Diet summaries from the SCAR Southern Ocean Diet and Energetics Database

Source: R/summary.R

Given a diet data.frame, the prey or predators are aggregated to group level and dietary importance values reported. Note that dietary importance values are currently calculated by unweighted averaging across studies (so that e.g. a study of 100 individuals will carry the same weight as a study of one individual).

diet_summary(
  x,
  summary_type = "prey",
  minimum_importance = 0,
  treat_trace_values_as = 0
)

Arguments

x

data.frame: diet data, as returned by so_diet
summary_type

string: either "predators" (report the predators in the data) or "prey" (report the prey items)
minimum_importance

numeric: ignore records with dietary importance less than this threshold
treat_trace_values_as

numeric: what numeric value to use for a dietary item recorded as "trace"

Value

data.frame with columns:

  • N_fraction_diet_by_weight - number of diet observations where fraction of diet by weight was quantified

  • fraction_diet_by_weight - mean fraction of diet by weight

  • N_fraction_occurrence - number of diet observations where fraction of occurrence quantified

  • fraction_occurrence - mean fraction of occurrence

  • N_fraction_diet_by_prey_items - number of diet observations where fraction of diet by number of prey items was quantified

  • fraction_diet_by_prey_items - mean fraction of diet by number of prey items

Examples

if (FALSE) {
  x <- so_diet()

  ## summary of what Electrona carlsbergi eats
  x %>% filter_by_predator_name("Electrona carlsbergi") %>%
  diet_summary(summary_type = "prey")

  ## summary of what eats Electrona carlsbergi
  x %>% filter_by_prey_name("Electrona carlsbergi") %>%
  diet_summary(summary_type = "predators")
}