Should We Consider Translocating Kaua‘i Forest Birds?

By Ruby Pap

The endangered ‘Akeke‘e, endemic to Kaua‘i, is projected to lose substantial range by the end of the century. Photo by Lucas Behnke

Kaua‘i’s native forest birds and the forest ecosystem that depends on them are in serious trouble. As I reported a year ago, studies on Hawaiian honeycreepers have confirmed temperatures in high elevation forests have increased so much that mosquitos carrying avian malaria are able to infect more and more birds causing a serious decline in the last decade.

As this trend continues with climate change, species like the ‘akikiki, ‘akeke‘e, and i‘iwi face extinction by the end of the century. Indeed, all of Kaua‘i’s seven honeycreeper species have experienced a rapid range contraction and many are only now found in a small area of the Alaka‘i Plateau (see Akeakamai Nov. 17, 2016).

Given the alarming decline of Kaua‘i’s forest birds we have very little time to save them. This is why conservation scientists are leaving no stone unturned in terms of options. These include, among others, safeguarding existing habitat, conventional and novel approaches to mosquito control, captive preservation of species, and translocation. The latter more novel approaches require detailed study before they can deployed to ensure they are effective and do not cause unintended effects on the ecosystem.

One scientist pursuing this work is Lucas Fortini, research ecologist with the USGS Pacific Islands Ecosystem Research Center. In a recent study, he and co-authors analyzed the feasibility of “assisted colonization,” or “translocation” of Kaua‘i’s forest birds to other Hawaiian islands.

The endangered ‘Akikiki, endemic to Kaua‘i, is projected to lose substantial range by the end of the century. Photo by Robby Kohley

“Assessing the potential of translocating vulnerable forest birds by searching for novel and enduring climatic ranges,” published in Ecology and Evolution August 2017 edition, puts forth a first look at what translocation of ‘akikiki and ‘akeke‘e from Kaua‘i to islands with higher elevation habitats would look like and the implications of such a technique.

Using quantitative ecological modeling methods, Fortini et al mapped where hospitable climates exist at upper elevations across the Hawaiian Archipelago for ‘akikiki and ‘akeke‘e, and whether those conditions would persist into the future with climate change. Because Kaua‘i’s habitat range for these species is declining fast, it was important to look at areas with higher elevations on other islands where they could potentially survive into the future. These were found on Maui and the Big Island.

When speaking to Fortini, he is the first to acknowledge the “touchiness” of translocation as a conservation technique. Conserving forest bird habitat on Kaua`‘i is still extremely important and valuable, and most Kauaians would agree. But because of the direness of the situation with avian malaria, Fortini suggests that even the remoteness of options be explored.

“Is this even remotely feasible from a climactic point of view?” This, Fortini said, is a critical first question that must be asked. The study ultimately answered, yes, possibly. Secondly, researchers conducted a “climate niche overlap analysis” to compare the spatial overlap between the Kaua‘i endemics and native species on Maui and the Big Island. In other words, could the birds get along and survive together? Results showed that suitable climate-based ranges exist for the Kaua‘i birds that offer climatically distinct areas compared to the needs of the destination island endemics. However, there are many more variables that would need to be explored such as species behavior, underlying biology, and dietary requirements.

So how do we move forward given the myriad of questions involved? Unfortunately, the studies take time, the permitting takes time, the funding takes time, and ensuring the public is comfortable with novel techniques take even more time. Given this, Fortini points out it is important for the community to prioritize and research multiple options simultaneously as there is not going to be one silver bullet. Let’s hope there’s enough bullets and time for the sake of Kaua‘i’s forest birds!

Visit onlinelibrary.wiley.com/doi/10.1002/ece3.3451/full for the full study. Visit kauaiforestbirds.org for more information.

• Ruby Pap is a Coastal Land Use Extension Agent at University of Hawai‘i Sea Grant College Program. She can be reached at rpap@hawaii.edu.