Natural resource condition assessment: National Park of American Samoa

Craig, Peter; Wimpy, Jeremy; Reigner, Nathan; Valliere, William; Cummings, Tonnie

The Natural Resource Condition Assessment Program (NRCA) provides managers of the National Park of American Samoa (NPSA) with an assessment of its most important natural resources. Overall, the NRCA document should help managers develop near-term management priorities, engage in partnership and education efforts, conduct park planning, and report program performance. A literature search has been provided to the park as a supplement to its digital library. NPSA is the only National Park located south of the equator. Its park units are located on three remote islands covered by tropical rainforests and surrounded by coral reefs. For this review, the NRCA team selected seven terrestrial resources (rainforests, cloud forests, fruit bats, forest birds, seabirds, streams, air quality) and four marine resources (marine water quality, coral reefs, fish, sea turtles) for evaluation. The park also requested reviews of four threats to these resources (climate change, fishing pressure, invasive plants, and invasive rats). The condition of these categories varied in 2015, and several components could not be accurately determined due to lack of data. Overall, NPSA’s natural resources were either in good condition or of moderate concern, with terrestrial resources scoring better than marine resources (Figure 1). Five terrestrial resources were in good condition (rainforests, cloud forests, forest birds, fruit bats, streams), one was of moderate conservation concern (seabirds), and another (air quality) was not evaluated due to insufficient data. Key terrestrial threats were of moderate concern (climate change, invasive rats) or of significant concern (invasive plants). The park’s marine resources were of moderate concern (marine water quality, coral reefs, fish) or significant concern (sea turtles). Key marine threats were also of moderate concern (climate change, fishing pressure). Climate change was the main reason why marine resources did not score as well as terrestrial resources. Climate induced increases in water temperatures have caused multiple coral bleaching events (which can kill corals) in the park. Baseline environmental conditions that formerly supported park reefs are changing and projected to worsen. Terrestrial impacts are likely occurring as well, but changes have been less visible and less studied to date. The absence of trends for many of NPSA’s resources reflected two points: first, the I&M Vital Signs monitoring program was relatively new in NPSA, and trend data were not available for most resources at the time of this review, and next, several resources selected for evaluation were not part of the Pacific Island Network (PACN) Vital Sign program (e.g., sea turtles, fruit bats, seabirds, fishing pressure, climate change, invasive rats) and lacked systematic monitoring. For these resources, the team developed ad hoc measures of resource condition based on available data, but confidence in these assessments was not high. This could be improved in future assessments by systematically obtaining data on the most appropriate condition measures. Two habitats in NPSA may warrant consideration as special management units: Ofu lagoon and Ta’u cloud forest.

Natural resource condition assessment: National Park of American Samoa

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