Predation governs the eulittoral distribution of a ubiquitous Mediterranean gastropod

This repository contains data and annotated R code accompanying article 10.1007/s10750-023-05143-4 in Hydrobiologia, split into the four data and code folders Introduction, Density, Predation and Physiology alongside the published Manuscript.pdf, Supplement.pdf and Figures in vector format. Below is a description of each column within each dataset and the input and output of each R script.

Introduction

1. Steromphala.csv: Data on the lower and upper limits of the vertical distributions of Steromphala cineraria and S. umbilicalis.
   • reference = author name and year of referenced data
   • doi = digital object identifier or uniform resource locator of referenced data
   • species = categorical variable with levels Steromphala cineraria and Steromphala umbilicalis
   • lower = lower distributional limit in relation to lowest astronomical tide given in metres
   • upper = upper distributional limit in relation to lowest astronomical tide given in metres
2. Steromphala.R: Code to calculate introductory descriptive statistics.
   • Input = Steromphala.csv
   • Output = Steromphala spp. distribution descriptive statistics in paragraph two of the introduction

Density

1. density.csv: Density data for Phorcus turbinatus, Stramonita haemastoma and Thalassoma pavo.
   • site = categorical variable with levels Xwejni, Dwejra and Ras
   • date = date given as DD.MM.YY
   • species = categorical variable with levels Phorcus turbinatus, Stramonita haemastoma and Thalassoma pavo
   • original = count of individuals in defined area (40-cm quadrat for Phorcus turbinatus and Stramonita haemastoma, 1×10-m transect for Thalassoma pavo)
   • adjusted = density given per square metre
2. density.R: Code to analyse and visualise Phorcus turbinatus density and distribution data.
   • Input = density.csv, distribution.csv from Predation
   • Output = Figure 1, Phorcus turbinatus site-specific density and distribution results

Predation

1. distribution.csv: Vertical distribution data for all studied species.
   • site = categorical variable with levels Xwejni, Dwejra and Ras
   • date = date given as DD.MM.YY
   • time = time given as HH:MM
   • species = categorical variable with levels Phorcus turbinatus, Stramonita haemastoma, Thalassoma pavo, Hermodice carunculata and Hexaplex trunculus
   • position = position in metres in relation to sea level at the time of observation
   • tide = tidal level in metres above lowest astronomical tide at the time of observation provided by the Lampedusa tide station
   • lat.position = position in relation to lowest astronomical tide given in metres
2. predation.csv: In situ predation data.
   • site = categorical variable with levels Xwejni, Dwejra and Ras
   • date = date given as DD.MM.YY
   • time = time given as HH:MM
   • position = position in metres in relation to sea level at the time of deployment
   • tide = tidal level in metres above lowest astronomical tide at the time of deployment provided by the Lampedusa tide station
   • lat.position = position in relation to lowest astronomical tide given in metres
   • length = Phorcus turbinatus shell length given in millimetres
   • mass = Phorcus turbinatus mass given in grams
   • predation = predation event recorded as 1
   • notes = notes on what predator ate Phorcus turbinatus or what organism occupied its empty shell
3. muricids.csv: In vitro predation data.
   • date = date given as DD.MM.YY
   • level = aquarium water level given in metres
   • volume = aquarium water volume given in litres
   • space = vertical air space between water level and mesh given in metres
   • fullness = aquarium water volume expressed as a proportion of total aquarium volume
   • predator = categorical variable with levels Stramonita haemastoma and Hexaplex trunculus
   • prey.length = Phorcus turbinatus shell length given in millimetres
   • prey.mass = Phorcus turbinatus mass given in grams
   • predator.length = muricid shell length given in millimetres
   • predator.mass = muricid mass given in grams
   • temperature = average aquarium water temperature over the 24-hour experiment (°C)
   • sst = average sea surface temperature for the day of the experiment (°C) provided by the Maltese weather station
   • difference = temperature difference between aquarium and sea surface (°C)
   • predation = predation event recorded as 1
4. predation.R: Code to analyse and visualise in situ predation and distribution data.
   • Input = predation.csv, distribution.csv
   • Output = Figure 2, in situ predation and distribution results across sites
5. muricids.R: Code to analyse and visualise in vitro predation data.
   • Input = muricids.csv
   • Output = Figure S4, in vitro predation results

Physiology

1. length.mass.csv: Paired measurements of length and mass for all studied gastropods.
   • species = categorical variable with levels Phorcus turbinatus, Stramonita haemastoma and Hexaplex trunculus
   • length = shell length given in millimetres
   • mass = gastropod mass given in grams
2. physiology.csv: Immersed, predator-free survival data for Phorcus turbinatus.
   • site = categorical variable with levels Xwejni, Dwejra and Ras
   • date = date given as DD.MM.YY
   • time = time given as HH:MM
   • position = position in metres in relation to sea level at the time of deployment
   • tide = tidal level in metres above lowest astronomical tide at the time of deployment provided by the Lampedusa tide station
   • lat.position = position in relation to lowest astronomical tide given in metres
   • length = Phorcus turbinatus shell length given in millimetres
   • mass = Phorcus turbinatus mass given in grams (NA when shell was empty)
   • day = time since deployment (initiation of full immersion) given in days
   • survival = survival recorded as 1
3. Irradiance.R: Code to analyse and visualise length-mass relationship and survival data.
   • Input = length.mass.csv, physiology.csv
   • Output = Figure 3, Figure S2, physiology and allometry results

Luka Seamus Wright, 28 February 2023