Comparison of adult census size and effective population size support the need for continued protection of two Solomon Island endemics

Sarah A. Cowles, Brian C. Weeks, Lindsey Perrin, Nancy Chen, J. Albert C. Uy

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Because a population’s ability to respond to rapid change is dictated by standing genetic variation, we can better predict a population’s long-term viability by estimating and then comparing adult census size (N) and effective population size (Ne). However, most studies only measure N or Ne, which can be misleading. Using a combination of field and genomic sequence data, we here estimate and compare N and Ne in two range-restricted endemics of the Solomon Islands. Two Zosterops White-eye species inhabit the small island of Kolombangara, with a high elevation species endemic to the island (Z. murphyi) and a low elevation species endemic to the Solomon Islands (Z. kulambangrae). Field observations reveal large values of N for both species with Z. kulambangrae numbering at 114,781 ± 32,233 adults, and Z. murphyi numbering at 64,412 ± 15,324 adults. In contrast, genomic analyses reveal that Ne was much lower than N, with Z. kulambangrae estimated at 694.5 and Z. murphyi at 796.1 individuals. Further, positive Tajima’s D values for both species suggest that they have experienced a demographic contraction, providing a mechanism for low values of Ne. Comparison of N and Ne suggests that Z. kulambangrae and Z. murphyi are not at immediate threat of extinction but may be at genetic risk. Our results provide important baseline data for long-term monitoring of these island endemics, and argue for measuring both population size estimates to better gauge long-term population viability.

Original languageEnglish (US)
Pages (from-to)45-54
Number of pages10
Issue number1-2
StatePublished - 2021


  • Zosterops
  • census population size
  • conservation genetics
  • effective population size

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Animal Science and Zoology
  • Nature and Landscape Conservation


Dive into the research topics of 'Comparison of adult census size and effective population size support the need for continued protection of two Solomon Island endemics'. Together they form a unique fingerprint.

Cite this