Returns a count of the number of unique species which have assessments.
Arguments
- key
(character) An IUCN API token. See
rl_use_iucn().- ...
Curl options passed to HttpClient
References
API docs at https://api.iucnredlist.org/.
See also
Red List information and statistics:
rl_api_version(),
rl_citation(),
rl_version()
