10.5061/dryad.bk200
https://zenodo.org/records/5007769
oai:zenodo.org:5007769
Bijleveld, Allert I.
Allert I.
Bijleveld
Royal Netherlands Institute for Sea Research
Twietmeyer, Sönke
Sönke
Twietmeyer
Piechocki, Julia
Julia
Piechocki
Royal Netherlands Institute for Sea Research
van Gils, Jan A.
Jan A.
van Gils
Royal Netherlands Institute for Sea Research
Piersma, Theunis
Theunis
Piersma
University of Groningen
Data from: Natural selection by pulsed predation: survival of the thickest
Zenodo
2016
predator defense
Cerastoderma edule
foraging
directional selection
intertidal mudflats
shorebirds
competitive release
Calidris canutus islandica
soft-sediment habitat
phenotypic selection
Holocene
selective predation
2016-01-13
10.1890/14-1845.1
https://zenodo.org/communities/dryad
Creative Commons Zero v1.0 Universal
Selective predation can lead to natural selection in prey populations and may alleviate competition among surviving individuals. The processes of selection and competition can have substantial effects on prey population dynamics, but are rarely studied simultaneously. Moreover, field studies of predator-induced short-term selection pressures on prey populations are scarce. Here we report measurements of density dependence in body composition in a bivalve prey (edible cockle, Cerastoderma edule) during bouts of intense predation by an avian predator (red knot, Calidris canutus). We measured densities, patchiness, morphology, and body composition (shell and flesh mass) of cockles in a quasi-experimental setting, i.e. before and after predation in three similar plots of 1 ha each, two of which experienced predation, and one of which remained unvisited in the course of the short study period and served as a reference. An individual's shell and flesh mass declined with cockle density (negative density dependence). Before predation, cockles were patchily distributed. After predation, during which densities were reduced by 78% (from 232 m-2 to 50 m-2), the patchiness was substantially reduced, i.e. the spatial distribution was homogenized. Red knots selected juvenile cockles with an average length of 6.9 mm (SD 1.0). Cockles surviving predation had heavier shells than before predation (an increase of 21.5 percentage points), but similar flesh masses. By contrast, in the reference plot shell mass did not differ statistically between initial and final sampling occasions, while flesh mass was larger (an increase of 13.2 percentage points). In this field-study, we show that red knots imposed a strong selection pressure on cockles to grow fast with thick shells and little flesh mass, with selection gradients among the highest reported in the literature.
data on cockle body composition and density
This file contains the field data underlying the analyses of density dependence among cockles (figure 1 and Table 1) as well as for calculating relative body composition (online figure S2). An explanation of the variables is included in the supplementary file "1_body_composition_density_dependence_readme.txt".
1_body_composition_density_dependence.csv
r script for calculating relative body composition
This is the R script to calculate relative cockle body compositions using the data from file 1: "1_body_composition_density_dependence.csv".
1_relative_body_composition.r
spatial data on densities of cockles before and after predation
This file contains the data underlying the analyses of spatial density distributions of cockles before and after predation (figure 2), and for calculating autocorrelation functions (figure 3). An explanation of the variables is included in the supplementary file "2_spatial_density_distribution_predation_readme.txt".
2_spatial_density_distribution_predation.csv
data on length distributions and body composition before and after predation
This is the data underlying the analyses of length distributions (figure 4) and cockle body composition (figure 5 and online Table S1) before and after predation by red knots, as well as for calculating selection gradients (Table 2). An explanation of the variables is included in the supplementary file "3_body_composition_predation_readme.txt".
3_body_composition_predation.csv
general documentation
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The Netherlands
Griend
5°15.219'E
53°14.615'N
Wadden Sea