Distribution and population of the endangered akiapolaau

Author:

Fancy, Steven G., Sandin, Stuart A., Reynolds, Michelle H., Jacobi, James D.

Title:

Distribution and population of the endangered akiapolaau

Periodical:

Pacific Science

Year:

1996

Volume:

50

Pages:

355-362

Subject:

Akiapolaau Hemignathus munroi Hawaiian honeycreepers Endangered species birds

Summary:

An endangered and specialized species, the Akiapolaau (Hemignathus munroi Rothschild), is a Hawaiian honeycreeper that is found only in high-elevation native forests on the island of Hawaii. Once fairly abundant and found as low as the 500 meter elevation of the koa (Acacia koa) forests near Hilo and in the koa-ohia (Metrosideros polymorpha) forests that are located above the 1700 meter elevation in the Hawaii Volcanoes National park, they had disappeared from the park and were less common elsewhere by the 1970s. During Hawaii Forest Bird Surveys (HFBS) that were done on the island of Hawaii from 1976 - 1979, four disjunct populations of Akiapolaau were found that equaled approximately 1500 birds. This included approximately 533 birds that were found in the Kau Forest Reserve and approximately 46 birds that were found in dry mamane (Sophora chrysophylla [Salisb.] Seem.) forest that is located on Mauna Kea. However, since the Akiapolaau are so rare, it was necessary to use data for other species in an effort to determine the effective area that was surveyed for the Akiapolaau. It was also necessary to use data interpolation and smoothing techniques in an effort to derive the HFBS estimate of 1500 Akiapolaau. During this study, a newly developed analysis approach was used to estimate the population size for Akiapolaau that was based on surveys that were conducted from 1990-1995. All of the latest detections of Akiapolaau were plotted and based on distribution of koa (Acacia koa A. Gray) forests and elevation contours the current distribution of the species was stratified. Through this technique, a population estimate was derived. This was done by multiplying the density of Akiapolaau within each stratum, (as determined from variable circular plot counts), by the area within each stratum. As a result, it was estimated that there were 1163 plus or minus 54 (or 90% CI) Akiapolaau in the world. It was found that the distribution of the Akiapolaau was greatly reduced in the Kau District, where the estimated population declined from 533 to 44 birds. It was also found that relic populations in the mamane forest and in the South Kona area were likely to become extinct within the next 5 years. Due to these findings, it was determined the protection and management of the remaining isolated stands of koa forest at higher elevations, where mosquitoes are absent or occur only seasonally, are critical to the survival of this species.

Label:

Birds - Akiapolaau

URL:

http://hdl.handle.net/10125/2908

Date:

1996

Collection:

Periodicals