2018–2019: return of the 1920s drought across the Australian drylands and savannas, soil and vegetation responses, and the carbon cycle — Australian Meteorological and Oceanographic Society
  1. Schedule
  2. 10(i). Land surface processes from local to global scales
  3. 2018–2019: return of the 1920s drought across the Australian drylands and savannas, soil and vegetation responses, and the carbon cycle

2018–2019: return of the 1920s drought across the Australian drylands and savannas, soil and vegetation responses, and the carbon cycle (#129)

James Cleverly 1 , Tonantzin Tarin 2 , Caitlin Moore 3 , Peter Isaac 4 , Lindsay Hutley 5 , Prober Suzanne 6 , Craig MacFarlane 6 , Alfredo Huete 7 , Jason Beringer 8
  1. UTS, TERN and Advances in Meteorology, Sydney, NSW, Australia
  2. University of Delaware, Newark, DE
  3. University of Illinois, Urbana-Champaign, IL, USA
  4. TERN, Melbourne, VIC, Australia
  5. Charles Darwin University, Darwin, NT, Australia
  6. CSIRO Land and Water, Floreat, WA, Australia
  7. UTS, Sydney, NSW, Australia
  8. The University of Western Australia, Perth, WA, Australia

The summer of 2018–2019 brought record drought across central, western and northern Australia. In this study, we compared carbon and water fluxes during this 100-year drought in the northern savanna, the central Mulga and hummock drylands, and the Great Western Woodlands. In the northern savanna, evapotranspiration and net ecosystem productivity was unaffected during the wet season 2018–2019 because more precipitation fell than was required for was needed for actual evapotranspiration despite the failure of the monsoon. By contrast, the drylands farther inland were characterised by a record lack of precipitation and record high temperature and vapour pressure deficit. In Mulga vegetation, carbon fluxes dropped to near zero, although net carbon uptake was maintained during winter 2019, despite receiving only 13 mm of precipitation since 1 January 2019. Soil moisture stores in the Mulga woodland were recharged during the extraordinarily wet summer of 2017–2018 (560 mm in 40 days), and this interannual soil moisture carry-over has permitted Mulga to survive with small but positive levels of photosynthesis and very high water-use efficiency. The hummock grassland has returned to a strong carbon source, as the biomass which was accumulated during the extraordinarily strong monsoon of 207–2018 has readily decomposed via abiotic photodegradation in the subsequent severe drought. Drought resistance, resilience and the carbon cycle of Australian drylands and savannas during severe drought are ultimately dependent upon the unique characteristics of Australian vegetation, which has evolved with increasing aridity for millions of years.

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