PACN Monitoring Focal Terrestrial Plant Communities

Gross, Jacob

The Pacific Island Network (PACN) is monitoring five focal terrestrial plant communities in seven national parks within the Pacific Island Network (PACN). Plant communities are important to monitor for a variety of reasons: (a) they are key indicators of ecosystem health, (b) they represent essential habitat for other biotic vital signs (e.g., land birds, bats), (c) plant communities reflect the dynamic relationship between invasive plant species and native species, and (d) their status and trends help to shape management needs and to evaluate the effectiveness of previous management practices at the community level. Of the many plant communities in PACN parks, scientists and resource managers identified five plant communities to monitor based on relative intactness, distinct species compositions made up of endemic species with limited ranges, prevalence across parks, and usefulness as indicators of environmental change. These plant communities include: (1) wet forests found within Hawai‘i Volcanoes National Park (HAVO), Haleakalā National Park (HALE), Kalaupapa National Historical Park (KALA), and the National Park of American Samoa (NPSA), (2) subalpine shrublands of HAVO and HALE, (3) coastal strand plant communities of KALA and Kaloko-Honokōhau National Historical Park (KAHO), (4) limestone forests of War in the Pacific National Park (WAPA), and (5) mangrove forests of American Memorial Park (AMME). These five plant communities overlay much of the habitat diversity found in PACN parks which encompass a wide range of ecosystems, climates, and topographic extremes across the Northern Mariana Islands, Hawai‘i, American Samoa, and Guam. To date, most vegetation studies in PACN parks have consisted of non-repeatable plant inventories used to describe and map the plant communities, or short-term monitoring associated with the control of nonnative ungulates, nonnative plants, or with restoration efforts. None of these studies were designed to detect specific levels of change over time at the park community level. This protocol takes a long-term systematic approach to monitor many of the major plant communities within parks in Hawai‘i, American Samoa, and the Mariana Islands to assess the status and trends of plant community composition and structure at five-year intervals. Specifically, data will be collected on selected plant community parameters including native and nonnative plant species diversity, cover, density, frequency, and coarse woody debris. This monitoring effort will provide park managers with new information that can be used to determine if current management actions are adequate to maintain the natural biological resources at acceptable levels. For example, if monitoring results indicate a significant increase in the number of or cover of invasive species, additional efforts may need to be taken to reduce these impacts. Similarly, if the data show that native species are being maintained or increasing relative to ungulate control and invasive species are decreasing, it may be possible to reduce active nonnative plant control within those management units. Additionally, monitoring will provide a temporal baseline that can be used to assess impacts and recovery potential relative to major landscape events such as fire, drought, hurricanes, and global climate change.

PACN Monitoring Focal Terrestrial Plant Communities

Program

Products

Collections