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Dynamic sensitivity to resource availability influences population responses to mismatches in a shorebird

Citation

Wilde, Luke; Simmons, Josiah; Swift, Rose; Senner, Nathan (2022), Dynamic sensitivity to resource availability influences population responses to mismatches in a shorebird, Dryad, Dataset, https://doi.org/10.5061/dryad.x69p8czh0

Abstract

Climate change has caused shifts in seasonally recurring biological events leading to the temporal decoupling of consumer-resource pairs – i.e., phenological mismatching. Although mismatches often affect individual fitness, they do not invariably scale up to affect populations, making it difficult to assess the risk they pose. Individual variation may contribute to this inconsistency, with changes in resource availability and consumer needs leading mismatches to have different outcomes over time. Nevertheless, most models estimate a consumer’s match from a single timepoint, potentially obscuring when mismatches matter to populations. We analyzed how the effects of mismatches varied over time by studying precocial Hudsonian godwit (Limosa haemastica) chicks and their invertebrate prey from 2009 to 2019. We developed individual and population level models to determine how age-specific variation affect the relationship between godwits and resource availability. We found that periods with abundant resources led to higher growth and survival of godwit chicks, but also that chick survival was increasingly related to the availability of larger prey as chicks aged. At the population level, estimates of mismatches using age-structured consumer demand explained more variation in annual godwit fledging rates than more commonly used alternatives. Our study suggests that modeling the effects of mismatches as the disrupted interaction between dynamic consumer needs and resource availability clarifies when mismatches matter to both individuals and populations.

Methods

During 2009 – 2011, 2014 – 2016, and 2019, we monitored godwit chicks in two plots – North (550 Ha) and South (120 Ha) – near Beluga River, Alaska (61.21°N, 151.03°W). We followed radioed chicks until fledge, resighting every 2-3 days and capturing each week to measure mass through time. In all years (shortened seasons of 2012 and 2017), we collected invertebrates each day along two, 100-m transects of five traps within godwit breeding habitat according to the Arctic Shorebird Demographics Network Breeding Camp Protocol, Version 5. We recorded identified all adult invertebrates to taxonomic order, but excluded Collembola from analyses (see text for details). We measured body lengths in mm and converted these to order-specific dry-mass using published equations. We estimated three metrics from invertebrate sampling data: resource peak, resource abundnance, and median resource quality. Resource peak was where the first derivative of a quadratic curve fit to invertebrate biomass abundnance was 0 (absolute maximum of the curve), resource abundance was the total biomass per day, averaged between the two transects, and resource quality was the per capita median body mass of sampled invertebrates.

Using these two datasets - invertebrates and chick mass, we performed analyses to determine the factors driving chick growth, chick survival, and the trends through time of invertebrate metrics.

Usage Notes

This dataset accompanies open-source code at the authors GitHub page (https://github.com/luke-wilde/DynSens2ResAvail_ECY21-0841.R1).

Funding

Association of Field Ornithologists, Award: E.A. Bergstrom Award

Wilson Ornithological Society, Award: P.A. Stewart Award

American Ornithological Society

Arctic Audubon Society

Cornell Lab of Ornithology

Athena Fund at Cornell Lab of Ornithology

Fauccett Family Foundation

David and Lucile Packard Foundation

National Science Foundation, Award: PCE-1110444

U.S. Fish and Wildlife Service, Award: 4074

National Science Foundation, Award: DGE-1144153

U.S. Fish and Wildlife Service, Award: 5147