Try this (see ?detach
for more details):
detach("package:vegan", unload=TRUE)
It is possible to have multiple versions of a package loaded at once (for example, if you have a development version and a stable version in different libraries). To guarantee that all copies are detached, use this function.
detach_package <- function(pkg, character.only = FALSE)
{
if(!character.only)
{
pkg <- deparse(substitute(pkg))
}
search_item <- paste("package", pkg, sep = ":")
while(search_item %in% search())
{
detach(search_item, unload = TRUE, character.only = TRUE)
}
}
Usage is, for example
detach_package(vegan)
or
detach_package("vegan", TRUE)