Annual Water Deficit Research Articles

The Analysis of Lawn Rebate Programs and Drought Tolerant Lawn Recommendations in California

California faces persistent cyclical droughts that are expected to worsen due to climate change. The state currently operates in an overall annual water deficit, and projections suggest a 10% reduction in water availability by 2040. To combat these water shortages, Governor Newsom's administration has unveiled a water supply strategy with substantial investments in water conservation policies, including rebate initiatives to encourage residents to replace lawns with drought-tolerant (DT) plants and non-living hardscapes. However, questions have arisen about the overall effectiveness and environmental impact of these costly programs. This study delves into the potential consequences of replacing living lawns with non-living hardscapes, specifically whether it might elevate local microclimate temperatures, akin to urban heat islands (UHI) caused by the substitution of natural land cover with man-made, impermeable surfaces. The research examines existing rebate programs across the state, assessing their reimbursement structures and variations. Surface temperatures of commonly recommended lawn alternatives are measured and compared, including comparisons between different alternatives and drought-tolerant ground cover plants. Additionally, the study includes an experiment involving a drought-tolerant ground cover seed mix to replace a traditional lawn. The findings indicate that hardscape lawn alternatives generate significantly higher temperatures than any of the drought-tolerant ground cover plants analyzed. Furthermore, there is notable temperature variability among the hardscapes studied. Consequently, this paper proposes modifications to the existing rebate programs and emphasizes the importance of ensuring that environmental solutions introduced to address one issue do not inadvertently exacerbate related problems.

Understanding the vulnerability of surface–groundwater interactions to climate change: insights from a Bavarian Forest headwater catchment

Headwaters play a crucial role in maintaining forest biodiversity by providing unique habitats and are important for the regulation of water temperature and oxygen levels for downstream river networks. Approximately 90% of the total length of streams globally originate from headwaters and these systems are discussed to be especially vulnerable to impacts of climate change. This study uses an integrated hydrological model (HydroGeoSphere) in combination with 23 downscaled ensemble members from representative concentration pathways (RCPs) 2.6, 4.5 and 8.5 to examine how climate change affects water availability in a headwater catchment under baseflow conditions. The simulations consistently predict increasing water deficits in summer and autumn for both the near (2021–2050) and far future (2071–2099). Annual mean water deficits were estimated to be 4 to 7 times higher than historical levels. This is mainly due to a projected reduction in precipitation inputs of up to – 22%, while AET rates remain similar to those observed during the historical reference period (1992–2018). The declining groundwater storage reserves within the catchment are expected to result in a significant decline in surface water availability during summer and autumn, with a reduction in mean annual stream discharge by up to 34% compared to the reference period. Due to declining groundwater levels, upstream reaches are predicted to become intermittent in summer leading to a reduction of the total stream flow length by up to 200 m. Findings from this study will enhance our understanding of future water availability in headwater systems and may aid in the development of effective management strategies for mitigating local impacts of climate change and preserving these vulnerable ecosystems.

Anthropogenic activities and the influence of desertification processes on the water cycle and water use in the Aral Sea basin

Study regionThe Aral Sea Basin (ASB) is a transboundary water catchment area in Central Asia, with an area of around 1.8 million km2 and straddled over six countries namely Kazakhstan, Uzbekistan, Kyrgyzstan, Tajikistan, Turkmenistan and Afghanistan. Study focusThis research investigated the associated controls of anthropogenic activities and desertification process on the water cycle in the ASB, produced long-term spatial maps, quantified and evaluated the changes in the water surface, volume and water level of the Aral Sea Lake, agricultural water yield and water use efficiency based on multiple streams of state-of-art high-resolution imageries, reanalyzed and in-situ observations during 1986–2022. New hydrological insights for the regionThe main findings of this research are as follows: (i) The Aral Sea Lake was characterized by sharp decline trends in the water surface area, volume and water level with the annual decreasing rates of approximately 1.02 × 103 km2.yr−1, 9.59 km3.yr−1 and 1.14 m. yr−1, respectively; (ii) Agricultural water yield indicated an overall annual decreasing rate of 0.45 mm. yr−1; (iii) Based on the imbalance between agricultural water demand and water supply, these results showed that the ASB has an annual water deficit for agricultural irrigation of approximately 0.071 km3.yr−1 and this water deficit has significantly affected wheat production in Kyrgyzstan and slightly in Afghanistan and Turkmenistan. (iv) The assessment of water threats shows that anthropogenic activities strongly influence the water cycle in the ASB compared to the factors of the desertification process. These results are of great importance and have significant implications for decision makers for future ecohydrological studies and water management in Central Asia and other hotspots of the global drylands.

AGROCLIMATIC ZONING OF ARABICA COFFEE CROPS IN THE REGION OF LAVRAS, MINAS GERAIS, BRAZIL

Coffee growing is the most relevant agricultural activity in the state of Minas Gerais. Arabica coffee (Coffea arabica L.) is the most widely cultivated in the state and is more sensitive to the climate, requiring milder temperatures for commercial production. Water deficit and airtemperature are the main factors used in the agroclimatic zoning of coffee, requiring annual water deficits below 150 mm and an average annual air temperature between 19°C and 21°C for suitability for cultivation. The Lavras region has municipalities with contrasting areas planted with Arabica coffee, being located in a transition zone of the growing crop. Therefore, the objective was to use interpolated climatic surfaces of mean monthly temperature and monthly precipitation, with high spatial resolution (30 seconds) of the WorldClim2 project, in order to perform the agroclimatic zoning for Arabica coffee in 11 municipalities around Lavras, Minas Gerais, Brazil. The water balance was calculated by the Thornthwaite method and the contour of existing plantations was obtained from a survey conducted by EPAMIG for the year 2018. The annual water deficit varied from 19 mm to 47 mm and the temperature from 17.5°C to 20.5°C. According to the geospatial analysis and scientific geovisualization techniques, it was observed that most of the region is suitable for cultivation of Arabica coffee, but spatial variations in water deficit may interfere with productivity and economic viability of implementation in certain areas.

Light use efficiency declines with water deficit and age in Eucalyptus plantations across Brazil

Eucalyptus plantations in Brazil are among the world’s most productive forests. We examined how differences in growth across an 1100 km environmental gradient related to light use and light use efficiency for 11 tropical Eucalyptus plantations, with the same 11 clones planted at each site. The long geographic gradient led to differences in precipitation, temperature, and soils, giving annual water deficits ranging from 40 to 500 mm yr−1. Mean annual increment (MAI) declined by about 2.2 Mg ha−1 yr−1 for each 100 mm yr−1 increase in water deficit. Across sites, about one-fourth of the differences in MAI related to light use (absorbed photosynthetically active radiation, APAR), and three-fourths to light use efficiency (LUE, wood growth per unit of light absorbed),. Light use did not relate to water deficit, so the decline in MAI resulted from a 0.1 g MJ−1 decline in LUE for each 100 mm yr−1 increase in water deficit. Though APAR accounted for a minor part of the decline in growth across sites, differences in both APAR and LUE among clones were important within each site. The pattern in wood growth per unit of light use likely includes the effects of water deficit on both total carbon (C) gain per unit of light use and partitioning of C belowground. A next step in harnessing production ecology insights for silviculture and breeding may be direct assessments of belowground partitioning (and perhaps respiration), and how opportunities vary with site conditions.

Climate seasonality and extremes influence net primary productivity across California’s grasslands, shrublands, and woodlands

Terrestrial vegetation is a substantial carbon sink and plays a foundational role in regional and global climate change mitigation strategies. The state of California, USA, commits to achieving carbon neutrality by 2045 in part by managing terrestrial ecosystems to sequester more than 80 MMT of CO2. We used a 35-year net primary productivity (NPP) remote sensing product with gridded climate, soil, topography, and vegetation data to evaluate spatiotemporal drivers of NPP variation and identify drivers of NPP response to extremes in water availability in California’s major grasslands, shrublands, and woodlands. We used generalized boosted models (GBMs) and linear mixed effects models (LMMs) to identify influential predictors of NPP and characterize their relationships with NPP across seven major vegetation cover types: annual grasslands, blue oak, chamise-redshank chaparral, coastal scrub, coastal oak woodland, mixed chaparral, and montane hardwood. Climate seasonality, specifically greater precipitation and warmer minimum temperatures in early spring and winter, was associated with greater NPP across space, particularly in chaparral, blue oak, and grassland systems. Maximum annual temperature and climatic water deficit (CWD) showed a negative relationship with NPP in most vegetation cover types, particularly chaparral and coastal scrub. We found a significant decrease in NPP over time in most vegetation types, appearing to coincide with the 2012–2016 California mega-drought. However, response to water availability extremes differed by vegetation type. In most vegetation types, especially grasslands, increases in NPP in extreme wet years were greater than declines in NPP in dry years. Our analysis characterizes several climate risks and conservation opportunities in using California’s natural lands to store carbon. Namely, shifts in climate seasonality and water availability extremes threaten these systems’ ability to fix carbon, yet hotspots of NPP resilience may exist and could be enhanced through conservation and restoration. Additional mechanistic work can help illuminate these opportunities and prioritize conservation decision making.

Drivers of tree demographic processes in forest fragments of the Brazilian Atlantic forest

In heterogeneous landscapes, such as the Brazilian Atlantic Forest, forest fragments are likely to undergo highly uncertain successional pathways because anthropogenic and environmental factors strongly affect demographic processes such as recruitment, growth, and mortality. We used data from 134 permanent plots (0.01–0.10 ha) across seven forest fragments in Minas Gerais, Brazil, to assess how anthropogenic variables and environmental factors drive demographic processes in Atlantic forest fragments. For each plot, we quantified anthropogenic variables related to land-use history (LUH) and estimated levels of fragmentation based on forest cover, forest fragment size, and distance to the forest edge. We also measured environmental factors related to topography (i.e., elevation and slope), soil chemical characteristics (i.e., soil pH in H2O, exchangeable cations, P content and soil organic matter), and climate (i.e., average annual precipitation and climatic water deficit [CWD]). We used plot basal area (BA) as a proxy for forest age. We quantified the effect of anthropogenic and environmental factors on relative recruitment, growth, and mortality rates using linear mixed-effects models (LMM). We found that anthropogenic variables (LUH and BA) were stronger predictors of relative recruitment (p-value < 0.001) than environmental variables. For relative growth, soil, elevation, and BA (p-value < 0.001) have the strongest effect. CWD (p-value < 0.001) was the most important predictor for mortality, suggesting that dry periods increase mortality rates in the studied fragments. Our findings suggest that the land-use history of individual fragments, combined with a higher frequency of drought events leading to increased mortality and turnover of individuals, will increase differences in demographic processes and successional pathways among fragments, thereby increasing the heterogeneity of these fragmented landscapes.

Agrometeorological water balance in the west of São Paulo State

The agriculture economic viability is a result of a correct planning and knowledge of the crop production environment. The level of meteorological information in the region can be improved through the water balance, making the agricultural planning more accurate. The objective of this study was to characterize the West of the São Paulo State through the agrometeorological water balance. Historical daily data from 1992 to 2021, from the meteorological station of the University of West Paulista in Presidente Prudente, São Paulo, were used in the study. The sequential water balance (deficit and excess of water in the soil) was evaluated during the agricultural season (from October to March) and off-season (from April to September). The annual water deficit was -303.2 mm, being -125.2 mm in the agricultural season and -178.0 mm in the off-season. The frequent occurrence of deficit in the region, in the beginning of spring and mainly during the autumn-winter, makes it necessary to adopt special management practices and to use irrigation in order to reach high agricultural productivity in West Paulista.

Human-Induced Resource Scarcity in the Colorado River Basin and Its Implications for Water Supply and the Environment in the Mexicali Valley Transboundary Aquifer

The Colorado River delta is a sedimentary alluvial formation that embodies the Lower Colorado River transboundary aquifer. The Mexicali Valley overlies the Mexican part of the aquifer, and the Imperial Valley the aquifer’s portion north of the Mexico–U.S. border. Mexico receives an annual water allocation from the Colorado River stipulated by an international treaty between Mexico and the United States. The Colorado River water allocation to Mexico is shared by farmers in the Mexicali Valley and by several border cities, rural communities, and industries in the northern region of the State of Baja California. Farmers withdraw groundwater from the Mexicali Valley’s aquifer to make up for insufficient Colorado River water to grow their crops. Groundwater withdrawal has created overdraft of the Mexicali Valley aquifer with associated adverse impacts: sea water intrusion, declining groundwater levels, upwelling of brackish groundwater, land subsidence, degradation of groundwater-dependent ecosystems, and emigration of displaced farmers. This article reviews the natural and human histories in the Colorado River basin and the Mexicali Valley, and presents a methodology applying remote sensing, geographic information analysis, and hydrologic analysis to calculate the annual water deficit in the Mexicali Valley. Finally, this work evaluates the valley’s annual water deficit in reference to current agricultural and socioeconomic trends observed in the study region. Aquifer and related environmental degradation have adversely affected small-scale farming and exacerbated demographic instability.

Assessing the Suitability of Oil Palm (Elaeis guineensis) Production in Peninsular Malaysia based on Soil, Climate and Land Use

In recent years, palm oil production has grown rapidly as a result of rising demand. Oil palm plantations have been established on thousands of acres to meet this demand. The objective of this study is to assess the suitability of oil palm production as driven by soil, climate, and land use. The land suitability assessment (LSA) method was adopted in this study. We use geospatial techniques of overlay mapping as a suitable land suitability assessment method, in which the evaluation criteria are recorded as superimposed layers. A land suitability map is produced by integrating these layers into a single layer. The method is also applied to delineate available areas for growing oil palm in Peninsular Malaysia. The findings revealed that suitable soil areas for oil palm production are extensively found in the selected regions of Peninsular Malaysia, in states like Selangor and some parts of Kedah, Kelantan, and Terengganu with clay loam and sandy loam soil properties, while in the southern region like Melaka, moderate suitability for oil palm production was found due to the domination of clay soil in the area. Highly suitable areas were estimated (mean annual water deficit &lt;150 mm) to be 3688254.00 ha (29.54%) of the total land area; suitable areas (mean annual water deficit &lt;250 mm) were 6540669.00 ha (52.38%); moderately suitable areas were (mean annual water deficit &lt;400 mm) 2227500.00 ha (17.84%), and unsuitable areas (mean annual water deficit &gt;400mm) for oil palm production as a result of poor water availability was 31104.00ha (0.25%). The Land Use Land Cover Map of Peninsular Malaysia revealed the suitable areas to cover an average of 10885001.46 ha (82.45%), water bodies 1239505.58 ha (9.39%), built-up areas (unsuitable areas) 1051544.34 ha (7.96%), and bare surface areas are also not suitable areas for oil palm production at 26509.73 ha (0.20%). This study recommends that oil palm plantations be expanded into areas with highly suitable soils and climates.

Climatic distribution of tree species in the Atlantic Forest

AbstractSpecies under milder climates (e.g., warm and wet) tend to experience lower variability in temperature and rainfall regimes and might occur in narrower climatic ranges than species that tolerate harsher conditions (e.g., cold or dry climates). Thus, tree species that occur under harsh conditions should have a broader climatic range, being a small subset of the flora. Here, we assess the influence of climate on species distribution of 1138 tree species from the Atlantic Forest biodiversity hotspot. We investigate their range (or niche breadth), and the “center of gravity” index (or niche optima), along with gradients of mean annual temperature and climatic water deficit (CWD). We further identified those species associated with conditions on different ends of temperature and moisture gradients. We found a small subset of species occurring under colder temperatures or under drier conditions, and these species had a wider niche breadth. The warm or wet‐affiliated species had narrower ranges along with the temperature and the CWD gradients, respectively. Moreover, species affiliated to warm and those to moister conditions had greater densities near their occurrence limits, thus they may be more susceptible to climate changes. We conclude that global climate changes will affect the incidence and abundance distribution patterns of tree species along this threatened biodiversity hotspot, mainly those with narrow niches and within the limit of its distribution.Abstract in Portuguese is available with online material

Classification, suitability and zoning of crops in the high course of the Paraíba River Basin – Brazil

Characterization, agroclimatic zoning and crop suitability are important for defining the agricultural potential of a given region or location, defining the planting season and types of crops suitable for the region. Based on the results of the Water Balance and the corresponding evapopluviogram, it was used to carry out the agroclimatic zoning and its aptitudes for crops suitable for planting in the area of ​​the hydrographic basin of the upper course of the Paraíba River. Monthly and annual rainfall data series were used, collected by the Northeast Development Superintendence and provided by the Executive Agency for Water Management of the State of Paraíba. Municipality to municipality). The average air temperature values ​​estimated by the Estima_ T software. The region has an annual water deficit of 794.0 mm, with no storage and excess of water in the soil. The indices of aridity, humidity and water were 65.38; 0.00 and -39.23%, respectively. The climate was classified as Semi-arid, Megathermal, with little or no excess of water and with 29.41% of the potential annual evapotranspiration concentrated in the hottest quarter of the year. There was restricted aptitude for the cultivation of pineapple, cashew, beans and corn; bananas and sugarcane are unsuitable for cultivation, while herbaceous cotton has moderate conditions. To ensure profitable agricultural productivity, the supply of water through irrigation is essential.

Annual water deficit in response to climate variabilities across the globe

Severe water deficits due to abnormal climatic conditions can be observed in hydrology and agriculture and can be assessed by various characteristics of the water system that showdifferent responses to climate variability. This paper comprehensively investigates the sensitivities of hydrological (i.e. streamflow and water storage) and agricultural (i.e. plant water availability) water deficits to climate variability at a global scale from a hydrological cycle perspective. The sensitivities of 77 large basins across the globe are quantified by both multiple linear regression (MLR) and the Budyko framework based on a newly released terrestrial water cycle dataset. We find that streamflow and water storage deficits are generally more sensitive to rainfall variation, while plant water availability is more responsive to variations of potential evapotranspiration. The climate sensitivities of the water deficit indices are shown to vary with the wetness index and are shaped by catchment surface properties like water storage capacity. The sensitivities of streamflow deficits to rainfall are higher in wetter regions, while the sensitivities of plant water availability to potential evapotranspiration are higher in drier regions. The findings about the divergent responses in water deficit indices can be conducive to developing region-dependent water resource management strategies to alleviate water deficits under a changing environment.

Optimal Control of a Reverse Osmosis Plant for Brackish Water Desalination Driven by Intermittent Wind Power

This work addresses the design of an online control system that continuously regulates a reverse osmosis (RO) desalination plant driven by wind power aided by water storage tanks. The control objective is to produce the exact hourly water demand in the presence of wind power intermittency, disturbances, and operational limitations. The manipulated variables are the RO feed pressure and the active number of RO vessels. The control system helped to decrease the annual water deficit by 20% under nominal conditions and when the plant is under the influence of disturbances. Moreover, the control system managed to decrease the annual water deficit by 73% when the plant operated under a shortage of an active number of wind turbines and RO vessels. The loss of redistributed production ratio (LPb) and the loss of raw production ratio (LP) were used as the controlled variables representing the proposed control objective. LPb was superior to LP by creating conservative control actions that produce the required water demand without violating the required water purity.

Climate and soil effect on oil palm (Elaeis guineensis Jacq.) yield

Objective: To determine potential and water-limited yields in oil palm producing areas in the State of Tabasco, México. Design/Methodology/Approach: The ERIC III v. 3.2 database (IMTA, 2009) was used to select climatological stations with daily precipitation and maximum and minimum temperature records, going back to more than 20 years. The methodology proposed by the FAO and improved by Fischer et al. (2012) was used to estimate the potential yield. The equation reported by Ruiz-Álvarez et al. (2012) was used to estimate the annual water deficit from the climatic water balance. Results: The average potential yield of oil palm with a high level of inputs varies from 35.8 to 40.6 t ha-1 of fresh fruit bunches. The average water-limited yield can vary from 15.6 to 23.5 t ha-1 in plantations of at least 8 years of age, under rainfed conditions. The reduction in the maximum average attainable yield was the result of 19.2-49.5% soil moisture deficits. Study limitations/Implications: In order to determine their impact on potential and water-limited yields, climate change horizons must be included in future studies; this would enable researchers to establish the future theoretical economic profitability of the crop. Findings/Conclusions: The analysis between the yields indicates that —if the gap between the current yields and water-limited yields is closed— output and percentage would be 6.5-14.4 t ha-1 and 72.8-129% higher than the potential yield.

CLIMATIC CHARACTERISTICS AND THEIR IMPLICATIONS AMONG THE PEDOLOGICAL AND TOPOGRAPHICAL ASPECTS OF SOUTHERN BAHIA, BRAZIL

In this paper, the climatic characteristics, and their advantages in the pedological and topographical aspects of the mesoregion of southern Bahia, Brazil, were evaluated. The study was developed in the territory of the Discovery Coast and Far South, located in the southern mesoregion of the state of Bahia. Temperature and precipitation data were obtained on the WordClim plataform and interpolated using ordinary kriging, these climate data were used to calculate evapotranspiration and soil water deficit. The soils were derived from the pedological mapping of Bahia, on a scale of 1:1250000; hypsometry and slope were obtained using the Digital Elevation Model. The climatic variables with the physical attributes of the region were tested by Pearson correlation and simple linear regression. The annual precipitation is distributed between 878.8 mm /year and maximums of 1,619 mm/year, while the average annual temperature is between 22.01 °C and 26.08 °C. The greatest potential annual evapotranspiration occurs in December and January, in the areas that have the highest rainfall and average annual temperatures. The annual water deficit of water showed values of 88.8 to 178 mm observed in the south and northwest of the area. The area has a predominant elevation of up to 320 m and the relief is predominantly flat to wavy. The relationship between climatic, pedological and topographic data indicated that, spatially, low and flat areas with a predominance of latosols are associated with higher precipitation and higher temperature between April and September. The pedology in relation to water deficit, temperature and evapotranspiration did not present significant correlation, which indicates that the territorial extensions of the soil types do not directly interact with the local climatic conditions. The analysis contributesto the understanding of climatic factors and their relationshipsto the other physical characteristics of the south of the Bahia.

IMPACT OF PROLONGED DRY PERIOD ON OIL PALM YIELD AND MILL EXTRACTION RATIO: A CASE STUDY

Based on current trends in climate change, El Nino and La Nina events are likely to become more frequent, with the former having a more significant negative impact on oil palm growth and production. Since 1980, ten El Nino events or prolonged dry periods have been recorded in Indonesia, of which three and five events have been categorised as severe and moderate, respectively. The most severe of the three El Nino events occurred in 1997, followed by a more recent one in 2015. This paper is a case study which examines the impact of the 2015 El Nino event on the fresh fruit bunch (FFB) production of two generations of oil palms planted in two neighbouring estates and oil extraction ratios (OER) of a mill receiving crop from the latter two estates. Four consecutive months of low rainfall in 2015, resulted in annual water deficits of 280 - 313 mm, which was followed by a decline in FFB production over two distinct periods i.e. 4 to 12 months and 24 to 30 months after the El Nino event, respectively. In both cases, a sharp decline in the number of harvestable bunches was the main contributing factor, likely to be due to an increase in inflorescence abortion and lowering of inflorescence sex-ratio. Average bunch weight (ABW) generally remained unaffected. The initial impact of the drought was more severe on the younger palms, but due to a better recovery rate, the overall yield decline (23%) over a 12-month period in the following year, was significantly lower than in older palms (30%). Analysis of 14 years’ yield and climatic data showed that apart from rainfall, other abiotic and biotic factors such as fruiting activity may also be contributing to the 3-year production cycles (peak crop, decline, recovery, peak crop) exhibited by both estates. As such, it was difficult to accurately apportion yield decline primarily due to water deficit from the other influencing factors. The study also indicated a negative effect of drought on mill OER. Extended dry periods in 2015 (4 months) and 2019 (4 months) were consistently correlated with periods of declining OER, 7 to 14 months later. Like FFB, the prolonged decline could also be attributed to multiple factors. Keywords: El Nino, oil palm, OER, rainfall, water deficit.

Geographic variation of leaf form among indigenous woody angiosperms in New Zealand

ABSTRACT Correlations of non-monocot woody angiosperm leaf traits to macroclimate are often used to reconstruct terrestrial paleoclimate under the assumption that macroclimate correlates with leaf phenotype are globally uniform, regardless of evolutionary history. Here, we evaluate if global trends in leaf trait variation with macroclimate are observed in the predominantly evergreen indigenous flora of New Zealand. A dataset of 557 indigenous woody dicot species and over 100,000 occurrences was employed to investigate community-level relationships of four leaf characters (leaf pubescence, margin teeth, area and length-to-width ratio) with geographic variation in temperature, precipitation, water deficit and solar radiation. Leaf area and the frequency of toothed leaves decline at higher latitudes in New Zealand. Variation in leaf pubescence and leaf teeth is associated primarily with measures of water availability, such as annual rainfall and annual water deficit; whereas leaf size is associated primarily with temperature. Variation in leaf length-to-width ratio was weakly correlated to climate parameters. The New Zealand relationship of leaf area with temperature aligns with global patterns, highlighting the importance of small leaves in limiting night-time chilling. The global negative correlation of leaf teeth with temperature is apparent in New Zealand trees and vines, but not in shrubs or all woody dicots combined. However, the primary correlate of leaf teeth in New Zealand is water availability, showing that the response of this trait to macroclimate is not globally uniform. The high occurrence of pubescent leaves in low rainfall and drought-prone environments in New Zealand suggests that the trait is associated with water retention in drier climates.

A scenario-based approach for urban water management in the context of the COVID-19 pandemic and a case study for the Tabriz metropolitan area, Iran

The world's poorest countries were hit hardest by COVID-19 due to their limited capacities to combat the pandemic. The urban water supply and water consumption are affected by the pandemic because it intensified the existing deficits in the urban water supply and sanitation services. In this study, we develop an integrated spatial analysis approach to investigate the impacts of COVID-19 on multi-dimensional Urban Water Consumption Patterns (UWCPs) with the aim of forecasting the water demand. We selected the Tabriz metropolitan area as a case study area and applied an integrated approach of GIS spatial analysis and regression-based autocorrelation assessment to develop the UWCPs for 2018, 2019 and 2020. We then employed GIS-based multi-criteria decision analysis and a CA-Markov model to analyze the water demand under the impacts of COVID-19 and to forecast the UWCPs for 2021, 2022 and 2023. In addition, we tested the spatial uncertainty of the prediction maps using the Dempster Shafer Theory. The results show that the domestic water consumption increased by 17.57% during the year 2020 as a result of the COVID-19 pandemic. The maximum increase in water consumption was observed in spring 2020 (April–June) when strict quarantine regulations were in place. Based on our results, the annual water deficit in Tabriz has increased from ~18% to about 30% in 2020. In addition, our projections show that this may further increase to about 40–45% in 2021. Relevant stakeholders can use the findings to develop evidence-informed strategies for sustainable water resource management in the post-COVID era. This research also makes other significant contributions. From the environmental perspective, since COVID-19 has affected resource management in many parts of the world, the proposed method can be applied to similar contexts to mitigate the adverse impacts and developed better informed recovery plans.

The influence of hydroclimate and management on forest regrowth across the western U.S

Forests are subject to a range of management practices but it is unclear which produce the most rapid rates of regrowth across heterogeneous moisture gradients produced by regional climate and complex terrain. We analyzed recovery rates of satellite derived net primary productivity (NPP) over 27 years for 26 069 individual silvicultural treatments (stands) across the western U.S. at a 30 m resolution. Rates of NPP recovery and forest regrowth were on average 116% higher in wet landscapes with lower annual climatic water deficits (8.59 ± 5.07 gC m−2 yr−2, median ± inter-quartile range) when compared to dry landscapes (3.97 ± 2.67 gC m−2 yr−2). This extensive spatial analysis indicates that hydroclimate is a dominant driver of forest regrowth and that responses can be highly nonlinear depending upon local climate conditions. Differences in silvicultural treatment also strongly controlled rates of regrowth within hydroclimatic settings; microclimates produced by shelterwood treatments maximized regrowth in dry landscapes whereas regrowth following clearcutting was among the fastest in wet landscapes due to enhanced energy availability. Conversely, commercial thinning regrowth rates were insensitive to hydroclimate and relatively consistent across the western U.S. Planting had a differential effect on forest structure and rates of regrowth across hydroclimate with negative effects in wet environments and positive effects in dry environments. In aggregate, this study provides a novel remote sensing approach for characterizing forest regrowth dynamics across climatic gradients and the common treatment options employed.