Jack Sytsma

Author    Correspondence author
International Journal of Molecular Ecology and Conservation, 2026, Vol. 16, No.   
Received: 01 Jan., 1970    Accepted: 01 Jan., 1970    Published: 08 Jun., 2026

Understanding how contemporary population declines translate into genomic consequences is critical for conservation, particularly in island ecosystems where species are highly vulnerable to environmental change. Here, we integrate long-term occurrence data with genome-wide diversity metrics to assess population status across four Hawaiian bird species representing a gradient of conservation concern: Hawaiʻi ʻamakihi (Chlorodrepanis virens), Maui parrotbill (Pseudonestor xanthophrys), ʻalalā (Corvus hawaiiensis), and Christmas shearwater (Puffinus nativitatis). Occurrence trends were quantified using reporting rates from 2000-2025 and genomic diversity was assessed using nucleotide diversity, heterozygosity, runs of homozygosity, and inbreeding coefficients from shotgun sequencing data. Results indicate that species exhibiting stronger declines in occurrence showed significantly reduced genomic diversity and elevated inbreeding. The ʻalalā and Maui parrotbill, which displayed the steepest declines in reporting rate, also exhibited the lowest nucleotide diversity and highest inbreed coefficients. In contrast, the Hawaiʻi ʻamakihi and Christmas shearwater showed relatively stable occurrence and retained higher genetic diversity. Elevational analyses further indicated upward shifts in detection for declining forest species, consistent with restriction to high elevation refugia. Across species, occurrence trends were strongly associated with genomic metrics, suggesting that recent demographic changes are reflected patterns of genetic variation. Our findings demonstrate that integrating occurrence data with genomic analyses provides a powerful framework for assessing population health. Such approaches are particularly valuable for conservation in island systems, where rapid environmental change and disease pressure continue to threaten endemic biodiversity.