Density dependence and phenological mismatch: consequences for growth and survival of sub-arctic nesting Canada Geese

Abstract

ABSTRACT. The extent to which species are plastic in the timing of their reproductive events relative to phenology suggests how climate change might affect their demography. An ecological mismatch between the timing of hatch for avian species and the peak availability in quality and quantity of forage for rapidly growing offspring might ultimately affect recruitment to the breeding population unless individuals can adjust the timing of breeding to adapt to changing phenology. We evaluated effects of goose density, hatch timing relative to forage plant phenology, and weather indices on annual growth of pre-fledging Canada geese (Branta canadensis) from 1993-2010 at Akimiski Island, Nunavut. We found effects of both density and hatch timing relative to forage plant phenology; the earlier that eggs hatched relative to forage plant phenology, the larger the mean gosling size near fledging. Goslings were smallest in years when hatch was latest relative to forage plant phenology, and when local abundance of breeding adults was highest. We found no evidence for a trend in relative hatch timing, but it was apparent that in early springs, Canada geese tended to hatch later relative to vegetation phenology, suggesting that geese were not always able to adjust the timing of nesting as rapidly as vegetation phenology was advanced. Analyses using forage biomass information revealed a positive relationship between gosling size and per capita biomass availability, suggesting a causal mechanism for the density effect. The effects of weather parameters explained additional variation in mean annual gosling size, although total June and July rainfall had a small additive effect on gosling size. Modelling of annual firstyear survival probability using mean annual gosling size as an annual covariate revealed a positive relationship, suggesting that reduced gosling growth negatively impacts recruitment.Dépendance à la densité et désynchronisation phénologique : conséquences sur la croissance et la survie des Bernaches du Canada nichant en milieu subarctique RÉSUMÉ. Le degré de plasticité que montrent les espèces dans la chronologie de leurs activités de reproduction en fonction de la phénologie nous en apprend sur la façon avec laquelle les changements climatiques pourraient affecter leur démographie. Un décalage entre la période d'éclosion des oiseaux et le pic de disponibilité des ressources alimentaires, tant en quantité qu'en qualité, pour les jeunes en croissance, peut ultimement perturber le recrutement dans la population nicheuse, à moins que les individus ne soient capables de synchroniser leur reproduction avec la phénologie changeante. Nous avons évalué les effets de la densité des bernaches, de la période d'éclosion relativement à la phénologie des plantes recherchées pour l'alimentation, et de paramètres météorologiques sur la croissance annuelle de Bernaches du Canada (Branta canadensis) avant leur premier envol, de 1993 à 2010, sur l'île Akimiski au Nunavut. Nous avons observé des effets de la densité et la période d'éc...

Decadal declines in avian herbivore reproduction: density‐dependent nutrition and phenological mismatch in the Arctic

“…(), and a study of sub‐arctic‐nesting Canada Geese ( Branta canadensis ) using similar NDVI data is presented in Brook et al. (). We assumed that the median day of year when NDVI 50 was attained for all vegetation was a reasonable proxy for the phenology of goose forage species alone, as have others (Brook et al.…”

Phenological mismatch in Arctic‐breeding shorebirds: Impact of snowmelt and unpredictable weather conditions on food availability and chick growth

“…By adjusting phenology, individuals can time life-history events so that peak food demands of developing young coincide with peak prey availability (Bronson, 1985;Durant, Hjermann, Ottersen, & Stenseth, 2007;Visser, Holleman, & Gienapp, 2006). However, organisms within different trophic levels may respond to changes in their environment at different rates (Cohen, Lajeunesse, & Rohr, 2018;Thackeray et al, 2016), potentially resulting in phenological mismatches between predators and their prey (Both, Asch, Bijlsma, Burg, & Visser, 2009;Brook, Leafloor, Abraham, & Douglas, 2015;Doiron, Gauthier, & Lévesque, 2015;Durant et al, 2007;Gaston, Gilchrist, Mallory, & Smith, 2009;Harrington, Woiwod, & Sparks, 1999;Visser et al, 2006;Visser, Noordwijk, Tinbergen, & Lessells, 1998).…”

Drivers and Environmental Responses to the Changing Annual Snow Cycle of Northern Alaska

“…Geese are observed to fledge fewer goslings in years with greater mismatch between nesting dates and vegetation phenology, especially when eggs hatch late (relative to the vegetation) and young growing birds are deprived of the seasonal peak in highquality forage (Brook et al 2015;Doiron et al 2015). Caribou calves <1 month in age, however, have higher survival rates in years with earlier snowmelt (Griffith et al 2002), although all resident grazing species in the Arctic (e.g., caribou, reindeer, muskox, voles, etc.)…”