Disentangling the diet composition of chicks of Arctic shorebirds provides a new perspective on trophic mismatches

Abstract

With rapid climatic changes over the past decades, organisms living in seasonal environments are suggested to increasingly face trophic mismatches: the disruption of synchrony between different trophic levels due to a different phenological response to increasing temperatures. Strong effects of mismatches are especially expected in the Arctic region, where climatic changes are most rapid. Nevertheless, relatively few studies have found strong evidence for trophic mismatches between the breeding period of Arctic-breeding shorebirds and the arthropod prey on which they rely. Here we argue that this is potentially caused by a generalisation of trophic interactions. While many studies have measured the mismatch relative to the peak in abundance of all available arthropod species, we use metabarcoding of prey items in faeces to show that chicks of four different shorebird species (red knot, curlew sandpiper, little stint, and red phalarope) strongly differ in their arthropod diet. Three out of the four species feed on arthropods peaking in availability five-ten days before the overall arthropod peak which had implications for the calculations of trophic mismatches. We conclude that ignoring diet selectivity hampers our understanding of phenological mismatches.

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

“…Some arctic shorebird species, like Dunlin ( Calidris alpina ) and Sanderling ( Calidris alba ), are already breeding late relative to seasonal peaks in arthropod abundance (McKinnon et al., 2012, 2013; Reneerkens et al., 2016; see also Figure 4) and hence may not benefit from a potential positive effect of temperature on arthropod peak biomass. Birds having more specialized diets or those dependant on highly nutritional food resources could also be more vulnerable to warming‐induced changes in prey phenology and quality (Arnold et al., 2010; Wilde et al., 2020; Zhemchuzhnikov et al., 2022). Hence, further investigations may be useful to fully quantify the risk of mismatch for arctic insectivorous birds, while considering that higher temperatures encountered by chicks could provide thermogenic relief that can compensate (or not) for their lack of synchrony (Lameris et al., 2022; McKinnon et al., 2013; Saalfeld et al., 2021).…”

Sanderlinks

“…A well described and common effect is phenological mismatch (Visser & Gienapp 2019): animals that previously would have synchronized patterns of occurrence and use (as prey and consumers) become desynchronized (e.g. , but also see Zhemchuznikov et al 2022). In the Wadden Sea, the advancement in shrimp settlement seems to have resulted in a match, rather than a mismatch.…”