How migratory populations become resident

Abstract

Migratory behaviour is rapidly changing in response to recent environmental changes, yet it is difficult to predict how migration will evolve in the future. To understand what determines the rate of adaptive evolutionary change in migratory behaviour, we simulated the evolution of residency using an individual-based threshold model, which allows for variation in selection, number of genes, environmental effects and assortative mating. Our model indicates that the recent reduction in migratory activity found in a population of Eurasian blackcaps (Sylvia atricapilla) is only compatible with this trait being under strong directional selection, in which residents have the highest fitness and fitness declines exponentially with migration distance. All other factors had minor effects on the adaptive response. Under this form of selection, a completely migratory population will become partially migratory in 6 and completely resident in 98 generations, demonstrating the persistence of partial migration, even under strong directional selection. Resident populations will preserve large amounts of cryptic genetic variation, particularly if migration is controlled by a large number of genes with small effects. This model can be used to realistically simulate the evolution of any threshold trait, including semi-continuous traits like migration, for predicting evolutionary response to natural selection in the wild.

Genetic growth potential, rather than phenotypic size, predicts migration phenotype in Atlantic salmon

“…These results widen our understanding of genetic and environmental importance in developmental transitions, as well as their thermal stability, thereby providing quantitative primers for future modelling relying on environmental versus genetic relationships among life-history traits across environmental temperatures (e.g. [33]).…”

“…The results, thereby, provide quantitative primers for future modelling relying on environmental versus genetic relationships among life-history traits across environmental temperatures [e.g. 4,26,33]. Given that the tested temperature difference of 2°C aligns with global warming scenarios [52], modelling may encompass evolution under current global warming.…”

Linking Socioeconomics to Biodiversity in the City: The Case of a Migrant Keystone Bird Species

“…Billions of wild animals migrate every year between breeding and non-breeding sites (Robinson et al, 2009;Dokter et al, 2018). These migrants commonly travel to reproduce in seasonal environments that offer a large amount of food for a short time (Dingle and Drake, 2007;de Zoeten and Pulido, 2020). Such massive animal movements not only benefit migrating animals but also underpin ecosystem functions along migration routes (e.g., Kauffman et al, 2021).…”

“…This adaptation to natural resource fluctuation in space and time can be affected by anthropogenic change. Migrant behavior is rapidly changing due to human impacts on the environment that pose a strong selective pressure on wild populations (de Zoeten and Pulido, 2020). Landscape and climate change can influence species phenology, such as periods of migration and reproduction.…”

Carryover effects of long-distance avian migration are weaker than effects of breeding environment in a partially migratory bird

“…Increasingly clement wintering conditions may also create phenological mismatches that disproportionately affect longer-distance migrants 25 . If anthropogenic change leads to a breakdown in the parity of fitness between migrants and residents it could lead to rapid changes in migratory behaviour, potentially ultimately leading to the disappearance of migration 26 . In light of the potential for cumulative carryover effects to manifest in the subsequent breeding season, we might expect long-distance migrants in partially migratory populations to be in worse condition than residents, breeding later and with lower reproductive fitness.…”