DNA sequencing unveils past environments
Manaaki Whenua has a long history of using microfossils to reconstruct past environments. Information about the past helps us to improve our understanding of how current ecosystems function, and provides pre-human baseline information, which can inform conservation and restoration planning.
More recently, ancient DNA (aDNA) analysis has been added to the traditional microfossil toolkit, and provides a new and unprecedented level of information about the past that was previously unobtainable with microscopes.
Manaaki Whenua’s Long Term Ecology Laboratory has been using aDNA analysis on a range of materials, including sediments taken from wetlands, caves and lakes, as well as preserved droppings from extinct and threatened birds, and introduced rats.
Wetland sediment samples
Ancient DNA from wetland sediment cores is helping to build a picture of what New Zealand’s wetlands looked like before human modification. The work builds on pollen records, which show that even wetlands with mostly native plants may have looked quite different in the past.
The work will have an important conservation impact in terms of helping to guide the restoration of wetlands to a natural state. The DNA will provide insights into how a wide range of wetland life has changed over time, from microscopic organisms up to large animals like eels.
Marsden project on kiore droppings
DNA sequencing from ancient kiore (Pacific rat) droppings is giving Manaaki Whenua scientists unique insights into the ecological impacts of New Zealand’s first naturalised invasive species.
A small rock cavity in Central Otago contained hundreds of 750-year-old kiore droppings. Analysis of these droppings is providing a fascinating snapshot of what the first rats in New Zealand were eating, and their environmental impact on birds, plants and invertebrates.
More droppings have since been found in the North Island, allowing our scientists to explore dietary change of an invasive species through space and time in a globally unique setting.
Manaaki Whenua scientists are supervising an Auckland PhD student based at Lincoln (through the joint University of Auckland – Manaaki Whenua Centre for Biodiversity and Biosecurity) to extract aDNA from kākāpō droppings dating back 2,000 years to see how the ecology and diet of these enigmatic parrots have changed over time, which may help inform their conservation.
The ancient droppings were collected from cave entrances where kākāpō once roosted, and they are being compared to contemporary and historical droppings collected by the Department of Conservation, who are close collaborators on the project. This long-term view of kākāpō diets could help expand options of where populations might survive in the future.
Gut parasites also have implications for the health of the birds, and Manaaki Whenua scientists are sequencing DNA from the coprolites to establish what the natural parasites of kākāpō were.