Authors: Duntsch, Laura; Whibley, Annabel;Bailey, Sarah;Brekke, Patricia;Ewen, John G.;Santure, Anna W.;

In small populations, inbreeding – the mating between close relatives – can exacerbate the loss of genetic diversity and may reduce the adaptive potential of the species. In addition, inbreeding can also prompt a reduction of fitness in a population, termed inbreeding depression.
One of Aotearoa’s species of conservation concern is the hihi (stitchbird; Notiomystis cincta), a threatened endemic passerine. In 1995, hihi individuals were translocated onto Tiritiri Mātangi island, and since then, a wealth of life history, pedigree and genetic data has been collected. Together with a recently developed genome assembly and 40k single nucleotide polymorphism (SNP) markers, these resources provide a unique opportunity to measure the impacts of inbreeding in hihi from the Tiritiri Mātangi population. Here, we present individual-based inbreeding levels and infer how severely the population has been impacted by the effects of inbreeding depression. With a genome-wide association approach, we examine whether effects of many slightly deleterious variants across the genome are contributing to inbreeding depression in the hihi, if at all, rather than fewer (but distinct) inbred regions.
My work draws a clearer picture of the adaptive potential of the species to adapt to future challenges such as climate change, and informs conservation management.