Phosphorus and water supply independently control productivity and soil enzyme activity responses to elevated CO2 in an understorey community from a Eucalyptus woodland

Aims While it is well-established that nitrogen (N) availability regulates elevated [CO2] (eCO(2)) effects on plant growth and soil carbon (C) storage in N-limited environments, there are fewer studies investigating the role of phosphorous (P) supply on such responses in P-limited environments. In this study, we explored whether P fertilization influences the response of plant growth, soil enzyme activity and C fluxes to eCO(2), and determined how different levels of water availability regulate these processes. Methods We used soil collected from a temperate, P-limited Eucalyptus woodland containing the native soil seed bank to grow a potted replica of local understory communities. We exposed the emerging communities to eCO(2) under two contrasting water levels and two levels of P fertilization. We assessed plant biomass allocation, the rhizosphere activity of extracellular enzymes related to C, N and P cycles, and pot-level CO2 fluxes. Results The positive effects of eCO(2) on plant production and ecosystem C dynamics were strongly constrained by low levels of P availability. Enhanced water supply increased rhizosphere enzyme activity with minor impacts on plant biomass responses to eCO(2.) Our data also suggest that plant and microbial mechanisms that increase nutrient release from SOM may not be able to overcome this P limitation. Conclusions While current Earth System Models predict positive feedback responses of terrestrial ecosystems on C storage under eCO(2), here we emphasize the importance of accounting for the widespread phenomenon of P-limitation in such responses

Plant Multi-element Coupling as an Indicator of Nutritional Mismatches Under Global Change

Global biogeochemical cycles have been widely altered due to human activities, potentially compromising the ability of plants to regulate their metabolism. We grew experimental herbaceous communities simulating the understory of eucalypt forests from southeastern Australia to evaluate the effects of elevated CO2 (400 vs. 650 ppm) and changes in soil resource availability (high-low water and high-low P) on the concentration of fourteen essential plant macro- and micronutrients, and their degree of coupling. Coupling was based on correlations among all elements in absolute value and a null modeling approach. According to the ancient nature of Australian soils, P addition was the main driver of changes in plant tissue chemistry, increasing the concentrations of P, Mg, Ca, and Mn and reducing the concentrations of C, N, S, Na, and Cu. Most treatment combinations showed coupled patterns of plant elements, particularly under ambient CO2. However, under elevated CO2, elements in plant tissues became more decoupled, which was interpreted as the result of a lack of enough supply of a range of elements to satisfy greater demands. Across treatments, P, Mn, and N were the least coupled elements, while K, Ca, and Fe were the most coupled ones. We provide evidence that plant element coupling was positively related to the concentration and coupling of elements measured in soils worldwide, suggesting that plant element coupling is conserved. Our results provide compelling evidence that evaluating the coupling of a representative range of chemical elements in plant tissues may represent a highly novel and powerful indicator of nutritional mismatches between demand and supply under specific environmental circumstances, including in a resource-altered global change context

Comment on: "The Casimir force on a piston in the spacetime with extra compactified dimensions" [Phys. Lett. B 668 (2008) 72]

We offer a clarification of the significance of the indicated paper of H. Cheng. Cheng's conclusions about the attractive nature of Casimir forces between parallel plates are valid beyond the particular model in which he derived them; they are likely to be relevant to other recent literature on the effects of hidden dimensions on Casimir forces.Comment: 6 pages, 1 figur

Altered precipitation and root herbivory affect the productivity and composition of a mesic grassland

Background Climate change models predict changes in the amount, frequency and seasonality of precipitation events, all of which have the potential to affect the structure and function of grassland ecosystems. While previous studies have examined plant or herbivore responses to these perturbations, few have examined their interactions; even fewer have included belowground herbivores. Given the ecological, economic and biodiversity value of grasslands, and their importance globally for carbon storage and agriculture, this is an important knowledge gap. To address this, we conducted a precipitation manipulation experiment in a former mesic pasture grassland comprising a mixture of C-4 grasses and C-3 grasses and forbs, in southeast Australia. Rainfall treatments included a control [ambient], reduced amount [50% ambient] and reduced frequency [ambient rainfall withheld for three weeks, then applied as a single deluge event] manipulations, to simulate predicted changes in both the size and frequency of future rainfall events. In addition, half of all experimental plots were inoculated with adult root herbivores (Scarabaeidae beetles). Results We found strong seasonal dependence in plant community responses to both rainfall and root herbivore treatments. The largest effects were seen in the cool season with lower productivity, cover and diversity in rainfall-manipulated plots, while root herbivore inoculation increased the relative abundance of C-3, compared to C-4, plants. Conclusions This study highlights the importance of considering not only the seasonality of plant responses to altered rainfall, but also the important role of interactions between abiotic and biotic drivers of vegetation change when evaluating ecosystem-level responses to future shifts in climatic conditions.This work was partially supported by a Higher Degree Research Scholarship from the Hawkesbury Institute for the Environment at Western Sydney University. Additional funding came from a project grant to SAP and SNJ from the Hermon Slade Foundation (P00021516) and funding provided by Western Sydney University. The Western Sydney University Library provided financial assistance for open access publication fees. Documen

Microbial competition for phosphorus limits the CO2 response of a mature forest

The capacity for terrestrial ecosystems to sequester additional carbon (C) with rising CO2 concentrations depends on soil nutrient availability1,2. Previous evidence suggested that mature forests growing on phosphorus (P)-deprived soils had limited capacity to sequester extra biomass under elevated CO2 (refs. 3–6), but uncertainty about ecosystem P cycling and its CO2 response represents a crucial bottleneck for mechanistic prediction of the land C sink under climate change7. Here, by compiling the first comprehensive P budget for a P-limited mature forest exposed to elevated CO2, we show a high likelihood that P captured by soil microorganisms constrains ecosystem P recycling and availability for plant uptake. Trees used P efficiently, but microbial pre-emption of mineralized soil P seemed to limit the capacity of trees for increased P uptake and assimilation under elevated CO2 and, therefore, their capacity to sequester extra C. Plant strategies to stimulate microbial P cycling and plant P uptake, such as increasing rhizosphere C release to soil, will probably be necessary for P-limited forests to increase C capture into new biomass. Our results identify the key mechanisms by which P availability limits CO2 fertilization of tree growth and will guide the development of Earth system models to predict future long-term C storage

VICTOR: Vinflunine in advanced metastatic transitional cell carcinoma of the urothelium: A retrospective analysis of the use of vinflunine in multi-centre real life setting as second line chemotherapy through Free of Charge Programme for patients in the UK and Ireland

There is no standard of care in the UK or Ireland for second-line chemotherapy for patients with advanced transitional cell carcinoma (TCCU). Vinflunine is approved for TCCU patients who have failed a platinum-based regimen, and is standard of care in Europe but is not routinely available in the UK. Data were collected retrospectively on patients who received vinfluine as a second-line treatment. The aims were to document the toxicity and efficacy in a real life setting. Data were collected on 49 patients from 9 sites across the UK and Ireland [median age, 64 (IQR, 57-70) years, 33 males]. All patients had advanced metastatic TCCU. Thirteen patients had bone or liver metastases, 4 patients had PS 2 and 11 patients had HB <10. Median vinflunine administration was 3.5 cycles (range 1-18). Most common grade 3-4 toxicities were constipation (4 patients) and fatigue (3 patients). Partial response rate was 29% (14 PR, 11 SD, 19 PD, 4 NE, 1 not available). Median OS was 9.1 (6.0, 12.7) months. Results are consistent with real life data from Europe. Toxicity is further reduced with prophylactic laxative and oral antibiotics. Vinflunine is an efficient and tolerable second line treatment in advanced TCCU

A framework to measure the wildness of managed large vertebrate populations

As landscapes continue to fall under human influence through habitat loss and fragmentation, fencing is increasingly being used to mitigate anthropogenic threats and enhance the commercial value of wildlife. Subsequent intensification of management potentially erodes wildness by disembodying populations from landscape‐level processes, thereby disconnecting species from natural selection. Tools are needed to measure the degree to which populations of large vertebrate species in formally protected and privately owned wildlife areas are self‐sustaining and free to adapt. We devised a framework to measure such wildness based on 6 attributes relating to the evolutionary and ecological dynamics of vertebrates (space, disease and parasite resistance, exposure to predation, exposure to limitations and fluctuations of food and water supply, and reproduction). For each attribute, we set empirical, species‐specific thresholds between 5 wildness states based on quantifiable management interventions. We analysed data from 205 private wildlife properties with management objectives spanning ecotourism to consumptive utilization to test the framework on 6 herbivore species representing a range of conservation statuses and commercial values. Wildness scores among species differed significantly, and the proportion of populations identified as wild ranged from 12% to 84%, which indicates the tool detected site‐scale differences both among populations of different species and populations of the same species under different management regimes. By quantifying wildness, this framework provides practitioners with standardized measurement units that link biodiversity with the sustainable use of wildlife. Applications include informing species management plans at local scales; standardizing the inclusion of managed populations in red‐list assessments; and providing a platform for certification and regulation of wildlife‐based economies. Applying this framework may help embed wildness as a normative value in policy and mitigate the shifting baseline of what it means to truly conserve a species.The South African National Biodiversity Institute, the Department of Environmental Affairs, E Oppenheimer & Son and De Beers Group of Companies, and the Endangered Wildlife Trust that funded the national Mammal Red List project. The University of Pretoria and the South African National Biodiversity Institute provided M.C. with funding.https://conbio.onlinelibrary.wiley.com/journal/152317392020-10-01hj2019Centre for Wildlife ManagementMammal Research InstituteZoology and Entomolog

Impacto da adubação orgânica sobre a incidência de tripes em cebola.

Analisou-se a relação entre adubação orgânica e a incidência de Thrips tabaci Lind. em cebola (Allium cepa L), na EE de Ituporanga,entre agosto e dezembro de 1998. Os tratamentos foram determinados de acordo com a necessidade de N para a cultura pela análise de solo. Empregou-se como fonte orgânica diversos adubos fornecendo 75 Kg/ha de N (esterco suíno; adubo Barriga Verde proveniente de esterco de aves; composto orgânico; esterco de peru; húmus); 37,5 Kg/ha de N (metade da dose normal com esterco de suíno); as testemunhas foram adubação mineral fornecendo 30-120-60 kg/ha de N-P2O5-K2O e o dobro da dose (60-240-120 kg/ha de N-P2O5-K2O); e testemunha sem adubação. Nenhum tratamento apresentou incidência de T. tabaci superior à testemunha sem adubo. A adubação mineral em relação à orgânica não favoreceu significativamente a incidência de T. tabaci . O processo de conversão do manejo do solo da área experimental de convencional para orgânico pode ter favorecido a infestação similar do inseto entre tratamentos. No período de maior incidência de T. tabaci, a relação com nutrientes foi descrita por um modelo envolvendo K/Zn, B e N de maneira positiva. A correlação entre nutrientes e T. tabaci não foi linear na maioria das avaliações. A adubação orgânica pode substituir a adubação mineral na cultura da cebola, pois foi possível atingir níveis de produtividade similares para ambos tratamentos

The fate of carbon in a mature forest under carbon dioxide enrichment

Atmospheric carbon dioxide enrichment (eCO2) can enhance plant carbon uptake and growth1 5, thereby providing an important negative feedback to climate change by slowing the rate of increase of the atmospheric CO2 concentration6. Although evidence gathered from young aggrading forests has generally indicated a strong CO2 fertilization effect on biomass growth3 5, it is unclear whether mature forests respond to eCO2 in a similar way. In mature trees and forest stands7 10, photosynthetic uptake has been found to increase under eCO2 without any apparent accompanying growth response, leaving the fate of additional carbon fixed under eCO2 unclear4,5,7 11. Here using data from the first ecosystem-scale Free-Air CO2 Enrichment (FACE) experiment in a mature forest, we constructed a comprehensive ecosystem carbon budget to track the fate of carbon as the forest responded to four years of eCO2 exposure. We show that, although the eCO2 treatment of +150 parts per million (+38 per cent) above ambient levels induced a 12 per cent (+247 grams of carbon per square metre per year) increase in carbon uptake through gross primary production, this additional carbon uptake did not lead to increased carbon sequestration at the ecosystem level. Instead, the majority of the extra carbon was emitted back into the atmosphere via several respiratory fluxes, with increased soil respiration alone accounting for half of the total uptake surplus. Our results call into question the predominant thinking that the capacity of forests to act as carbon sinks will be generally enhanced under eCO2, and challenge the efficacy of climate mitigation strategies that rely on ubiquitous CO2 fertilization as a driver of increased carbon sinks in global forests. © 2020, The Author(s), under exclusive licence to Springer Nature Limited