U.S.-New Zealand DDEP: Using a Chronosequence to Investigate Ecosystem Recovery Following Invasive Rat Eradication

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0853846SchmitzTitle: U.S.-New Zealand Doctoral Dissertation Enhancement Project: Using a Chronosequence to Investigate Ecosystem Recovery Following Invasive Rat EradicationThis award supports a doctoral dissertation enhancement project between Professor Oswald Schmitz and his graduate student Holly Jones from Yale University, Professor Nicola Nelson at Victoria University in Wellington, New Zealand and Dr. David Towns at the Department of Conservation in Auckland, New Zealand. A key predication of restoration ecology is that systems can be restored to a previous state following a disturbance. However, the potential for systems to entrain into an unrestorable alternate state following a disturbance is often overlooked. Motivated by a test for alternate states, this study combines scientific experimentation with ongoing conversation management actions on offshore islands in New Zealand to learn whether island ecosystems can recover from rat invasion and eradication. Rat invasion and predation on all members of island food webs, and seabirds in particular, can have ecosystem-level consequences, usually mediated by a reduction in seabird-derived nutrients. Seabirds are integral food web members on islands providing nutrients to all members of island food webs and affecting ecosystem properties. As a result, eradication of invasive rats from nonnative ecosystems is a common tool used to restore systems to their preinvasion states. However, it remains unclear whether ecosystems can recover their natural function following invasive rat removal, or whether, without active seabird restoration, rat removal causes ecosystems to jump to alternate, low nutrient states. The measurements the researchers will take on the New Zealand Islands will serve as indicators of recovery relative to currently invaded and never invaded controls.The unique study design will provide a rare ecosystem-scale test of theory and will be effective at informing island managers, due to its realistic scale. The study can accurately assess the success of New Zealand?s island restoration efforts, and this will help in advancing scientific theory and in helping managers to set realistic baselines and recovery expectations for island ecosystems. Local Mori communities will send representatives on island trips to learn more about conservation related research. Scientists at New Zealand?s Landcare Research and at the New Zealand Museum of Natural History will also be involved in the project. The project will also provide the U.S. graduate student with a global research experience. It is anticipated that the student will maintain scientific connections with her New Zealand collaborators for many years after the project is completed.