In the context of the paragraph, the word "endangered" carries denotative meaning. It refers specifically to the state of a species being at risk of extinction. The term does not carry any additional negative or positive connotations in this context; it is used to describe the factual situation of certain species, like the bull trout and the meltwater stonefly, without implying any emotional or figurative meanings. Therefore, the correct response is:
denotative meaning