The past, the present and the future of Willow ptarmigan (Lagopus lagopus) and Rock ptarmigan (Lagopus muta): A bird's eye view

Genomics has been shown to be an important tool when conducting conservation evaluations. Genetic diversity can greatly affect a population’s health, survival and ability to adapt to a changing environment. An important factor all species must face in recent times is changing environments with increasing temperatures and anthropogenic processes; genetic diversity gives the population a possibility to adapt to these factors. So, evaluating species conservation status should include genetic analyses as well as demographic analyses. The species willow (Lagopus lagopus) and rock ptarmigan (Lagopus muta) have a northern distribution and are well adapted to a colder climate, which make them especially affected by a changing environment. In recent years both species have been facing a population decrease. In the IUCN red list, rock ptarmigan was considered near threatened and willow ptarmigan considered vulnerable in Europe in 2015. This study was conducted to aid in the evaluation of these species. Genetic analyses of samples ranging in time from 1840 to 2024 were used to see genetic structure and change in genetic variation of the populations. Demographic analyses were performed from hunting data ranging from 1955 to 2023 to see population trends as well as being the foundation for predictions of the future. The results showed a decrease in population size for both species as well as a high probability of quasi-extinction for rock ptarmigan within the next 50 years. Both species had low levels of heterozygosity and rock ptarmigan had a high proportion of runs of homozygosity. Similar to previous studies, the most important factor to increase growth rate of the willow population was the survival rate of adults. The results suggest that a re-evaluation could be necessary for these species. This would help determine whether they are in need of conservation efforts before they end up on the red list again. Potential conservation efforts should be focused on increasing the survival of adults in willow ptarmigan.