Life‐history attributes of Arctic‐breeding birds drive uneven responses to environmental variability across different phases of the reproductive cycle

Abstract

Animals exhibit varied life-history traits that reflect adaptive responses to their environments. For Arctic-breeding birds, traits related to diet, egg nutrient allocation, clutch size, and chick growth are predicted to be under increasing selection pressure due to rapid climate change and increasing environmental variability across high-latitude regions. We compared four migratory birds (black brant [Branta bernicla nigricans], lesser snow geese [Chen caerulescens caerulescens], semipalmated sandpipers [Calidris pusilla], and Lapland longspurs [Calcarius lapponicus]) with varied life histories at an Arctic site in Alaska, USA, to understand how life-history traits help moderate environmental variability across different phases of the reproductive cycle.We monitored aspects of reproductive performance related to the timing of breeding, reproductive investment, and chick growth from 2011 to 2018. In response to early snowmelt and warm temperatures, semipalmated sandpipers advanced their site arrival and bred in higher numbers, while brant and snow geese increased clutch sizes; all four species advanced their nest initiation dates. During chick rearing, longspur nestlings were relatively resilient to environmental variation, whereas warmer temperatures increased the growth rates of sandpiper chicks but reduced growth rates of snow goose goslings. These responses generally aligned with traits along the capitalincome spectrum of nutrient acquisition and altricial-precocial modes of chick growth.Under a warming climate, the ability to mobilize endogenous reserves likely provides geese with relative flexibility to adjust the timing of breeding and the size of clutches.Higher temperatures, however, may negatively affect the quality of herbaceous foods and slow gosling growth. Species may possess traits that are beneficial during one phase of the reproductive cycle and others that may be detrimental at another phase, uneven responses that may be amplified with future climate warming. These results underscore the need to consider multiple phases of the reproductive cycle when assessing the effects of environmental variability on Arctic-breeding birds.

A circumpolar study unveils a positive non‐linear effect of temperature on arctic arthropod availability that may reduce the risk of warming‐induced trophic mismatch for breeding shorebirds

“…Our results also suggest that some generalist insectivorous arctic bird populations may be less vulnerable to mismatch than expected due to a potential warming‐induced increase in food availability. Moreover, some shorebirds (and other insectivorous birds) can advance their breeding dates under warmer conditions (Kwon et al., 2019; Liebezeit et al., 2014; Ruthrauff et al., 2021). Although this advancement may not perfectly track phenological shifts in environmental conditions (Saalfeld & Lanctot, 2017), it should also reduce the risk of trophic mismatch.…”

Use of amino acid isotope analysis to investigate capital versus income breeding strategies in migratory avian species

“…Resource allocation trade‐offs between survival and reproduction are a fundamental aspect of individual fitness and affect the long‐term persistence of populations (Lameris et al, 2019). Income and capital breeders represent opposing ends of an exogenous‐to‐endogenous resource allocation continuum, with migratory avian and mammalian species exhibiting variable reliance on each (Hupp et al, 2018; Meijer & Drent, 1999; Ruthrauff et al, 2021). This may be attributed to variability in environmental conditions, resource phenology, individual physiology, body size and genotype (Williams et al, 2017).…”