The anatomy of a phenological mismatch: interacting consumer demand and resource characteristics determine the consequences of mismatching

Abstract

Climate change has caused shifts in seasonally recurring biological events and the temporal decoupling of consumer-resource pairs – i.e., phenological mismatching. Despite the hypothetical risk mismatching poses to consumers, they do not invariably lead to individual- or population-level effects. This may stem from how mismatches are typically defined, e.g., an individual or population is ‘matched’ or ‘mismatched’ based on the degree of asynchrony with a resource pulse. However, because both resource availability and consumer demands change over time, this categorical definition can obscure within- or among-individual fitness effects. We therefore developed models to identify the effects of resource characteristics on individual- and population-level processes and determine how the strength of these effects change throughout a consumer’s life. We then measured the effects of resource characteristics on the growth, daily survival, and fledging rates of Hudsonian godwit (Limosa haemastica) chicks hatched near Beluga River, Alaska. At the individual-level, chick growth and survival improved following periods of higher invertebrate abundance but were increasingly dependent on the availability of larger prey as chicks aged. At the population level, seasonal fledging rates were best explained by a model including age-structured consumer demand. Our study suggests that modelling the effects of mismatching as a disrupted interaction between consumers and their resources provides a biological mechanism for how mismatching occurs and clarifies when it matters to individuals and populations. Given the variable responses to mismatching across consumer populations, such tools for predicting how populations may respond under future climatic conditions will be invaluable.

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).…”

Behavioural adjustments in the social associations of a precocial shorebird mediate the costs and benefits of grouping decisions

“…For instance, in this study, godwit chicks were predated by gulls only in the first 14 days of development but were predated by generalist predators at similar rates throughout the pre‐fledging period. Meanwhile, previous observations suggest that the effects of resource availability also change over ontogeny, whereby periods of low resource quality reduce a chick’s survival more strongly as they age and require more energy (Wilde et al, 2020). The fact that neither gull density nor distance to the forest edge predicted the mortality rates of older chicks may therefore suggest that resources, rather than predation, play a stronger role during the later stages of chick development.…”

“…the Euclidian distance between tagged chicks) calculated with the package ‘ spatstat ’ in each plot separately (Baddeley & Turner, 2005) and the [2] godwit brood density per day per plot. Next, we estimated the effect of [3] chick hatch date to account for the survival effects of nesting attempt and phenology (Senner et al, 2017; Wilde et al, 2020). Finally, we tested the effect of heterospecific associations at time t with the [4] distance to the forest edge at a chick’s location in each plot separately as a proxy for risk from generalist predators that are typically more abundant nearer the forest edge in boreal regions (Lima, 2009; Robinson et al, 1995; Roos et al, 2018) and [5] relative gull density.…”