Current selection for lower migratory activity will drive the evolution of residency in a migratory bird population

Abstract

Global warming is impacting biodiversity by altering the distribution, abundance, and phenology of a wide range of animal and plant species. One of the best documented responses to recent climate change is alterations in the migratory behavior of birds, but the mechanisms underlying these phenotypic adjustments are largely unknown. This knowledge is still crucial to predict whether populations of migratory birds will adapt to a rapid increase in temperature. We monitored migratory behavior in a population of blackcaps (Sylvia atricapilla) to test for evolutionary responses to recent climate change. Using a common garden experiment in time and captive breeding we demonstrated a genetic reduction in migratory activity and evolutionary change in phenotypic plasticity of migration onset. An artificial selection experiment further revealed that residency will rapidly evolve in completely migratory bird populations if selection for shorter migration distance persists. Our findings suggest that current alterations of the environment are favoring birds wintering closer to the breeding grounds and that populations of migratory birds have strongly responded to these changes in selection. The reduction of migratory activity is probably an important evolutionary process in the adaptation of migratory birds to climate change, because it reduces migration costs and facilitates the rapid adjustment to the shifts in the timing of food availability during reproduction.adaptation | bird migration | climate change | genetic variation | natural selection

Partial migration and decreasing migration distance in the Hungarian population of the Common Blackbird (Turdus merula Linnaeus, 1758): Analysis of 85 years of ring recovery data

“…The breeding and wintering ranges of migratory birds, along with the timing of their migrations are among the most affected, particularly at higher latitudes and altitudes (Fiedler 2003). Rising global temperatures have been linked to earlier arrival on the breeding grounds (Pulido 2007), shorter migration distances, likely due to shifting wintering ranges (Fiedler et al 2004, Visser et al 2009), changing migration routes (Sutherland 1998), and changes in the proportion of migrating individuals as migratory birds are becoming more sedentary (Pulido & Berthold 2010, Knudsen et al 2011.…”

Transboundary Wildlife Conservation in A Changing Climate: Adaptation of the Bonn Convention on Migratory Species and Its Daughter Instruments to Climate Change

“…Hence, currently migratory populations or species could become partly or wholly sedentary under influence of climate change [15,16]. Indeed, with regard to birds there is already "ample observational evidence […] of migratory birds becoming more sedentary" [16].…”

“…As regards the content of this article, thanks are due to the CMS Secretariat for inviting the author to contribute to the process of "climate-proofing" the CMS regime. The author, furthermore, gratefully acknowledges helpful comments acquired when presenting and discussing the research for this article at, inter alia, the 8th Colloquium of the IUCN Academy of Environmental Law (Ghent, [14][15][16][17] …”

Climate change alters the optimal wind-dependent flight routes of an avian migrant

“…Moreover, although such temporal adjustments can save the population from extinction, the birds will bear the costs of delayed arrival in wintering grounds. Another possibility for the population to survive would be to adjust their migratory strategy, by either becoming sedentary (see [30,36]) or switching to an overland route through the Korean peninsula and China while fuelling their migration by adopting a stop-and-forage strategy. Again, it remains unclear whether the population will be able to adapt to such changes through phenotypic adjustments or evolutionary responses over such a short period of time.…”