Influence of dispersal processes on the global dynamics of Emperor penguin, a species threatened by climate change

Abstract

Statement of authorship: † SJ and JG contributed equally to the study. SJ designed the study, SJ, 10JG and LD developed the model, SJ, JG, FP performed modeling work and analyzed output data. JG 11 and FP performed the theoretical mathematical analysis, SJ and JG wrote the manuscript, and all authors 12 contributed to revisions. 45When the population decline is driven by climate changes that exceed species' tolerance 46 or when acclimation and adaptation are insufficient to allow species persistence in a partic-47 ular location (Visser, 2008), species' dispersal capabilities could be the key for persistence 48 (Travis et al., 2012;Ponchon et al., 2015). Here, we study whether dispersal will act as an 49 ecological rescue mechanism to reverse the global population decline of species endangered by 50 climate change. We distinguish this ecological rescue from the local population rescue effect 51 in source-sink dynamic models (Hanski, 1982). Here, ecological rescue focuses on species 52 persistence, i.e. global population viability. local and global population declines are projected by the end of the century if sea ice con-58 centration (SIC) decreases at the rates projected by climate models (Jenouvrier et al., 2012, 59 2014). EPs depend on sea ice to breed, feed, and molt , and there is 60 an optimal amount of sea ice for population growth (Jenouvrier et al., 2012). Because sea 61 ice is projected to decline at geographically heterogeneous rates, some habitats will be more

Comparative population genomics reveals key barriers to dispersal in Southern Ocean penguins

“…Our results show that pelagic penguins can, and do, disperse among colonies separated by thousands of kilometres. Dispersal can decouple the relationship between local climate and demographic rates (Jenouvrier et al., ), facilitate range shifts, furnish populations with potentially adaptive genetic variants, and bolster population stability by compensating for low birth rates or survival (Lowe & Allendorf, ). Modelling studies that forecast population trends for pelagic penguins under future climate change scenarios should incorporate the dispersal patterns that we have outlined here, as in a recent study of emperor penguins (Jenouvrier et al., ).…”

“…Dispersal can decouple the relationship between local climate and demographic rates (Jenouvrier et al., ), facilitate range shifts, furnish populations with potentially adaptive genetic variants, and bolster population stability by compensating for low birth rates or survival (Lowe & Allendorf, ). Modelling studies that forecast population trends for pelagic penguins under future climate change scenarios should incorporate the dispersal patterns that we have outlined here, as in a recent study of emperor penguins (Jenouvrier et al., ). The conclusions of modelling studies for pelagic penguins that do not incorporate dispersal (Abadi, Barbraud, & Gimenez, ; Cimino et al., ; Jenouvrier et al., ) should be treated with caution.…”

“…This appears to be the case for Antarctic and sub‐Antarctic penguins, but they present a significant logistical challenge for studying dispersal (defined here as movement away from natal colonies to alternate breeding sites), as the vast majority of colonies are in remote locations. Banding studies initially suggested a high degree of philopatry in many species (Weimerskirch, Jouventin, Mougin, Stahl, & Van, ), and, until recently (Jenouvrier, Garnier, Patout, & Desvillettes, ), forecasts of extinction risk had not considered the potential buffering effect of dispersal (Cimino, Lynch, Saba, & Oliver, ; Jenouvrier et al., ). Genetic analyses (Clucas, Younger et al., ; Freer et al., ; Roeder et al., ; Younger, Clucas, et al., , ), observations of colony movements (LaRue, Kooyman, Lynch, & Fretwell, ) and fluctuations in colony size (Kooyman & Ponganis, ) indicate that dispersal may be common.…”

The Paris Agreement objectives will likely halt future declines of emperor penguins

“…We utilize a unique ensemble of transient climate simulations which are subject to emissions scenarios that have been specifically designed to meet the Paris Agreement targets (Sanderson et al, ) and provide the first analysis of Antarctic sea ice conditions in these simulations. Our study integrates these new climate projections with a mechanistic metapopulation model previously developed by Jenouvrier, Caswell, Barbraud, and Weimerskirch () and Jenouvrier et al (, , ), providing fundamental insight into the capacity for near‐term global action on climate policy to alter the future of an iconic marine predator.…”

“…Emperor penguins ( Aptenodytes forsteri ) are iconic examples of a species threatened by future climate change (Barbraud & Weimerskirch, ; Forcada & Trathan, ; Jenouvrier, Caswell, et al, ; Jenouvrier, Garnier, Patout, & Desvillettes, ; Jenouvrier et al, ; Ropert‐Coudert et al, ). The emperor penguin is classified as ‘near threatened’ by the International Union for the Conservation of Nature and is currently under consideration for inclusion under the United States Endangered Species Act.…”