farmers. The frequency of extreme weather events such as droughts and floods has also exacerbated the water crisis, leading to inequitable distribution and access to water resources. The study highlights the importance of hydrological justice in addressing the water crisis in Pakistan. The government, policymakers, and stakeholders must prioritize the needs of vulnerable communities and ensure equitable distribution of water resources. Additionally, promoting sustainable agriculture practices and investing in climate-resilient infrastructure can help reduce the impacts of climate change on Pakistan's hydrological system and agriculture sector. Overall, the study emphasizes the urgent need for a comprehensive approach to address the water crisis in Pakistan and pursue hydrological justice. The research findings provide valuable insights for policymakers, practitioners, and academics interested in climate change, hydrology, agriculture, and environmental justice.

Does shading and ground cover of moss and litter improve germination and establishment of Betula pendula Roth, Salix caprea L. and Populus tremula L. seedlings during drought stress in climate change? – A greenhouse study

The climate change is leading to a significant increase in temperatures and dry periods in spring, for example in parts of middle and north Europe. Thus, the important factor for tree growth, the water availability, decreases on forest sites. It is to be expected that the successful establishment of pioneer tree species as pre-forests on large damaged areas will considerable be limited in the future. The phases of germination and establishment are the most dangerous phase in the life of trees. In this greenhouse study, we tested how different microsite conditions (open soil, moss and litter cover as well as different shading) under reduced water availability influence establishment success and growth of Betula pendula, Populus tremula and Salix caprea.The initial high germination success were reduced to 14%, 7% and 12% for Populus tremula, Salix caprea and Betula pendula, respectively, and the growth were significantly slower when the relevant soil water resource was just above the permanent wilting point. Therefore, in the first year the germination and establishment is linked to persistent moist conditions. If the soil dries out during germination, e.g. if there is no watering for more than 3 weeks, all seedlings died. Equivalent germination microsites (shading or ground cover) with comparable possible seedling densities to the moist open soil does not exist under water stress. Although moss and litter cover retain longer soil moisture under extremely dry conditions and guarantee significantly better seedling development than on open soil, initially significantly fewer seeds germinate on these substrate types.Radiation shows no influence on germination and seedling survival. The seedlings are able to survive radiation conditions of 3% and 27% of open area radiation. This makes establishment possible under (remaining) light canopy, at the edge of damaged areas or in small islands of remaining shelter trees on damaged areas. However, radiation had a significant effect on growth. With increasing radiation, shoot lengths and above ground biomasses are higher and the root collar diameter larger.Overall, Betula pendula is the most drought stress resistant of the tested tree species. While Populus tremula and Salix caprea already had problems establishing themselves on dry sites, the problem will become more serious under climate change. The lack of moist, vegetation-free open soils will result in a significant reduction of establishment success for tested pioneer tree species in climate change.

Agroclimatic zoning for eucalyptus in the southern mesoregion of Bahia State, Brazil

Forestry promotion is one of the approaches to forestry production with an increasing tendency in Brazil. The objective of this work was to present an agroclimatic zoning (AGZ), based on environmental conditions necessary for the planting of four species of eucalyptus in the southern mesoregion of Bahia State, Brazil, on a surface of 54,642.35 km². AGZ was proposed for Eucalyptus grandis Hill, E. urophylla, E. camaldulensis and Eucalyptus urograndis (E. grandis X E. urophylla), using geographic information systems for crossing spatial variables of temperature, precipitation, water deficit, evapotranspiration, soils, altitude, slope, conservation units and land use. The region showed planting aptitude of 27.93, 11.87, 3.74 and 1.70%, for E. grandis, E. urophylla, E. camaldulensis and Eucalyptus urograndis, respectively. The AGZ is an important alternative to minimize, in the long term, the negative effects of a monoculture with a high rate of transpiration that could compromise environmental sustainability and reduce water availability in a region.

Response of Spontaneous Plant Communities to Sedum mexicanum Cover and Water Availability in Green Roof Microcosms

Lack of maintenance can lead to ‘weedy’ spontaneous vegetation on green roofs. Aspects of green roof design, including substrate depth and roof height, have been shown to influence the composition of spontaneous vegetation. In drier climates, Sedum species are often planted on shallow substrate ‘extensive’ green roofs and irrigated during summer to maintain cover. However, the response of spontaneous vegetation to Sedum cover and water availability is unclear. Understanding this relationship could help minimise maintenance and maintain Sedum vegetation cover. We hypothesised that increasing Sedum (Sedum mexicanum) cover and reduced water availability would reduce the abundance, biomass, species and functional richness, and the community weighted mean specific leaf area (SLA; CWM by abundance) of spontaneous plant communities. We conducted a 10-month experiment in green roof microcosms planted with S. mexicanum (0%, 25%, 50%, 75% and 100% total cover), subjected to a well-watered or water-deficit irrigation treatment, and sown with a mix of 14 plant species that commonly occur as spontaneous on green roofs. We measured spontaneous species abundance, community biomass, and functional traits (specific leaf area, leaf dry matter content, and relative growth rate), and calculated species and functional richness. Increasing S. mexicanum cover reduced spontaneous species abundance and species and functional richness but did not affect community biomass. Species richness was affected by the interaction of S. mexicanum cover and watering treatment and was greatest in well-watered microcosms with 0% S. mexicanum cover. Increased water availability increased spontaneous plant biomass but did not affect functional richness. The SLA of spontaneous communities was affected by the interaction of S. mexicanum cover and watering and was significantly greater in well-watered treatments where S. mexicanum cover was <100%. Therefore, maximising Sedum cover and limiting water availability on green roofs will likely limit the abundance, biomass, and diversity of spontaneous vegetation. Conversely, for green roofs where substrate is left to be naturally colonised, increasing water availability could encourage establishment and increase functional richness of spontaneous vegetation.

Analyzing the informative value of alternative hazard indicators for monitoring drought hazard for human water supply and river ecosystems at the global scale

Abstract. Streamflow drought hazard indicators (SDHIs) are mostly lacking in large-scale drought early warning systems (DEWSs). This paper presents a new systematic approach for selecting and computing SDHIs for monitoring drought for human water supply from surface water and for river ecosystems. We recommend considering the habituation of the system at risk (e.g., a drinking water supplier or small-scale farmers in a specific region) to the streamflow regime when selecting indicators; i.e., users of the DEWSs should determine which type of deviation from normal (e.g., a certain interannual variability or a certain relative reduction of streamflow) the risk system of interest has become used to and adapted to. Distinguishing four indicator types, we classify indicators of drought magnitude (water anomaly during a predefined period) and severity (cumulated magnitude since the onset of the drought event) and specify the many relevant decisions that need to be made when computing SDHIs. Using the global hydrological model WaterGAP 2.2d, we quantify eight existing and three new SDHIs globally. For large-scale DEWSs based on the output of hydrological models, we recommend specific SDHIs that are suitable for assessing the drought hazard for (1) river ecosystems, (2) water users without access to large reservoirs, and (3) water users with access to large reservoirs, as well as being suitable for informing reservoir managers. These SDHIs include both drought magnitude and severity indicators that differ by the temporal averaging period and the habituation of the risk system to reduced water availability. Depending on the habituation of the risk system, drought magnitude is best quantified either by the relative deviation from the mean or by the return period of the streamflow value that is based on the frequency of non-exceedance. To compute the return period, we favor empirical percentiles over the standardized streamflow indicator as the former do not entail uncertainties due to the fitting of a probability distribution and can be computed for all streamflow time series. Drought severity should be assessed with indicators that imply habituation to a certain degree of interannual variability, to a certain reduction from mean streamflow, and to the ability to fulfill human water demand and environmental flows. Reservoir managers are best informed by the SDHIs of the grid cell that represents inflow into the reservoir. The DEWSs must provide comprehensive and clear explanations about the suitability of the provided indicators for specific risk systems.

Integrating glacio-hydrological and power grid models to assess the climate-resiliency of high mountain hydropower in Nepal

Climate change significantly impacts hydrological systems resulting in hydropower generation uncertainties. In this study, a high-resolution glacio-hydrological model is coupled with an hourly-resolution power grid model to evaluate the climate change influences on hydropower generation across Nepal. Four climate future scenarios namely Cold-Dry, Warm-Dry, Cold-Wet, and Warm-Wet are developed to compare the changes in water availability and optimal power system with historical climate. The total flow increases for the wet scenarios (+11.4% under Cold-Wet for the Koshi basin), compared to the dry scenarios (−24.6% under Warm-Dry for the Karnali basin) for all the major river basins in Nepal. The results illustrate the distribution and magnitude of changes in total water availability and power generation are not proportional for dry and wet scenarios as a ∼20% reduction of water availability in the dry scenarios only results in a ∼2–3% decrease in electricity generation. The capacity requirements of hydro storage decrease by 7.2 GW for Cold-Wet and 6.8 GW for Warm-Wet scenarios compared to historical climate indicating higher capacity requirements in dry scenarios. Larger impacts observed at higher altitudes suggest more attentive adaptation strategies in developing climate-resilient hydropower systems. Results suggest that Nepal should not be entirely focused on exploiting its hydropower potential but rather diversifying the generation mix including solar PV and hydrogen technology. For the least-cost power system expansion, the Warm-Wet climate appears to be the most desirable and a cost savings of about 3.76 billion USD in hydropower development can be realized if better adaptation strategies are employed.

Effect of soluble dietary fibre from barley on the rheology, water mobility and baking quality of wheat flour dough

Incorporation of dietary fibre in a bread recipe is a technological challenge. Therefore, the aim was evaluating the impact of substitution of wheat flour with extracted soluble dietary fibre from barley (BDF) at two levels (4.0% and 8.0%) on dough and bread characteristics. The percent water absorption and mixograph peak mixing time increased for both BDF substitution levels, while T22 relaxation time reduced significantly. In addition, 4.0 and 8.0% BDF substitution levels resulted in a 20.6% and 33.4% reduction in freezable water (FW) content, respectively, and increased G′ and G″ values. In creep tests, BDF dough showed reduced creep compliance values and recoverable strain percentages. BDF limits the water availability in dough for the other biopolymers as reflected in more β-sheet structures, reduced water mobility and lower FW content. The reduction in water availability results in impaired development of an elastic gluten network and an increased resistance to deformation, eventually translating in higher crumb hardness and lower loaf volume. These insights can serve as basis for targeted interventions to recipes and processing to counteract the adverse effects of BDF on bread properties. This study also revealed that 4.0% BDF substitution of wheat flour does not adversely affect bread quality.

Impacts of climate change on vegetable production and ways to overcome them

Vegetables play a key role in food security and nutrition as the food system shifts from food quantity to dietary quality and health benefits. One of the main reasons for the low production and declining average yields of most vegetable crops is climate change. Important limiting factors in maintaining and increasing vegetable crop yields are rising temperatures, reduced water availability for irrigation, flooding and salinity. Under changing climatic conditions, crop failures, declining quality and increasing pest and disease problems are becoming commonplace and making vegetable production unprofitable. Since many physiological processes and enzyme activity are temperature dependent, they will be greatly affected. Drought and salinity are two important effects of rising temperatures that reduce vegetable crop yields. These impacts of climate change also affect the emergence of pests and diseases, host-pathogen interactions, distribution and ecology of insects, timing of emergence, migration to new locations, and their ability to overwinter, all of which become a major barrier to vegetable production. To mitigate the adverse effects of climate change on the productivity and quality of vegetable crops, sound adaptation strategies need to be developed. Emphasis should be placed on the development of production systems that improve water efficiency and are adapted to hot and dry conditions. Technological practices, such as mulching with crop residues and plastic materials, help maintain soil moisture. Excessive soil moisture due to heavy rains becomes a serious problem that can be solved by growing crops in raised beds. An effective way to solve these problems is to create genotypes that are resistant to high temperatures, moisture, salinity and resistance to climatic conditions, using traditional and non-traditional breeding methods, genomics, biotechnology, etc.

Limited change in silicate chemical weathering intensity during the Permian–Triassic transition indicates ineffective climate regulation by weathering feedbacks

Vast emissions of volcanogenic greenhouse gases resulted in rapid global warming during the latest Permian mass extinction (LPME, ∼252 Ma), the impact of which on continental chemical weathering conditions was complex. Here, we compile Chemical Index of Alteration (CIA) records from 25 terrestrial and 12 marine sections with a near-global paleogeographic distribution to reconstruct the evolution of chemical weathering intensity of silicates during the LPME. This compilation shows that the CIA profiles, except those from the Australian Sydney and Bowen basins of the high-latitude Southern Hemisphere, exhibit either indiscernible changes or decreases through the LPME interval, contrary to previous inferences of increased silicate chemical weathering intensity. The lack of major changes in silicate chemical weathering intensity is further supported by the near uniformity of clay mineral assemblages through the LPME interval, with only minor increases of illite and chlorite and, if present, decreases in kaolinite content in some terrestrial sections. We infer a shift from dominantly transport-limited to kinetic-limited weathering regimes, likely caused by environmental climate factors such as widespread devegetation, river-flow changes (i.e., toward flashier and more intense discharge), and aridification during the earliest Triassic that effectively reduced water availability on land for water/rock reactions. Combined with limited changes in chemical weathering fluxes from previous estimates, our data imply possibly ineffective climate regulation by silicate chemical weathering at a (near-)global scale, despite high erosion rates, amid the intense global warming that followed the LPME.

Impacts of climate change on streamflow in the McKenzie Creek watershed in the Great Lakes region

Introduction: This study explored streamflow dynamics of the McKenzie Creek watershed in Southern Ontario, Canada under a changing climate. The Creek is located in the southern portion of the Grand River watershed in the Great Lakes region and is an important water and ecosystem service provider for the Six Nations of the Grand River reserve, the largest (by population) Indigenous community in Canada and the fourth largest in North America.Methods: The Coupled Groundwater and Surface-Water Flow Model (GSFLOW) was used to simulate streamflow from 1951 to 2020 using observed gridded meteorological data from Natural Resources Canada (NRCANmet) and in situ data from Environment and Climate Change Canada (ECCC). Downscaled data from the Coupled Model Intercomparison Project Phase 5 (CMIP5) for two Intergovernmental Panel on Climate Change (IPCC) Representative Concentration Pathways (RCP) climate warming scenarios, RCP 4.5 and RCP 8.5 were used to run GSFLOW for the historic (1951–2020) and projected (2021–2099) period.Results: Results suggested that streamflow in the McKenzie Creek will be significantly impacted by climate change in winter months when streamflow is projected to increase due to higher temperatures causing early melting of snowpack and increasing winter precipitation. Consequently, spring streamflow is expected to decrease and little or no change in streamflow in the summer and autumn. These changes in streamflow dynamics may lead to more flooding incidents in the winter, while at the same time, the region may face reduced water availability or dry conditions in late spring and summer due to warm temperatures.Discussion: This study provides important information about streamflow and hydrologic dynamics of this watershed that will help managers and planners to better manage water resources and be prepared to deal with climate change and its impacts on water availability and security not only for the Six Nations area but also for Southern Ontario which houses one-third of Canada’s population.

DISSECTION OF YIELD AND FIBER QUALITY TRAITS UNDER DROUGHT CONDITION IN GOSSYPIUM HIRSUTUM L.

Moisture is a significant component in cotton growth and yield, but stress is the main factor limiting crop productivity since it has a negative impact on cotton's ability to produce high-quality fiber as well as square/boll and lint output. Reduced water availability during the development of the bolls could lead to drastically decreased yield. Four cotton genotypes (MNH-1020, FH-114, BH-178 and CIM-602) were grown under regular irrigation and water-deficit circumstances to examine the tolerance to water scarcity. To further understand the impacts of water shortage, four watering treatments were used in this study: control 100% field capacity, 70% field capacity, 60% field capacity, and 40% field capacity at the squaring stage till boll formation. As the amount of soil moisture declines, we have observed fall in fiber length, fiber fineness, and fiber strength. Yield/plant reduced under water stress due to less no of flowers and bolls, but also because of reduced boll weight. When the stress was extreme during the reproductive growth stage. MNH-1020 showed drought tolerance as by exhibiting maximum yield, boll weight and fiber characters when compared to other three varieties, while FH-114 being second. CIM-602 showed drought susceptibility as it exhibited least no of bolls/plant, yield/plant and boll weight.

Response of vegetative performance in soybean cultivars submitted to deficit irrigation

Agricultural crops present phenological stages of less susceptibility to soil water deficit, in which the deficit irrigation management strategy can be used. In this context, the objective was to evaluate the influence of deficit irrigation management during different stages of development in three soybean cultivars in the edaphoclimatic conditions of the southern cerrado of Piauí. The research was conducted from September 2020 to January 2021, in the municipality of Uruçuí-PI (with geographic coordinates of 07º 13’ 46” S, 44º 33’ 22” W), under an experimental design of randomized blocks, in a split-plot scheme, where the treatments, composed in the plots, were defined according to the time of induction of the water deficit of 50% of the crop’s potential evapotranspiration - ETpc, via climate, in three soybean phenological stages (vegetative, flowering and production formation), and the subplots, were composed of three cultivars (FT 4191; FT 3181 and BG 478 IPRO), with three replications. In order to verify the effects of the imposed treatments, the following variables were evaluated: plant height, number of leaves and total dry mass of the aerial part. Variables were maintained for statistical analysis by Tukey’s test (cultivars) and Scott-Knott’s test (deficient irrigation treatments). The vegetative characteristics of the investigated soybean cultivars (plant height, number of leaves and shoot dry mass production) are drastically affected when the imposition of water deficit (50% of ETpc) is induced throughout the production cycle. Under such water conditions, the FT 4181 and 3191 IPRO cultivars stood out among the investigated cultivars, thus being identified as the most tolerant to reduced water availability in their different phenological stages.

Use of Thermography to Evaluate Alternative Crops for Off-Season in the Cerrado Region.

Future predictions due to climate change are of decreases in rainfall and longer drought periods. The search for new tolerant crops is an important strategy. The objective of this study was to evaluate the effect of water stress on the physiology and productivity of crops with potential for growing in the off-season period in the Cerrado, and evaluate correlations with the temperature of the canopy obtained by means of thermography. The experiment was conducted under field conditions, with experimental design in randomized blocks, in a split-plot scheme and four replications. The plots were: common bean (Phaseolus vulgaris); amaranth (Amaranthus cruentus); quinoa (Chenopodium quinoa); and buckwheat (Fagopyrum esculentum). The subplots were composed of four water regimes: maximum water regime (WR 535 mm), high-availability regime (WR 410 mm), off-season water regime (WR 304 mm) and severe water regime (WR 187 mm). Under WR 304 mm, the internal concentration of CO2 and photosynthesis were reduced by less than 10% in amaranth. Common bean and buckwheat reduced 85% in photosynthesis. The reduction in water availability increased the canopy temperature in the four crops and, in general, common bean was the most sensitive species, while quinoa had the lowest canopy temperatures. Furthermore, canopy temperature correlated negatively with grain yield, biomass yield and gas exchange across all plant species, thus thermal imaging of the canopy represents a promising tool for monitoring crop productivity for farmers, For the identification of crops with high water use management for research.

Latitudinal variation in the functional response of Quercus suber seedlings to extreme drought

Many plant species are being threatened by increasingly drought conditions due to current climate change at planetary scale. This global trend is leading to the scientific community to investigate the potential role of local adaptations through intraspecific differences in functional traits that may boost conservation strategies by modulating the plant responses to reduced water availability. We assessed under controlled conditions the effect of four different drought intensities on the survival time and morphological traits of Quercus suber seedlings collected from nine populations covering the complete latitudinal distribution of the species. Functional morphological traits related to biomass allocation and leaf and root display were analyzed. We then related these traits with the survival time after a terminal desiccation, used as a drought-resistance proxy and expressed as survival time without watering. Abundant watering availability allowed seedlings to survive for a longer period compared to drier conditions. Further, all morphological traits differed across watering levels, showing a very plastic response. Acorns from southern latitudes produced very large seedlings compared to those gathered from northern latitudes. However, the larger biomass implied higher evaporative water loss, inducing lower survival of southern populations under extreme drought conditions. We further found a clear trend toward maximizing those traits related with belowground growth (i.e., root surface area, root average diameter and root volume) in southern populations aimed to increase water uptake, overcoming the most limiting factor for plant growth in that area. Our results support that increased root development allow cork oak to maintain its functioning after being subjected to damage caused by reduced water availability, whereas high aerial biomass allocation is a handicap for survival under drought stress conditions. This study identifies drought-resistant populations and morphological traits related to drought resistance, which can be applied to improve restoration actions under a warmer climate.

Physiological Responses and Adaptations of the Halophyte Atriplex halimus to Soil Contaminated with Cd, Ni, and NaCl

Soils contaminated with potentially toxic elements (PTEs) and salt manifest a large number of physical, chemical, and structural problems by various processes such as reduced water availability, water and air movement in soil space, water holding capacity of soil, as well as perilous effects on plant growth and physiology. Halophytes have the ability to grow in saline environments and are better adapted to accommodate environmental constraints including PTE ions. An experiment was designed to study the response of the halophyte Atriplex halimus to a range of salinities and different concentrations of Cd and Ni. Tolerance and soil remedial potential of the plant were quantified in terms of PTE uptake and portioning, plant biomass, root/shoot ratio, chlorophyll and anti-oxidative enzyme production, along with stress markers such as lipid peroxidation, proline, and glycine betaine. The plant was also evaluated for its potential to phytoremediate PTE contaminated soil. The results suggest that A. halimus can tolerate moderate concentrations of both the PTEs and salt. The species holds promise for bio-reclamation of saline and PTE-contaminated soil.

Growing ‘Genovese’ and ‘Valentino’ Basil in Pots Using Peat Substrate Combined with Phytoremediated Sediment: Effects on Yield and Nutraceutical Content

Climate change is causing a decline in the availability of crucial resources such as water and fertile soil, leading to a detrimental impact on crop yields. Basil (Ocimum basilicum L.), an annual aromatic plant used worldwide for culinary, cosmetic, and medicinal purposes, is especially at risk due to its high water demand and specific growing requirements typical of the Mediterranean climate. In Italy, basil is an essential part of any herb garden and is also commonly found in households as a potted plant. Nowadays, the conventional practice of growing basil in pots with peat as the primary medium is not environmentally sustainable, which underscores the need for alternative and sustainable cultivation techniques to ensure the continued growth of this majestic king of herbs. A greenhouse factorial experiment was conducted to study the impact of peat replacement and reduced water supply on the growth and biochemical traits of basil plants. The study included two cultivars (‘Genovese’ and ‘Valentino’), three substrate mixes with phytoremediated dredged sediment (TS) at varying volume percentages (0%, 12.5%, and 25%), and three levels of water irrigation (normal, reduced by 25%, and reduced by 37.8%). Increasing the TS percentage resulted in higher germination rates and greater biomass production in both cultivars compared with the control. ‘Valentino’ potted plants produced a higher yield than those of ‘Genovese’, while the latter had higher pigment contents due to its genetic characteristics. All combinations of substrates mixed with the highest water amounts of irrigation positively impacted seed germination and biomass-based outputs, while control peat with reduced water availability led to lower plant yields and germination capacity. Substrates with TS had suitable physicochemical characteristics for plant development. Our findings suggest that using peat–TS mixtures can produce quality results comparable to or even better than conventional soilless culture using only peat. Thus, replacing peat with moderate percentages of TS can be an effective and sustainable practice for recycling phytoremediated sediments.

Understanding the Potential Impact of Climate Change on Hydropower Generation in Rwanda

The primary energy sources used in Rwanda include solar energy, methane gas, diesel and heavy oil generators, hydropower plants, and thermal power plants. Hydropower is a significant renewable low-carbon energy source, generates more than 45% of Rwanda's total electricity. It requires water to produce energy, therefore any modifications to the natural hydrological cycle brought on by climate change have an impact and will continue to have an influence on the production of electricity. Hydropower is sorrow from an increase in extreme weather occurrences and erosion. Therefore, by altering flow (discharge) and head, climate change may have an effect on hydropower. The amount of sediment that is transferred to the reservoir lowers its capacity, and the dry season may result in less water in the reservoir, which has an impact on the hydroelectric power generation process. According to the study, changes in river flow have the greatest impact on how hydropower is affected by climate change. Droughts, seasonal and frequent floods, and greater variability due to climate change are the main contributors. The results show that climate change is likely to have a more pronounced impact on hydropower operations, with reductions in water availability due to climate change expected to result in reduced power generation. Additionally, existing dams will be located in areas at high risk of flooding due to climate change. In order to ensure electricity availability throughout the year, especially during the hot or dry seasons when discharges are often low, the required changes should be performed. These adjustments include using alternate backup sources and storage systems. Water consumers can be conserved and optimized through water resource management, drought resistance, flood protection, and conservation.

Impact of management practices on the tropical riverine grasslands of Brahmaputra floodplains: Implications for conservation

Globally, the conservation value of tropical grasslands, unlike tropical forests, is underappreciated, and their degradation is widespread. Conservation of this vulnerable ecosystem requires scientifically validated management strategies. The present study examines the impact of flooding, herbivory, and other management practices on the riverine grasslands of Brahmaputra floodplains of Assam, India, for devising effective conservation strategies. Inundation period-based unsupervised classification was used to derive the types and extent of grasslands viz., short (SG) and tall (TG). Subsequently, the data on vegetation composition and nutrient status viz., soil carbon (C), nitrogen (N), phosphorus (P), and potassium (K), was collected from inside and outside of 15 exclosures that were subjected to different management regimes, including grazing (freely accessed by mega- and meso-herbivores), ungrazed (not accessed by mega- and meso-herbivores), ungrazed with controlled burning and ungrazed with invasive removal. A total of 1152 plots were monitored for two-year, from January 2014 to December 2015. The results of the study revealed that the areas inundated for a longer duration were dominated by SG and had higher species diversity, while areas inundated for the shorter duration were dominated by TG and had low species diversity. We further observed that grazing exclusion promoted heterogeneity, woody and invasive growth, and soil nutrient content. Burning and invasive removal reduced woody and invasive growth and enhanced soil nutrient conditions. Grazing and burning decreased heterogeneity, while invasive removal increased heterogeneity. Alteration of the flooding regime due to reduced water availability may affect the ratio of SG and TG extent in the long run, which may alter the vegetation composition and the productivity of these grasslands. We recommend short-term rotational grazing for SG and long-term for TG to promote heterogeneity and soil quality. Controlled burning can be carried out in dry and invaded areas post uprooting of invasives to mitigate the effect of succession.

Sustainability Consequences of Making Land Change Decisions Based on Current Climatology in the Brazilian Cerrados

Brazil is one of the largest suppliers of commodities in the world, partly due to the agricultural expansion in the Brazilian savannas (also known as Cerrado) that began in the 1970s. However, as areas with better soil and climate for agriculture become scarce, farmers have been advancing to the ecotone between the savanna and xeric shrubland, where precipitation is less reliable for rainfed agriculture. The expected increase in temperature will lead to extended drought periods, with negative consequences for surface and groundwater resources. This study explores the hazards associated with making land-use decisions based on current climatology in regions where projected increases in temperature and reductions in water availability are anticipated to pose significant challenges to rainfed agriculture in the Brazilian Cerrado biome. We modeled future farmland expansion and how that matches with future climate change predictions (2016–2046). According to our estimates, at least 129 thousand km2 of cropland and 418 thousand km2 of pastures will be added in places with projected higher annual temperatures ranging from 26–30 °C. This is equivalent to ~60% of the current agricultural areas, and a novel agro-climatology will emerge for the Cerrado biome. Therefore, we discuss the agro-environmental policies that are pushing and pulling farmland expansion in the Cerrado. For instance, payments for environmental services could support the conservation of native vegetation on private land in regions with the highest temperature increases and deforestation risks. Moreover, in areas with expected reduced water yields, such as in the western Cerrado, the protection of riparian vegetation and strict regulation of water use could mitigate future risks to agriculture.

Impact of Climate Change and Consumptive Demands on the Performance of São Francisco River Reservoirs, Brazil

Climate change in the coming decades could intensify extreme events such as severe droughts. Combined with the possible increase of water demands, these changes exert a great deal of pressure on the water systems. In order to confirm this assumption, a set of scenarios was proposed in this study to consider the combined impact of climate changes and the increase in water demand on the main multiple-use reservoirs of São Francisco River, Brazil. For this purpose, five CMIP6 climate models were used, considering two greenhouse gas emissions scenarios: the SSP2-4.5 and SSP5-8.5. The affluent natural flows and regulated flows were estimated to the adopted reservoirs considering all existing, new and projected demands. The combination of scenarios indicated an increase in Potential Evapotranspiration; possible significant reduction in water availability, with a decrease in precipitation with a magnitude of −15% in the most pessimistic scenarios and a decrease in flows with a magnitude varying between −5% and −40% in the Sobradinho and Três Marias reservoirs; growth in water demand, mainly for irrigation, with annual rates of 6.80%, 7.42%, 10.99% and 9.29% for Itaparica, Sobradinho, Três Marias and Retiro Baixo, respectively; and a substantial reduction in the performance of the evaluated reservoirs, mainly for the Retiro Baixo and Itaparica reservoirs, which showed a high vulnerability index and a low sustainability index.