Engineering Coastal Habitat: Past, Present and Future of water and seabird habitat in Maunalua Bay

Rachelle Tom, Maggie Enzweiler, Brooke Friswold

Maunalua bay is home to many native water and seabirds despite global population declines and heavy urbanization in the area. However, if climate change trends continue with the NOAA projected sea level rise of 1.1 feet by 2050, most of their nesting habitat will be underwater; therefore human-engineered habitat (HEH) is required to allow these populations to persist in Maunalua Bay. Water and seabirds are crucial to the health of Maunalua Bay. They are apex predators, important bio-indicators, contribute essential nutrients through guano, control invasive species, and have spiritual and cultural importance. Inhabited areas will need human assistance in the form of HEH to allow future generations to enjoy these magnificent native species.

The Freeman Seabird Preserve at Black Point has already been successful at providing beneficial HEH for native seabirds. Using Black Point as a model, we explore the possibilities of HEH required at 5 areas of interest in Maunalua Bay to support native bird populations into the future: China Walls/Spitting Caves, Paikō Lagoon, Koko Marina/Kuapā Pond, Keawāwa Wetland, and Maunalua Bay Beach Park. The areas were chosen due to their native water- and sea-bird presence, their ability to support HEH, as well as being major attractions within Maunalua Bay. We provide the history of each region, historic presence of species of interest, current habitat conditions, and current bird species presence. From there we detail the present native species threats and their habitat requirements and preferences to make recommendations for HEH in the future.

We conducted a literature review that consisted of journal articles containing historic accounts and data of the water and seabirds of Maunalua Bay. This provided an informative natural history of these species in the area and population trends over time. We also created a map showing our model for HEH and areas of interest can be found at http://arcg.is/0bm4iu. Through this map you are able to explore our areas of interest with their history, present habitat and future of human-engineered habitat corresponding to their water or seabird presence.

A storyboard was created on arcGIS.com using the Planet Story Maps feature, and provides a narrative intended for educational purposes and can be found here: https://arcg.is/18Xq55.

We used the NOAA projected sea level rise of 1.1 feet at 2050. Unanimously, sites have most or all water and seabird habitat entirely flooded. We cultivated HEH recommendations for each region using bird-specific habitat requirements and preferences, determining what each region could support. Mālama Maunalua can implement these HEH recommendations in future projects. All HEH recommendations are relatively inexpensive to implement and have a manageable amount of labor intensity. As climate change further eliminates native Hawaiian bird habitat, forms of proactive as opposed to reactive conservation is required. Implementing HEH before sea level rise has saturated habitats entirely is a form of proactive conservation that may increase the bird population’s ability to exist in these areas.

Human engineered habitat recommendation for Maunalua Bay Beach Park. Including “cups” embedded in the tree for the chicks.