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Aims: Our goal was to better understand tree growth and photosynthetic responses to variations in plant available water and elucidate the role of the inverse texture effect in snow dominated montane forests. Methods: We measured tree ring carbon isotope composition and annual growth over a 31-year record for lodgepole pine (Pinus contorta Douglas ex Loudon) growing on three different-aged glacial till surfaces in Wyoming, USA. Results: Soils of different ages developed on till surfaces from three separate glaciation events were significantly different in clay content and distribution with depth; maximum clay content at depth ranged from 19 to 20% on the two youngest till surfaces, but was as high as 36% on the oldest till surface. Ring growth was lowest at the youngest till sites, and only on these coarse-textured soils was growth positively correlated with annual maximum snow water equivalent (SWEmax). Δ13C was highest for trees at these young till sites, suggesting that hydraulic conductivity and stomatal conductance is comparatively high during growth periods on these coarse-textured soils. Conclusion: Taken together, we found that age of glacial till and related soil texture differences strongly influenced tree-ring growth and Δ13C response of lodgepole pine to interannual variation in precipitation and drought severity, but responses did not support an inverse texture effect in these semi-arid forest systems. [ABSTRACT FROM AUTHOR]

• Paper combines 3 Elements Model, with Systems of Provision model. • Model shows how central government influenced local authority grant bidding practices. • Meanings travel from central government and influence the type of schemes delivered. • Funding identified as a means of exerting government power within this system. • Model enhances policy-maker understanding of the wider impacts of interventions. Changing mobility behaviour towards activities and actions that have a less detrimental impact on the environment, public health and society is an objective of transport policy jurisdictions globally. In line with a burgeoning body of research examining behaviour and social change, this paper explores the governmental systems that influence mobility behaviours through a social practice lens. This paper blends two social practice theoretical models, the '3-Elements Model' and 'Systems of Provision', as a means of understanding the delivery of the Local Sustainable Transport Fund (LSTF), a central government grant scheme for English local authorities. We examine how the meanings, materials and competences within the practices of bid writing by local authorities and scheme selection by government influenced the distribution of funding to local authorities. The research starts from the principle that, where funding is provided by central government, in the case of this research that of the UK, an opportunity is created for mobility practices to change. The significance of funding is not easily theorised by the 3-Elements model but is more helpfully explained when that model is blended with the wider Systems of Provision model to create a model of practice ecology. Our theorisation allows for a rigorous exploration of the 'practice scaffolding' which shapes how people travel. Policymakers are recommended to consider a practice ecology approach when developing mobility management schemes to tackle air quality, climate change and obesity issues more effectively. [ABSTRACT FROM AUTHOR]

Grassland soils are significant carbon (C) sinks as more than half of grassland plant biomass is belowground and roots are the main source of soil C. It is uncertain if grassland soils will continue as C sinks in the future because climate change may affect the dynamic, belowground relationships among crown and root biomass, root chemistry and morphology, and root and soil decomposition, all of which influence C sequestration potential. To better understand future belowground C cycling in semiarid grasslands we analyzed three native species ( Bouteloua gracilis, Carex eleocharis, and Pascopyrum smithii ) and mixed-grass community crown and root biomass, root chemistry, morphology, and decomposability, and soil organic carbon (SOC) priming following seven years of simulated climate change at the Prairie Heating and CO2 Enrichment (PHACE) experiment in Wyoming, USA. We found that individual species and the community respond uniquely to the climate change field treatments, indicating that species composition is important when analyzing climate change effects on grassland C cycling. Root biomass in the C3 sedge, C. eleocharis, increased under elevated CO 2 , especially when combined with warming. Decomposition rates of roots from warming plots were higher than those from ambient plots for B. gracilis and P. smithii . Across species, root decomposition rates increased with C and N concentrations. Root morphology was altered as well: B. gracilis root diameter increased under warming, and P. smithii specific root length and surface area increased under elevated CO 2 . P. smthii roots induced short-term, negative SOC priming across all field treatments. Together, our results indicate that grass roots may play a critical role in maintaining soil C stocks in grasslands in the future. [ABSTRACT FROM AUTHOR]

Background The plant family Cactaceae provides some of the most striking examples of adaptive evolution, expressing undeniably the most spectacular New World radiation of succulent plants distributed across arid and semi-arid regions of the Americas. Cacti are widely regarded for their cultural, economic and ecological value, yet they are also recognized as one of the most threatened and endangered taxonomic groups on the planet. Scope This paper reviews current threats to species of cacti that have distributions in arid to semi-arid subtropical regions. Our review focuses primarily on four global change forces: (1) increases in atmospheric CO2 concentrations; (2) increases in mean annual temperatures and heat waves; (3) increases in the duration, frequency and intensity of droughts; and (4) and increases in competition and wildfire frequency from invasion by non-native species. We provide a broad range of potential priorities and solutions for stemming the extinction risk of cacti species and populations. Conclusions Mitigating ongoing and emerging threats to cacti will require not only strong policy initiatives and international cooperation, but also new and creative approaches to conservation. These approaches include determining species at risk from climate extremes, enhancing habitat quality after disturbance, approaches and opportunities for ex situ conservation and restoration, and the potential use of forensic tools for identifying plants that have been removed illegally from the wild and sold on open markets. [ABSTRACT FROM AUTHOR]

Ecological disturbances driving state changes in ecosystems are likely to be exacerbated with climate shifts during this century. Temperate montane ecosystems of the Western United States (Mountain West) are especially vulnerable due to their low fertility, heterogeneous landscapes, and tight coupling between terrestrial and aquatic components. We review how catchment level pulse and press disturbances will intensify, and how they are reflected by coupled measurements of stream water chemistry and flow. Detecting effects on watershed processes can be complex and depend on the type and extent of disturbance. Within this context, we discuss the impacts of wildfire (pulse), bark beetle outbreaks (pulse), snowpack shifts (press), and progressive vegetation community shifts (press) on streamflow and chemistry dynamics (hydrochemographs). We used long-term data from three mid- to high-elevation watersheds as examples of how disturbances may influence stream hydrochemographs, including increased variability in winter nitrate export in more recent years with extremes in snowmelt runoff export; variable nitrate export when snow water equivalent was abnormally high or low; and high nitrate flux in the years immediately following sudden forest loss. These examples illustrate the need for long-term continuous monitoring to fill the gap in our understanding of the short- and long-term consequences of climate change-induced disturbances to watersheds. As disturbances increase in severity and frequency and induce ecological state changes, it is critical that we develop our understanding of impacts on downstream communities that depend sociologically and economically on water availability and quality. [ABSTRACT FROM AUTHOR]

Distractibility can lead to accidents and academic failures as well as memory problems. Recent evidence suggests that intentional recognition memory can be biased by unintentional recognition of distracting stimuli in the same environment. It is unknown whether unintentional and intentional recognition depend on the same underlying neurocognitive mechanisms. We assessed whether human participants' recognition of previously seen (old) or not seen (new) target stimuli was affected by whether a to-be-ignored distractor was old or new. ERPs were recorded to investigate the neural correlates of this bias. The results showed that the old/new status of salient distractors had a biasing effect on target recognition accuracy. Both intentional and unintentional recognition elicited early ERP effects that are thought to reflect relatively automatic memory processes. However, only intentional recognition elicited the later ERP marker of conscious recollection, consistent with previous suggestions that recollection is under voluntary control. In contrast, unintentional recognition was associated with an enhanced late posterior negativity, which may reflect monitoring or evaluation of memory signals. The findings suggest that unintentional and intentional recognition involve dissociable memory processes. [ABSTRACT FROM AUTHOR]

Vegetation greenness, detected using digital photography, is useful for monitoring phenology of plant growth, carbon uptake and water loss at the ecosystem level. Assessing ecosystem phenology by greenness is especially useful in spatially extensive, water-limited ecosystems such as the grasslands of the western United States, where productivity is moisture dependent and may become increasingly vulnerable to future climate change., We used repeat photography and a novel means of quantifying greenness in digital photographs to assess how the individual and combined effects of warming and elevated CO2 impact ecosystem phenology (greenness and plant cover) in a semi-arid grassland over an 8-year period., Climate variability within and among years was the proximate driver of ecosystem phenology. Individual and combined effects of warming and elevated CO2 were significant at times, but mediated by variation in both intra- and interannual precipitation. Specifically, warming generally enhanced plant cover and greenness early in the growing season but often had a negative effect during the middle of the summer, offsetting the early season positive effects. The individual effects of elevated CO2 on plant cover and greenness were generally neutral., Opposing seasonal variations in the effects of warming and less so elevated CO2 cancelled each other out over an entire growing season, leading to no net effect of treatments on annual accumulation of greenness. The main effect of elevated CO2 dampened quickly, but warming continued to affect plant cover and plot greenness throughout the experiment. The combination of warming and elevated CO2 had a generally positive effect on greenness, especially early in the growing season and in later years of the experiment, enhanced annual greenness accumulation. However, interannual precipitation variation had larger effect on greenness, with two to three times greater greenness in wet years than in dry years., Synthesis. Seasonal variation in timing and amount of precipitation governs grassland phenology, greenness and the potential for carbon uptake. Our results indicate that concurrent changes in precipitation regimes mediate vegetation responses to warming and elevated atmospheric CO2 in semi-arid grasslands. Even small changes in vegetation phenology and greenness in response to warming and rising atmospheric CO2 concentrations, such as those we report here, can have large consequences for the future of grasslands. [ABSTRACT FROM AUTHOR]

[Display omitted] • The δ15N of biomonitors reveal N dep gradients and emission sources. • The δ15N of lichen and moss biomonitors integrate both source and isotope effects. • Interpretation of δ15N of biomonitors requires consideration of multiple factors. • δ15N of biomonitors often exhibits a negative correlation with ratio of NH x :NO x in N dep. • Lichen/moss from herbaria show anthropogenic shifts in N dep δ15N over the past century. Anthropogenic nitrogen (N) emissions and subsequent deposition can cause harm to ecosystem function and processes. Identifying emission sources of atmospheric N deposition (N dep) is critical for land management and policy development to understand what N species are impacting an area and where action can be taken to reduce loading. Measuring and monitoring deposition is time intensive and expensive, but biomonitors, such as mosses and lichens, can be used to evaluate finer-scale deposition patterns and source attribution using stable isotope analysis. The N stable isotope composition (δ15N) of N dep provides unique insight into emission sources and chemistry at different temporal and spatial scales because it is determined in part by the δ15N of contributing N emission sources that vary at a local, regional, and global level. The δ15N of biomonitor organisms can be used to monitor N dep at these diverse scales capturing the spatial and temporal heterogeneity of N dep rates and source chemistries. However, the δ15N of biomonitors integrates not only source effects, but also isotopic effects associated with canopy dynamics and organism biology, thus interpretation of biomonitor δ15N needs to consider multiple factors including emission source, atmospheric transformations, and canopy and physiological effects. Despite local scale and organism specific responses, lichens and mosses from herbaria collections document coherent anthropogenically driven shifts in N dep δ15N signals over the last century consistent with observations from lake sediments and ice cores. [ABSTRACT FROM AUTHOR]

The woolly apple aphid ( WAA), Eriosoma lanigerum Hausmann, is a worldwide pest of apple orchards that has become widespread in apple-growing regions of Australia. Several WAA populations that are geographically distant may have evolved into biotypes having different fitness (e.g. fecundity) in similar biotic and abiotic conditions. In this study, we investigated the performance of four different lines of WAA (designated as ALB, STA, BAT and YAR) originating from four locations in Victoria and New South Wales ( Australia). Nymph establishment, nymph development to adult, nymph developmental time, female fecundity and adult weight of apterous virginoparae on apple trees (cv Granny Smith) were monitored under glasshouse conditions. Results showed that at least three lines examined here differ significantly in one or more performance parameters. Nymphs of the STA lineage showed a significantly higher establishment success after 7 days (64.3%) compared with lines BAT (53.1%) and YAR (43.6%). Nymph development to adulthood followed a similar trend. The average fecundity/female/7 days of the ALB lineage (19.7 ± 1.6 nymphs) was the lowest and significantly reduced relative to all other lines (from 36.6 to 40.5 nymphs). These results demonstrate the existence of at least three different biotypes in Australia. Antibiosis and antixenosis, respectively, could explain lower aphid establishment and lower female fecundity once settled. The characterisation of different WAA biotypes could have important implications for WAA management, and further studies should evaluate the overall diversity of biotypes, their geographical distribution and their growth characteristics to fully optimise pest control strategies. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented which discusses the medical practice design to decrease the risk of a malpractice litigation among obstetricians.

Three field experiments were conducted in stone fruit orchards in the Goulburn Valley, northern Victoria, Australia to identify a user-friendly trap for use in attract and kill stations for control of Carpophilus spp. (Coleoptera: Nitidulidae). A funnel trap design was compared with two types of delta trap in one experiment and two types of Lucitrap in another experiment. All traps were baited with synthetic co-attractant and synthetic pheromone. The funnel trap was the most effective type of trap tested. The funnel traps caught significantly more beetles than either the delta traps with bio-attractant or delta traps wrapped with insecticide impregnated banana wrap. No difference was observed between catches in either delta trap design. Lucitraps without covers caught significantly more beetles than Lucitraps with covers but funnel traps caught significantly more beetles than either type of Lucitrap. Beetle numbers caught in the funnel traps were three to five times higher than in Lucitrap. The use of funnel traps in attract and kill stations to protect stone fruit crops by suppressing the Carpophilus spp. population gave superior control to ‘grower normal practice of spraying insecticides’ both in terms of Carpophilus spp. numbers and in terms of reduction in percentage of fruit damaged. [ABSTRACT FROM AUTHOR]

Stable isotope measurements are employed extensively in plant–water relations research to investigate physiological and hydrological processes from whole plant to ecosystem scales. Stable isotopes of hydrogen and oxygen are routinely measured to identify plant source water. This application relies on the assumption that no fractionation of oxygen and hydrogen isotopes in water occurs during uptake by roots. However, a large fraction of the water taken up through roots in halophytic and xerophytic plants transverses cell membranes in the endodermis before entering the root xylem. Passage of water through this symplastic pathway has been hypothesized to cause fractionation leading to a decrease in 2H of root xylem water relative to that in the surrounding soil medium. We examined 16 woody halophytic and xerophytic plant species in controlled conditions for evidence of hydrogen isotope fractionation during uptake at the root–soil interface. Isotopic separation (Δ2H = δ2Hsoil water − δ2Hxylem water) ranging from 3‰ to 9‰ was observed in 12 species. A significant positive correlation between salinity tolerance and the magnitude of Δ2H was observed. Water in whole stem segments, sapwood, and roots had significantly lower δ2H values relative to soil water in Prosopis velutina Woot., the species expressing the greatest Δ2H values among the 16 species examined. Pressurized water flow through intact root systems of Artemisia tridentata Nutt. and Atriplex canescens (Pursh) Nutt. caused the δ2H values to decrease as flow rate increased. This relationship was not observed in P. velutina. Destroying the plasma membranes of root cells by excessive heat from boiling did not significantly alter the relationship between δ2H of expressed water and flow rate. In light of these results, care should be taken when using the stable isotope method to examine source-water use in halophytic and xerophytic species. [ABSTRACT FROM AUTHOR]

During two growing seasons, the use of an attract-and-kill system for control of Carpophilus spp. (Coleoptera: Nitidulidae) and the effective range or drawing power of the attract-and-kill stations were examined in stone fruit orchards in the Goulburn Valley, northern Victoria, Australia. Three attract-and-kill stations, baited with synthetic aggregation pheromone plus co-attractant, were placed about 50 m apart in the upwind corner of each treated block 5–6 weeks before the fruit began to ripen. Large numbers of Carpophilus spp. were caught in the attract-and-kill stations immediately after placement. By the time fruit had ripened, the number of Carpophilus spp. caught had decreased greatly. Fruit damage caused by Carpophilus spp. in treated blocks, especially in 2000–2001 season, was almost zero (0.1% and 0.6%) in trees and on the ground, respectively, whereas the damage levels in control blocks were 5.2% and 19.9% in trees and on the ground, respectively. This study indicates that excellent protection of ripening stone fruit may be achieved by using attract-and kill-stations. [ABSTRACT FROM AUTHOR]

Stable hydrogen and oxygen isotopic composition of bulk leaf water (δDlw and δ18Olw) in piñon pine ( Pinus edulis and P. monophylla) and gas exchange parameters were measured under field conditions to examine the effects of seasonal moisture stress on leaf water isotopic enrichment. Study sites were located near the lower elevation limit for piñon in the southwestern USA. Leaf-level transpiration measurements were made four times daily in spring, summer and early autumn; simultaneously, leaf samples were collected for water extraction and stable isotope analysis. Diurnal variations in δDlw and δ18Olw values were small, especially when leaf water residence times (molar leaf water content divided by transpiration rate) were high. Stomatal conductance explained most of the variance (60%) in leaf water enrichment across the dataset. Observed leaf water enrichment was compared with predictions of steady-state and nonsteady-state models. Nonsteady-state predictions fit observations the best, although D enrichment was often lower than predicted by any model. Hydrogen isotope ratios of leaf water and cellulose nitrate were strongly correlated, demonstrating preservation of a leaf water signal in wood and leaf cellulose. [ABSTRACT FROM AUTHOR]

The relative contributions of overstory and understory plant transpiration and soil evaporation to total evapotranspiration (ET) in a semiarid savanna woodland were determined from stable isotope measurements of atmospheric water vapor. The savanna overstory was dominated by the deeply rooted, woody legume Prosopis velutina (“mesquite”), and the understory was dominated by a perennial C4 grass, Sporobolus wrightii. “Keeling plots” (turbulent mixing relationships) were generated from isotope ratios (δD and δ18O) of atmospheric water vapor collected within the tree (3–14 m) and understory (0.1–1 m) canopies during peak (July) and post-monsoon (September) periods of 2001. The unique regression intercepts from upper and lower profiles were used to partition the ET flux from the understory layer separately from that of the whole ecosystem. Although ET partitioning was problematic during the first sampling period in July, our results in September provided support to the validity of this method for measuring and understanding the dynamic behavior of water balance components in this semiarid savanna woodland.During the post-monsoon period (22nd September), transpiration accounted for 85% of ecosystem ET. Transpiration by the grass layer accounted for 50% of the understory ET over the same period. The total ecosystem ET estimated by eddy covariance (EC) on 22nd September was 3.5 mm per day. Based on partitioning by the isotope method, 2.5 mm per day (70%) was from tree transpiration and 0.5 mm per day (15%) was from transpiration by the grass layer. Independent estimates of overstory and understory ET partitioning from distributed understory EC measurements were remarkably consistent with our isotope approach. [Copyright &y& Elsevier]

Evaluates monsoon rain usage by dominant tree species of the pinyon-juniper ecosystem along a broad monsoon precipitation gradient in southwestern United States. Plant water potential and leaf gas exchange responses; Geographic differences in seasonal water use; Associations between functional rooting depth, drought tolerance and water-use efficiency.

Examines the literary style of Derek Mahon in his work 'The Yellow Book.' Analysis of the verses of 'The Hudson Letter'; Creation of a hybridized style articulating different facets of Mahon's responses to living in New York; Reflection of Mahon's concern for the marginalized and outcast individuals; Influence of Decadent and late Romanic views of art.

Offers information on poet Derek Mahon, with focus on the poem `Journalism.' Insight on the concerns and sympathies revealed in his books of poetry which Mahon wrote in 1968; Examination of some of his other poems; In-depth look at `Journalism'; Identification of aspects of Mahon that were revealed in his work as a poet.

Focuses on the `Martian' poetry of Craig Raine and Christopher Reid, and looks at their admiration and connection with the work of writer Elizabeth Bishop. Perceptions of Raine on Bishop's work; Examples of Bishop's poetry; Background information on Bishop.

Argues that governance as presented by the World Bank is best understood in terms of discipline defined as a form of correction or control. Explanation for the actions of the World Bank; Key areas of governance concerns; Governance discipline techniques used by the World Bank; Relationship between governance discipline and liberalism.

Studies the role of phenotypic plasticity in the ecophysiology of introduced Pennisetum setaceum on Hawaii. Patterns of mortality; Physiological characteristics determined by environment; Total aboveground biomass at harvest; Statistical analysis.

Abstract: Classic methods of soil amino acid (SAA) determination involve field collection of soils and disturbance during storage, sieving, mixing and extraction in the laboratory. We describe a novel inexpensive method for extraction of SAA''s in situ with minimal soil disturbance. In a comparison between methods of SAA extraction from a semiarid grassland site, glu-x and arginine were the dominant SAA nitrogen sources detected by the novel method while serine and glycine were the dominant SAA nitrogen sources detected using the classic method. The extraction method employed is likely to be useful for accurate determination of SAA availability to plants and soil microbes. [Copyright &y& Elsevier]

Background: Small randomized trials of early postoperative oral nutritional supplementation (ONS) suggest various health benefits following colorectal surgery (CRS). However, real-world evidence of the impact of early ONS on clinical outcomes in CRS is lacking. Methods: Using a nationwide administrative-financial database (Premier Healthcare Database), we examined the association between early ONS use and postoperative clinical outcomes in patients undergoing elective open or laparoscopic CRS between 2008 and 2014. Early ONS was defined as the presence of charges for ONS before postoperative day (POD) 3. The primary outcome was composite infectious complications. Key secondary efficacy (intensive care unit (ICU) admission and gastrointestinal complications) and falsification (blood transfusion and myocardial infarction) outcomes were also examined. Propensity score matching was used to assemble patient groups that were comparable at baseline, and differences in outcomes were examined. Results: Overall, patients receiving early ONS were older with greater comorbidities and more likely to be Medicare beneficiaries with malnutrition. In a well-matched sample of early ONS recipients (n = 267) versus non-recipients (n = 534), infectious complications were significantly lower in early ONS recipients (6.7% vs. 11.8%, P < 0.03). Early ONS use was also associated with significantly reduced rates of pneumonia (P < 0.04), ICU admissions (P < 0.04), and gastrointestinal complications (P < 0.05). There were no significant differences in falsification outcomes. Conclusions: Although early postoperative ONS after CRS was more likely to be utilized in elderly patients with greater comorbidities, the use of early ONS was associated with reduced infectious complications, pneumonia, ICU admission, and gastrointestinal complications. This propensity score-matched study using real-world data suggests that clinical outcomes are improved with early ONS use, a simple and inexpensive intervention in CRS patients. [ABSTRACT FROM AUTHOR]

Premise of the Study: Giant cacti species possess long cylindrical stems that store massive amounts of water and other resources to draw on for photosynthesis, growth, and reproduction during hot and dry conditions. Across all giant cacti taxa, stem photosynthetic surface area to volume ratio (S:V) varies by several fold. This broad morphological diversity leads to the hypothesis that giant cacti function along a predictable resource use continuum from a "safe" strategy reflected in low S:V, low relative growth rates (RGR), and low net assimilation rates (Anet) to a high‐risk strategy that is reflected in high S:V, RGR, and Anet. Methods: To test this hypothesis, whole‐plant gas exchange, chlorophyll fluorescence, and whole‐spine‐tissue carbon isotope ratios (δ13C) were measured in four giant cacti species varying in stem morphology and RGR. Measurements were conducted on five well‐watered, potted plants per species. Key Results: Under conditions of mild diel temperatures and low atmospheric vapor pressure deficit, Anet, transpiration (E), and stomatal conductance (Gs) were significantly higher, and water‐use efficiency (Anet : Gs) was lower in fast‐growing, multi‐stemmed species compared to the slower growing, single‐stemmed species. However, under warmer, less optimal conditions, gas exchange converged between stem types, and neither δ13C nor chlorophyll fluorescence varied among species. Conclusions: The results add to a growing body of evidence that succulent‐stemmed plants function along a similar economic spectrum as leaf‐bearing plants such that functional traits including stem RGR, longevity, morphology, and gas exchange are correlated across species with varying life‐history strategies. [ABSTRACT FROM AUTHOR]

Compound-specific δ2H values of leaf wax n -alkanes are increasingly being used to infer past hydroclimates. However, differences in n -alkane production and apparent fractionation factors (ε app) among different plant groups complicate the relationships between n -alkane δ2H values and those of environmental water. Mid- and long-chain n -alkanes in sedimentary archives (i.e., n -C 23 and n -C 29) are thought to derive from aquatic and terrestrial plants, respectively, and track the isotopic composition of either lake water or precipitation. Yet, the relationship between n -C 23 δ2H values and lake water δ2H values is not well constrained. Moreover, recent studies show that n -alkane production is greater in terrestrial plants than in aquatic plants, which has the potential to obscure n -alkane aquatic inputs to sedimentary archives. Here, we investigated n -alkane contributions to sedimentary archives from both aquatic and terrestrial plants by analyzing n -alkane δ2H values in plants and lake sediments at 29 sites across mid-latitude North America. We find that both aquatic and terrestrial plants synthesize n -C 23 and that sedimentary n -C 23 δ2H values parallel those of terrestrial plants and differ from those of aquatic plants. Our results indicate that across mid-latitude North America, both mid- and long-chain n -alkanes in lake sediments commonly derive from terrestrial higher plants challenging the assumption that submerged aquatic plants produce the n -C 23 -alkane preserved in lake sediments. Moreover, angiosperm and gymnosperm plants exhibit similar ε app values between n -C 29 and mean annual precipitation (MAP) δ2H values across North America. Therefore, vegetation shifts between angiosperm and gymnosperm plants do not strongly affect ε app values between n -C 29 and MAP. Our results show that both mid- and long-chain n -alkanes track the isotopic composition of MAP in temperate North America. [ABSTRACT FROM AUTHOR]

The effects of climate change on plants and ecosystems are mediated by plant hydraulic traits, including interspecific and intraspecific variability of trait phenotypes. Yet, integrative and realistic studies of hydraulic traits and climate change are rare. In a semiarid grassland, we assessed the response of several plant hydraulic traits to elevated CO2 (+200 ppm) and warming (+1.5 to 3°C; day to night). For leaves of five dominant species (three graminoids and two forbs), and in replicated plots exposed to 7 years of elevated CO2, warming, or ambient climate, we measured: stomatal density and size, xylem vessel size, turgor loss point, and water potential (pre‐dawn). Interspecific differences in hydraulic traits were larger than intraspecific shifts induced by elevated CO2 and/or warming. Effects of elevated CO2 were greater than effects of warming, and interactions between treatments were weak or not detected. The forbs showed little phenotypic plasticity. The graminoids had leaf water potentials and turgor loss points that were 10% to 50% less negative under elevated CO2; thus, climate change might cause these species to adjust their drought resistance strategy away from tolerance and toward avoidance. The C4 grass also reduced allocation of leaf area to stomata under elevated CO2, which helps explain observations of higher soil moisture. The shifts in hydraulic traits under elevated CO2 were not, however, simply due to higher soil moisture. Integration of our results with others' indicates that common species in this grassland are more likely to adjust stomatal aperture in response to near‐term climate change, rather than anatomical traits; this contrasts with apparent effects of changing CO2 on plant anatomy over evolutionary time. Future studies should assess how plant responses to drought may be constrained by the apparent shift from tolerance (via low turgor loss point) to avoidance (via stomatal regulation and/or access to deeper soil moisture). [ABSTRACT FROM AUTHOR]

The article examines the relationship between mental illness and population density. The relationship between population density and a variety of social problems has been the focus of a number of studies in recent decades. The results of these studies have often been inconsistent for example, research on the relationship between violent crimes and population density is frequently characterized by conflicting outcomes. Clearly, there is a strong positive correlation between the rate of inpatient treatment and population density. For the purpose of statistical analysis, it is important to note that all state populations, programs, services and funding patterns differ but the present research demonstrates that the relationship between mental illness and population density may be extraordinarily powerful in American society.

It is proposed that trade-offs between growth and stress tolerance in stem succulents are defined by stem volume-to-surface area ratio. This simple relationship may predict responses of columnar cacti to climate change.Columnar cacti occur naturally in many habitats and environments in the Americas but are conspicuously dominant in very dry desert regions. These majestic plants are widely regarded for their cultural, economic, and ecological value and, in many ecosystems, support highly diverse communities of pollinators, seed dispersers, and frugivores. Massive amounts of water and other resources stored in the succulent photosynthetic stems of these species confer a remarkable ability to grow and reproduce during intensely hot and dry periods. Yet many columnar cacti are potentially under severe threat from environmental global changes, including climate change and loss of habitat. Stems in columnar cacti and other cylindrical-stemmed cacti are morphologically diverse; stem volume-to-surface area ratio (V:S) across these taxa varies by almost two orders of magnitude. Intrinsic functional trade-offs are examined here across a broad range of V:S in species of columnar cacti. It is proposed that variation in photosynthetic gas exchange, growth, and response to stress is highly constrained by stem V:S, establishing a mechanistic framework for understanding the sensitivity of columnar cacti to climate change and drought. Specifically, species that develop stems with low V:S, and thus have little storage capacity, are expected to express high mass specific photosynthesis and growth rates under favourable conditions compared with species with high V:S. But the trade-off of having little storage capacity is that low V:S species are likely to be less tolerant of intense or long-duration drought compared with high V:S species. The application of stable isotope measurements of cactus spines as recorders of growth, water relations, and metabolic responses to the environment across species of columnar cacti that vary in V:S is also reviewed. Taken together, our approach provides a coherent theory and required set of observations needed for predicting the responses of columnar cacti to climate change. [ABSTRACT FROM PUBLISHER]

Carbon (C) allocation strategy plays a critical role in plant adaptability, which are also important to assess the productivity stability under environmental change. Based on optimal partitioning theory, we asked two questions: (1) How is plant C allocation within tissues affected by nutrient enrichment (N addition)? And (2) does long‐term N addition alter how plants allocate C under drought?To address these questions, we conducted a greenhouse experiment using the widespread perennial C3 grass, Leymus chinensis, under four treatments: 'Watered', 'Dry', 'Watered + N' and 'Dry + N'. 13CO2 pulse labelling was used to trace C transport through the plant–soil system.We found that drought and N addition resulted in additive effects on C allocation. Greater above‐ground biomass under N addition resulted in higher C loss via above‐ground plant respiration, even under drought, which plays a more important role in the adjustment of root:shoot ratio than does the trade‐off between above‐ and below‐ground organs.Compared to the concept of active phenotype adjustment for maximized growth rate in traditional optimal partitioning theory, our results imply that pre‐drought allometry, which changes under long‐term resource addition, also determines how plants respond to drought and their adaptability to changing environmental conditions. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Premise of research. Leaf stomatal and mesophyll conductances limit photosynthesis and influence water use efficiency. Few studies have quantified the relative limitations imposed by these CO2 diffusion pathways on photosynthesis in mature conifer trees under natural conditions. Here, we report observations of stomatal and mesophyll conductance changes during seasonal drying across contrasting topographic positions in two Rocky Mountain conifers. We predicted that topographic controls on soil water availability and energy balance would determine limitations to photosynthesis by mesophyll conductance across conifer species with contrasting patterns of stomatal and hydraulic traits. Methodology. Concurrent measurements of leaf gas exchange and carbon isotope discrimination were used to estimate stomatal (g s) and mesophyll (g m) conductance in branches of an isohydric species, lodgepole pine (Pinus contorta), and an anisohydric species, Engelmann spruce (Picea engelmannii), in the central Rocky Mountains. Quantitative limitation analysis of photosynthesis (A) was then performed using data from CO2 response curves. Pivotal results. Stomatal conductance imposed greater limitations on photosynthesis (42%–67%) than mesophyll conductance (5%–17%), but no significant differences in g m were observed between the two conifer species. At the mesic lower hillslope position, A , g s, and g m increased during the growing season despite declines in soil moisture. In contrast, at the drier upper hillslope position, declines in soil moisture and increases in air temperature during the growing season are correlated with reductions in g s but not with A or g m. Conclusions. Adjustments in g m played a potentially important role in sustaining photosynthesis and improving plant water use efficiency when stomatal conductance decreased with water limitation during the growing season at the research site. Sustained g m with seasonal drought may be an important mechanism allowing conifers to survive and maintain competitive dominance in low-resource habitats. [ABSTRACT FROM AUTHOR]

Focuses on the role of terrestial ecosystem in modulating the balance uptake and release of carbon dioxide. Implication of industrial activity and changes for the carbon cycle; Incorporation of carbon into long-lived components; Sequestration of carbon from atmospheric carbon and of older ones.

Climate controls vegetation distribution across the globe, and some vegetation types are more vulnerable to climate change, whereas others are more resistant. Because resistance and resilience can influence ecosystem stability and determine how communities and ecosystems respond to climate change, we need to evaluate the potential for resistance as we predict future ecosystem function. In a mixed-grass prairie in the northern Great Plains, we used a large field experiment to test the effects of elevated CO2, warming, and summer irrigation on plant community structure and productivity, linking changes in both to stability in plant community composition and biomass production. We show that the independent effects of CO2 and warming on community composition and productivity depend on interannual variation in precipitation and that the effects of elevated CO2 are not limited to water saving because they differ from those of irrigation. We also show that production in this mixed-grass prairie ecosystem is not only relatively resistant to interannual variation in precipitation, but also rendered more stable under elevated CO2 conditions. This increase in production stability is the result of altered community dominance patterns: Community evenness increases as dominant species decrease in biomass under elevated CO2. In many grasslands that serve as rangelands, the economic value of the ecosystem is largely dependent on plant community composition and the relative abundance of key forage species. Thus, our results have implications for how we manage native grasslands in the face of changing climate. [ABSTRACT FROM AUTHOR]

The flux of carbon dioxide (CO2) between terrestrial ecosystems and the atmosphere may ameliorate or exacerbate climate change, depending on the relative responses of ecosystem photosynthesis and respiration to warming temperatures, rising atmospheric CO2, and altered precipitation. The combined effect of these global change factors is especially uncertain because of their potential for interactions and indirectly mediated conditions such as soil moisture. Here, we present observations of CO2 fluxes from a multi-factor experiment in semi-arid grassland that suggests a potentially strong climate – carbon cycle feedback under combined elevated [CO2] and warming. Elevated [CO2] alone, and in combination with warming, enhanced ecosystem respiration to a greater extent than photosynthesis, resulting in net C loss over four years. The effect of warming was to reduce respiration especially during years of below-average precipitation, by partially offsetting the effect of elevated [CO2] on soil moisture and C cycling. Carbon losses were explained partly by stimulated decomposition of soil organic matter with elevated [CO2]. The climate – carbon cycle feedback observed in this semiarid grassland was mediated by soil water content, which was reduced by warming and increased by elevated [CO2]. Ecosystem models should incorporate direct and indirect effects of climate change on soil water content in order to accurately predict terrestrial feedbacks and long-term storage of C in soil. [ABSTRACT FROM AUTHOR]

ABSTRACT Accurate estimates of the δ13C value of CO2 respired from roots ( δ13CR_root) and leaves ( δ13CR_leaf) are important for tracing and understanding changes in C fluxes at the ecosystem scale. Yet the mechanisms underlying temporal variation in these isotopic signals are not fully resolved. We measured δ13CR_leaf, δ13CR_root, and the δ13C values and concentrations of glucose and sucrose in leaves and roots in the C4 grass Sporobolus wrightii and the C3 tree Prosopis velutina in a savanna ecosystem in southeastern Arizona, USA. Night-time variation in δ13CR_leaf of up to 4.6 ± 0.6‰ in S. wrightii and 3.0 ± 0.6‰ in P. velutina were correlated with shifts in leaf sucrose concentration, but not with changes in δ13C values of these respiratory substrates. Strong positive correlations between δ13CR_root and root glucose δ13C values in P. velutina suggest large diel changes in δ13CR_root (were up to 3.9‰) influenced by short-term changes in δ13C of leaf-derived phloem C. No diel variation in δ13CR_root was observed in S. wrightii. Our findings show that short-term changes in δ13CR_leaf and δ13CR_root were both related to substrate isotope composition and concentration. Changes in substrate limitation or demand for biosynthesis may largely control short-term variation in the δ13C of respired CO2 in these species. [ABSTRACT FROM AUTHOR]

Developmental mechanisms that enable perception of and response to the environment may enhance fitness. Ecophysiological traits typically vary depending on local conditions and contribute to resource acquisition and allocation, yet correlations may limit adaptive trait expression. Notably, photosynthesis and stomatal conductance vary diurnally, and the circadian clock, which is an internal estimate of time that anticipates diurnal light/dark cycles, may synchronize physiological behaviors with environmental conditions. Using recombinant inbred lines of Brassica rapa, we examined the quantitative-genetic architecture of ecophysiological and phenological traits and tested their association with the circadian clock. We also investigated how trait expression differed across treatments that simulated seasonal settings encountered by crops and naturalized populations. Many ecophysiological traits were correlated, and some correlations were consistent with expected biophysical constraints; for example, stomata jointly regulate photosynthesis and transpiration by affecting carbon dioxide and water vapor diffusion across leaf surfaces, and these traits were correlated. Interestingly, some genotypes had unusual combinations of ecophysiological traits, such as high photosynthesis in combination with low stomatal conductance or leaf nitrogen, and selection on these genotypes could provide a mechanism for crop improvement. At the genotypic and QTL level, circadian period was correlated with leaf nitrogen, instantaneous measures of photosynthesis, and stomatal conductance as well as with a long-term proxy (carbon isotope discrimination) for gas exchange, suggesting that gas exchange is partly regulated by the clock and thus synchronized with daily light cycles. The association between circadian rhythms and ecophysiological traits is relevant to crop improvement and adaptive evolution. [ABSTRACT FROM AUTHOR]

The C isotope composition of leaf dark-respired CO (δC) integrates short-term metabolic responses to environmental change and is potentially recorded in the isotopic signature of ecosystem-level respiration. Species differences in photosynthetic pathway, resource acquisition and allocation patterns, and associated isotopic fractionations at metabolic branch points can influence δC, and differences are likely to be modified by seasonal variation in drought intensity. We measured δC in two deep-rooted C trees ( Prosopis velutina and Celtis reticulata), and two relatively shallow-rooted perennial herbs (a C dicot Viguiera dentata and a C grass Sporobolus wrightii) in a floodplain savanna ecosystem in southeastern Arizona, USA during the dry pre-monsoon and wet monsoon seasons. δC decreased during the nighttime and reached minimum values at pre-dawn in all species. The magnitude of nocturnal shift in δC differed among species and between pre-monsoon and monsoon seasons. During the pre-monsoon season, the magnitude of the nocturnal shift in δC in the deep-rooted C trees P. velutina (2.8 ± 0.4‰) and C. reticulata (2.9 ± 0.2‰) was greater than in the C herb V. dentata (1.8 ± 0.4‰) and C grass S. wrightii (2.2 ± 0.4‰). The nocturnal shift in δC in V. dentata and S. wrightii increased to 3.2 ± 0.1‰ and 4.6 ± 0.6‰, respectively, during the monsoon season, but in C trees did not change significantly from pre-monsoon values. Cumulative daytime net CO uptake was positively correlated with the magnitude of the nocturnal decline in δC across all species, suggesting that nocturnal δC may be controlled by C/C fractionations associated with C substrate availability and C metabolite partitioning. Nocturnal patterns of δC in dominant plant species in the semiarid savanna apparently have predictable responses to seasonal changes in water availability, which is important for interpreting and modeling the C isotope signature of ecosystem-respired CO. [ABSTRACT FROM AUTHOR]

Abstract: Interactions between biological control agents and how they impact on their invasive plant hosts have received little research attention. This study examined the individual and combined effects of the rust fungus Puccinia myrsiphylli (Thuem.) Wint. and an undescribed leafhopper (Tribe Erythroneurini, formerly referred to as Zygina sp.) introduced for the biological control of the invasive plant bridal creeper (Asparagus asparagoides (L.) Druce) in Australia. Bridal creeper is a geophyte with extensive rhizomes and tubers from which climbing foliage is produced annually. The response of individual bridal creeper plants following exposure to the agents was measured in exclusion experiments in a glasshouse (using cages) and in the field (using pesticides). In the glasshouse experiment, the two agents acting together had an additive impact on all growth parameters measured, except the above-ground biomass for which an effect equivalent to that caused by the rust fungus alone was observed. The agents acted synergistically in reducing the relative growth rate of rhizome length, tuber number and tuber biomass. Depletion of storage organs occurred in treatments comprising the rust fungus solely or both agents. While phytotoxicity occurred in treatments involving insecticide applications in the field experiment, results from the other treatments corresponded with those of the glasshouse experiment. In both experiments, leafhopper damage decreased as infection by the rust fungus increased. This study provides additional evidence of the potential gains to be made from deploying multiple biological control agents where they can partition the target resources in space and/or time. [ABSTRACT FROM AUTHOR]

Abstract: Seasonal and annual variations of rainfall and humidity are recorded in the carbon and oxygen stable isotope ratios of sequentially grown spines found on the columnar cactus, Carnegiea gigantea. A 26-year long composite δ 18O and δ 13C isotope record from the spines of five saguaro cacti was created using bomb radiocarbon and semi-annual variations in δ 13C. Once dating errors in the composite record are corrected, mean annual spine δ 18O is negatively correlated (P <0.001) with total annual precipitation (TAP) from November through October and positively correlated (P <0.01) with mean annual nighttime vapor pressure deficit (VPD). Year-to-year decreases (>2‰) in the maximum annual spine δ 18O are positively correlated (P <0.01) with the Southern Oscillation Index (SOI). We attribute these decreases to enhanced winter rainfall associated with the El Niño phase of the El Niño-Southern Oscillation. Minimum annual δ 13C is negatively correlated with TAP (P <0.05) and mean nighttime VPD (P <0.05). These results bolster proposed mechanistic models of isotopic variation in the spines of columnar cactus and demonstrate how isotopic spine series may be used as climate proxies in regions of the Americas where trees suitable for traditional or isotopic dendrochonology are absent. [Copyright &y& Elsevier]

Attract and kill (A&K) is an effective control technique for Carpophilus spp. attacking stone fruit but high cost has limited its adoption by growers. Field experiments during two successive growing seasons evaluated the potential to reduce the spatial density of A&K traps from three traps per ha (3 A&K) to two traps per ha (2 A&K), against medium to low beetle populations. Fruit damage in 2 A&K and 3 A&K treated blocks was significantly lower than in pesticide-treated control blocks. However there were no significant differences in blocks treated with either 2 A&K or 3 A&K traps in either season. The results suggest that the number of traps per ha can be reduced without reducing the efficacy of the A&K treatment where Carpophilus population levels are medium to low. [ABSTRACT FROM AUTHOR]

We evaluated diurnal and seasonal patterns of carbon isotope composition of leaf dark-respired CO2 ( δ13Cl) in the C3 perennial shrub velvet mesquite ( Prosopis velutina) across flood plain and upland savanna ecosystems in the south-western USA. δ13Cl of darkened leaves increased to maximum values late during daytime periods and declined gradually over night-time periods to minimum values at pre-dawn. The magnitude of the diurnal shift in δ13Cl was strongly influenced by seasonal and habitat-related differences in soil water availability and leaf surface vapour pressure deficit. δ13Cl and the cumulative flux-weighted δ13C value of photosynthates were positively correlated, suggesting that progressive 13C enrichment of the CO2 evolved by darkened leaves during the daytime mainly resulted from short-term changes in photosynthetic 13C discrimination and associated shifts in the δ13C signature of primary respiratory substrates. The 13C enrichment of dark-respired CO2 relative to photosynthates across habitats and seasons was 4 to 6‰ at the end of the daytime period (1800 h), but progressively declined to 0‰ by pre-dawn (0300 h). The origin of night-time and daytime variations in δ13Cl is discussed in terms of the carbon source(s) feeding respiration and the drought-induced changes in carbon metabolism. [ABSTRACT FROM AUTHOR]

Climate change predictions for the desert southwestern U.S. are for shifts in precipitation patterns. The impacts of climate change may be significant, because desert soil processes are strongly controlled by precipitation inputs (“pulses”) via their effect on soil water availability. This study examined the response of soil respiration—an important biological process that affects soil carbon (C) storage—to variation in pulses representative of climate change scenarios for the Sonoran Desert. Because deserts are mosaics of different plant cover types and soil textures—which create patchiness in soil respiration—we examined how these landscape characteristics interact to affect the response of soil respiration to pulses. Pulses were applied to experimental plots of bare and vegetated soil on contrasting soil textures typical of Sonoran Desert grasslands. The data were analyzed within a Bayesian framework to: (1) determine pulse size and antecedent moisture (soil moisture prior to the pulse) effects on soil respiration, (2) quantify soil texture (coarse vs. fine) and cover type (bare vs. vegetated) effects on the response of soil respiration and its components (plant vs. microbial) to pulses, and (3) explore the relationship between long-term variation in pulse regimes and seasonal soil respiration. Regarding objective (1), larger pulses resulted in higher respiration rates, particularly from vegetated fine-textured soil, and dry antecedent conditions amplified respiration responses to pulses (wet antecedent conditions dampened the pulse response). Regarding (2), autotrophic (plant) activity was a significant source (∼60%) of respiration and was more sensitive to pulses on coarse- versus fine-textured soils. The sensitivity of heterotrophic (microbial) respiration to pulses was highly dependent on antecedent soil water. Regarding (3), seasonal soil respiration was predicted to increase with both growing season precipitation and mean pulse size (but only for pulses between 7 and 25 mm). Thus, the heterogeneity of the desert landscape and the timing or the number of medium-sized pulses is expected to significantly impact desert soil C loss with climate change. [ABSTRACT FROM AUTHOR]

Across many dryland regions, historically grass-dominated ecosystems have been encroached upon by woody-plant species. In this paper, we compare ecosystem water and carbon dioxide (CO2) fluxes over a grassland, a grassland–shrubland mosaic, and a fully developed woodland to evaluate potential consequences of woody-plant encroachment on important ecosystem processes. All three sites were located in the riparian corridor of a river in the southwest US. As such, plants in these ecosystems may have access to moisture at the capillary fringe of the near-surface water table. Using fluxes measured by eddy covariance in 2003 we found that ecosystem evapotranspiration (ET) and net ecosystem exchange of carbon dioxide (NEE) increased with increasing woody-plant dominance. Growing season ET totals were 407, 450, and 639 mm in the grassland, shrubland, and woodland, respectively, and in excess of precipitation by 227, 265, and 473 mm. This excess was derived from groundwater, especially during the extremely dry premonsoon period when this was the only source of moisture available to plants. Access to groundwater by the deep-rooted woody plants apparently decouples ecosystem ET from gross ecosystem production (GEP) with respect to precipitation. Compared with grasses, the woody plants were better able to use the stable groundwater source and had an increased net CO2 gain during the dry periods. This enhanced plant activity resulted in substantial accumulation of leaf litter on the soil surface that, during rainy periods, may lead to high microbial respiration rates that offset these photosynthetic fluxes. March–December (primary growing season) totals of NEE were −63, −212, and −233 g C m−2 in the grassland, shrubland, and woodland, respectively. Thus, there was a greater disparity between ecosystem water use and the strength of the CO2 sink as woody plants increased across the encroachment gradient. Despite a higher density of woody plants and a greater plant productivity in the woodland than in the shrubland, the woodland produced a larger respiration response to rainfall that largely offset its higher photosynthetic potential. These data suggest that the capacity for woody plants to exploit water resources in riparian areas results in enhanced carbon sequestration at the expense of increased groundwater use under current climate conditions, but the potential does not scale specifically as a function of woody-plant abundance. These results highlight the important roles of water sources and ecosystem structure on the control of water and carbon balances in dryland areas. [ABSTRACT FROM AUTHOR]

Drug overdoses are a national and global epidemic. However, while overdoses are inextricably linked to social, demographic, and geographical determinants, geospatial patterns of drug-related admissions and overdoses at the neighborhood level remain poorly studied. The objective of this paper is to investigate spatial distributions of patients admitted for drug-related admissions and overdoses from a large, urban, tertiary care center using electronic health record data. Additionally, these spatial distributions were adjusted for a validated socioeconomic index called the Area Deprivation Index (ADI). We showed spatial heterogeneity in patients admitted for opioid, amphetamine, and psychostimulant-related diagnoses and overdoses. While ADI was associated with drug-related admissions, it did not correct for spatial variations and could not account alone for this spatial heterogeneity. [ABSTRACT FROM AUTHOR]

Premise: The impact of elevated CO2 concentration ([CO2]) and climate warming on plant productivity in dryland ecosystems is influenced strongly by soil moisture availability. We predicted that the influence of warming on the stimulation of photosynthesis by elevated [CO2] in prairie plants would operate primarily through direct and indirect effects on soil water. Methods: We measured light‐saturated photosynthesis (Anet), stomatal conductance (gs), maximum Rubisco carboxylation rate (Vcmax), maximum electron transport capacity (Jmax) and related variables in four C3 plant species in the Prairie Heating and CO2 Enrichment (PHACE) experiment in southeastern Wyoming. Measurements were conducted over two growing seasons that differed in the amount of precipitation and soil moisture content. Results: Anet in the C3 subshrub Artemisia frigida and the C3 forb Sphaeralcea coccinea was stimulated by elevated [CO2] under ambient and warmed temperature treatments. Warming by itself reduced Anet in all species during the dry year, but stimulated photosynthesis in S. coccinea in the wet year. In contrast, Anet in the C3 grass Pascopyrum smithii was not stimulated by elevated [CO2] or warming under wet or dry conditions. Photosynthetic downregulation under elevated [CO2] in this species countered the potential stimulatory effect under improved water relations. Warming also reduced the magnitude of CO2‐induced down‐regulation in this grass, possibly by sustaining high levels of carbon utilization. Conclusions: Direct and indirect effects of elevated [CO2] and warming on soil water was an overriding factor influencing patterns of Anet in this semi‐arid temperate grassland, emphasizing the important role of water relations in driving grassland responses to global change. [ABSTRACT FROM AUTHOR]

Resprouting is an ancestral trait in angiosperms that confers resilience after perturbations. As climate change increases stress, resprouting vigor is declining in many forest regions, but the underlying mechanism is poorly understood. Resprouting in woody plants is thought to be primarily limited by the availability of non‐structural carbohydrate reserves (NSC), but hydraulic limitations could also be important. We conducted a multifactorial experiment with two levels of light (ambient, 2–3% of ambient) and three levels of water stress (0, 50 and 80 percent losses of hydraulic conductivity, PLC) on two Mediterranean oaks (Quercus ilex and Q. faginea) under a rain‐out shelter (n = 360). The proportion of resprouting individuals after canopy clipping declined markedly as PLC increased for both species. NSC concentrations affected the response of Q. ilex, the species with higher leaf construction costs, and its effect depended on the PLC. The growth of resprouting individuals was largely dependent on photosynthetic rates for both species, while stored NSC availability and hydraulic limitations played minor and non‐significant roles, respectively. Contrary to conventional wisdom, our results indicate that resprouting in oaks may be primarily driven by complex interactions between hydraulics and carbon sources, whereas stored NSC play a significant but secondary role. Here we show that root non‐structural carbohydrate reserves only play a minor role as drivers of basal resprouting in Mediterranean oaks. The probability of resprouting was mostly driven by the degree of antecedent hydraulic limitations and the growth of the resprouts depended largely on photosynthetic C uptake. [ABSTRACT FROM AUTHOR]

Presents a study which investigated some generalizations regarding organic planning, a form of citizen participation in local governance. Promotion and deliberation, a public participation in policy deliberation; Emergence of citizen participation through organic planning; Conclusions.

The plant family Cactaceae is considered among the most threatened groups of organisms on the planet. The threatened status of the cacti family has created a renewed interest in the highly evolved physiological and morphological traits that underpin their persistence in some of the harshest subtropical environments in the Americas. Among the most important anatomical features of cacti is the modification of leaves into spines, and previous work has shown that the stable isotope chemistry of cacti spines records potential variations in stem water balance, stress, and Crassulacean acid metabolism (CAM). We review the opportunities, challenges, and pitfalls in measuring δ 13C, δ 2H, and δ 18O ratios captured in spine tissues that potentially reflect temporal and spatial patterns of stomatal conductance, internal to atmospheric CO2 partial pressures, and subsequent patterns of photosynthetic gas exchange. We then evaluate the challenges in stable isotope analysis in spine tissues related to variation in CAM expression, stem water compartmentalization, and spine whole-tissue composition among other factors. Finally, we describe how the analysis of all three isotopes can be used in combination to provide potentially robust analysis of photosynthetic function in cacti, and other succulent-stemmed taxa across broad spatio-temporal environmental gradients. [ABSTRACT FROM AUTHOR]