Dry Summer Research Articles

Updating the Methodology of Identifying Maize Hybrids Resistant to Ear Rot Pathogens and Their Toxins—Artificial Inoculation Tests for Kernel Resistance to Fusarium graminearum, F. verticillioides, and Aspergillus flavus

Resistance to toxigenic fungi and their toxins in maize is a highly important research topic, as mean global losses are estimated at about 10% of the yield. Resistance and toxin data of the hybrids are mostly not given, so farmers are not informed about the food safety risks of their grown hybrids. According to the findings aflatoxin regularly occurs at preharvest in Hungary and possibly other countries in the region can be jeopardized. We tested, with an improved methodology (two isolates, three pathogens, and a toxin control), 18 commercial hybrids (2017–2020) for kernel resistance (%), and for toxin contamination separately by two–two isolates of F. graminearum, F. verticillioides (mg/kg), and A. flavus (μg/kg). The preharvest toxin contamination was measured in the controls. Highly significant kernel resistance and toxin content differences were identified between hybrids to the different fungi. Extreme high toxin production was found for each toxic species. Only about 10–15% of the hybrids showed higher resistance to the fungal species tested and lower contamination level of their toxins. The lacking correlations between resistance to different fungi and toxins suggest that resistance to different fungi and response to toxin contamination inherits independently, so a toxin analysis is necessary. For safety risk estimation, separated artificial and natural kernel infection and toxin data are needed against all pathogens. Higher resistance to A. flavus and F. verticillioides stabilizes or improves feed safety in hot and dry summers, balancing the harmful effect of climate changes. Resistance and toxin tests during variety registration is an utmost necessity. The exclusion of susceptible or highly susceptible hybrids from commercial production results in reduced toxin contamination.

Harmful algal bloom dynamics in a tidal river influenced by hydraulic control structures

The Singok weir, an instream structure in the Han River estuary constructed in the 1980s for multiple purposes, has interfered with natural river flow. Removal of this structure has been considered to restore water quality, including reducing algal blooms. Spatiotemporal changes in water quality, hydrodynamics, hydrology, and algal growth resulting from the removal of the Singok weir were analyzed using 3-D hydrodynamic, water quality, and sediment transport modules in the Environmental Fluid Dynamics Code model for a five-year period (2013 ∼ 2017) with field data. Weir removal decreased water depth and thus water volume by >10%, which increased average nutrient concentrations given fixed pollutant inputs. With the weir removal, average cyanobacteria decreased in the upper region during summer but increased in the lower region. However, differences in cyanobacteria biomass were less than 1.0 mg Chl-a/m3 except during 2015, the driest summer, where peak cyanobacteria increased by 20% (11.8 mg/m3). Factors limiting summer algal growth tended to increase modestly during normal flow (<3.1%), which suggests the weir removal can potentially enhance algal growth. The role of hydrology stood out as the major factor determining algal growth, with greater relative importance than nutrients, light, and temperature. Simulations showed minimum discharge of 150 m3/s from the Paldang dam was required to avoid excessive cyanobacteria growth downstream. Hydraulic residence time during summer determined the growth potential of algae; low discharge provided sufficient residence time for algae to proliferate, and conversely. This result also emphasizes the importance of seasonal and hydrodynamic assessments when analyzing cyanobacteria in response to external changes, which can be masked in annual average values by numerous factors.

Record summers in Europe: Variations in drought and heavy precipitation during 1901–2018

AbstractDuring the last 20 years some very hot and dry summers affected Europe, resulting in regionally record‐breaking high temperature or low precipitation values. Long‐term changes of such extremely hot and dry summers are of great relevance for our society, as they are connected with manifold negative impacts on human society, natural ecosystems, and diverse economic sectors. Long‐term variations in drought and five record drought summer half years are studied based on 63 stations across Europe with high‐quality precipitation and temperature time series spanning the period 1901–2018. Eight drought indices are deployed to analyse drought intensity, frequency, and duration; four of them purely precipitation‐based and four integrating potential evapotranspiration in the computation. Additionally, three heavy precipitation indices and simultaneous increases in drought and heavy precipitation are studied. The five driest summer half years over Europe are identified (1947, 2018, 2003, 1921, and 1911). They are analysed by aggregating eight drought indices into the aggregated drought evaluation index (ADE) for five subregions. The ADE shows increasing summer drought conditions over most of Europe, except for some stations in northern Europe. The increase in drought conditions during the warm part of the year is particularly pronounced for indices integrating evapotranspiration in their definition. At the same time, the intensity of heavy precipitation events shows a positive trend, as well as an increased contribution to total precipitation. Several stations in central Europe show simultaneously increasing drought conditions and increasing heavy precipitation events. This increases the risks connected with precipitation extremes.

How summer sleepers stave off desiccation

Have you ever left your house on a sweltering day and immediately gone back inside because it is too hot to even think? Not all creatures have the luxury of escaping torrid heat, so some have found ways to survive even when their homes become as dry as a bone. They can either deal with water shortages and scorching temperatures or use a hibernation-like ‘summer sleep’ called aestivation, when they become inactive and shut off most biological processes except those necessary for survival. Aestivating animals such as earthworms can alter which genes they turn off and on to survive until the rains return. These stoic burrowers are also true unsung heroes in our battle against the effects of climate change because they help store carbon in the ground and help other smaller animals by providing shelter while they undergo aestivation. Since scientists predict climate change will increase the number of droughts, figuring out how these climate change mitigators aestivate during an exceptionally dry summer is critical. Natasha Tilikj and Marta Novo from the Complutense University of Madrid, Spain, investigated which genes earthworms (Carpetania matritensis) from the Iberian Peninsula activate and switch off during aestivation.The duo collected earthworms from El Molar, Spain, and returned with them to the lab. Once there, the team needed the right soil conditions to produce both active and aestivating worms – when they tie themselves into mucus-covered knots – to compare the two. To reproduce the correct conditions, they placed some worms in dry soil to encourage them to begin aestivating and maintained the remaining worms in moist soil to keep them active. After a month, the team checked whether or not the worms were aestivating and then analyzed how the animals changed the patterns of gene expression – which genes they upregulated and which they downregulated – after slipping into a summer sleep.Unsurprisingly, the team found that the aestivating worms reduced expression of most genes. Other aestivating animals conserve energy by destroying and producing fewer proteins, to extend their state of suspended animation until conditions improve, and worms could be using the same strategy. The aestivating worms reduced expression of genes involved in the production of proteins and other macromolecules in addition to genes involved in protein breakdown and digestion. As worms go into this state of dormancy, they shut down processes that are not vital for survival. The team also found evidence that the worms were under stress and increased the levels of toxic oxygen by-products, known as reactive oxygen species, which can damage DNA after aestivation. In addition, there was an increase in the expression of genes that typically help combat and repair the DNA damage caused by these harmful products, and the stress experienced by the worms also activated the worms’ immune response for protection from possible infection.Finally, the team discovered that aestivating worms may stave off water loss using an innovative mechanism that researchers have yet to study in earthworms: the worms increased the expression of genes involved in the production of the amino acid arginine. The duo suggest that an increase in arginine, or a build-up of nitrogenous waste, might reduce the amount of water lost by the worms.Aestivating earthworms employ various strategies to survive desiccation. With increasing drought in the future, whether these protective mechanisms will be sufficient is unknown. The researchers recommend further investigation into the role of digestion, excretion and the central nervous system in aestivation to help scientists design better drought mitigation strategies to protect these uncelebrated champions of the subterranean world.

The Diurnal Dynamics of Gross Primary Productivity Using Observations From the Advanced Baseline Imager on the Geostationary Operational Environmental Satellite‐R Series at an Oak Savanna Ecosystem

AbstractGross primary productivity (GPP) is the largest flux in the global carbon cycle and satellite‐based GPP estimates have long been used to study the trends and interannual variability of GPP. With recent updates to geostationary satellites, we can now explore the diurnal variability of GPP at a comparable spatial resolution to polar‐orbiting satellites and at temporal frequencies comparable to eddy covariance (EC) tower sites. We used observations from the Advanced Baseline Imager on the Geostationary Operational Environmental Satellite‐R series (GOES‐R) to test the ability of subdaily satellite data to capture the shifts in the diurnal course of GPP at an oak savanna EC site in California, USA that is subject to seasonal soil moisture declines. We compared three methods to estimate GPP: (a) a light‐use efficiency model, (b) a linear relationship between the product of near‐infrared reflectance of vegetation and photosynthetically active radiation (LIN‐NIRvP) and EC tower GPP, and (c) a light response curve (LRC‐NIRvP) between NIRvP and EC GPP. The LRC‐NIRvP achieved the lowest mean absolute error for winter (2 µmol CO2 m−2 s−1), spring (2.51 µmol CO2 m−2 s−1), summer (1.43 µmol CO2 m−2 s−1), and fall (1.35 µmol CO2 m−2 s−1). The ecosystem experienced the largest shift in daily peak GPP in relation to the peak of incoming solar radiation toward the morning hours during the dry summers. The LRC‐NIRvP and the light‐use efficiency model were in agreement with these patterns of a shift in peak daily GPP toward the morning hours during summer. Our results can help develop diurnal estimates of GPP from geostationary satellites that are sensitive to fluctuating environmental conditions during the day.

Carbon concentrations in natural and restoration pools in blanket peatlands

AbstractOpen‐water perennial pools are common natural features of peatlands globally, and peatland restoration often results in new pool creation, yet the concentrations of different forms of aquatic carbon (C) in natural and artificial restoration pools are not well studied. We compared carbon concentrations in both natural pools and restoration pools (4–15 years old) on three blanket peatlands in northern Scotland. At all sites, restoration pools were more acidic and had mean dissolved organic carbon (DOC) concentrations in restoration pools of 23, 22, and 31 mg L−1 compared with natural pool means of 11, 11 and 15 mg L−1 respectively across the three sites. Restoration pools had a greater fulvic acid prevalence than the natural pools and their DOC was more aromatic. Restoration pools were supersaturated with dissolved CO2 at around 10 times atmospheric levels, whereas for natural pools, CO2 concentrations were just above atmospheric levels. Dissolved CH4 concentrations were not different between pool types, but were ~200 times higher than atmospheric levels. Regular sampling at one of the peatland sites over 2.5 years showed that particulate organic carbon (POC) concentrations were generally below 7 mg L−1 except during the warm, dry summer of 2013. At this regularly‐sampled site, natural pools were found to process DOC so that mean pool outflow concentrations in overland flow were significantly lower than mean inflow DOC concentrations. Such an effect was not found for the restoration pools. Soil solution and pool water chemistry, and relationships between DOC and CO2 concentrations suggest that different processes are controlling the transformation of C, and therefore the form and amount of C, in natural pools compared to restoration pools.

Drier Winters Drove Cenozoic Open Habitat Expansion in North America

AbstractThe shift from denser forests to open, grass‐dominated vegetation in west‐central North America between 26 and 15 million years ago is a major ecological transition with no clear driving force. This open habitat transition (OHT) is considered by some to be evidence for drier summers, more seasonal precipitation, or a cooler climate, but others have proposed that wetter conditions and/or warming initiated the OHT. Here, we use published (n = 2,065) and new (n = 173) oxygen isotope measurements (δ18O) in authigenic clays and soil carbonates to test the hypothesis that the OHT is linked to increasing wintertime aridity. Oxygen isotope ratios in meteoric water (δ18Op) vary seasonally, and clays and carbonates often form at different times of the year. Therefore, a change in precipitation seasonality can be recorded differently in each mineral. We find that oxygen isotope ratios of clay minerals increase across the OHT while carbonate oxygen isotope ratios show no change or decrease. This result cannot be explained solely by changes in global temperature or a shift to drier summers. Instead, it is consistent with a decrease in winter precipitation that increases annual mean δ18Op (and clay δ18O) but has a smaller or negligible effect on soil carbonates that primarily form in warmer months. We suggest that forest communities in west‐central North America were adapted to a wet‐winter precipitation regime for most of the Cenozoic, and they subsequently struggled to meet water demands when winters became drier, resulting in the observed open habitat expansion.

Difference in the atmospheric water cycle over the Hengduan Mountains between wet and dry summers

The atmospheric water cycle over the Hengduan Mountains (HM) is crucial to the local and downstream ecosystem and social economy, while its characteristics and variability have not been thoroughly revealed yet. Based on a bulk method, the atmospheric water cycle over the HM and its difference between wet and dry summers is analysed in this study. Results show that the summer precipitation recycling ratio over the HM is 11.5% in climatology and is significantly and negatively correlated with precipitation there on interannual timescale. In wet summers, the precipitation recycling ratio decreases by 13% compared to dry summers. The origin of water vapour for precipitation over the HM is mainly contributed by the external water vapour transport (local evaporation) in wet (dry) summers. August is found to have the strongest climatological mean precipitation recycling ratio (15.2%) and atmospheric water cycle among 3 months in summer. Also in August, the difference in precipitation recycling ratio between wet and dry summers is largest. In wet summers, although the increase in the external moisture inflow is the largest in June (3.0 × 107 kg·s−1), the increase of precipitation is the largest in August (2.6 × 107 kg·s−1) due to its stronger atmospheric water cycle. Our study promotes the knowledge of the atmospheric water cycle over the HM and provides a new perspective to understand the interannual variations of the precipitation over the HM.

Severe drought can delay autumn senescence of silver birch in the current year but advance it in the next year

Historically, the autumn dynamics of deciduous forest trees have not been investigated in detail. However, autumn phenological events, like onset of loss of canopy greenness (OLCG), onset of foliar senescence (OFS) and cessation of wood growth (CWG), have an important impact on tree radial growth and the entire ecosystem's seasonal dynamics. Here, we monitored the leaf and wood phenological events of silver birch (Betula pendula) at four different sites in Ås, southeastern Norway: (a) a natural mature stand, (b) a plantation on former agricultural ground, (c) young natural trees, and (d) young trees in pots under different fertilization levels. The study took place over four consecutive years (from 2017 to 2020), with a particular focus on 2018, a year in which there was a severe summer drought, and the next year, 2019, which featured more normal conditions. First, we provided a description of birch phenology within its mid-north distributional. Second, we showed that drought advanced CWG by about 5 to 6 weeks and it delayed OLCG and OFS up to 30 days. Third, we observed an unexpected advance in OLCG in 2019 compared to 2018 (30 days) and 2020 (14 days). OFS presented similar dynamics as OLCG, whereas CWG was advanced only in 2018. These findings might indicate lag-effects of severe drought on the next year autumn leaf phenology but not on wood growth. On the other hand, the comparison between the natural stand and the plantation showed that, under drought conditions, wood growth is more sensitive to site fertility than autumn leaf phenology. In summary, our study elucidated the autumn dynamics of an important deciduous forest species in the northern temperate zone and showed unexpected impacts of a severely dry and warm summer on the current and next year leaf phenology.

Seasonal effect on physiological and haematological profiles, scrotal circumference and testicular parameters in indigenous goat bucks under tropical humid island ecosystem

Andaman local goat (ALG) is meat animal in Andaman and Nicobar islands (ANI) of India. Present study was conducted to measure the seasonal effect on physiological and haematological profiles, scrotal circumference (SC) and testicular weight during rainy and dry summer seasons in ALG. A total of 10 adult intact ALG bucks (body condition score: 3.0-3.5 and classified as good; 3-4 years) were selected from the goat breeding farm, ICAR-CIARI, Port Blair, ANI, India. Results revealed that these experimental profiles differed significantly (p &lt; 0.05) between the seasons. Significantly (p &lt; 0.05) higher haematological profiles, SC and testicular weight were observed in rainy season than in dry summer season whereas physiological profiles such as rectal, skin and scrotal temperatures were higher in dry summer than in wet rainy season. The study concluded that the rainy season has significantly greater beneficial effects than dry summer season on reproduction and artificial breeding programmes in semi-intensive management of goat in the present location.

Increasing the resistance of Mediterranean extensive green roofs by using native plants from old roofs and walls

BackgroundWhile the use of extensive green roofs (EGRs) is increasing worldwide, Mediterranean conditions complicate EGR design due to their long, dry summers with intense solar radiation. AimTo inform sustainable EGR design for Mediterranean regions, we explored the use of resilient, drought-tolerant species in experimental EGRs. MethodsWe selected four native species that are known to spontaneously establish themselves on urban structures, including roofs, in Lisbon, Portugal: Antirrhinum linkianum, Asphodelus fistulosus, Centranthus ruber, and Sedum sediforme. We evaluated growth and aesthetic value under two irrigation treatments (100 and 60% ETo, reference evapotranspiration). The presence of moss covering for the lower level of irrigation was also evaluated. ResultsAntirrhinum linkianum presented the highest number of flowers, most extended seed production duration, and the highest area coverage. Irrigation level did not significantly affect flowering and green coverage for any of the species. ConclusionAntirrhinum linkianum is an ideal starting species for Lisbon EGRs. Irrigation costs can be reduced by starting at a 60%ETo irrigation level.

Prospective crop yield and income return based on a retrospective analysis of a long-term rainfed agriculture experiment in Nebraska

CONTEXTNebraska, US, is projected to face increased winter and spring precipitation, and drier summers as the climate changes over the next 20 to 30 years. Agricultural adaptations and adjustments would be critical to mitigate the adverse impact of climate change and achieve global food security. OBJECTIVEFocusing on the projected climatic change projections for Nebraska, our objective is to analyze data from a long-term (31 years; 1986–2016) rainfed agriculture experiment to determine how past years, that had similar conditions to the projected future climate - wetter winter (WW), wetter spring (WS), and dry summer (DS), responded to these conditions and attempt to describe the near-future (upcoming 20–30 years) corn and soybean yield, and income returns in northeast Nebraska. METHODSFirst, we used a meteorological drought index, to determine years with projected future climate (6 years with WW, 4 years with WS, and 4 years with DS) and 9 all normal (AN) seasons years during the study period. Second, we performed a linear mixed-model analysis of variance to compare treatment (tillage: no-till, disk-till and plow-till; crop rotation: continuous-corn, corn-soybean; Nitrogen rates: 0–160 kg-N/ha) interaction and their effect on crop yield between projected future climate (WW, WS and DS) years and AN years. Finally, we used partial budgeting to calculate change in income and income risk across imposed management practices. RESULTS AND CONCLUSIONSResults indicate that corn years with WW, WS, and DS seasons showed yield reductions of 9.1%, 10.9%, and 38.6% compared to an average AN season corn yield, which was 11.3 Mg/ha. Compared to the average AN season yield of 3.6 Mg/ha, soybean yields were + 1.4%, −3.3%, and − 31.8% for WW, WS, and DS, respectively. These yield differences did not significantly affect average corn and soybean income return in WW and WS years compared to the AN years (900 $/ha). However, total income returns in DS seasons regardless of pre-season conditions was about 40% of income return in AN seasons from CS (900 $/ha) and CC (800 $/ha), respectively. Soybean yield and income returns were more stable than corn, which resulted in the corn-soybean rotation system always being higher in yields and being more profitable. SIGNIFICANCEOur recommended management practice of disk tillage and corn-soybean rotation with 80 kg-N/ha could result in highest and stable income returns in near-future. Such long-term crop experimental studies can serve as an important complement to crop-model studies to get improved insight into future crop yield and income returns.

Four years of daily stable water isotope data in stream water and precipitation from three Swiss catchments

Time series of the natural isotopic composition (2H, 18O) of precipitation and streamwater can provide important insights into ecohydrological phenomena at the catchment scale. However, multi-year, high-frequency isotope datasets are generally scarce, limiting our ability to study highly dynamic short-term ecohydrological processes. Here we present four years of daily isotope measurements in streamwater and precipitation at the Alp catchment (area 47 km2) in Central Switzerland and two of its tributaries (0.7 km2 and 1.6 km2). This data set reveals short-term responses of streamflow isotopes to precipitation events, which otherwise remain obscured when isotopes are sampled weekly or monthly. The observations span the period June 2015 through May 2019, during which several hydrometeorologic extreme events occurred, including a very dry summer in 2018 and below-average snow accumulation in winter 2016/2017. In addition, we provide daily time series of key hydrometeorological variables that, in combination with the isotope data, can be useful for assessing the robustness of ecohydrological models.

Are chromosome number and genome size associated with habit and environmental niche variables? Insights from the Neotropical orchids.

The entangled relationship of chromosome number and genome size with species distribution has been the subject of study for almost a century, but remains an open question due to previous ecological and phylogenetic knowledge constraints. To better address this subject, we used the clade Maxillariinae, a widely distributed and karyotypically known orchid group, as a model system to infer such relationships in a robust methodological framework. Based on the literature and new data, we gathered the chromosome number and genome size for 93 and 64 species, respectively. We built a phylogenetic hypothesis and assessed the best macroevolutionary model for both genomic traits. Additionally, we collected together ecological data (preferences for bioclimatic variables, elevation and habit) used as explanatory variables in multivariate phylogenetic models explaining genomic traits. Finally, the impact of polyploidy was estimated by running the analyses with and without polyploids in the sample. The association between genomic and ecological data varied depending on whether polyploids were considered or not. Without polyploids, chromosome number failed to present consistent associations with ecological variables. With polyploids, there was a tendency to waive epiphytism and colonize new habitats outside humid forests. The genome size showed association with ecological variables: without polyploids, genome increase was associated with flexible habits, with higher elevation and with drier summers; with polyploids, genome size increase was associated with colonizing drier environments. The chromosome number and genome size variations, essential but neglected traits in the ecological niche, are shaped in the Maxillariinae by both neutral and adaptive evolution. Both genomic traits are partially correlated to bioclimatic variables and elevation, even when controlling for phylogenetic constraints. While polyploidy was associated with shifts in the environmental niche, the genome size emerges as a central trait in orchid evolution by the association between small genome size and epiphytism, a key innovation to Neotropical orchid diversification.

The Impact of the Neophyte Tree Fraxinus pennsylvanica [Marshall] on Beetle Diversity under Climate Change

We studied the impact of the neophyte tree Fraxinus pennsylvanica on the diversity of beetles in floodplain forests along the river Elbe in Germany in 2016, 2017 and in 2020, where 80% of all Fraxinus excelsior trees had died following severe droughts. Beetles were collected by insecticidal knock-down from 121 trees (64 F. excelsior and 57 F. pennsylvanica) and identified to 547 species in 15,214 specimens. The trees sampled in 2016 and 2017 showed no signs of drought stress or ash dieback and serve as a reference for the comparison with the 2020 fauna. The data proved that F. excelsior harbours the most diverse beetle community, which differed also significantly in guild composition from F. pennsylvanica. Triggered by extremely dry and long summer seasons, the 2020 ash dieback had profound and forest-wide impacts. Several endangered, red-listed beetle species of Saxonia Anhalt had increased in numbers and became secondary pests on F. excelsior. Diversity decreased whilst numbers of xylobionts increased on all trees, reaching 78% on F. excelsior. Proportions of xylobionts remained constant on F. pennsylvanica. Phytophages were almost absent from all trees, but mycetophages increased on F. pennsylvanica. Our data suggest that as a result of the dieback of F. excelsior the neophyte F. pennsylvanica might become a rescue species for the European Ash fauna, as it provides the second-best habitat. We show how difficult it is to assess the dynamics and the ecological impact of neophytes, especially under conditions similar to those projected by climate change models. The diversity and abundance of canopy arthropods demonstrates their importance in understanding forest functions and maintenance of ecosystem services, illustrating that their consideration is essential for forest adaptation to climate change.

Trends and drivers of recent summer drying in Switzerland

The Alpine region recently experienced several dry summers with important and adverse impacts on economy, society and ecology. Here, we analyse drought indicators, evapotranspiration and meteorological data from point observations, reanalyses and regional climate model data to assess trends and drivers of summer drought in Switzerland in the period 1981–2020. The drought indicators from station observations and ERA5-Land and ERA5 reanalyses show a tendency towards drier summer half-years (climatic water balance: −39 mm decade−1, 0–1 m integrated soil water content: −5 to −7 mm decade−1) with a drying in most months from March to October. Both, increasing evapotranspiration (potential evapotranspiration: +21 mm decade−1 or +7% K−1 warming; actual evapotranspiration: +8 to +15 mm decade−1) and a non-significant precipitation decrease of 17 mm decade−1 are identified as important and roughly equivalent drivers. The reanalyses show considerable differences for soil water and actual evapotranspiration, especially in drought summers. The ERA5 soil is clearly drier than the one in ERA5-Land. ERA5 evapotranspiration is smallest and partly soil moisture-limited in drought years while evapotranspiration in ERA5-Land is highest, still mainly energy-limited and scales well with temperature (+4% K−1 warming). ERA5-Land seems to better match with in situ measurements of soil water and evapotranspiration than ERA5, but considerable differences with in situ measurements remain. Variability and trends of the drought drivers temperature and precipitation are also investigated in the EURO-CORDEX regional climate model ensemble. Most simulations considerably underestimate the recent warming and the ensemble shows a large possible range of precipitation changes with a mean change near zero. The summer precipitation-temperature scaling and the correlation between summer temperature and precipitation on the interannual time scale are mostly overestimated. Our results highlight that the analysis of Central European summer drought evolution and its drivers remains challenging especially with regional climate model data, but considerable uncertainties also exist in reanalyses.

Trehalose provisioning in Daphnia resting stages reflects local adaptation to the harshness of diapause conditions.

Environmental fluctuations often select for adaptations such as diapause states, allowing species to outlive harsh conditions. The natural sugar trehalose which provides both cryo- and desiccation-protection, has been found in diapause stages of diverse taxa. Here, we hypothesize that trehalose deposition in resting stages is a locally adapted trait, with higher concentrations produced in harsher habitats. We used resting stages, produced under standardized conditions, by 37 genotypes of Daphnia magna collected from Western Palaearctic habitats varying in their propensity to dry in summer and freeze in winter. Resting eggs produced by D. magna from populations from summer-dry habitats showed significantly higher trehalose than those from summer-wet habitats, suggesting that trehalose has a protective function during desiccation. By contrast, winter-freezing did not explain variation in trehalose content. Adaptations to droughts are important, as summer dryness of water bodies is foreseen to increase with ongoing climate change.

Methodology for monitoring soil moisture in systems of double-acting irrigation

The purpose of the research is, based on the analysis of field studies, to select a well for sampling soil moisture relative to the entire inter-drain space for monitoring double-acting irrigation systems. To solve the problem, a monitoring system on double-acting irrigation systems, providing two-way regulation of the water regime in the root layer of the soil, as well as to ensure fire safety of the entire peat profile. Based on the results of field studies on the peat bogs of the Dubna river floodplain in the Moscow Region, a representative sampling point for monitoring double-acting irrigation systems has been substantiated. The sampling point should be located on an area with the same relief, the soil profile should be uniform with the properties and soil morphology characteristic of the entire field. Wells for taking moisture samples are recommended to be installed at a distance of ¼E (E is the distance between channels), in this case the measured moisture value will be closest to the average value in relation to the entire site. For the soil conditions of the experimental site, the moisture content in the selected well during sluicing in the dry summer period increased by 1.5 times to the anti-fire moisture standard. If the water level in the canal is maintained up to 85 cm for 5 or more hours, the humidity will rise to anti-fire moisture in the dry period.

Effects of land use type and seasonal climate on ground nesting wild bees

Abstract Agricultural intensification leads to wide ranging changes in habitats along with reduction in nesting site availability and flower resources for wild pollinators. Yet, little is known about the impact of these changes on functional traits of communal ground‐nesting bees. This study assesses the abundance and body size of a common and widespread North American ground‐nesting bee, Agapostemon virescens, throughout three consecutive years at three land use types: (i) unmowed meadows, (ii) conventional pesticide use and mowed agricultural and (iii) organic pesticide‐free mowed landscapes. We found no difference in abundance among the three land use types, but body size of spring bees was smaller at farmlands than meadow sites. Body size also varied among years, and bees were smaller in years that followed warm and dry summer seasons. Spring bees were particularly small at organic farms in years following dry and warm summers. Our results suggest that the smaller size of overwintering bees at agricultural lands could compromise their long‐term survival. This study indicates that a higher frequency of dry and warm summers as a consequence of climate change can impede bee populations in the future.

Investigating hydrological model versatility to simulate extreme flood events

We adapted a semi-distributed hydrological model (GRSD) to improve its versatility to simulate flood events occurring under different conditions, especially flash-floods after dry summer periods in the Mediterranean region. The adaptation introduces a dependency on rainfall intensity in the production function. The evaluation over 2008-2018 in the Aude catchment (France) showed that the new model structure does not deteriorate long-term model simulations obtained from the original model. The adapted model performed better than or equal to the original model in terms of differences in the timing of peak discharges, regardless of the season of the year when the flood occurs. The most important improvement was observed in the simulation of the magnitude of the flood peaks during autumn floods. A visualisation of model versatility allows detecting the time steps when the new model tends to behave more similarly or differently from the original model in terms of runoff production.