Forage plants of an Arctic-nesting herbivore show larger warming response in breeding than wintering grounds, potentially disrupting migration phenology.

Thomas K Lameris,Juul Limpens,Femke Jochems,Alexandra J Van Der Graaf,Bart A Nolet,Mattias Andersson

doi:10.1002/ece3.2859

Abstract

During spring migration, herbivorous waterfowl breeding in the Arctic depend on peaks in the supply of nitrogen‐rich forage plants, following a “green wave” of grass growth along their flyway to fuel migration and reproduction. The effects of climate warming on forage plant growth are expected to be larger at the Arctic breeding grounds than in temperate wintering grounds, potentially disrupting this green wave and causing waterfowl to mistime their arrival on the breeding grounds. We studied the potential effect of climate warming on timing of food peaks along the migratory flyway of the Russian population of barnacle geese using a warming experiment with open‐top chambers. We measured the effect of 1.0–1.7°C experimental warming on forage plant biomass and nitrogen concentration at three sites along the migratory flyway (temperate wintering site, temperate spring stopover site, and Arctic breeding site) during 2 months for two consecutive years. We found that experimental warming increased biomass accumulation and sped up the decline in nitrogen concentration of forage plants at the Arctic breeding site but not at temperate wintering and stop‐over sites. Increasing spring temperatures in the Arctic will thus shorten the food peak of nitrogen‐rich forage at the breeding grounds. Our results further suggest an advance of the local food peak in the Arctic under 1–2°C climate warming, which will likely cause migrating geese to mistime their arrival at the breeding grounds, particularly considering the Arctic warms faster than the temperate regions. The combination of a shorter food peak and mistimed arrival is likely to decrease goose reproductive success under climate warming by reducing growth and survival of goslings after hatching.

Highlights

The matching of animal’s annual cycles to peaks in food availability is considered to be an important adaptation for successful reproduction (Lack, 1968)
The effects of climate warming on forage plant growth are expected to be larger at the Arctic breeding grounds than in temperate wintering grounds, potentially disrupting this green wave and causing waterfowl to mistime their arrival on the breeding grounds
We studied the potential effect of climate warming on timing of food peaks along the migratory flyway of the Russian population of barnacle geese using a warming experiment with open-top chambers

Summary

Introduction

The matching of animal’s annual cycles to peaks in food availability is considered to be an important adaptation for successful reproduction (Lack, 1968). | 2653 arrival on stopover sites to local peaks of food abundance along the gradient, described as the “green wave hypothesis” (Drent, Ebbinge, & Weijand, 1978; Shariatinajafabadi et al, 2014; Thorup et al, 2017; van der Graaf, Stahl, Klimkowska, Bakker, & Drent, 2006) This strategy is especially important for species which partly rely on capital body stores accumulated at staging sites for egg formation and incubation, such as geese (Drent et al, 2007; Gauthier, Bêty, & Hobson, 2003; Hahn, Loonen, & Klaassen, 2011). Accelerated warming in the Arctic is expected to cause food peaks in Arctic regions to advance at a faster rate than in temperate regions, which could cause mismatches especially for Arctic long- distance migrants (McKinnon, Picotin, Bolduc, Juillet, & Bêty, 2012)

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