Population Ecology

, Volume 53, Issue 3, pp 473–481

Long-term population trends of endangered Hawaiian waterbirds

Authors

    • Department of BiologyTufts University
  • Chris S. Elphick
    • Department of Ecology and Evolutionary Biology, Center for Conservation and BiodiversityUniversity of Connecticut
  • Elena N. Ieno
    • Highlands Statistics, Ltd.
    • OceanlabUniversity of Aberdeen
  • Alain F. Zuur
    • Highlands Statistics, Ltd.
    • OceanlabUniversity of Aberdeen
Original Article

DOI: 10.1007/s10144-011-0262-9

Cite this article as:
Reed, J.M., Elphick, C.S., Ieno, E.N. et al. Popul Ecol (2011) 53: 473. doi:10.1007/s10144-011-0262-9

Abstract

We analyzed long-term winter survey data (1956–2007) for three endangered waterbirds endemic to the Hawaiian Islands, the Hawaiian moorhen (Gallinula chloropus sandvicensis), Hawaiian coot (Fulica alai), and Hawaiian stilt (Himantopus mexicanus knudseni). Time series were analyzed by species–island combinations using generalized additive models, with alternative models compared using Akaike information criterion (AIC). The best model included three smoothers, one for each species. Our analyses show that all three of the endangered Hawaiian waterbirds have increased in population size over the past three decades. The Hawaiian moorhen increase has been slower in more recent years than earlier in the survey period, but Hawaiian coot and stilt numbers still exhibit steep increases. The patterns of population size increase also varied by island, although this effect was less influential than that between species. In contrast to earlier studies, we found no evidence that rainfall affects counts of the target species. Significant population increases were found on islands where most wetland protection has occurred (Oahu, Kauai), while weak or no increases were found on islands with few wetlands or less protection (Hawaii, Maui). Increased protection and management, especially on Maui where potential is greatest, would likely result in continued population gains, increasing the potential for meeting population recovery goals.

Keywords

Endangered speciesGeneralized additive modelsManagementRecoveryTime seriesWetland

Supplementary material

10144_2011_262_MOESM1_ESM.pdf (270 kb)
Supplementary material (PDF 269 kb)

Copyright information

© The Society of Population Ecology and Springer 2011