Will the Effects of Sea-Level Rise Create Ecological Traps for Pacific Island Seabirds?

PLoS One. 2015 Sep 23;10(9):e0136773. doi: 10.1371/journal.pone.0136773. eCollection 2015.

Abstract

More than 18 million seabirds nest on 58 Pacific islands protected within vast U.S. Marine National Monuments (1.9 million km2). However, most of these seabird colonies are on low-elevation islands and sea-level rise (SLR) and accompanying high-water perturbations are predicted to escalate with climate change. To understand how SLR may impact protected islands and insular biodiversity, we modeled inundation and wave-driven flooding of a globally important seabird rookery in the subtropical Pacific. We acquired new high-resolution Digital Elevation Models (DEMs) and used the Delft3D wave model and ArcGIS to model wave heights and inundation for a range of SLR scenarios (+0.5, +1.0, +1.5, and +2.0 m) at Midway Atoll. Next, we classified vegetation to delineate habitat exposure to inundation and identified how breeding phenology, colony synchrony, and life history traits affect species-specific sensitivity. We identified 3 of 13 species as highly vulnerable to SLR in the Hawaiian Islands and quantified their atoll-wide distribution (Laysan albatross, Phoebastria immutabilis; black-footed albatross, P. nigripes; and Bonin petrel, Pterodroma hypoleuca). Our models of wave-driven flooding forecast nest losses up to 10% greater than passive inundation models at +1.0 m SLR. At projections of + 2.0 m SLR, approximately 60% of albatross and 44% of Bonin petrel nests were overwashed displacing more than 616,400 breeding albatrosses and petrels. Habitat loss due to passive SLR may decrease the carrying capacity of some islands to support seabird colonies, while sudden high-water events directly reduce survival and reproduction. This is the first study to simulate wave-driven flooding and the combined impacts of SLR, groundwater rise, and storm waves on seabird colonies. Our results highlight the need for early climate change planning and restoration of higher elevation seabird refugia to prevent low-lying protected islands from becoming ecological traps in the face of rising sea levels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Birds*
  • Breeding
  • Climate
  • Ecology*
  • Ecosystem*
  • Hawaii
  • Oceans and Seas*
  • Pacific Islands
  • Quantitative Trait, Heritable
  • Seasons

Grants and funding

This study was funded primarily by the National Climate Change and Wildlife Science Center NCCWSC's FY09 RFP (https://nccwsc.usgs.gov/projects-list/5050cc14e4b0be20bb30eac8) with supplemental funding from USFWS National Wildlife Refuge System Inventory and Monitoring grants IAA F11RG00373 and IAA F11RG00376 (“Predicting the Impact of Storm Waves and Sea-Level Rise within the Papahānaumokuākea Marine National Monument”). These funders had no role in directing the study design, data collection, analysis, decision to publish this article, or preparation of this manuscript. Partial funding was provided salary support by the US Geological Survey's Pacific Island Ecosystems Research Center and Pacific Coastal and Marine Science Center and US Fish and Wildlife Service. These entities provided scientists’ salary support, in kind support, data collection facilitation, author salary support, and supported publication of this work.