Strandberg, N.A., Sear, D.A., Langdon, P.G., Cronin, S.J., Langdon, C., Maloney, A., Bateman, S., Bishop, T., Croudace, I., Leng, M., Sachs, J.P., Prebble, M., Gosling, W.D., Edwards, M. & Nogue, S. (2023) Island ecosystem responses to the Kuwae eruption and precipitation change over the last 1600 years, Efate, Vanuatu. Frontiers in Ecology and Evolution 11, 1087577. DOI: 10.3389/fevo.2023.1087577
Supervsiory team:Dr. Sandra Nogué, Prof Mary Edwards, Prof. David Sear, Dr. William Gosling (University of Amsterdam), Prof. Inger (Tromso University), Prof. Janet Wilmshurst (Landcare research and University of Auckland)
Rationale: The Pacific islands of Polynesia were among the last places on earth to be colonised by humans. The precise dates of colonisation are debated – a situation which arises from the different sources of evidence (1, 2). New lake sediment records from the Cook Islands (Atiu, Mangaia) and Samoa (Upolu) and Tonga show very clear evidence of disturbance, but what is unclear is to what extent the signal represents the arrival of humans or a change in climate (2). A key question for the analysis of sedimentary records is the ability to distinguish natural variability in the environment of Pacific Islands from that arising from the arrival of humans in a temporal and spatial context. We aim to use a multi-proxy approach based on SedDNA, lipid biomarkers, fossil charcoal, and pollen preserved in lake sediments to identify: a) the presence of humans and/or livestock that were brought with them, and b) the related environmental change. Multiproxy approaches supported by statistical analysis, will be deployed to four sites where we already have good chronological controls and high resolution records of palaeoclimate. We are well placed to apply new methods and higher resolution analyses to address fundamental questions about the response of remote pacific islands to climate and human forcings.
Supervisory team: Prof. David Sear, Prof. Justin Sheffield, Prof Ian Croudace (National Oceanographic Centre, Southampton).
Rationale: Because of their small size and isolation, islands in the Pacific have limited and fragile natural resources, making them more vulnerable to climate hazards and stresses than are continents1. Pacific Island Nations (PINS) also occupy the region of the earth’s surface most immediately impacted by ENSO events. The impacts of El Nino events are felt across 3,975 islands, 13 island nations, affecting a population of 12.9 million who rely on rainfall for freshwater and food security. To date our understanding of the mechanisms of drought, their frequency and duration, and their biophysical effects in PINs remain poorly quantified. In addition island types experience droughts differently, varying according to their location, topography, geological history and ecology. Droughts are also thought to have been important drivers of the human colonization of the Pacific2. Drought frequency is likely to increase in the tropical pacific but again its specific impacts are largely unknown. This PhD seeks to develop a step change in our understanding of droughts based on novel coupling of long term data on drought frequency with process based drought modelling.