Spatio-temporal patterns of wheat yield losses and environmental stresses in Europe

Back to table of contents Previous article Next article Clinical & ResearchFull AccessSpecial Report: Stress and Distress During Pregnancy—How to Protect Both Mother and ChildLaura J. Miller, M.D.Laura J. Miller, M.D.Published Online:24 Feb 2022https://doi.org/10.1176/appi.pn.2022.03.3.1AbstractResearch suggests that different patterns of stress during pregnancy can either promote or impede healthy fetal development. What are the clinical implications?Bridgeman Images/ Mother, 1933, by Mikulas Galanda (1895-1938)"I just feel like I am broken. I am the worst pregnant woman ever."These are the words of a woman interviewed by Aleksandra Staneva, Ph.D., and colleagues as they conducted a study on how women experience and interpret psychological distress while they are pregnant. The study was reported in the June 2017 Health Care for Women International. What they learned is that for many women, experiencing distress during pregnancy runs smack into unrealistic cultural expectations and fuels excessive guilt. Women report feeling totally responsible for the well-being of their babies. With increasing media attention to the harmful effects of stress on fetuses, some women believe they are supposed to remain happy and serene throughout their pregnancies, and if they don't, it's their fault. So what does research to date actually tell us about the effect of maternal antenatal distress on offspring?First, a word about the term "distress." In the context of research on the effects of antenatal maternal psychological states on offspring, "distress" encompasses maternal anxiety, depression, and perceived stress. This is because studies to date have found that any of these, or any mixture of these, has similar effects on offspring. Though there are some distinctions, most researchers have found it more valuable to examine these collectively.Distress During Pregnancy: A Case ExampleDelia* is a 28-year-old woman with recurrent major depression and posttraumatic stress disorder (PTSD) stemming from prolonged childhood emotional, physical, and sexual trauma. She is raising her 2-year-old daughter, Keisha, on her own with limited financial resources and housing insecurity. While pregnant with Keisha, she was highly stressed and severely depressed. Being pregnant made her feel vulnerable and intensified her PTSD symptoms. She had previously responded well to sertraline but discontinued it because she thought she shouldn't take medication while pregnant. Her pregnancy was complicated by preeclampsia, which was frightening. Keisha was born a month early; she was a healthy baby but fussy. As a toddler, she is sensitive and reacts with fear to new situations.Delia has just learned she is pregnant again. Recalling how difficult her last pregnancy was and how that may have affected Keisha, she sees a psychiatrist, Dr. Wilkins, for ideas about how to maintain mental health.To provide context for how a psychiatrist can help, we'll review some relevant information.Homeostasis, Allostasis, and Allostatic LoadAs a prelude to understanding the effects of distress during pregnancy, it helps to understand how bodies handle stress in general. Certain body systems need to be maintained within narrow ranges to operate effectively. Blood pH and body temperature are examples. Processes that maintain these systems within range are known as homeostasis. Stress can disturb homeostasis. To counter threats to homeostasis, our bodies mobilize the hypothalamic-pituitary-adrenal (HPA) axis, the sympathetic nervous system, and the immune system. That mobilization is known as allostasis. For example, the sympathetic nervous system prepares the body for fight or flight by activating the heart, blood vessels, and muscles, and the immune system prepares to respond to possible wounds or infection. Mobilizing these responses intermittently enhances health. Exercise is an example of healthy allostasis. As with intermittent physical challenges, intermittent cognitive and/or emotional challenges can promote health. On an emotional level, insufficient challenge can lead to boredom, an affective state that can drive a person to seek new goals and positive stimulation.By contrast, when allostatic processes are repeatedly and chronically mobilized, we pay a price. The resultant wear and tear are known as allostatic load. High allostatic load includes physiologic dysregulation of multiple body systems that contributes to disease.Pregnancy is itself a physiologic stressor. It is sometimes referred to as a natural stress test, bringing out vulnerabilities to cardiovascular disease, diabetes, depression, and other conditions. Adding psychological stress, trauma, and/or chronic societal strains such as economic deprivation and racism can lead to substantial allostatic load during pregnancy. This can influence the likelihood of adverse pregnancy outcomes and can influence fetal development.Just as different patterns of stress can be healthy or unhealthy for people in general, research to date suggests that different patterns of antenatal stress can either promote or impede healthy fetal development.Healthy Stress During PregnancyHow can researchers know how fetuses react when their mothers are stressed? One particularly helpful clue is how the fetal heart rate changes in response to maternal stress. To restore homeostasis under stress, it's important for some parameters to vary flexibly (for example, heart rate) to keep others (for example, blood pressure) constant. For this reason, beat-to-beat variability of the fetal heart rate is an indicator of health. When a pregnant woman experiences mild to moderate intermittent stress, her fetus responds with a temporary increase in heart rate variability. That response to maternal stress intensifies as the fetus matures, and it becomes increasingly well coupled with fetal movement. These changes suggest that the fetus is becoming more adept at normal allostasis, which may promote healthy development later in life. Research by Janet DiPietro, Ph.D., published in the August 2012 Journal of Adolescent Health shows that newborns who were exposed to mild to moderate intermittent maternal distress in utero have faster neural conduction, consistent with the hypothesis that exposure to healthy stress in utero advanced their neural development. Similarly, toddlers who were exposed to mild to moderate intermittent maternal distress in utero show more advanced motor and cognitive development.Unhealthy Stress During PregnancyBy contrast to the salutary effects of intermittent mild to moderate maternal stress on fetal development, severe and/or chronic maternal distress is associated with higher risks for adverse perinatal outcomes and long-term adverse effects on offspring. The difference can be detected in utero. Fetuses of pregnant women who have high anxiety tend to have heart rates that are more reactive to acute stressors. The fetuses of pregnant women with low socioeconomic status tend to have reduced beat-to-beat variability.When maternal distress reaches the level of a clinically diagnosable disorder that remains untreated, long-term adverse effects can ensue. For example, untreated antenatal major depression is associated with increased risk of premature birth and low birth weight. Infants and toddlers exposed to maternal depression in utero show excessive crying; reduced motor and language development; and more distress, fear, and shyness than offspring not exposed to maternal depression. Children and adolescents exposed to antenatal maternal depression have an increased risk of emotional, behavioral, and cognitive problems.Epigenetics and Fetal ProgrammingThere is increasing evidence that intrauterine environmental exposures can "program" a fetus to develop in a certain way. It is posited that this programming confers the evolutionary advantage of using intrauterine cues to predict what awaits in the outside world and to develop accordingly. An example is that when women are pregnant during famines, their offspring have a higher likelihood of being overweight and experiencing reduced glucose tolerance later in life. It is hypothesized that the famine-exposed fetuses developed a "thrifty phenotype" to adapt to a resource-poor environment. Health problems ensue when there is a mismatch between the intrauterine environment and the external world—for example, when an individual who has developed a slow metabolism in response to in utero nutritional deprivation grows up in an environment replete with food.There is evidence that fetal programming also occurs in response to maternal psychological distress. If a fetus will be born into a world filled with constant dangers, it might be adaptive to develop a highly reactive stress response system. This appears to be what happens to offspring of women who experience prolonged, clinically significant levels of anxiety, depression, and stress while pregnant. In babies, exposure to substantial maternal distress in the womb is associated with increased physiologic and behavioral reactivity to stress, such as a routine heel stick at birth. Over time, the offspring's hyper-responsive physiologic responses can contribute to poor health.Fetal programming is thought to occur via epigenetic pathways—environmental factors triggering molecular processes that change the expression of fetal or placental genes. A major caution regarding fetal programming research is that it is difficult to tease out the effects of the in utero environment from other influences. Studies have examined newborn stress reactivity, brain connectivity, and temperament to separate in utero from environmental influences after birth. For example, newborns of women who had untreated antenatal depression show reduced connectivity between their prefrontal cortex and amygdala. This is associated with increased heart rate reactivity when they were fetuses.What's especially difficult to disentangle are shared genetic tendencies. It is likely that genetic and epigenetic factors interact to confer varying levels of resilience and vulnerability.Gender Differences in Response to in Utero Maternal DistressResearch by Catherine Monk, Ph.D., and her team published November 26, 2019, in PNAS shows that women with clinically meaningful levels of antenatal distress are less likely to give birth to boys than women with normal distress levels. This and other research suggest that female fetuses can adapt more effectively to in utero stressors in general, including inflammation and malnutrition. Female fetuses are therefore more likely to survive. However, they may be more vulnerable to subsequent mental health challenges as a result of in utero exposure to maternal distress. Social support can influence this gender effect. Distressed pregnant women with high levels of social support are more likely to give birth to sons than distressed pregnant women with low levels of social support.Intergenerational Transmission of AdversityJust as there are marked inequities in the intergenerational transmission of wealth, there can be marked inequities in the intergenerational transmission of health. Pregnancy outcomes are influenced not only by acute stressors during the pregnancy, but by a pregnant woman's past traumas and cumulative lifetime stress. These, in turn, are shaped by chronic environmental strains such as economic deprivation, racism, gender discrimination, and exposure to violence. The pregnancies of women who experience multiple intersectional areas of disadvantage may be especially affected.The concept of intersectional adversity may also apply in utero. A fetus who is exposed to substantial maternal distress may also be exposed to other adverse influences, such as pollutants and poor nutrition.An area of current study is whether intergenerational transmission of disadvantage occurs in part via epigenetic changes. In animal models, parental epigenetic changes induced by environmental stress can be passed to subsequent generations. It is not yet clear whether this happens in people. It is also possible that de novo epigenetic changes could arise in a fetus due to adverse maternal mental health effects from prior maternal traumas or ongoing disadvantage. For example, there is evidence that maternal stress reactivity is heightened by prior traumas and high cumulative stress.There are also preliminary data suggesting that intergenerational transmission of disadvantage can happen via placental genetic changes. A study by Kelly Brunst, Ph.D., and her colleagues published in Biological Psychiatry on March 15, 2021, found that women who experienced higher levels of cumulative lifetime stress had higher levels of placental mitochondrial mutations.Can Epigenetic Changes Be Reversed?The notion of health-sapping changes in gene expression being passed down in perpetuity from generation to generation paints a darkly pessimistic picture. Fortunately, evidence suggests that adversity-related epigenetic changes can be reversed. For example, rats who were exposed to antenatal stress have reduced axonal density and altered behavior. Giving an enriched environment to pregnant rats and their offspring (increased social interaction, larger cages, and varied climbing objects) alleviates these adverse effects. Studies in humans suggest that people exposed to adverse in utero environments can achieve mental health but may need more support. They also may have to work harder at maintaining mental health through ongoing self-care. People who were exposed to substantial maternal distress in the womb may also have considerable resilience; after all, their mothers were survivors.Detoxifying Stress During Pregnancy: How Can Delia's Psychiatrist Help?After evaluating Delia, Dr. Wilkins saw that she had a severe major depressive episode and active PTSD symptoms in the context of chronic environmental strain. Dr. Wilkins was aware that this level of antenatal distress could increase the risk of pregnancy complications and adverse outcomes for both Delia and her baby. While his first impulse was to prescribe sertraline, he realized the importance of setting the stage with psychoeducation and rapport building. Here's what he did:Validated her concerns and supported her difficult decision to come see him.Explained the difference between healthy and unhealthy stress in a way that clarified Delia was not to blame for harming her baby.Explained omission bias, which is the tendency to worry more about the risks of things we do (for example, taking or prescribing medications) than the risks of failing to do anything (for example, leaving symptoms untreated).Elicited her concerns about untreated symptoms and her concerns about medications.Discussed perinatal risks of untreated symptoms versus risks of sertraline in language Delia could relate to.Explained the role of psychotherapy as an alternative or additional intervention.With these explanations, Delia decided to resume sertraline. She liked the idea of interpersonal psychotherapy but couldn't attend in person due to lack of childcare and transportation money. Dr. Wilkins arranged for psychotherapy via telehealth.Sertraline and psychotherapy were a great start, but given the constant strain Delia experienced, Dr. Wilkins felt they weren't enough. He explained the concept of converting chronic stress to intermittent stress by creating "oases" of calm in an otherwise stressful life. He asked Delia how she might do that. She noted that dancing and reading graphic novels were activities she found enjoyable and relaxing and that she hadn't done either of these since Keisha was born. Now that she saw how these activities could improve her health and that of her baby, she stopped regarding them as "wasted time." She agreed to do these several times a week while Keisha napped. She also identified that both she and Keisha felt relaxed while coloring, so she resolved that they could do more of that together.Dr. Wilkins also referred Delia to a social worker who helped her identify housing and financial resources, reducing some of her chronic environmental strain.Table 1 summarizes how psychiatrists can distinguish between healthy and unhealthy stress during pregnancy. Figure 1 summarizes interventions to help women who experience unhealthy levels of distress during pregnancy.Clinical ImplicationsAlthough much more research is needed to fully understand the impact of maternal stress and distress on pregnancy outcomes and offspring, some clinical implications are already clear:Not all maternal distress is toxic. Distress doesn't behave like a teratogen, for which any amount of exposure might be problematic. Rather, evidence to date suggests that mild to moderate, intermittent stress promotes healthy fetal development, and more severe, prolonged distress is associated with adverse outcomes.It's not entirely clear where to "draw the line" between healthy and unhealthy amounts of stress. However, one evidence-based distinction seems to be between clinically significant distress (for example, a major depressive episode, an anxiety disorder) and distress that doesn't meet criteria for a psychiatric disorder. Another key distinction is between distress that is persistent (for example, stemming from ongoing inequities) and intermittent life stressors.Just as the physical challenge of exercise is healthy during pregnancy, manageable emotional challenges are healthy during pregnancy.By contrast, psychiatric disorders during pregnancy can pose substantial risks if left untreated. These risks must be weighed against the risks of psychotropic medication and/or the treatment burden of psychotherapy. Understanding this can protect against omission bias, which is the tendency for doctors to worry more about the risks of things we do (for example, prescribe) than the risks stemming from our failure to act.It's important for women to know that even in instances in which severe stress adversely affected them and/or their babies, those adverse effects can likely be alleviated by subsequent support and healthy practices.Public Health ImplicationsFocusing on a woman's choices and behaviors is insufficient to improve maternal mental health, pregnancy outcomes, and offspring development. Societal factors such as racism, economic deprivation, and gender inequity are strong influences.An intersectional perspective explains how various social disadvantages intertwine and amplify one another to affect health in individuals and populations. The concept of intersectionality can also help make sense of the myriad interacting influences on maternal and fetal mental health during pregnancy.The perinatal period is an especially opportune time to positively affect the health of women and their offspring. Public health initiatives supporting maternal mental health can be especially influential.As a natural "stress test," pregnancy can unmask physical and mental health vulnerabilities that could later become chronic illnesses. Preventive approaches during pregnancy and postpartum can help women maintain a healthier trajectory for the remainder of their lives. ■* The case of Delia is based on a composite of several patients to ensure patient confidentiality.The author has no conflicts of interest to disclose.The study by Aleksandra Staneva, Ph.D., et al., " 'I Just Feel Like I Am Broken. I Am the Worst Pregnant Woman Ever': A Qualitative Exploration of the 'At Odds' Experience of Women's Antenatal Distress," is posted here.The study by Janet DiPietro, Ph.D., "Maternal Stress in Pregnancy: Considerations for Fetal Development," is posted here.The study by Kelly Brunst, Ph.D., et al., "Associations Between Maternal Lifetime Stress and Placental Mitochondrial DNA Mutations in an Urban Multiethnic Cohort," is posted here.The study by Catherine Monk, Ph.D., et al., "Maternal Prenatal Stress Phenotypes Associate With Fetal Neurodevelopment and Birth Outcomes," is posted here.Laura J. Miller, M.D., is medical director of reproductive mental health in the Office of Mental Health and Suicide Prevention at the Veterans Health Administration and a professor of psychiatry at the Loyola University Stritch School of Medicine in Maywood, Ill. ISSUES NewArchived

Eleven data sets, including two from North Carolina, three from Texas, and six from Oregon were used to assess wheat (Triticum aestivum L.) yield loss in response to Italian ryegrass (Lolium multiflorum Lam.) infestations. Linear regression of yield loss from data in the individual data sets and the combined data from all the sets with Italian ryegrass proportion of the total plant population provided a better fit than that of yield loss with ryegrass density. Moreover, only two of the slopes relating yield loss and ryegrass proportion were significantly heterogenous from the combined data sets. The relatively high r2 value of 0.88 from regressing wheat yield loss against Italian ryegrass proportion of the combined data was quite striking considering the differences in wheat cultivars, soils, and weather among the sites. Little relationship was found among the individual data sets between wheat yield loss and either accumulated heat units or precipitation. The most accurate equation describing the effect of Italian ryegrass interference was a simple linear regression: percentage wheat yield loss = 5.7 + (1.15 × percentage of ryegrass plants in the total plant population). Thus, it may be possible to predict potential yield loss in wheat fields from Italian ryegrass interference by scouting. These predictions may be used to assess the economic benefits of a postemergence herbicide application to control Italian ryegrass. They may also help to determine whether a wheat field with an Italian ryegrass infestation is better used for forage rather than grain production.Research QuestionThis study sought to develop a simple assessment of wheat yield loss in response to Italian ryegrass infestations in a diversity of environments.Literature SummaryItalian ryegrass is a widely distributed and an important weed of winter wheat in the USA. The effect of Italian ryegrass density on wheat yield was measured in Oregon, North Carolina, and Texas. Published data provided an opportunity to assess the reaction of wheat to Italian ryegrass across diverse wheat cultivars and environments.Study DescriptionTwo data sets from North Carolina, three from central Texas, and six from Oregon showed winter wheat yield loss from Italian ryegrass interference in the USA. To assess the response of wheat to Italian ryegrass interference, yield loss data from the individual data sets and the combined data were regressed against two measures of ryegrass infestation. One measure was density, the number of ryegrass plants per square foot. The other measure was the proportion of Italian ryegrass plants in the total plant population of the two species.Applied QuestionsIs wheat yield loss in response to Italian ryegrass better predicted by Italian ryegrass density or proportion of ryegrass in the plant population?Linear regression of wheat yield loss with Italian ryegrass proportion of the total plant population provided a better fit than that of yield loss with ryegrass density.What was the best description of the relationship between Italian ryegrass proportion and wheat yield loss?The equation that most accurately described this relation was: percentage wheat yield loss = 5.7 + (1.15 × percentage of ryegrass plants in the total plant population)RecommendationThe simple linear relationship between wheat yield loss and proportion of Italian ryegrass in the plant population highlighted the potential of effective scouting of ryegrass in predicting wheat yield loss in diverse situations.

Resource selection of herbivores is a complex ecological process that operates in relation to biological or non-biological factors, which may affect the feeding and movement, and subsequently their spatial distribution and environmental stress. Here, we estimated moose (Alces alces cameloides) resource selection for habitat variables and the effect of interspecific interactions related to roe deer (Capreolus pygargus bedfordi) on its population distribution and environmental stress in the Khingan Mountain region of northeast China at local and regional scales. Different response patterns of moose resource selection, spatial distribution, and environmental stress to interspecific interaction-linked habitat factors were shown at the two scales. A general ecological chain, response of moose to interspecific interaction-linked habitat factors, was exhibited at the regional scale, and at the local scale, heterogeneous responses, linkages of habitat selection and environmental stress of moose population might be driven by different interspecific interaction patterns. Our study firstly suggested that moose resource selection, food availability, diet quality, population density and environmental stress indicators were impacted by interactions with the distribution of other sympatric herbivore species and showed differences in ecological response chains at various spatial scales. These findings are useful for sympatric herbivore assembly conservation, habitat quality monitoring and management.

A retrospective study was conducted to evaluate temporal patterns of environmental heat stress during the in-uterus period of development (IUP) and the 3-month post-natal (PN) period of dairy heifers, and to estimate their association with the age at first calving (AFC). Data from 30 dairy herds in Northern Greece including 9098 heifers were extracted from National Cattle Database. Data (2005–2019) regarding 230,100 farm-specific ambient daily temperature and relative humidity records, were obtained from ERA5-Land. Average monthly Temperature-Humidity-Index values (THI; low≤68, and high>68) were calculated and matched for each heifer to their IUP and PN. Subsequently, Cluster Analysis was used with monthly THIs as predictors to allocate heifers to THI clusters. The association of clusters with AFC was assessed with Generalized Linear Mixed Model analysis, an extended form of multiple linear regression. Finally, 8 Heat Stress Clusters (HSC; namely HSC-1 to HSC-8) were identified. Compared to HSC-8 (8th-9th IUP months and 1st PN month) heifers of HSC-5 (4th-7th IUP months) and HSC-6 (6th-8th IUP months) calved 13.8 and 17.8 days later, respectively (P < 0.01–0.001). Moreover, when AFC was treated as a binary variable, heifers of HSC-5 and HSC-6 had 1.15 and 1.34 (P < 0.01–0.001) higher risk of calving for the first time later than 787 days compared to HSC-8, respectively.

Uncovering New Functions for MicroRNAs in Caenorhabditis elegans

During the evolution, plants acquired the ability to synthesize different phenylpropanoid compounds like chlorogenic acid (CGA), which plays vital roles in resistance mechanisms to abiotic stresses. These environmental factors, including heavy metal, cold, heat, ultraviolet (UV) light, drought, and salinity affect the plant physiological processes, resulting in massive losses of agriculture production. As plants evolve from green algae to bryophytes, ferns, gymnosperms and angiosperms, phenylpropanoids are produced and accumulated in different tissues, giving the plant the capacity to counteract the harmful effects of the adverse environments. Studies have been performed on the metabolic evolution of rosmarinic acid, flavonoids and lignin, showing that the biosynthesis of phenylpropanoids begins in green algae until the emersion of genes found in angiosperms; however, the evolution of the CGA pathway has not yet been reviewed. We hypothesize that CGA could also be synthesized from algae to angiosperms. In the present review, the evolutionary analysis of CGA pathway and the function of this compound in plant tolerance to abiotic stresses are summarized. Bioinformatics analyzes were carried out on CGA-related genes across 37 plant species and revealed that the metabolic pathway starts in algae and gradually increases until it becomes complete in angiosperms. The key genes exhibited different expression patterns in stress and plant tissues. Interestingly, some genes accumulated rapidly during evolution and were more sensitive to environmental stresses, while others appeared only later in angiosperms. Further studies are needed to better understand the evolution of the CGA metabolic pathway in plants under environmentally stressed conditions.

Is a nappy change stressful to neonates?

The influence of PDL principal fibers in a 3-dimensional analysis of orthodontic tooth movement.

Sharp environmental gradients encountered within the intertidal zone have driven the evolution of physiological adaptations that allow its inhabitants to maintain cellular function in the presence of fluctuating abiotic factors. These adaptations are mediated by gene-regulatory networks that, despite their inherent complexity, must remain evolvable and capable of responding to different selection pressures associated with specific ecological niches. Phosphorylation events catalyzed by cell-signaling enzymes represent a parsimonious mechanism to integrate new functional or regulatory properties into these gene-regulatory networks. In this study, proteins phosphorylated on consensus sequences for protein kinases A, B, and C; cyclin-dependent kinases; and mitogen-activated protein kinases, as well as the abundance of phosphorylated stress-activated protein kinase (phospho-SAPK/JNK), were quantified in order to ascertain whether phosphorylation events are divergent among native (Mytilus californianus and Mytilus trossulus) and invasive (Mytilus galloprovincialis) species of mussels that differ in their tolerance toward environmental stress. Abundances of phosphorylated substrate proteins for each of the major signaling proteins that were investigated, as well as the abundance of phospho-SAPK/JNK, differed both within and between species during thermal and osmotic stress. These data suggest that modulating protein function via phosphorylation may be an important mechanism to integrate novel properties into stress-regulatory networks. In turn, differential phosphorylation during environmental stress may contribute to species-specific tolerances toward abiotic stress, interspecies dynamics, and biogeographic patterns in Mytilus congeners.

Yield losses due to weeds are a major threat to wheat production and economic well-being of farmers in the United States and Canada. The objective of this Weed Science Society of America (WSSA) Weed Loss Committee report is to provide estimates of wheat yield and economic losses due to weeds. Weed scientists provided both weedy (best management practices but no weed control practices) and weed-free (best management practices providing &gt;90% weed control) average yield from replicated research trials in both winter and spring wheat from 2007 to 2017. Winter wheat yield loss estimates ranged from 2.9% to 34.4%, with a weighted average (by production) of 25.6% for the United States, 2.9% for Canada, and 23.4% combined. Based on these yield loss estimates and total production, the potential winter wheat loss due to weeds is 10.5, 0.09, and 10.5 billion kg with a potential loss in value of US$2.19, US$0.19, and US$2.19 billion for the United States, Canada, and combined, respectively. Spring wheat yield loss estimates ranged from 7.9% to 47.0%, with a weighted average (by production) of 33.2% for the United States, 8.0% for Canada, and 19.5% combined. Based on this yield loss estimate and total production, the potential spring wheat loss is 4.8, 1.6, and 6.6 billion kg with a potential loss in value of US$1.14, US$0.37, and US$1.39 billion for the United States, Canada, and combined, respectively. Yield loss in this analysis is greater than some previous estimates, likely indicating an increasing threat from weeds. Climate is affecting yield loss in winter wheat in the Pacific Northwest, with percent yield loss being highest in wheat-fallow systems that receive less than 30 cm of annual precipitation. Continued investment in weed science research for wheat is critical for continued yield protection.

AimStrong social‐ecological trade‐offs between resource extraction and protection have created challenges for large, protected area management in natural resource‐dependent countries. Therefore, local governments and community conservation activities are becoming common and information about low environmental exposure and high biodiversity can provide for planning localized conservation activities.LocationThe western Indian Ocean.MethodsCoral reef sites were evaluated for local‐scale environmental and species richness to elucidate local patterns in spatial heterogeneity. Local coral and fish taxonomic richness and coral community susceptibility to stress were normalized to partially account for common and heterogenous disturbances to coral cover and fish biomass. Residuals of these three response variables were evaluated for local geographic patterns and specific relationships with 21 environmental variables using machine learning methods.ResultsRichness was highly variable at local geographies and had a double‐peaked shape with latitudes. Thirteen of the 21 examined variables were selected and indicated complex, spatially heterogeneous and weak cumulative predictive relationships with specific environmental and human influences. For example, each selected variable contributed 7% to 25% of the variance but with different relationships for the three responses. Coral fish richness and coral community susceptibility correlations were positive but weak and therefore produced different local spatial patterns. Nevertheless, these spatial patterns exhibited some coarse‐scale similarities indicating locations with shared positive community attributes and potential climate refugia. Shared richness variables included depth and wave energy, temperature variables of SST skewness, excess heat and rate of rise. Human influences of distance to shore, human populations and cities were also selected for richness and community susceptibility responses.Main ConclusionsPlanning to include local stress and richness patterns variability could contribute to species persistence. From these specific data, sites in the Pemba Channel between the Tanzanian mainland and Pemba Island, and northern Mozambique and Madagascar fit refugia characteristics.

Detecting vulnerability of humid tropical forests to multiple stressors

Measuring environmental stress in East Greenland polar bears, 1892–1927 and 1988–2009: What does hair cortisol tell us?

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 411:33-48 (2010) - DOI: https://doi.org/10.3354/meps08644 Ecology of antifouling resistance in the bladder wrack Fucus vesiculosus: patterns of microfouling and antimicrobial protection M. Wahl1,*, L. Shahnaz1,2, S. Dobretsov1,3, M. Saha1, F. Symanowski1, K. David1, T. Lachnit1, M. Vasel1, F. Weinberger1 1Leibniz Institute of Marine Sciences, IFM-GEOMAR, Duesternbrookerweg 20, 24105 Kiel, Germany 2Present address: Department of Botany, University of Karachi, Karachi, Pakistan 3Present address: Department of Marine Science and Fisheries, Sultan Qaboos University, Muscat, Oman *Email: mwahl@ifm-geomar.de ABSTRACT: The impact of moderate environmental stress may be modulated by stress-induced shifts of biotic interactions such as host–epibiont relationships. We studied the stress regime in shallow Western Baltic habitats, the variability of fouling at different temporal and spatial scales, and whether common stressors—low light, high temperature and grazing—affect the abundance and composition of the biofilm on a regionally important macroalga, the bladder wrack Fucus vesiculosus. We further explored the alga’s capacity to chemically modulate the recruitment of microfoulers and analyzed whether this ability is impacted by stress. In laboratory, mesocosm and field experiments, fouling pressure and epibiotic cover on the alga varied strongly with changing environmental conditions such as temperature, irradiance, depth and grazing. The expectation that abiotic stress affects the fouling-modulating ability of the alga and thus indirectly produces the observed variability of epibiosis was not generally confirmed. Indeed, while the strength of chemical antifouling resistance varied seasonally, with a maximum in winter–spring and a minimum in late summer, this could not be related to temporal patterns of environmental stress, fouling pressure, or growth of F. vesiculosus. Only the seasonal variation in reproduction seemed to be in phase with antifouling activity. Controlled experiments confirmed that resistance strength was not affected by temperature or grazing, and only moderately by light. We conclude that the fouling modulation ability of F. vesiculosus may suffer from light reduction (e.g. by eutrophication effects), but is not sensitive to predicted warming or enhanced grazing. KEY WORDS: Marine algae · Stress · Epibiosis · Fouling modulation · Interacting stressors · Fucus vesiculosus Full text in pdf format Supplementary material PreviousNextCite this article as: Wahl M, Shahnaz L, Dobretsov S, Saha M and others (2010) Ecology of antifouling resistance in the bladder wrack Fucus vesiculosus: patterns of microfouling and antimicrobial protection. Mar Ecol Prog Ser 411:33-48. https://doi.org/10.3354/meps08644 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 411. Online publication date: July 29, 2010 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2010 Inter-Research.

Nitrogen fertilizer is one of the essential nutrients for wheat growth and development, and it plays an important role in increasing and stabilizing wheat yield. Future climate change will affect wheat growth, development, and yield, since climate change will also alter nitrogen cycles in farmland. Therefore, further research is needed to understand the response of wheat yield and nitrogen losses to climate change during cultivation. In this study, we investigate the wheat-producing region in the middle and lower reaches of the Yangtze River in China, one of the leading wheat-producing areas, by employing a random forest model using wheat yield records from agricultural meteorological observation stations and spatial data on wheat yield, nitrogen application rate, and nitrogen losses. The model predicts winter wheat yield and nitrogen losses in the middle and lower reaches of the Yangtze River based on CMIP6 meteorological data and related environmental variables, under SSP126 and SSP585 emission scenarios. The results show that future climate change (temperature and precipitation changes) will decrease winter wheat yield by 2~4% and reduce total nitrogen losses by 0~5%, but in other areas, the total nitrogen losses will increase by 0~5% and the N leaching losses per unit of yield will increase by 0~10%. The results of this study can provide a theoretical basis and reference for optimizing nitrogen application rates, increasing yield, and reducing nitrogen losses in wheat cultivation under climate change conditions.