As many as one-third of the nation's species are at risk, and at least 500 species have already gone extinct or are missing.
(As many as one-third of the nation's species; are; at risk) (at least 500 species; have gone; extinct; T:already) (at least 500 species; are missing; T:already)
As many as one-third of the nation's species at least 500 species at least 500 species
are have gone are missing
at risk
extinct T:already
T:already