Sahul's megafauna were vulnerable to plant-community changes due to their position in the trophic network

Autor: John Llewelyn, Frédérik Saltré, Sara N. de Visser, Daniel B. Stouffer, Matthew C. McDowell, Katharina J. Peters, Giovanni Strona, Christopher N. Johnson, Corey J. A. Bradshaw
Přispěvatelé: Ecological Data Science, Organismal and Evolutionary Biology Research Programme, Olff group, University of Zurich, Llewelyn, John
Jazyk: angličtina
Rok vydání: 2022
Předmět:
10207 Department of Anthropology
0106 biological sciences
AUSTRALIA
Environmental change
Pleistocene
Evolution
010603 evolutionary biology
01 natural sciences
Predation
FOOD WEBS
03 medical and health sciences
Behavior and Systematics
Late Pleistocene
biology.animal
Megafauna
Trophic cascade
ecological network
Ecology
Evolution
Behavior and Systematics
Trophic level
030304 developmental biology
BODY-SIZE
LATE QUATERNARY MEGAFAUNA
0303 health sciences
Ecology
biology
food web
300 Social sciences
sociology & anthropology
Vertebrate
BIOTIC INTERACTIONS
Plant community
social sciences
15. Life on land
musculoskeletal system
EXTINCTION RISK
MAMMAL FAUNAS
humanities
PLEISTOCENE CLIMATE-CHANGE
1105 Ecology
Evolution
Behavior and Systematics
Geography
1181 Ecology
evolutionary biology
coextinction
extinction event
TOP-DOWN
geographic locations
NARACOORTE CAVES
Zdroj: Ecography, 2022(1):e06089
ISSN: 1600-0587
Popis: Extinctions stemming from environmental change often trigger trophic cascades and coextinctions. Bottom-up cascades occur when changes in the primary producers in a network elicit flow-on effects to higher trophic levels. However, it remains unclear what determines a species' vulnerability to bottom-up cascades and whether such cascades were a large contributor to the megafauna extinctions that swept across several continents in the Late Pleistocene. The pathways to megafauna extinctions are particularly unclear for Sahul (landmass comprising Australia and New Guinea), where extinctions happened earlier than on other continents. We investigated the potential role of bottom-up trophic cascades in the megafauna extinctions in Late Pleistocene Sahul by first developing synthetic networks that varied in topology to identify how network position (trophic level, diet breadth, basal connections) influences vulnerability to bottom-up cascades. We then constructed pre-extinction (-80 ka) network models of the ecological community of Naracoorte, south-eastern Sahul, to assess whether the observed megafauna extinctions could be explained by bottom-up cascades. Synthetic networks showed that node vulnerability to bottom-up cascades decreased with increasing trophic level, diet breadth and basal connections. Extinct species in the Naracoorte community were more vulnerable overall to these cascades than were species that survived. The position of extinct species in the network - tending to be of low trophic level and therefore having relatively narrow diet breadths and fewer connections to plants - made them vulnerable. However, these species also tended to have few or no predators, a network-position attribute that suggests they might have been particularly vulnerable to new predators. Together, these results suggest that trophic cascades and naivety to predators could have contributed to the megafauna extinction event in Sahul.
Databáze: OpenAIRE
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