Frequency Of Severe Droughts Research Articles

Change in Yields of Cereal Crops in European Russia Caused by the Quasi-Biennial Oscillation of Atmospheric Processes

The objective of work is to study the influence of quasi-biennial oscillation of atmospheric processes on precipitation and frequency of the spring-summer drought against the background of the statistics of cyclonic and anticyclonic activity in different phases of the quasi-biennial oscillation and, consequently, on the yield of wheat in the European part of Russia. The area of the study is the grain zone of European Russia including the North Caucasus, Central Chernozem zone, Volga region and Southern Urals. The timeseries of values of speed and direction of zonal wind on an isobaric surface of 30 hPa for the period 1953–2011 was accepted as data characterizing the “classical” quasi-biennial (Data of Free University of Berlin, https://climatedataguide.ucar.edu). Decadic precipitation totals, indices of PDSI and SPI, snow depth in March, the frequency of centers of cyclones during the period of vegetation classified by phases of quasi-biennial. The increase of snow depth in March is revealed, as well as significant increase in precipitation and a reduction in the frequency of severe droughts in May associated with the intensification of cyclonic activity during the Western phase in relation to Eastern on a vast territory: the western region of Central Chernozem zone, Rostov region and Krasnodar krai. As a result of changing agro-climatic conditions depending on the phase of the quasi-biennial in the territory, it is found a significant excess of productivity of spring wheat during the Western phase against the Eastern phase. The yield of winter wheat was less sensitive to the quasi-biennial. The results of the study can be used to adequately address the problem of increasing the sustainability of harvests in Russia (improvement of agrometeorological practice, including prognostic aspects, and agroinsurance).

Intensity–area–duration analysis of droughts in China 1960–2013

In this study, the intensity, area, and duration of droughts in China are analyzed using the Standardized Precipitation Index (SPI). The SPI was calculated on monthly data for 530 meteorological stations in China for the period 1960–2013. The time series were analyzed for ten major hydrological regions of China, respectively. The relationships between the intensity and the area of droughts for a specific duration were analyzed by the intensity–area–duration method. The results show that areas with a significant trend in dryness can be found in a band reaching from the southwest to the northeast of China, while areas with significant trends in wetness are especially detected in the northern river basins in recent decades. In addition, for recent years (2000–2013), most of the ten major hydrological regions show opposite trends in the SPI when compared to the whole study period (1960–2013) except for the central and southwestern parts of China. This dryness/wetness trends are related to the intensity and duration of drought events, which have been stronger and lasted longer in the detected dryness band except for some northern river basins. A regional shift of drought centers is found from the northwest to the southeast within Central China. Moreover, a decreasing trend in drought area is observed, which might be related to the regional changes in precipitation pattern associated with the atmosphere–ocean interaction. Changes in the SST of the Tropical Pacific and the Tropical Indian Ocean may have resulted in frequent severe drought events of small areal extent in the central and southwestern parts of China. For the study period, the most severe droughts that covered large areas mainly occurred in the north and west of China during the mid-to-late twentieth century. However, in the early twenty-first century, the most severe droughts were located in the southwest of China covering areas less than 0.7 million km2. Conclusively, drought areas show a decreasing tendency, while more intense droughts of longer duration have been experienced, especially in the south of China, in the last decades.

Larger trees suffer most during drought in forests worldwide.

The frequency of severe droughts is increasing in many regions around the world as a result of climate change(1-3). Droughts alter the structure and function of forests(4,5). Site- and region-specific studies suggest that large trees, which play keystone roles in forests(6) and can be disproportionately important to ecosystem carbon storage(7) and hydrology(8), exhibit greater sensitivity to drought than small trees(4,5,9,10). Here, we synthesize data on tree growth and mortality collected during 40 drought events in forests worldwide to see whether this size-dependent sensitivity to drought holds more widely. We find that droughts consistently had a more detrimental impact on the growth and mortality rates of larger trees. Moreover, drought-related mortality increased with tree size in 65% of the droughts examined, especially when community-wide mortality was high or when bark beetles were present. The more pronounced drought sensitivity of larger trees could be underpinned by greater inherent vulnerability to hydraulic stress(11-14), the higher radiation and evaporative demand experienced by exposed crowns(4,15), and the tendency for bark beetles to preferentially attack larger trees(16). We suggest that future droughts will have a more detrimental impact on the growth and mortality of larger trees, potentially exacerbating feedbacks to climate change.

CLIMATE CHANGE, TREE-RING WIDTH AND WOOD DENSITY OF PINES IN MEDITERRANEAN ENVIRONMENTS

During the second half of the 20th century, the Mediterranean area has experienced an increase in temperature, and a decrease in precipitation leading to a higher frequency of severe droughts. Consequently, widespread Mediterranean pine species suffered a shift in their climate-growth relationships that might lead to detrimental consequences. Wood features such as wood density are also affected by recent climatic changes producing an effect on wood structure and quality. Tree-ring anatomy was analyzed in three species (Pinus halepensis, P. pinaster and P. sylvestris), the three main pine species in Spain, in order to understand the relationships between tree-ring width and wood density as well as the influence of the climatic variations on these variables. Precipitation influenced tree radial growth and wood density for the three species, but at different times of the growth period. Mean and maximum density followed different patterns for the three species, decreasing with time in P. pinaster and increasing in P. halepensis and P. sylvestris. Growth and mean density trends were followed by a 5-year moving average with low variability in the three species. However, a high variability was observed in the inter-annual trends during the most recent years presumably related to climate. These climate-triggered modifications could adversely effect wood properties and wood quality.

Paleoprecipitation Reconstruction in the Indus and Ganges Basins by Inverse Modeling of Tree-Ring-Based PDSI

Abstract The South Asian monsoon is critically important for agricultural production in the region that includes the vast, fertile Indus and Ganges basins. However, the behavior of the South Asian monsoon is not well understood because of its complex nature, and existing instrumental climate records are insufficient for investigating the risks of the low-frequency but high-impact megadroughts that have historically occurred. This paper develops an inverse Palmer drought severity index (PDSI) model to retrieve paleoprecipitation for the region during the time period of 1300–1899, using available data of the water-holding capacity of soil, temperature, and reconstructed PDSI based on the tree-ring analysis of Cook et al.. Temperature data are reconstructed by a regression analysis utilizing an existing temperature reconstruction in an adjacent region and the Pacific decadal oscillation. Based on the retrieved paleoprecipitation, several megadroughts are identified during the reconstruction period. The drought frequency in the Indus basin is higher than that in the Ganges basin. The intensity, frequency, and spatial extent of severe droughts increased from 1300–1899 to 1900–2010. As a signal of climate change, increasing intensity and frequency of severe drought in the Indus and Ganges River basins needs adaptation strategies and drought preparedness measures to secure the food production in this area.

The statistics of precipitation and droughts during opposite phases of the quasi-biennial oscillation of atmospheric processes and its relation to the yield in the European part of Russia

As a result of the analysis of the data from weather stations and the values of Palmer Drought Severity Index (PDSI), territorial regularities are revealed in the distribution of total ten-day precipitation, frequency of severe atmospheric droughts in May and June, and spring wheat yield in the European part of Russia depending on the phase of the quasi-biennial oscillation of equatorial stratospheric wind (QBO) in 1953–2010. It is demonstrated that the variations can be explained by differences in the statistics of synoptic cyclonic and anticyclonic vortices during different QBO phases. The spatial structure of differences in ten-day precipitation and frequency of severe droughts on the European part of Russia during opposite phases of the QBO agrees with differences in spring wheat yield. The QBO was considered in the modeling of spring wheat yield in the Rostov oblast, and this allowed improvement of prognostic values of yield by 14%. The results of the simulation of spring wheat yield with account of the quasi-biennial oscillation of stratospheric equatorial wind as a predictor with the relative spatiotemporal stability of values can be used for working out new methods for forecasting the crop yield.

Drought and Grain Crop Yields over the East European Plain under Influence of Quasibiennial Oscillation of Global Atmospheric Processes

Monthly precipitation and the 3-month Standardized Precipitation Index (SPI) were used to reveal the patterns of rainfall and severe drought frequency over the East European Plain in the period 1953–2011 in the opposite phases of the quasibiennial oscillation (QBO). Differences of precipitation and severe drought frequency in May and in June in the westward and eastward phases of the QBO phases are explained by circulation variations. The analysis indicates less frequent severe drought events over Ukraine and at the center of the European part of Russia in May in the westward QBO phase due to the intensification of the storm track over the East European Plain. The weather conditions in May and in June in the years of the westward QBO phase were more favorable for the yield. The difference of spring wheat yield in the westward and eastward QBO phase exceeds the same difference of winter wheat yield in the Central Black Earth region and in the south regions. Ukraine and the region to the east of the Sea of Azov are the most vulnerable areas of increased risk of severe drought during the active growing season at the end of the 20th and beginning of the 21st century.

Regionalization and Spatiotemporal Variation of Drought in China Based on Standardized Precipitation Evapotranspiration Index (1961–2013)

China is considered to be one of the most drought prone countries. This study is dedicated to analyzing the regionalization and spatiotemporal variations of drought based on the Standardized Precipitation Evapotranspiration Index, which covers the period 1961–2013 across 810 stations in China. Using Spatial “K”luster Analysis by Tree Edge Removal method, China was divided into eight regions: southwest (SW), northeast (NE), north (N), southeast (SE), Yangtze River (YR), northwest (NW), central China (C), and Tibet Plateau (TP). The spatiotemporal variations of drought characteristics indicated that the drought count in NE and C was generally high. Southern China and NW had suffered long drought duration and extreme severity. The MK test results show that stations with significant drying trends mainly locate in SW, N, NW, and C. The severe drought frequency was very high in 1990s and 2000s. Furthermore, more attention should be paid to abnormal less precipitation in summer and abnormal high temperature in spring in SW, NE, N, and C. Besides, abnormal less precipitation is the main factor of drought in SE and YR in whole year. This study is anticipated to support the water resources management, and to promote the realization of environmental protection and agricultural production.

Drought analysis in southern Paraguay, Brazil and northern Argentina: regionalization, occurrence rate and rainfall thresholds

The objective of the present study is to characterize the drought occurrences in a region comprising Paraguay, southern Brazil and northeastern Argentina. To recognize the drought occurrences the standardized precipitation index at the time-scales of 3 and 6 months was applied to the rainfall records from 1961 to 2011 at 51 rain gauges located in that region. After a drought regionalization using principal component analysis, a new approach, the Kernel occurrence rate estimation method coupled with bootstrap confidence band was used to quantify yearly drought occurrence rates. The study also includes the results of an additional and new approach based on rainfall threshold surfaces aimed at recognizing and monitoring the drought occurrence at the early stages of their development. For both time-scales, the study allowed identification of some spatial homogeneous regions regarding the severe droughts. In some of those regions, trends in the severe drought frequency occurrence were identified. The rainfall threshold surfaces, besides providing an adequate interpretation of the meaning of the standard precipitation index, can be quite easily and reliably utilized to identify the drought episodes.

Climate change impacts of legume-grass swards: implications for organic farming in the Federal State of Brandenburg, Germany

Multispecies legume-grass swards (LGS) within crop rotations are the primary source for nitrogen and livestock forage in organic farming systems (OFS) in Europe. At the same time, LGS are very susceptible to the effects of climate change on OFS in dryer regions. In order to predict changes in annual and seasonal LGS yields, the number and dates of LGS cuts and drought impact, an empirical statistical yield model based on alfalfa (A) and red clover (B) was applied to two of the driest areas within Germany: the ‘Spreewald’ (SP), with sandy soils only suited for red clover and the ‘Uckermark’ (UM) with sandy loams. Weather data series from 1972 to 2008 and two regional warming scenarios for 2062–2092, namely ‘Dry’ and ‘Wet’, were used to calculate the impacts. Only the scenario ‘Dry’ predicts an annual yield reduction (about 20 %), for both regions. This impact can be attributed to (1) the first cut is early by four weeks (decreasing the yield by 0.5 t ha−1), (2), the third cut is often delayed (caused by water deficiency) and (3) eventual impracticality of a fourth cut. In contrast, the second cut increased by 1 t ha−1 for ‘Wet’. In SP, frequent severe drought impacts are predicted for red clover LGS. This deleterious impact of the ‘Dry’ scenario can be partially compensated only in UM when alfalfa is used, which showed lower susceptibility to drought. Along with the predicted yield reduction, an increased vulnerability of organic farms in both study regions cannot be prevented.

Temporal-spatial characteristics of severe drought events and their impact on agriculture on a global scale

To identify the world's severely drought-prone areas, given that the corresponding ground area for a 0.5-degree grid in different latitudes is different, we proposed a more precise spherical area-based statistical method. The corresponding ground area per 0.5-degree grid is obtained by integral calculation in latitude and longitude directions. The analysis of the drought based on the global Standardized Precipitation Evapotranspiration Index dataset from 1902 to 2008, where global, Northern Hemisphere, Southern Hemisphere, and major crop-planting regions from six continents are treated as statistical units. The interannual variability characteristics of the severe drought area for each statistical unit are investigated. To study the spatial distribution characteristics of the global frequency of severe drought, the drought frequency was calculated based on drought events identified by continuous drought months on a grid level. Six major crops (wheat, maize, rice, soybean, barley, and sorghum) were chosen to study the impact of drought events on agriculture. The results suggested that severe droughts in global, Northern Hemisphere, and Southern Hemisphere areas have indicated a downward trend since 1990, but an upward trend overall in all continents except Oceania. The identified drought-prone areas show a patchy distribution and frequently drought-prone areas (with 10–20% occurrence probability of drought) were distributed in regions surrounding chronically drought-prone areas (with more than 20% probability). Global chronically drought-prone areas have increased significantly, from 16.19% in 1902–1949 to 41.09% in 1950–2008. Chronically drought-prone areas of agriculture are located in the center of southern Europe, South America, and eastern Asia.

Climate simulations and projections with a super-parameterized climate model

The mean climate and its variability are analyzed in a suite of numerical experiments with a fully coupled general circulation model in which subgrid-scale moist convection is explicitly represented through embedded 2D cloud-system resolving models. Control simulations forced by the present day, fixed atmospheric carbon dioxide concentration are conducted using two horizontal resolutions and validated against observations and reanalyses. The mean state simulated by the higher resolution configuration has smaller biases. Climate variability also shows some sensitivity to resolution but not as uniform as in the case of mean state. The interannual and seasonal variability are better represented in the simulation at lower resolution whereas the subseasonal variability is more accurate in the higher resolution simulation. The equilibrium climate sensitivity of the model is estimated from a simulation forced by an abrupt quadrupling of the atmospheric carbon dioxide concentration. The equilibrium climate sensitivity temperature of the model is 2.77°C, and this value is slightly smaller than the mean value (3.37°C) of contemporary models using conventional representation of cloud processes. The climate change simulation forced by the representative concentration pathway 8.5 scenario projects an increase in the frequency of severe droughts over most of the North America.

Spatiotemporal variation of meteorological droughts based on the daily comprehensive drought index in the Haihe River basin, China

Meteorological droughts can affect large areas and may have serious environmental, social and economic impacts. These impacts depend on the severity, duration, and spatial extent of the precipitation deficit and the socioeconomic vulnerability of the affected regions. This paper examines the spatiotemporal variation of meteorological droughts in the Haihe River basin. Meteorological droughts events were diagnosed using daily meteorological data from 44 stations by calculating a comprehensive drought index (CI) for the period 1961–2011. Based on the daily CI values of each station over the past 50 years, the drought processes at each station were confirmed, and the severity, duration and frequency of each meteorological drought event were computed and analyzed. The results suggest the following conclusions: (1) the use of the CI index can effectively trace the development of drought and can also identify the duration and severity of each drought event; (2) the average drought duration was 57–85 days in each region of the Haihe River basin, and the region with the highest average values of drought duration and drought severity was Bohai Bay; (3) drought occurred more than 48 times over the study period, which is more than 0.95 times per year over the 50 years studied. The average frequencies of non-drought days, severe drought days and extreme drought days over the study period were 51.2, 3.2 and 0.4 %, respectively. Severe drought events mainly occurred in the south branch of the Hai River, and extreme drought events mainly occurred in the Shandong Peninsula and Bohai Bay; (4) the annual precipitation and potential evapotranspiration of the Haihe River basin show decreasing trends over the past 50 years. The frequency of severe drought and extreme drought events has increased in the past 20 years than during the period 1961–1990. The results of this study may serve as a reference point for decision regarding basin water resources management, ecological recovery and drought hazard vulnerability analysis.

Non-Parametric Low-Flow Frequency Analysis Using RCPs Scenario Data : A Case Study of the Gwangdong Storage Reservoir, Korea

In this study, we applied an advanced non-parametric low-flow frequency analysis using boundary kernel by Representative Concentration Pathways (RCPs) climate change scenarios through Arc-SWAT long-term runoff model simulation at the Gwangdong storage reservoir located in Taeback, Gangwondo. The results show that drought frequency under RCPs was expected to increase due to reduced runoff during the near future, and the variation of low-flow time series was appeared greatly under RCP8.5 scenario, respectively. The result from drought frequency of Median flow in the near future (2030s) compared historic period, the case of 30-year low-flow frequency was increased (the RCP4.5 shows +22.4% and the RCP8.5 shows +40.4%), but in the distant future (2080s) expected increase of drought frequency due to the reduction of low-flow (under RCP4.5: -4.7% and RCP8.5: -52.9%), respectively. In case of Quantile 25% flow time series data also expected that the severe drought frequency will be increased in the distant future by reducing low-flow (the RCP4.5 shows -20.8% to –60.0% and the RCP8.5 shows -30.4% to –96.0%). This non-parametric low-flow frequency analysis results according to the RCPs scenarios have expected to consider to take advantage of as a basis data for water resources management and countermeasures of climate change in the mid-watershed over the Korean Peninsula.

Variability of rainfall characteristics over the South Coast region of South Africa

Thirty years of daily rainfall data are analysed for the South Coast region of South Africa, a region which experiences substantial rainfall variability and frequent severe drought and flood events, but whose climate variability has not been much researched. It is found that El Nino–Southern Oscillation (ENSO) exerts an influence since most wet years correspond to mature phase La Nina years. ENSO also influences South Coast rainfall via increases in the number of cut-off lows in southern South Africa during mature phase La Nina years. A statistically significant correlation between the Nino 3.4 index and monthly rainfall totals, and between this index and the frequency of wet days, exists for two summer months and also for June. There are also changes in the heavy rainfall day frequencies from one decade to another. Examination of NCEP re-analyses indicates that wet (dry) years result from an equatorward (poleward) shift in the subtropical jet, cyclonic (anticyclonic) pressure anomalies over the South Atlantic and South Africa, and increased (decreased) density of mid-latitude cyclonic systems.

Spatial Analysis of Meteorological Drought in Iran from 1965 to2003

The present study examined year-to-year variations in areas affected by drought during a period of 39 water yearsin Iran. Ninety-five meteorological stations were chosen to provide near-continuous long-term records, althoughsome data was missing (less than 10%). The missing data points were estimated using a linear correlation methodbetween the reference station with the missing data points and a neighboring station that had a complete record. At allstations, the standard index of annual precipitation (SIAP) was calculated for water year (sum of precipitation fromOctober 1 to September 31). The geo-statistical method of weighting moving average (WMA) was applied to a 2×2km grid network map of Iran and the geographical distribution of SIAP was calculated and displayed. From this, thepercentage of area affected by severe, moderate, and mild drought was computed for each year; the frequency ofdrought was analyzed by severity and the behaviors of the most extensive historical droughts were determined. Theresults showed that: a) the maximum frequency of severe drought was 5.1 times and moderate drought was 23.1 timesper 100 years; b) the most extensive droughts (more than 80% of the country) occurred during 1970-1971 (82.21%),1988-1989 (92.05%), and 1999-2000 (96.27%); and c) drought spread in Iran beginning from the northwestern andsoutheastern regions, gradually extending to the central regions.

Opportunities and Challenges of Setting-Up an Articulate HACCP System in Export Slaughterhouses in Countries Emerging from Conflict: An Appraisal of North-Western Somalia

An investigation in North-Western Somalia (Somaliland) to determine opportunities and challenges of setting up a Hazard Analysis and Critical Control Points (HACCP) system to be adopted and complied with during operations in an export slaughterhouse was carried out for more than two years. A baseline and after intervention microbiological analysis was carried out on 500 wet and dry meat swab samples collected from carcasses from the slaughterhouse. The analysis was against total viable counts, E. coli counts and Salmonella species. It was established that after intervention through capacity building and supply of basic livestock slaughter equipments and tools, levels of carcass contamination reduced though not statistically significant. Slaughterhouse workers were trained on food safety quality assurance systems of good hygiene practices, standard operating procedures, sanitary standard operating procedures among others. Good opportunities of establishing HACCP system were high as the slaughterhouse had a ready supply of livestock for slaughter and high demand of Somalia small ruminant carcasses in the Middle East countries. However, the implementation faced severe challenges including lack of transport plane for carcasses to export market, frequent severe drought shocks, stiff competition from export of live livestock from Somalia, stiff competition from other countries exporting carcasses to Middle East countries; among others. These led to interruptions to operations and subsequent closure of the slaughterhouse impacting negatively on establishment of a vibrant operational HACCP system.

A longitudinal examination of business performance indicators for drought-affected farms

Frequent severe droughts can financially cripple dryland farm businesses and farmers need effective business strategies to survive. This study analysed the economic performance of 123 farms in a rainfed agricultural region of Australia from 2004 to 2009, a period that included severe droughts in 2006 and 2007. The business indicators examined were business equity, operating profit/ha, return on capital, and the debt to income ratio and the droughts altered these indicators for many of the farms surveyed. Over the study period the equity position of just over 60% of farms declined, although 55% of these had more than 80% equity in the business initially and were able to absorb a short term decline in equity caused by the drought. In addition, 9% of farms had levels of equity below 80% at the start of the investigation, but actually improved their equity position by the end of the study. Strong links were found between wheat yield and the business indicators. Mostly this was due to the crop dominant nature of the farm businesses where wheat was by far the main crop. However, farms that were able to capitalise on favourable conditions in other years were better placed to enhance or recover their financial position. Farms that cropped a higher proportion of their farm area were at an advantage. Structural indicators, including the percentage of area cropped, had a small but significant effect on the debt to income ratio, the return on capital and operating profit. Farm diversity also favourably lessened the debt to income ratio. Other factors, including farm size did not influence the outcome of any business indicator. Farms that remained resilient, despite the serious droughts were those that cropped more than 50% of their farm area, were prudent in their expenditure, maintained some enterprise diversity and often generated wheat yields in each year that were near the yield potential for that year.

Growth Sensitivity to Drought of Co-OccurringPinusspp. along an Elevation Gradient in Northern Mexico

Climate change is predicted to increase the frequency of severe drought, yet little information exists on the impacts of drought on dominant trees of Mexican pine forests, which are among the most biologically diverse forests in the world. We conducted the first comparison of growth sensitivity to drought of two co-occurring Pinus species in Mexico to understand whether growth of dominant pines of the Sierra Madre Occidental in northern Mexico is sensitive to drought and temperature variation and to understand how sensitivity differs between tree species and elevations. We sampled and analyzed tree-ring data across a 400-m elevation gradient for the years 1945–2004 for co-occurring Pinus engelmannii and Pinus lumholtzii at Basaseachi National Park, Chihuahua, Mexico. We hypothesized that growth sensitivity to drought would be highest at low elevations, annual basal area increment (BAI) would be lowest at low elevations, and winter precipitation would covary positively with BAI at all elevations. Growth sensitivity to drought, as measured by a wet-dry ring-width index ratio (W:D), was significantly higher for both species at low elevations (W:D range 2.2–2.8) than at intermediate and high elevations (WD range 1.5–1.9). Pinus engelmannii had significantly higher W:D (2.2) than P. lumholtzii (1.8). Annual BAI did not differ between elevations or species. Annual ring—width index was positively and significantly associated with winter (December–April) precipitation. This association was stronger at low elevations than at high elevations. Other seasons of precipitation and other climatic variables were not significantly associated with annual growth. Our results suggest that the increasing frequency and severity of drought predicted for this region in the coming decades will reduce growth of P. engelmannii and P. lumholtzii, with greater impacts on low-elevation populations and on P. engelmannii.

How do extreme drought and plant community composition affect host plant metabolites and herbivore performance?

Water availability and plant community composition alter plant nutrient availability and the accumulation of plant defence compounds therefore having an impact on herbivore performance. Combined effects of drought stress and plant community composition on leaf chemicals and herbivore performance are largely unexplored. The objective of our study was, therefore, to find out the impact of extreme drought and of plant community composition on plant–herbivore interactions. Larvae of the generalist butterfly Spodoptera littoralis were reared on leaves of the grass Holcus lanatus which was grown in experimental communities, differing in species- and functional group richness. These communities were either subjected to extreme drought or remained under ambient climatic conditions. Drought decreased relative water content, soluble protein content, nitrogen and total phenol content and increased the content of carbohydrates in the grass. As a consequence, the larvae feeding on drought-exposed plants revealed a longer larval stage, increased pupal weight and higher adult eclosion rates. Plant community composition mainly caused changes to the defensive compounds of the grass, but also marginally affected protein and carbohydrate content. Larvae feeding on species-richest communities without legumes showed the highest mortality. Our findings imply that climate change that is projected to increase the frequency of severe droughts, as well as alter plant community compositions, is likely to affect arthropod–plant interactions through an alteration of leaf chemicals.