Invasive species that alter ecosystem structure and function (i.e., “foundational invaders”) are among the primary threats to Threatened and Endangered (T&E) species, particularly on oceanic islands. Department of Defense (DoD) installations on islands are critical to the U.S. military mission and often contain high numbers of T&E species, protected by installation fences from habitat loss, herbivory, and direct exploitation. Charged with simultaneously carrying out training and military readiness activities and protecting federally listed species, installation managers must select and implement invasive species controls that are effective, efficient, and minimize non-target impacts. The objective of this project is to address Statement of Need #RCSON-23-C1 and advance scientific understanding of the changes in distribution, abundance, and population dynamics of invasive species, and their potential foreseeable impacts to military readiness as a result of changes to threatened and endangered species and species at risk. Specifically, the project team aims to use an existing array of invasive species manage/no management plots in the largest DoD installation in Hawaii (Pōhakuloa Training Area [PTA] on Hawai’i Island) to evaluate the impacts of two invasive foundational plant species on six T&E plant species, both currently and within a context of future projected climate change; assess the impact of existing control measures on both focal invaders and T&E species; project future T&E species population trajectories given feedbacks with invaders under various control method scenarios; and develop decision-support guidance for DoD managers selecting invasive species control protocols while adjusting for T&E species requirements and climate change. This work builds on the five-year, recently completed, SERDP-funded study of endangered plant species responses to invasive predators at PTA.

Award# RC23-3805