Humans are fragmenting ecosystems into habitat ‘islands’, causing an unprecedented global collapse of large mammal populations just as science is discovering their essential ecological roles. The impact of these losses is such that our understanding of the contemporary biosphere is clearly shaped by a world artificially depleted of terrestrial giants. However, we lack a continuous record in one location to fully understand how the loss of megafauna impacted ecosystem resilience over long timescales, and how these processes interact with human arrival and ecological modification. We also do not understand what drove these animals to extinction in many parts of the world. Was it climate alone, or human overkill, or some combination of both? The feedbacks and ecological legacies of these extinctions have important lessons for the current biodiversity crisis, yet the dearth of good quality fossil and contextual data from many regions, settings and species has prevented robust appraisal.
ISLANDLAB is exploring these questions using the Maltese Islands as a frame of reference for the effects of anthropogenic ecosystem fragmentation. This is because Malta is (i) one of the most remote islands in the Mediterranean, and was therefore a 'final frontier' of pristine natural systems, (ii) featured a miniaturised megafauna of its own, although the ecosystem-animal size ratio still holds, (iii) as an island, there are a number of parameters that can be controlled, e.g. animals cannot wander off anywhere else, and remains are easier to find than on vast continental regions. The project is reconstructing a 200,000 year climate record using multiple different proxies, from cave formations (speleothems) to the isotopes of animal teeth. At the same time, archaeological excavations are determine when humans first arrived on the islands and what their impacts were on the natural systems they found there. The project has already uncovered evidence for the late survival of many species thought to have gone extinct on Malta in a much earlier timeframe, as well as evidence of species we never knew were present. As a result, ecosystem reconstructions, including both animals and vegetation, are also yielding new insights into this "Mediterranean Galapagos" over the the timeframe of the project. The extinction dates of a series of diverse endemic species are also being established for the first time using cutting-edge chronometric estimates, creating a timeline of faunal collapse that can be compared both with changes in climate as well as, ultimately, human arrivals. This is allowing the project to start clarifying what the drivers of extinction were in every major case.
The impacts of the first humans on their ecosystems are being explored through extremely details archaeological and sedimentological analyses, with the first suite of publication forthcoming in 2025. As Maltese prehistory is defined by more than one wave of human arrivals, it is also possible to explore periods of ecosystem recovery inbetween and understand the legacies of ecological changes down to the era of Europe’s oldest monumental buildings. What emerges is a nuanced picture of both extinctions and conservation practices with lessons for the current climate and biodiversity crisis.
By the end of the project, ISLANDLAB will have shed important light on (i) the causes of megafauna collapse in the Mediterranean region, (ii) the impact of megafaunal loss on island ecosystems, (iii) the long-term legacies of megafaunal losses both on human societies and human-dominated landscapes. At the same time, ISLANDLAB will also have created a detailed local climate record for the Central Mediterranean, and pieced together the peopling of the Central Mediterranean island region, which is currently unclear. The project therefore has multiple outcomes, with significance for earth sciences, human sciences and policy making.
