69 research outputs found
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Applied phosphorus has long-term impacts on vegetation responses in restored jarrah forest
Nutrient enrichment can result in long-term negative impacts on a range of native and semi-native plant communities worldwide. Despite this knowledge, fertiliser application is generally viewed as a necessary step in re-establishing native plant communities in post-mining restoration. However, long-term effects of nutrient addition to restored plant communities, particularly in native ecosystems that are adapted to inherently low-nutrient soils, have received little attention. Here we report results of two experiments run for 15 and 20 years, respectively, to investigate the effect of applied P fertiliser on responses of Eucalyptus marginata (jarrah) forest re-sprouter understorey species in sites restored after bauxite mining in Western Australia. Re-sprouter species are abundant in unmined forest but are under-represented in restored sites. At the end of the two experiments (i.e. after 15 and 20 years), the abundance of three groups of re-sprouter understorey species was reduced, compared with the zero-fertiliser treatment, when P fertiliser was applied at rates from 20 to 120 kg P ha-1. In both experiments, the cover associated with P responsive legumes increased with increasing P application rates. This result suggests that when fertiliser is applied, slow-growing re-sprouter species are susceptible to being outcompeted by more vigorous understorey species. Consequently, if the goal of restoration is to re-establish a diverse plant community, then minimising fertiliser application rates may be appropriate
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Enduring effects of large legumes and phosphorus fertiliser on jarrah forest restoration 15 years after bauxite mining
Restoring nutrients lost in the mining process and re-establishing nutrient-cycling are often key goals of mine restoration. One common strategy to facilitate these goals is to seed fast-growing legumes combined with one application of P-fertiliser to maximise legume growth and increase soil-N. However, the longer term effects of this strategy have received little attention. Here we report the results of a 15-year-old experiment that was established to test the effects of fertiliser-P application and seeding large understorey legumes, both singly and in combination, on jarrah forest restoration after bauxite mining.
Fifteen years after the establishment of this experiment, the majority of the seeded legumes had senesced, with total legume cover having declined significantly compared with results of the same experiment at 5-years-of-age. Yet, despite the legumes having senesced there were still negative effects of both large legumes and P-fertiliser on species richness and abundance of non-leguminous understorey species. These negative effects may be mediated by the persistent effects of legume competition that was evident at 5 years and the accumulation of significant quantities of leaf litter and fine woody debris in the large legume × P-addition treatments. Compared with the 0 kg P ha−1 treatment, application of 20 kg P ha−1 significantly increased jarrah tree growth, but there was no additional benefit of 80 kg P ha−1. These data suggest that moderation of P-fertiliser and large understorey legumes could maximise understorey cover, tree growth and understorey species richness, and therefore simultaneously address multiple key restoration goals
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Initial conditions can have long-term effects on plant species diversity in jarrah forest restored after bauxite mining
Much of the remarkable plant species diversity of the Southwest Australian Floristic Region can be attributed to high diversity of the understorey in its forests and woodlands, including 400–600 understorey species per km2 in the Northern Jarrah Forest alone. Consequently, returning species diversity is a key challenge for postmining ecological restoration in the region. Each year, Alcoa of Australia undertakes restoration of mined areas within the Northern Jarrah Forest with a goal of returning a self-sustaining jarrah forest ecosystem. To meet this goal, it is important to understand long-term (i.e. > 20 years) trajectories of vegetation development and the restoration practices that direct species diversity outcomes. Here, we report the results of several experiments, the oldest of which is 45 years of age, which together demonstrate significant longer-term effects on understorey species diversity of restoration practices determining initial conditions including topsoil handling, fertiliser application, seeding rates of large legumes, and tree (overstorey) species stocking rates. Our research highlights (1) that ‘historical contingency’ can determine the trajectory of jarrah forest restoration and (2) that longer-term studies are critical as they give a different, sometimes conflicting, perspective to short-term datasets. Notably, after 27 years, we found an inverse relationship between plant cover and P fertilisation, where plant cover was highest in the in the absence of P fertiliser and lowest at the uppermost P amendment rate. We also found that the long-accepted Initial Floristics Model of succession does not fit well with our data. Our overall findings are likely useful to restore understorey diversity to woodlands, forests, and abandoned farmlands elsewhere in the region
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Nutrient enrichment diminishes plant diversity and density, and alters long-term ecological trajectories, in a biodiverse forest restoration
Nutrient enrichment can negatively affect natural plant communities and result in the loss of species diversity and productivity. Despite this, fertiliser (especially phosphorus) is typically applied to restore highly biodiverse communities. Long-term effects of nutrient addition to restored plant communities, particularly those adapted to inherently low nutrient soils, have received little attention. We report results of a large-scale 20-year field experiment established in West Australian jarrah forest restored after bauxite mining Three P-application rates were applied (0, 80 and 120 kg ha−1) once at the beginning of the experiment, and plant communities monitored after 1, 6, 13 and 20 years. One year after the onset of restoration, native plant species richness and plant density was highest at 80 and 120 kg P ha−1. Subsequently, native species richness, plant density, and the richness and density of seeder and slow-growing resprouter species were highest without fertilisation, establishing the negative impact of P enrichment on plant community and ecosystem development in P impoverished soils. Total plant cover was similar for all P treatments across the chronosequence which, when combined with higher stem densities at zero P, suggests zero P favoured smaller, slower growing species. Applied-P initially favoured weeds and ephemerals and, while these species declined over time, other species were lost from these plots. The similarity of the restored communities to unmined reference jarrah forest increased over time and was consistently highest at in the absence of P fertiliser. Jarrah forest restoration is assumed to follow the initial floristic model of plant succession. However, we question this assumption and instead suggest that successional outcomes are contingent on P fertilisation rather than initial floristics per se. Applied P retarded recruitment of resprouter species that were present at zero P, debunking the assumption under IFM that these species do not disperse to restored areas. Consequently, based on the most comprehensive long-term study of P-fertilisation in the context of restoration of P-impoverished ecosystems yet reported, we propose that P limitation is important for the recreation of species diversity in inherently P impoverished forests. These results highlight the necessity of long-term experiments for understanding forest successional dynamics and implications for restoration practices
Development of Core Outcome Measures sets for paediatric and adult Severe Asthma (COMSA)
BACKGROUND: Effectiveness studies with biological therapies for asthma lack standardised outcome measures. The COMSA (Core Outcome Measures sets for paediatric and adult Severe Asthma) working group sought to develop Core Outcome Measures (COM) sets to facilitate better synthesis of data and appraisal of biologics in paediatric and adult asthma clinical studies.METHODS: COMSA utilised a multi-stakeholder consensus process among patients with severe asthma, adult, and paediatric clinicians, pharmaceutical representatives and health regulators from across Europe. Evidence included a systematic review of development, validity, and reliability of selected outcome measures plus a narrative review and a pan-European survey to better understand patients' and carers' views about outcome measures. It was discussed using a modified GRADE Evidence to Decision framework. Anonymous voting was conducted using predefined consensus criteria.RESULTS: Both adult and paediatric COM sets include forced expiratory volume in 1 s (FEV1) as z scores, annual frequency of severe exacerbations and maintenance oral corticosteroid use. Additionally, the paediatric COM set includes the Paediatric Asthma Quality of Life Questionnaire, and Asthma Control Test (ACT) or Childhood-ACT while the adult COM includes the Severe Asthma Questionnaire and the Asthma Control Questionnaire-6 (symptoms and rescue medication use reported separately).CONCLUSIONS: This patient-centred collaboration has produced two COM sets for paediatric and adult severe asthma. It is expected that they will inform the methodology of future clinical trials, enhance comparability of efficacy and effectiveness of biological therapies, and help assess their socioeconomic value. COMSA will inform definitions of non-response and response to biological therapy for severe asthma.</p
Idarubicin dose escalation during consolidation therapy for adult acute myeloid leukemia
Purpose Higher doses of the anthracycline daunorubicin during induction therapy for acute myeloid leukemia (AML) have been shown to improve remission rates and survival. We hypothesized that improvements in outcomes in adult AML may be further achieved by increased anthracycline dose during consolidation therapy. Patients and Methods Patients with AML in complete remission after induction therapy were randomly assigned to receive two cycles of consolidation therapy with cytarabine 100 mg/m daily for 5 days, etoposide 75 mg/m daily for 5 days, and idarubicin 9 mg/m daily for either 2 or 3 days (standard and intensive arms, respectively). The primary end point was leukemia-free survival (LFS). Results Two hundred ninety-three patients 16 to 60 years of age, excluding those with core binding factor AML and acute promyelocytic leukemia, were randomly assigned to treatment groups (146 to the standard arm and 147 to the intensive arm). Both groups were balanced for age, karyotypic risk, and FLT3–internal tandem duplication and NPM1 gene mutations. One hundred twenty patients in the standard arm (82%) and 95 patients in the intensive arm (65%) completed planned consolidation (P, .001). Durations of severe neutropenia and thrombocytopenia were prolonged in the intensive arm, but there were no differences in serious nonhematological toxicities. With a median follow-up of 5.3 years (range, 0.6 to 9.9 years), there was a statistically significant improvement in LFS in the intensive arm compared with the standard arm (3-year LFS, 47% [95% CI, 40% to 56%] v 35% [95% CI, 28% to 44%]; P = .045). At 5 years, the overall survival rate was 57% in the intensive arm and 47% in the standard arm (P = .092). There was no evidence of selective benefit of intensive consolidation within the cytogenetic or FLT3–internal tandem duplication and NPM1 gene mutation subgroups. Conclusion An increased cumulative dose of idarubicin during consolidation therapy for adult AML resulted in improved LFS, without increased nonhematologic toxicity
Evaluating Patterns of a White-Band Disease (WBD) Outbreak in Acropora palmata Using Spatial Analysis: A Comparison of Transect and Colony Clustering
. Likewise, there is little known about the spatiality of outbreaks. We examined the spatial patterns of WBD during a 2004 outbreak at Buck Island Reef National Monument in the US Virgin Islands. colonies with and without WBD.As the search for causation continues, surveillance and proper documentation of the spatial patterns may inform etiology, and at the same time assist reef managers in allocating resources to tracking the disease. Our results indicate that the spatial scale of data collected can drastically affect the calculation of prevalence and spatial distribution of WBD outbreaks. Specifically, we illustrate that higher resolution sampling resulted in more realistic disease estimates. This should assist in selecting appropriate sampling designs for future outbreak investigations. The spatial techniques used here can be used to facilitate other coral disease studies, as well as, improve reef conservation and management
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Analysis combining correlated glaucoma traits identifies five new risk loci for open-angle glaucoma
Open-angle glaucoma (OAG) is a major cause of blindness worldwide. To identify new risk loci for OAG, we performed a genome-wide association study in 3,071 OAG cases and 6,750 unscreened controls, and meta-analysed the results with GWAS data for intraocular pressure (IOP) and optic disc parameters (the overall meta-analysis sample size varying between 32,000 to 48,000 participants), which are glaucoma-related traits. We identified and independently validated four novel genome-wide significant associations within or near MYOF and CYP26A1, LINC02052 and CRYGS, LMX1B, and LMO7 using single variant tests, one additional locus (C9) using gene-based tests, and two genetic pathways - “response to fluid shear stress” and “abnormal retina morphology” - in pathway-based tests. Interestingly, some of the new risk loci contribute to risk of other genetically-correlated eye diseases including myopia and age-related macular degeneration. To our knowledge, this study is the first integrative study to combine genetic data from OAG and its correlated traits to identify new risk variants and genetic pathways, highlighting the future potential of combining genetic data from genetically-correlated eye traits for the purpose of gene discovery and mapping
Hydrological response to bauxite mining and rehabilitation in the jarrah forest in south west Australia
Study region: Jarrah forest in south west Australia.
Study focus: The hydrological response to bauxite mining in the jarrah forest could differ from other land uses such as timber harvesting or clearing for agriculture, since mining involves excavation of the upper regolith in addition to changes in forest cover due to clearing and subsequent rehabilitation. Three catchments, one subject to mining, a second subject to an intensive forest thinning treatment and an untreated control were monitored for streamflow, rainfall, groundwater and leaf area index over a 36-year period.
New hydrological insights for the region: Mining caused a peak streamflow response of 225 mm or 18% of rainfall, before returning to pre-disturbance levels 11 years after mining commenced. Streamflow changes were closely associated with changes in a groundwater discharge area in the valley floor. Changes in groundwater level, in turn, were related to rainfall and leaf area index, and these effects did not differ between mine rehabilitation and unmined catchment areas. The streamflow response to mining could not be distinguished from the intensive thinning treatment in this study, or from clearfelling or clearing for agriculture reported elsewhere in the jarrah forest. The results indicate that shallow subsurface flow processes, considered to dominate streamflow generation in jarrah forest catchments, do not extend beyond the valley floor and immediately adjacent slopes which were not disturbed by mining
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