2020 State of Papahānaumokuākea Marine National Monument Report: Resource Status and Trends Summary Table

1

Have recent, accelerated changes in climate altered water conditions and how are they changing?

Climate-related changes have caused severe degradation in some, but not all, attributes of ecological integrity.

Increasing ocean temperature has resulted in four mass coral bleaching events. The number of hurricanes and tropical storms has increased. Calcification and aragonite saturation states are relatively low.

Monitoring the physical environment across the monument is important to understand how it is changing over time and space.

2

What are the area and distribution of abiotic habitat types and how are they changing?

Selected habitat loss or alteration has caused, or is likely to cause, severe declines in some, but not all, living resources or water quality.

Terrestrial habitats are severely eroding; data are lacking to evaluate the status of submerged habitats, but they are generally eroding on the seaward side of reef crests.

Measurements of net carbonate accretion rates on reef crests and sediment accretion rates on land are critical for understanding the future of these habitats. Completing high-resolution bathymetry and substrate mapping is important for monitoring large-scale changes in marine abiotic habitats. Erosion control is needed to preserve terrestrial ecosystems.

3

What is the water quality condition of PMNM nearshore and inland waters and how is it changing?

Selected conditions may preclude full development of living resource assemblages and habitats but are not likely to cause substantial or persistent declines.

Data on nearshore water quality are lacking. Avian botulism has occurred in inland waters at Midway Atoll, Laysan Island and Kure Atoll, causing mortality in protected bird species.

Consistent water quality monitoring and threat prevention and mitigation strategies are needed for both nearshore and inland waters.

4

What are the known contaminant concentrations in PMNM habitats and how are they changing?

Selected contaminants may inhibit the development of assemblages and may cause measurable, but not severe, declines in living resources or water quality.

Historical contaminants remain despite remediation. Most efforts have taken place at Kure, Midway, and French Frigate Shoals (Tern Island), but contamination sites are also present at Laysan Island and Pearl and Hermes Atoll. Protected species continue to be exposed to these contaminants.

Prioritize investigations to address data gaps regarding local sources and exposures, and develop containment and disposal strategies to prevent future contaminant releases from hazardous marine debris.

5

What is the status of biodiversity and how is it changing?

Biodiversity appears to reflect pristine or near-pristine conditions and promotes ecosystem integrity (full community development and function).

Biodiversity is characteristic of pristine conditions, which promotes ecosystem integrity. Endemism is high.

Monitoring biodiversity is important for understanding the monument’s resilience as the nature, frequency, and intensity of disturbances change.

Selected biodiversity loss has taken place, precluding full community development and function, but it is unlikely to cause substantial or persistent degradation of ecosystem integrity.

Seabird species are recovering following rat eradication in 1995. Native plant richness, abundance, and distribution are increasing due to invasive weed control measures.

Continued weed management is essential to restore native plant communities and improve reproductive success of seabirds.

6

What is the status of historically targeted species and how is it changing?

The reduced abundance of species has caused, or is likely to cause, severe declines in some, but not all, ecosystem components and reduce ecosystem integrity; or, species are at substantially reduced levels, and prospects for recovery are uncertain.

As of the late 2000s, lobster stocks remain depressed from historical levels, while bottomfish stocks remain healthy. The black-lipped pearl oyster was overharvested in 1930 and had not recovered as of 2006.

Research surveys are needed to provide updated population status and other information.

7

What is the status of non-indigenous species and how is it changing?

Non-indigenous and/or invasive species exist, precluding full community development and function, but are unlikely to cause substantial or persistent degradation of ecosystem integrity.

Habitat restoration programs have improved native terrestrial ecosystems, but the non-indigenous plant seed bank will threaten ecosystem integrity for many years to come.

Reestablishing year-round operations, continuing eradication projects, and continuing habitat restoration are critical to improve biodiversity of flora and fauna and protect abiotic structures from erosion.

Non-indigenous and/or invasive species may inhibit full community development and function and may cause measurable, but not severe, degradation of ecosystem integrity.

Surveys have revealed a number of established non-indigenous marine species; some are broadly distributed. Marine invertebrates make up the largest category of non-indigenous species.

Continuing best practices to minimize transport of marine non-indigenous species will help protect the integrity of marine habitats in PMNM.
Continued monitoring and characterization are also needed.

8

What is the status of key species and how is it changing?

The reduced abundance of selected keystone species has caused, or is likely to cause, severe declines in some, but not all, ecosystem components and reduce ecosystem integrity; or, selected key species are at substantially reduced levels, and prospects for recovery are uncertain.

Monument populations increased by 2% from 2013–2017. Site-specific trends in population have been observed.

Monitoring populations for demographic trends, as well as detecting and mitigating threats to seal survival, are the highest priorities for recovery of the species. Limited funding has shortened field seasons, curtailing this work and introducing uncertainty about future monitoring.

The condition of selected key resources is not optimal, perhaps precluding full ecological function, but substantial or persis­tent declines are not expected.

The Central North Pacific population of the threatened green turtle ranges throughout the Hawaiian Archipelago and Johnston Atoll. About 96% of nesting takes place at French Frigate Shoals, and nesting activity there is improving.

Data and models are needed to predict the impacts of sea level rise on nesting sites and rising sand temperature on hatchling success and sex ratios. Monitoring of nesting sites throughout the monument is needed to assess the impact from the catastrophic habitat loss at East Island, French Frigate Shoals, caused by Hurricane Walaka.

Key and keystone species appear to reflect pristine or near-pristine conditions and may promote ecosystem integrity (full community development and function).

Reef fish assemblages exhibit high biomass across the majority of family and trophic groups, particularly for large-bodied taxa. The high abundance of large apex predators on monument reefs contrasts with that of the eight inhabited Main Hawaiian islands.

The large area and diversity of reef fish habitats in the monument present challenges for assessment. Deeper reef habitats (>30m), soft-sediment habitats, and diurnally active reef fish species are particularly undersampled. Reef fish assemblages are likely vulnerable to future impacts of climate change.

The diminished condition of selected key resources may cause a measurable, but not severe, reduction in ecological function, but recovery is possible.

Mass coral bleaching occurred in 2009, 2010, 2014 and 2019. The 2014 event caused a 68% loss in coral cover at Lisianski and reduced habitat complexity and volume. Mortality from the 2019 event, observed at Lisianski, French Frigate Shoals, Pearl and Hermes, Midway, and Kure, is unknown. In 2018, Hurricane Walaka destroyed Rapture Reef, a known habitat for uncommon acroporid corals at FFS.

Annual monitoring of coral reefs is needed to assess and address impacts from natural disasters such as coral bleaching, hurricane damage, and invasive species. Assisted restoration should be considered for these reefs, which already have calcification limitations, are near the thermal limit for coral growth, and will continue to experience climate change impacts such as ocean warming and changing ocean chemistry.

Key and keystone species appear to reflect pristine or near-pristine conditions and may promote ecosystem integrity (full community development and function).

Only a small portion of potential deep-water coral habitat in the monument has been explored. Only a few sites have been revisited, making it difficult to report temporal trends.

The large geographic area and extreme depths of deep-water corals in the monument challenge our ability to assess their status. A plan is needed to resurvey known locations of deep-water corals in PMNM to assess temporal trends and life histories, as well as the effects of climate change and ocean acidification.

The condition of selected key resources is not optimal, perhaps precluding full ecological function, but substantial or persistent declines are not expected.

Recent data on seabird nesting and abundance have mostly been limited to colonies of Laysan albatross and black-footed albatross. Although nesting activity has remained stable or increased slightly, albatross populations have been negatively affected by flooding and tsunami events, mouse predation, commercial fishing, and contamination from legacy contaminants. Monument expansion has increased the protections for foraging seabirds.

Only 12 of the 21 seabird species in the monument have been monitored. Resuming annual Tern Island monitoring is necessary to track albatross breeding in PMNM. Monument expansion and the removal of predatory mice at Midway Atoll will reduce threats to Laysan albatross.

The reduced abundance of selected key species has caused, or is likely to cause, severe declines in some, but not all, ecosystem components and reduce ecosystem integrity; or, selected key species are at substantially reduced levels, and prospects for recovery are uncertain.

All four species are endemic, listed as endangered, and threatened by the introduction or spread of invasive species. The Laysan duck is found on three islands, the Laysan finch and Nihoa millerbird on two, and the Nihoa finch on only Nihoa. With the 2011 translocation of the Nihoa millerbird to Laysan Island, Laysan now supports three of the four land bird species.

High-priority management actions include ongoing monitoring of established populations and identifying habitat on other islands for establishing additional populations.

Translocation of the Nihoa finch, the only PMNM land bird restricted to a single island, would reduce extinction risk.

The reduced abundance of selected key species has caused, or is likely to cause, severe declines in ecosystem integrity; or, selected key species are at severely reduced levels, and recovery is unlikely.

Five species of terrestrial plants are endemic to PMNM. Two others are endemic to the broader archipelago, but the majority of their population is in PMNM.
All seven are protected under the Endangered Species Act due to disruptions caused by humans, principally the introduction of invasive species.

Strict controls on access, as well as long-term commitments to monitoring, outplanting, and invasive species control are needed to maintain, restore, and establish new populations outside historical ranges, and safeguard the genetic diversity of these species.
 

9

What is the condition of known maritime archaeological resources and how is it changing?

The diminished condition of selected archaeological resources has reduced, to some extent, their historical, scientific, or educational value and may affect the eligibility of some sites for listing in the National Register of Historic Places.

Due to their remoteness, maritime heritage sites in the monument are less threatened by humans than those in the MHI. Natural degradation is the greatest threat to these sites.

Fulfilling mandates to protect known maritime heritage resources and identify new sites, as well as inventorying and interpreting these sites, is critical, given the ongoing loss of information to natural degradation. Long-term management should prioritize monitoring, National Register of Historic Places nominations, and focused interpretive efforts.

10

What is the condition of known historic resources and how is it changing

The diminished condition of selected historic resources has reduced, to some extent, their historical, scientific, or educational value and may affect the eligibility of some sites for listing in the National Register of Historic Places.

Approximately half of the remaining 56 historic structures on Midway are in good to fair condition and are in use by the USFWS as a biological station. Deterioration due to exposure is apparent in the remaining half, potentially affecting their eligibility for listing in the National Register of Historic Places.

Degradation by harsh environmental conditions, exacerbated by the high cost of working in such remote locations, make much-needed maintenance and repair a significant challenge. Web-based tools facilitate public access to ongoing research and other efforts.

11

What is the condition of known Native Hawaiian archaeological resources and how is it changing?

12

Do known historic and archaeological resources pose an environmental hazard and how is this threat changing?

Selected heritage resources may pose isolated or limited environmental threats, but substantial or persistent impacts are not expected.

The exterior of historic properties on Midway have been treated for lead paint by encapsulation. Rehabilitation of officers' houses and Midway House included removal of lead paint and asbestos materials. Most historic shop buildings are sided with transite, which contains an inert form of asbestos. Deterioration could increase the risk of exposure to lead and asbestos.

USFWS has abated lead paint on all historic properties. Continued monitoring and maintenance is needed. Removal of buildings and infrastructure may be necessary to reduce risks.

Known heritage resources pose few or no environmental threats.

Though no significant threats from archaeological resources exist, unexploded ordnance, shells embedded in stone outcrops, and metal fragments in bomb pits still exist on Mokumanamana. It is possible that eroding structures on the islands could present a hazard to birds or native plants.

In order to assess changes in the risk posed by these resources, more detailed and frequent monitoring and research are needed. However, the relative contribution of cultural resources as sources of environmental hazards is expected to be minimal.