Loss of biodiversity – a term encompassing the variety and variability of life on earth – is one of the most urgent threats to humans and the broader biosphere. The fossil record documents a long history of where animals lived, what they ate, and when they went extinct, and understanding what influenced this record gives essential context for guiding modern conservation efforts. Biodiverse islands such as Madagascar, which are being deforested and invaded by introduced animals, are foci of biodiversity conservation efforts. People arrived on Madagascar at least 1,500 years ago and brought with them exotic predators such as dogs and rats. Though these animals are known today to threaten native animals on Madagascar by eating them, competing over resources, and spreading disease, the antiquity, past consequences, and legacy of these threats are poorly known.
This project uses novel chemical analyses of ancient animal bones to learn more about when exotic predators first arrived on Madagascar, how the diet of these predators compared with that of their native counterparts, and any adjustments that these animals likely made in response to past loss of forest and climate drying. We predicted that the history of interaction between exotic animals (specifically dogs, rats, and mice) and native animals (fosa, mouse lemurs, and rodents) extends for at least one millennium. We also expected exotic predators to have eaten a relatively broad range of foods and to have adjusted to past forest loss by increasingly eating in grasslands. Meanwhile, we expected native animals to adjust relatively well to past and ongoing climate drying by eating foods in dry areas. By testing these ideas, we will give novel insight on how vulnerable native animals are to particular stressors. This information can then contribute directly to biodiversity conservation planning, which is otherwise solely informed by direct observations of living animals.
