Winter Rains Research Articles

Tomato dry farming as an agroecological model for California’s drought resilient future: Farmers’ perspectives and experiences

Small, diversified farms on California’s Central Coast have been dry farming for decades, allowing farmers to use water stored in soils from winter rains to grow tomatoes and other vegetables with little-to-no irrigation in summers without rainfall. As recent water shortages in California have forced a reckoning with the precariousness of the state’s water supply, policy groups and the general public have become increasingly interested in dry farming as a promising means of achieving water conservation goals. Academic research on this practice, however, has been scarce. Amid growing urgency to develop low-water agricultural systems in the state, we interviewed 10 Central Coast dry farmers, representing over half of the commercial dry farm operations in the region where this practice was developed, to collaboratively answer 2 central research questions: (1) What business and land stewardship practices characterize successful tomato dry farming on California’s Central Coast? (2) What is the potential for dry farming to expand beyond its current adoption while maintaining its identity as a diversified practice that benefits small-scale operations? We summarize farmers’ wisdom into 9 themes about current dry farm practice, its potential for expansion and future opportunities. We also synthesize farmer-stated environmental constraints on dry farm feasibility into a map of suitable areas in California. As we consider how dry farming might expand to new areas and operations, we highlight dry farming’s history as an agroecological alternative to industrial farming in the region and the need for careful policy planning to maintain that identity. In examining this California Central Coast dry farming system, we ask if and how it can enhance the viability of nonindustrial farming operations as the food system adapts to less water availability. Because policies that encourage dry farm expansion could change economic landscapes in which dry farming operates, we caution that well-intentioned policies could edge small growers out of dry farm markets if not carefully designed. At the same time, we emphasize the opportunity for dry farm tomato systems to model an agroecological transition toward water savings in California.

Chía and its wild relatives: A superfood Salvia (Lamiaceae)

Societal Impact StatementAlternative crops are a promising approach to address the global food shortage that is exacerbated by climate change and wealth disparities. Some of these alternative crops are traditional food plants that have been widely traded for centuries, whereas others have only recently become more popular. Chía is a traditional native “superfood” that is the fruit of three distinct mint species. Chía (Salvia hispanica) is commercially cultivated and shares nutritional properties with California thistle sage (Salvia carduacea) and desert chía (Salvia columbariae). These wild relatives of S. hispanica are adapted to arid conditions and have potentially valuable genetic variation for the development of chía agricultural varieties. The development of nutritious, drought‐tolerant crops such as chía will increase the resilience of people to the impact of climate upheaval.SummaryIn the Spanish language, the word chía refers to the nutlet fruits of several Salvia species native to Mesoamerica. The process of domestication of S. hispanica altered several traits, including the absence of shattering fruits, which makes harvest easier and mechanizable. S. hispanica is commercially cultivated in Mexico, South America, Australia, and less so in Europe and Africa. Other edible chía species are not commercially cultivated, including S. carduacea, and S. columbariae. These Californian chías are traditionally harvested by hand since the fruiting calices shatter and release the nutlets. Here we compare these three edible chía species, review their uses by native peoples, describe their morphology, summarize their natural distributions and cultivation, and provide an identification key. Native peoples in North America have traditionally used chías for food, medicine, and oil. S. hispanica naturally occurs throughout areas of Mexico that receive summer monsoonal rains. As such, it is a summer annual with an erect habit and cauline, simple leaves. In contrast, the Californian chía species are distributed through areas of the Mojave and Sonoran deserts that receive winter rains. They are winter annuals and their rosettes of lobed, pubescent leaves are typical adaptations to arid conditions. Nutlets in these chía species are similar when dry, but cultivated S. hispanica nutlets produce extensive mucilage when wetted, while the other chía produce mucilage to a lesser extent. As consumer interest grows in superfoods like chía, crop breeders may use wild chía to breed varieties appropriate for areas affected by drought or in desert agroecological systems.

Deep nutrients and soil fungal communities support tomato fruit yield and quality in dry farm management systems

Changing climates are causing agricultural water shortages at unprecedented scales and magnitudes, especially in regions historically reliant on irrigation. Identifying and understanding systems of farming that allow continuity in agricultural operations in times of water scarcity are increasingly urgent needs. Vegetable dry farming relies on winter rains stored in soils to reduce irrigation to 0–2 events per season and has become prevalent on California’s Central Coast in recent decades. Until now, this system has been unexplored in scientific literature beyond extension publications, despite its promise as a model for low-water agriculture in arid regions. Dry farm management presents a unique challenge given that low water content restricts nutrient access in surface soils, which farmers typically target for fertility management. Managing soil nutrients at depth, as well as microorganisms that help plants access nutrients and alleviate water stress (e.g. arbuscular mycorrhizal fungi, or AMF) could be crucial to dry farm success. We engaged in a collaborative research design process with farmers managing seven commercial dry farm tomato fields to identify and answer three key management questions: 1. What are the depths at which nutrients influence harvest outcomes given low water content in surface soils?, 2. Are commercially available AMF inoculants effective at improving harvest outcomes?, and 3. How does the broader fungal community change in dry farm soils, and are those changes associated with harvest outcomes? Only soil nutrients below 60 cm depth were correlated with tomato yield and fruit quality. We identified a fungal class, Sordariomycetes, as a ‘signature’ fungal group in dry farm soils that distinguished them from irrigated management and correlated with positive fruit quality, while commercial AMF inoculation showed little benefit. These findings can inform management practices that optimize fruit yield and quality, and can guide farmers and policymakers alike in efforts to minimize agricultural water use.

Evolution of winter precipitation in the Nile river watershed since the last glacial

Abstract. Between 14.5 and 5 ka, the Sahara was vegetated owing to a wet climate during the African humid period. However, the climatic factors sustaining the “green Sahara” are still a matter of debate. Particularly the role of winter precipitation is poorly understood. Using the stable hydrogen isotopic composition (δD, where D stands for deuterium) of high molecular weight (HMW) n-alkanoic acids in a marine sediment core from the eastern Mediterranean, we provide a continuous record for winter precipitation in the Nile river delta spanning the past 18 kyr. Pairing the data with δD records from HMW n-alkanes from the same core, we show that HMW n-alkanoic acids constantly derived from the delta, while the HMW n-alkanes also received significant contributions from the headwaters between ∼ 15–1 ka when fluvial runoff enhanced. This enables us to reconstruct the evolution of Mediterranean (winter) and monsoonal (summer) rainfall in the Nile river watershed in parallel. In the delta, the Heinrich stadial 1 (HS1) evolved in two phases, with a dry episode between ∼ 17.5–16.0 ka, followed by wet conditions between ∼ 16–14.5 ka. Winter rainfall enhanced substantially between 11–6 ka, lagging behind the intensification of the summer monsoon by ca. 3 kyr. Heavy winter rainfall resulted from a southern position of the Atlantic storm track combined with elevated sea surface temperatures in the eastern Mediterranean, reinforcing local cyclogenesis. We show that during the green Sahara, monsoon precipitation and Mediterranean winter rainfall were both enhanced and infer that the winter rainfall zone extended southwards, delivering moisture to the Sahara. Our findings corroborate recent hypotheses suggesting that winter rains that extended southward were a crucial addition to the northward displacement of the summer monsoon in helping to sustain a green Sahara.

Inventário de algas vermelhas da Reserva da Biosfera Sian Ka’an, Caribe Mexicano

Abstract Studies of marine and estuarine red algae (Rhodophyta) are in the early stages in the littoral of the Sian Ka’an Biosphere Reserve, Mexico. The inventory of these organisms was made based on samples obtained from ten sampling during 2009 to 2015 in 22 localities, eight of them in marine and fourteen in estuarine environments. We found 182 species and subspecific taxa of Rhodophyta. The Rhodomelaceae family was the best represented with 65 taxa, followed by Ceramiaceae 13 and Delesseriaceae 12. Of the 182 taxa, 25 are new records Sian Ka’an Biosphere Reserve with Harveylithon rupestre, Spongites fruticulosus, Acrochaetium barbadense, Dasya harveyi, Chondria pumila, Spermothamnion repens, Metapeyssonnelia milleporoides and M. tangerina being new records for the Mexican Caribbean. Of the 182 species, 119 of them are epiphytes, most of them, 54, grew exclusively on other macroalgae, 29 on mangrove roots and 8 on Thalassia leaves. The floristic list is accompanied by data on seasonality, reproduction, habitat, and environment. Species diversity was compared between the winter rains, dry and rainy seasons during the period study. The Rhodophyta of the Sian Ka’an Biosphere Reserve is tropical, and the greatest diversity was found in the marine environment with 83 taxa and during the winter rains with 132.

INFLUENCE OF SHELTERBELTS OF DIFFERENT DESIGNS ON SOIL FERTILITY AND MOISTURE AVAILABILITY IN THE RIGHT-BANK FOREST-STEPPE

During 2020-2023, the authors studied nutrient reserves, namely the content of humus, mobile nitrogen, phosphorus and potassium, as well as the level of acidity in the soil layers of 0-20 and 20-50 cm in openwork-blowing, openwork, dense forest strips, determined the reserves of total and available moisture, the dynamics of productive moisture and moisture availability during the growing season in individual collective farms in the Uman district of Cherkasy region. Studies have shown that the humus content in forest strips of various designs ranges from 2.5 to 3.6%. That is, the humus content is low. The highest amount of humus was found in the openwork design of the forest belt. The pH level in the 0-20 cm soil layer ranges from 5.87 in the openwork-blown forest belt to 7.3 units in the dense one. The highest NO3 content is observed in the 20-50 cm soil layer in the openwork forest belt - 141.4 mg/kg. The P2O5 content in the lower soil layer ranges from 62.1 mg/kg to 142.0 mg/kg. The highest P2O5 content of 168.0 mg/kg was found in the 0-20 cm soil layer of the openwork-blow forest belt. The amount of K2O in the upper soil layer is the same for all variants, in the lower layer it varies from 73.3 to 91.0 mg/kg. The openwork-blown forest belt has an available moisture reserve of 44.88 mm, the openwork belt - 51.03 mm, and the dense belt - 67.24 mm, which, compared to the dense forest belt, the moisture content of the openwork-blown belt is 33.27% lower and that of the openwork belt is 24.11% lower. Investigating the dynamics of changes in moisture productivity and moisture availability during the growing season (May-October) in all variants of the experiment both in 0-20 cm and 0-50 cm soil layer, a significant decrease in these indicators is observed. Thus, in the openwork-blown forest strip in the 0-20 cm soil layer in May, from 68 mm and 78%, these indicators decreased in October to 17 mm and 18%, respectively, i.e., in terms of moisture productivity by 4 times and moisture availability by 4.3 times. This indicates that the productivity and moisture content of the experimental forest strips are much higher compared to the control (open field), where the moisture productivity is 42 mm and the moisture availability is 35%. At a depth of up to 50 cm, the soil moisture content in the blown forest strips is one and a half to two times less than in the openwork forest strips. In favorable years, this difference in soil moisture remains throughout the growing season. The growth and development of tree species in the first half of the growing season (May-June) is carried out at the expense of moisture accumulated during snowmelt or winter rains in the lower soil layers. In the second half of the growing season, tree species receive moisture from summer precipitation that falls in late July and early August and accumulates in the upper soil layers.

Winter Rains Support Butterfly Diversity, but Summer Monsoon Rainfall Drives Post-Monsoon Butterfly Abundance in the Arid Southwest of the US.

Butterfly populations are declining worldwide, reflecting our current global biodiversity crisis. Because butterflies are a popular and accurate indicator of insect populations, these declines reflect an even more widespread threat to insects and the food webs upon which they rely. As small ectotherms, insects have a narrow range of habitable conditions; hence, extreme fluctuations and shifts caused by climate change may increase insects' risk of extinction. We evaluated trends of butterfly richness and abundance and their relationship with relevant climate variables in Arizona, U.S.A., using the past 40 years of community science data. We focused on precipitation and temperature as they are known to be influential for insect survival, particularly in arid areas like southwestern U.S.A. We found that preceding winter precipitation is a driver of both spring and summer/fall butterfly richness and spring butterfly abundance. In contrast, summer/fall butterfly abundance was driven by summer monsoon precipitations. The statistically significant declines over the 40-year period were summer/fall butterfly abundance and spring butterfly richness. When controlling for the other variables in the model, there was an average annual 1.81% decline in summer/fall season butterfly abundance and an average annual decline of 2.13 species in the spring season. As climate change continues to negatively impact winter precipitation patterns in this arid region, we anticipate the loss of butterfly species in this region and must consider individual butterfly species trends and additional management and conservation needs.

Effect of Mechanical and Chemical Treatments on Astragalus spinosus (Forssk.) Muschl. Seed Dormancy

In this study, two specific methods of breaking seed dormancy were chosen to break the dormancy of Astragalus spinosus (Fabaceae) seeds. The first is sulfuric acid with a soaking time of seeds in it. The treatment of seeds with acid 98% at 15 minutes, the treatment with sulfuric acid 50% for soaking for 30 minutes, the treatment with acid 10% at a soaking period of 60 Minutes and for 24 hours, and all these treatments were in different degrees of incubation 16, 20, 22, 25 °C, while the second method that treated the seeds by scarification at degrees of incubation 16, 20, 22, 25 °C with the observation of no damage to the embryos when scarified the seeds, as well as the application of not treat seeds with any method (control) in same degrees for seven days of incubation, and such methods are considered inexpensive and effective. The results showed that when applying the treatment of seeds with sulfuric acid 98% at a soaking period 15 min and incubation degree 20 °C the germination rate have reached 86.66%, while the best germination rate of seeds when treated with scarification at an incubator of 22 and 25 °C and the germination rate reached 100%. We conclude from the present study that the seeds of A.spinosus has dormancy and the lack of optimal conditions from late winter rains under optimal temperatures will lead to the lack of the environmentally important desert species A.spinosus, or it will be absent or loss.

Extended soil surface drying triggered by subsurface drip irrigation decouples carbon and nitrogen cycles and alters microbiome composition

IntroductionIrrigation management dramatically alters soil water availability and distribution and could impact soil microbial communities and carbon (C) and nitrogen (N) cycling to an even greater degree than observed in rainfed systems. Adoption of subsurface drip irrigation (SDI) in California’s Mediterranean agroecosystems provides agronomic benefits but wets only a portion of the soil volume near the root zone, leaving the rest dry throughout the growing season. In contrast, traditional furrow irrigation (FI) has periodic wetting events with more homogenous moisture distribution. With conversion to precision irrigation methods, how will the microbiome respond to changes moisture availability, and how is their response influenced by soil C and N resource levels?MethodsIn a field experiment in California, we compared SDI and FI’s effects on microbial communities and evaluated how long-term organic and conventional management systems impact outcomes. Throughout the growing season, soil samples were collected at two depths (0-15, 15-30 cm) and three distances from bed center (10, 25, 45 cm) where the drip tape is located.ResultsAt harvest, soils irrigated using SDI had lower microbial biomass C (MBC) than under FI at the surface and showed a build-up of soluble C and N relative to MBC at the bed edge, indicating reduced microbial uptake. Community composition at the bed edge also diverged between SDI and FI, favoring Actinobacteria in the former and Acidobacteria and Gemmatimonadetes in the latter. Regardless of irrigation type, dry areas of the bed had the highest alpha diversity indices. Response to SDI was similar in organic and conventional systems, though organic had higher MBC, DOC, and relative abundance of Proteobacteria and fungal lipids, regardless of irrigation.DiscussionProlonged dry conditions in SDI appeared to limit microbial access to resources and changed community composition. As seen in non-agricultural systems, the severity and frequency of moisture changes, adaptation of the communities, and resource availability affect microbial response. Decoupling of C and N pools in dry surface soils under SDI may increase the potential for losses of DOC and nitrate with the first winter rains in this Mediterranean climate.

Rainwater Harvesting at Universities. Case study: Valle de las Palmas

Rainwater harvesting systems have become a necessary strategy in universities to reduce water consumption and to achieve efficient use of water resources, particularly in semi-arid areas, where the use of these systems is ideal and innovative for sustainable water management. However, the design and implementation of these systems needs to be well planned and cost-effective as well as compliant of the needs of the specific college campus. This work proposes to implement this technology for the design of a rainwater harvesting system at the Valle de las Palmas academic unit: the Faculty of Engineering and Technology Sciences (FCITEC), in order to take advantage of the area’s Winter rainfall, and to be used on the landscape areas of the campus. There is evidence that certain universities have obtained significant savings and a decreasing demand for water from their municipal hydraulic networks, such as the Federal University of Pará, in Japan and the Federal University of Viçosa in Brazil. The FCITEC is located in the municipality of Tijuana, Baja California; a region considered as semi-arid, with long drought periods, high temperatures and a short season of Winter rainfall. Baja California’s main source of water supply comes from the Colorado River, representing 80% of the state’s water supply while 20% comes from underground aquifers. Due to the limited rainfall in the Colorado River basin, water levels have dropped significantly in recent years, affecting the city of Tijuana since, during hot seasons, the public water system implemented rotation practices which provoked many neighborhoods to run out of water (including the FCITEC). Therefore, it is a priority to consider water collection systems to take advantage of winter rains as a sustainable and profitable short-term solution for water management in universities, thus reducing the demand for consumption from the water supply network and contributing to the environmental sustainability of water resources.

Soil nematode assemblages respond to interacting environmental changes.

Multi-factor experiments suggest that interactions among environmental changes commonly influence biodiversity and community composition. However, most field experiments manipulate only single factors. Soil food webs are critical to ecosystem health and may be particularly sensitive to interactions among environmental changes that include soil warming, eutrophication, and altered precipitation. Here, we asked how environmental changes interacted to alter soil nematode communities in a northern Chihuahuan Desert grassland. Factorial manipulations of nitrogen, winter rainfall, and nighttime warming matched predictions for regional environmental change. Warming reduced nematode diversity by 25% and genus-level richness by 32%, but declines dissipated with additional winter rain, suggesting that warming effects occurred via drying. Interactions between precipitation and nitrogen also altered nematode community composition, but only weakly affected total nematode abundance, indicating that most change involved reordering of species abundances. Specifically, under ambient precipitation, nitrogen fertilizer reduced bacterivores by 68% and herbivores by 73%, but did not affect fungivores. In contrast, under winter rain addition, nitrogen fertilization increased bacterivores by 95%, did not affect herbivores, and doubled fungivore abundance. Rain can reduce soil nitrogen availability and increase turnover in the microbial loop, potentially promoting the recovery of nematode populations overwhelmed by nitrogen eutrophication. Nematode communities were not tightly coupled to plant community composition and may instead track microbes, including biocrusts or decomposers. Our results highlight the importance of interactions among environmental change stressors for shaping the composition and function of soil food webs in drylands.

A study on the seasonal cyclicity of ovarian development in adult Himalayan snow trout, Schizothorax plagiostomus.

Schizothorax plagiostomus, commonly known as snow trout, is a popular food fish found in parts of Central Asia and the Indo-Himalayan region. Despite such a broad range of distribution and potential financial value, it is a highly neglected cold-water ichthyofauna. Furthermore, an alarming decline in Schizothoracine population has been reported in the recent past due to climate change and uncontrolled anthropogenic interference. In this study, the seasonal variations in ovarian architecture and development were examined in adult S. plagiostomus from Garhwal Himalayan region, Uttarakhand, India. Ovarian-somatic index ranged from 16.86 ± 0.29 to 0.31 ± 0.56, with a maximal value in September and a minimal value in April. Ovarian histology revealed the abundance of primary growth oocytes in resting and preparatory stages; primary/secondary vitellogenic oocytes with numerous cortical alveoli were predominant in the developing stage of pre-spawning ovaries; secondary/tertiary vitellogenic oocytes were conspicuous in actively spawning ovaries; and atretic follicles/oocytes were discernible during the regressing stage of spent ovaries. Scanning electron microscopy of mature ova (mean diameter 2.003 ± 0.01 mm) prominently showed the structure micropyle (mean diameter 12.93 ± 3.38 μm). Fecundity analyses suggested that September was the principal breeding season, whereas residual spawning occurred with fresh rain in late winter during February-March. Collectively, this is the first comprehensive qualitative and quantitative report of the seasonal variations in the ovarian development and function for S. plagiostomus. These data may provide valuable information towards the captive breeding programme as well as conservation and management for Schizothoracine fishes in normal and altered climatic conditions.

Last Glacial Maximum and subsequent glacial chronology in the monsoon-dominated Sikkim Himalaya, India

The study investigates sequential evolution of glacial-landforms in relation to paleo-climate by establishing glacial chronology in Zemu and East-Rathong Glaciers valleys, Sikkim, Eastern Himalaya during the Late-Quaternary. This region is dominated by the Indian summer monsoon, followed by winter rain from the NE-monsoon and Westerlies which influence the glaciers. The study relies on field-based geomorphological mapping and geospatial datasets. The Toe-to-Headwall Altitude Ratio, Toe-to-Summit Altitude Method, and Maximum Elevation of Lateral Moraines methods have been used to calculate the equilibrium line altitudes (ELA) to assess magnitudes of glacial changes over time. OSL dating is used to assess the timing of glacial stages. Additionally, a comparison is made with ELA changes, the distance of moraines from the present glacier snouts, and established glacial chronologies in neighboring areas. The existing landscape depicts the dominant role of the region's present and past glacial processes. The region is also modified by periglacial, paraglacial, and fluvial processes. Four glacial stages have been identified in the region during the late-Quaternary period, contemporaneous to the Last Glacial Maximum, Younger Dryas, Late-Holocene, and Little Ice Age. The first stage (Sikkim-I), marked by dissected trimlines up to ∼16 km downstream, appears to belong to the global Last Glacial Maximum and dated to ∼18.276 ± 0.589 ka with a change of −519.5 m and − 3.4 °C in ELAs and temperature, respectively. The second stage, Sikkim-II is represented by lateral moraines running up to ∼5 km downstream in U-shaped valleys and seems to coincides with the Younger Dryas with ELAs depression of −261.8 m along with a − 1.7 °C drop in temperature. The third Stage (Sikkim-III), marked by small pairs of stable lateral moraines covered with shrubs within ∼3 km downstream, probably belongs to the late Holocene when ELAs and temperature dropped by −177.3 m and − 1.2 °C, respectively. The fourth stage (Sikkim-IV) is notified by a dumped heap of end moraines within ∼2 km downstream, possibly occurred during the LIA with a depression of −72.4 m in ELAs and − 0.5 °C in temperature. These glacial stages are synchronous with the glaciations in the neighboring regions of Thangu in north-Sikkim, Bhutan, and eastern Himalaya syntax. However, the findings of the study differ from the westerly dominated NW Himalayas, broadly.

Soil surface grass phytolith morphotypes across bioclimatic gradients and biomes at about latitude 29°S in South Africa

This study examines the distribution patterns of grass subfamilies and their diagnostic silica phytoliths along a transect running approximately at latitude 28° S in South Africa. The transect encompasses 77 surface samples collected along moisture and temperature gradients, across 6 biomes and 39 ecozones, and spanning elevations between near-sea level and over 2253 m. This study tests the relation between the distribution and density of grass subfamilies and the proportions of their diagnostic grass silica short cell phytoliths (GSSCP) representing them, and how these proportions correlate with five climatic variables (mean temperature of the wettest quarter, annual precipitation, precipitation of the wettest quarter, precipitation variability, and the aridity index). The results suggest that C3-grass diagnostic GSSCP morphotypes increase with a decline in temperature in the wettest quarter, occurring in areas receiving mostly winter rain or at high elevations in areas of summer rain. Of the C4 grass subfamilies, the Panicoideae increase with summer precipitation and low precipitation variability, while the Aristidoideae-Stipagrostis the opposite. The distribution of Chloridoideae depends on complex changes in all climatic variables, suggesting aridity gradients only in the eastern half of the transect. In view of the data, this study reviews the usefulness of the phytolith humidity-aridity index (Iph) and the water stress index (Fs) and proposes the Panicoideae index (PI) and Stipagrostis index (SI) as indicator of aridity and high precipitation variability in southern Africa.

Evocations of Multispecies Justice

Taralga RoadEarly spring, goldwattle lining the lanes, damsbrimming, fieldsemerald-greenand clotted with long-eared lambs, roaddeeply pot-holed from the winter rains,a cyclistcome a cropperbeing loaded into an ambulanceseven kilometers north of Kenmore.“Wombat”she announces just after Tarlo, and stops, gets out.I see her in the rearview mirrorturn the body overbefore walking quickly backfor gloves and a cloth from the first-aid kit. “She'sdead,” she says, “but there'sa tiny pawreaching from the pouch. I'vegot to check.” Across the road, twoyoung black steers, earsblue-tagged for slaughter,amble to the fence to watch, then othersand still more, a dozen, twenty, eyeswide in concern; if they weren'tanimals you'd almost think they knew her. Herbaby dead also, she tells me when she returns; paleand furless, barelyfilling the palm of her hand.Three kilometers later there's another. “Their pouchesare so wet,” she says, then speaksin awe of the size of their teeth.By Oberonthere have been two moreand almost a dozen roos. Somewe stop at, others you can just tellit's far too late; or there'sa truck on your tail, or the road's so narrowthere's no space to pull over,let alone any place to run.Near the turnoff to Jenolan, dusk coming on,we stop at a young swamp wallaby, headcrushed by a curb-side wheel, the roada single lane, then, ourexamination done, stepback to allow a four-wheel drive to pass, watchas it grinds her—eyes, ears, brain—even deeper into the gravel. Her joeywho'd beenstill breathingdies in our hands.

Inorganic geochemistry of saline substrates associated with coastal turf, Otago Peninsula, New Zealand

ABSTRACT Halophytic plant communities have developed on exposed coastal landforms to form low-stature turf in several locations around New Zealand. We quantify the inorganic geochemistry, mineralogy and simulated ephemeral surface water composition of saline soil-free bare ground at a well-preserved site at Maori Head on Otago Peninsula, where halophytes have colonised from adjacent coastal turf. The community at this site is dominated by Leptinella dioica, Samolus repens, Disphyma australe and Selliera radicans. Maori Head substrates are dominated by clay-altered basalt colluvium and show a general trend from high electrical conductivity (EC > 10 mS/cm) and weakly acid pH (< 6) on bare ground to low EC (< 1 mS cm−1) and higher pH (> 7) in turf and adjacent pasture soils. High salinities on dry substrates and in simulated ephemeral surface waters result from surface evaporation of airborne sea spray and contain halite (NaCl) with some gypsum (CaSO4.2H2O). Chemical interactions with the substrate are minor. The high surface salinities were maintained despite a major winter rain event with strong onshore winds. However, surface salinity is frequently leached by rain and shallow groundwater, whereas inland saline sites (pH 8–11) have substantial salt accumulations driven by lower rainfall, high evaporation and chemical interaction with Otago Schist-derived substrates.

A New Digital Twin for Climate Change Adaptation, Water Management, and Disaster Risk Reduction (HIP Digital Twin)

The paper analyzes the national DK-model hydrological information and prediction (HIP) system and HIP portal viewed as a ‘digital twin’ and how the introduction of real-time dynamic updating of the DK-model HIP simulations can make room for plug-in submodels with real-time boundary conditions made available from an HIP portal. The possible feedback to a national real-time risk knowledge base during extreme events (flooding and drought) is also discussed. Under climate change conditions, Denmark is likely to experience more rain in winter, more evapotranspiration in summer, intensified cloudbursts, drought, and sea level rise. These challenges were addressed as part of the Joint Governmental Digitalization Strategy 2016–2020 for better use and sharing of public data about the terrain, water, and climate to support climate adaptation, water management, and disaster risk reduction. This initiative included the development of a new web-based data portal (HIP portal) developed by the Danish Agency for Data Supply and Infrastructure (SDFI). GEUS delivered 5 terabytes of hydrological model data to the portal, with robust calibration methods and hybrid machine learning (ML) being key parts of the deliverables. This paper discusses the challenges and potentials of further developing the HIP digital twin with ‘plug-in digital twins’ for local river basins, including feedback to the national level.

Climatic Water Balance and Groundwater Recharge in Abu-Jir Village, Al-Anbar Governorate, Western Iraq

The study area is located in Al-Anbar Governorate, western Iraq. The climatic data were collected from Al-Ramadi Meteorological Station for the period 1990 to 2020 and used to assess the climatic condition of the study area. The total annual rainfall, relative humidity, monthly average temperature, evaporation, wind speed and sunshine duration are 108 mm, 52.7 %, 22.6˚C, 2814.3 mm, 2.2 m/s and 8.8 h/day, respectively. The climate of the study area is described as an arid to sub arid and relatively hot in summer and cold with low rain in winter. During the data used, the highest potential evapotranspiration was 217.1 mm in July, while the lowest value was 10.7 mm in January, with a total amount of 1170.07 mm. The highest and lowest corrected evapotranspiration becomes 264.2 mm in July and 9.4 mm in January, with 1310.3 mm. water Surplus (WS) is 2.1mm, 10.71mm, and 5.65mm in December, January and February, respectively. The WS was 18.46mm, forming 17.09 % of the total annual rainfall. The groundwater recharge (18.46 mm) with a rate of 17.09% represents the recharge from the total rainfall zero surface runoff. It has been found that the low amount of rain and sandy soil are among the most important factors causing the absence of surface runoff.

Simulation of Episodic Winter Warming on Dehardening of Boreal Forest Seedlings in Northern Forest Nurseries

In recent decades, forest nurseries in eastern Canada have been faced with periods of mild winter weather, delayed snowfall, and low seedling protective snow cover combined with winter rains instead of snowfall. These extreme conditions have resulted in the loss of millions of seedlings, in particular those that overwinter outdoors, probably due to their winter dehardening. The main objective of this study is to simulate different periods of warm weather at the beginning and end of winter and evaluate their effects on the dehardening and growth of Picea mariana and Picea glauca seedlings in response to different freezing temperatures. Three warming treatments were simulated (control, 1 day, and 3 days of warming at 10 °C) followed by three freezing temperatures (−4, −12, and −20 °C). In winter, regardless of the warming treatment, the seedlings of the two species tolerated the different freezing temperatures without any apparent damage. However, at the end of winter and in the absence of snow cover, the seedlings did not show frost tolerance at −20 °C. On the other hand, the seedlings showed normal growth after undergoing frosts at −4 °C and −12 °C, similar to that observed for control seedlings. Different cultural practices and protection strategies are proposed to improve frost tolerance and reduce the winter loss of seedlings.

Expansion and Intensification of the North American Monsoon During the Pliocene

AbstractSouthwestern North America (SWNA), like many subtropical regions, is predicted to become drier in response to anthropogenic warming. However, during the Pliocene, when carbon dioxide was above pre‐industrial levels, multiple lines of evidence suggest that SWNA was much wetter. While existing explanations for a wet Pliocene invoke increases in winter rain, recent modeling studies hypothesize that summer rain may have also played an important role. Here, we present the first direct evidence for an intensified mid‐Pliocene monsoon in SWNA using leaf wax hydrogen isotopes. These new records provide evidence that the mid‐Pliocene featured an intensified and expanded North American Monsoon. Using proxies and isotope‐enabled model simulations, we show that monsoon intensification is linked to amplified warming on the southern California margin relative to the tropical Pacific. This mechanism has clear relevance for understanding present‐day monsoon variations, since we show that intervals of amplified subtropical warming on the California margin, as are seen during modern California margin heat waves, are associated with a stronger monsoon. Because marine heat waves are predicted to increase in frequency, the future may bring intervals of “Pliocene‐like” rainfall that co‐exist with intensifying megadrought in SWNA, with implications for ecosystems, human infrastructure, and water resources.