Projected climate change implications for the South Australian flora

South Australia has warmed since 1950 and further temperature increases are forecast this century. We explore the implications of climatic warming for individual plant species and the State’s plant biodiversity, which is significant and includes 418 endemic taxa. Environmental constraints and interspecific interactions operate on species to determine which survive in which environment, with resulting compositional signatures. Climate change influences such ‘filtering’ processes via mechanisms such as altered mortality or recruitment rates and indirectly through fire regimes. While modest environmental changes can be absorbed within a given ecological community, significant change will eventually drive species turnover. We use the Hopbush, Dodonaea viscosa subsp. angustissima (DC.) J.G.West as a case study that shows morphological adaptations to arid conditions (narrower leaves and higher stomatal densities), observed in more northern populations in South Australia. Leaves of this species have narrowed through time in conjunction with climatic warming, matching predictions from the spatial cline. Genomic sequencing has also revealed genetic correlations with temperature and aridity, suggesting key climate change variables are impacting the selection of functional genes including those linked to leaf characters. Despite such adaptations in individual species, plant community composition is sensitive to small changes in climate. As a result, predicted climatic changes may ultimately drive complete species turnover, if the more severe scenarios are realised. Spatial analysis highlights a climatic transition zone, between desert and Mediterranean South Australia, where community composition changes more rapidly with climate and this area is therefore likely to be more vulnerable to climate change. Notwithstanding potential evolutionary adaptation, significant climate change will influence ecophysiology, leading to changes in primary productivity and water stress and is predicted to ultimately lead to lower species richness, altered species composition and more uneven abundances. Although we have an empirical understanding of climate sensitivity for South Australian plant communities, we need sophisticated ecological forecasting that considers complex interactions with fire, habitat configuration and evolutionary adaptation.G.R. Guerin, M.J. Christmas, B. Sparrow, A.J. Low

Para-infectious brain injury in COVID-19 persists at follow-up despite attenuated cytokine and autoantibody responses

To understand neurological complications of COVID-19 better both acutely and for recovery, we measured markers of brain injury, inflammatory mediators, and autoantibodies in 203 hospitalised participants; 111 with acute sera (1–11 days post-admission) and 92 convalescent sera (56 with COVID-19-associated neurological diagnoses). Here we show that compared to 60 uninfected controls, tTau, GFAP, NfL, and UCH-L1 are increased with COVID-19 infection at acute timepoints and NfL and GFAP are significantly higher in participants with neurological complications. Inflammatory mediators (IL-6, IL-12p40, HGF, M-CSF, CCL2, and IL-1RA) are associated with both altered consciousness and markers of brain injury. Autoantibodies are more common in COVID-19 than controls and some (including against MYL7, UCH-L1, and GRIN3B) are more frequent with altered consciousness. Additionally, convalescent participants with neurological complications show elevated GFAP and NfL, unrelated to attenuated systemic inflammatory mediators and to autoantibody responses. Overall, neurological complications of COVID-19 are associated with evidence of neuroglial injury in both acute and late disease and these correlate with dysregulated innate and adaptive immune responses acutely

Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

Background: Many patients with COVID-19 have been treated with plasma containing anti-SARS-CoV-2 antibodies. We aimed to evaluate the safety and efficacy of convalescent plasma therapy in patients admitted to hospital with COVID-19. Methods: This randomised, controlled, open-label, platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]) is assessing several possible treatments in patients hospitalised with COVID-19 in the UK. The trial is underway at 177 NHS hospitals from across the UK. Eligible and consenting patients were randomly assigned (1:1) to receive either usual care alone (usual care group) or usual care plus high-titre convalescent plasma (convalescent plasma group). The primary outcome was 28-day mortality, analysed on an intention-to-treat basis. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936. Findings: Between May 28, 2020, and Jan 15, 2021, 11558 (71%) of 16287 patients enrolled in RECOVERY were eligible to receive convalescent plasma and were assigned to either the convalescent plasma group or the usual care group. There was no significant difference in 28-day mortality between the two groups: 1399 (24%) of 5795 patients in the convalescent plasma group and 1408 (24%) of 5763 patients in the usual care group died within 28 days (rate ratio 1·00, 95% CI 0·93–1·07; p=0·95). The 28-day mortality rate ratio was similar in all prespecified subgroups of patients, including in those patients without detectable SARS-CoV-2 antibodies at randomisation. Allocation to convalescent plasma had no significant effect on the proportion of patients discharged from hospital within 28 days (3832 [66%] patients in the convalescent plasma group vs 3822 [66%] patients in the usual care group; rate ratio 0·99, 95% CI 0·94–1·03; p=0·57). Among those not on invasive mechanical ventilation at randomisation, there was no significant difference in the proportion of patients meeting the composite endpoint of progression to invasive mechanical ventilation or death (1568 [29%] of 5493 patients in the convalescent plasma group vs 1568 [29%] of 5448 patients in the usual care group; rate ratio 0·99, 95% CI 0·93–1·05; p=0·79). Interpretation: In patients hospitalised with COVID-19, high-titre convalescent plasma did not improve survival or other prespecified clinical outcomes. Funding: UK Research and Innovation (Medical Research Council) and National Institute of Health Research

Increased genetic diversity via gene flow provides hope for Acacia whibleyana, an endangered wattle facing extinction

In this paper we apply a conservation genomics approach to make evidence-based management recommendations for Acacia whibleyana, an endangered shrub endemic to Eyre Peninsula, South Australia. We used population genomic analysis to assess genetic connectivity, diversity, and historical inbreeding across all known stands of the species sampling remnant stands, revegetated stands of unknown origin, and a post-fire seedling cohort. Our results indicate a degree of historical connectivity across the landscape, but habitat loss and/or pollinator community disruption are potential causes of strong genetic structure across the remnant stands. Remnant stands had low genetic diversity and showed evidence of historical inbreeding, but only low levels of intra-stand relatedness indicating that risks of contemporary inbreeding are low. Analysis of a post-fire first generation cohort of seedlings showed they likely resulted from intra-stand matings, resulting in reduced genetic diversity compared to the parents. However, admixed seedlings in this cohort showed an increase in heterozygosity relative to likely sources and the non-admixed seedlings of the same stand. Assisted inter-stand gene flow may prove an effective management strategy to boost heterozygosity and corresponding increases in adapting capacity in this endangered species.Colette Blyth, Matthew J. Christmas, Doug C. Bickerton, Renate Faast, Jasmin G. Packer, Andrew J. Lowe and Martin F. Bree