Ray Pierce, Associate, Pacific Expeditions, Ltd., and Trustee, Pacific Conservation Action Trust.
With support from the Critical Ecosystem Partnership Fund (CEPF), Pacific Expeditions Ltd. launched an ecological survey of the isolated Phoenix Islands of Kiribati to determine the priorities for restoration of native plants and animals and the feasibility of eradicating invasive alien species.
What was the most important lesson learned?
Expedition members need to be experienced in their specific fields in order for them to be able to problem-solve difficult situations and adapt their survey methods accordingly.
Describe how you learned this and whether / how you have adapted your approach or specific project elements as a result.
In April-May 2006 Pacific Expeditions undertook an ecological survey of the isolated Phoenix Islands, Kiribati. The survey was the first step of a feasibility study for pest eradication and island restoration within the group. Key needs were to determine the status of seabirds and invasive alien species.
In rapid assessment programs, survey methods for seabirds and mammals generally comprise a wide range of diurnal and nocturnal counting methods, including bird colony counts, war-whooping (a method for attracting petrels), day- and night-spotlight transects for birds and mammals, trapping rodents, and looking for mammal spoor.
Difficulties arose in the Phoenix Islands when dangerous sea conditions prevented landing on one of the eight islands and limited the period ashore to a few daytime hours on a second island, both islands being of medium to high priority to survey.
Here, established survey methods were not going to work and other methods were needed in order to determine which of the 19 or so potential seabird species were present. The best method was to identify and count seabirds flying onto the leeward side of the islands in the last 1.5 hours of daylight.
Comparisons were subsequently made with other islands within the group on which more complete datasets were able to be collected both ashore and during the evening “fly-on.” There was a direct correlation between the two data-collecting methods, enabling us to draw conclusions about the avifauna composition of the two “difficult” islands with considerable confidence.
Another tactic was to circumnavigate the islands, which allowed us to map the locations of bird colonies without going ashore.
For mammals the standard trapping methods were frequently not feasible because of short time ashore, the danger of trapping birds, and/or the interference from high numbers of crabs which were also likely to remove animal spoor before we saw it.
Spotlighting proved to be a very effective mammal-detecting alternative particularly on the treeless islands. It had the added bonus of providing density data for rodents and rabbits (important data to help develop pest eradication plans), as well as having a high detection rating for cats.
Other methods were adapted to help confirm mammal species present, including providing hanging fish lures for cats (out of crab reach) and assessing signs of browsing on plants. Throughout this expedition, we were grateful to have an experienced boat crew, given the often tricky nature of coral reefs and landings.
- February 2, 2007