| Title: | Historical reconstruction unveils the risk of mass mortality and ecosystem collapse during pancontinental megadrought |
| Author(s): | Godfree RC; Knerr N; Godfree D; Busby J; Robertson B; Encinas-Viso F; |
| Address: | "Commonwealth Scientific and Industrial Research Organization National Research Collections Australia, Canberra, ACT 2601, Australia; Robert.Godfree@csiro.au. Commonwealth Scientific and Industrial Research Organization National Research Collections Australia, Canberra, ACT 2601, Australia. Private address, Narrabri, NSW 2390, Australia" |
| ISSN/ISBN: | 1091-6490 (Electronic) 0027-8424 (Print) 0027-8424 (Linking) |
| Abstract: | "An important new hypothesis in landscape ecology is that extreme, decade-scale megadroughts can be potent drivers of rapid, macroscale ecosystem degradation and collapse. If true, an increase in such events under climate change could have devastating consequences for global biodiversity. However, because few megadroughts have occurred in the modern ecological era, the taxonomic breadth, trophic depth, and geographic pattern of these impacts remain unknown. Here we use ecohistorical techniques to quantify the impact of a record, pancontinental megadrought period (1891 to 1903 CE) on the Australian biota. We show that during this event mortality and severe stress was recorded in >45 bird, mammal, fish, reptile, and plant families in arid, semiarid, dry temperate, and Mediterranean ecosystems over at least 2.8 million km(2) (36%) of the Australian continent. Trophic analysis reveals a bottom-up pattern of mortality concentrated in primary producer, herbivore, and omnivore guilds. Spatial and temporal reconstruction of premortality rainfall shows that mass mortality and synchronous ecosystem-wide collapse emerged in multiple geographic hotspots after 2 to 4 y of severe (>40%) and intensifying rainfall deficits. However, the presence of hyperabundant herbivores significantly increased the sensitivity of ecosystems to overgrazing-induced meltdown and permanent ecosystem change. The unprecedented taxonomic breadth and spatial scale of these impacts demonstrate that continental-scale megadroughts pose a major future threat to global biodiversity, especially in ecosystems affected by intensive agricultural use, trophic simplification, and invasive species" |
| Keywords: | "Animals Australia Droughts/*history *Ecosystem *Extinction, Biological History, 19th Century History, 20th Century Humans *Models, Biological Federation Drought ecosystem collapse mass mortality megadrought trophic impact;" |
| Notes: | "MedlineGodfree, Robert C Knerr, Nunzio Godfree, Denise Busby, John Robertson, Bruce Encinas-Viso, Francisco eng Historical Article 2019/07/17 Proc Natl Acad Sci U S A. 2019 Jul 30; 116(31):15580-15589. doi: 10.1073/pnas.1902046116. Epub 2019 Jul 15" |
