"The species/species'/species's survival..."

The online Chicago Manual of Style (both 16th and 17th editions) states:

When the singular form of a noun ending in s is the same as the plural (i.e., the plural is uninflected), the possessives of both are formed by the addition of an apostrophe only. If ambiguity threatens, use of to avoid the possessive.

And gives the following examples:

politics’ true meaning
economics’ forerunners
this species’ first record (or, better, the first record of this species)

This is section 7.19 of the 16th edition and 7.20 of the 17th edition (2017).

Obviously this differs to my comments saying that the CMOS says species's, which I took on faith from a third party website.

However, in speaking, despite remarks by others, I'm not sure I would rule out saying the species's survival (with the extra syllable) just to clarify that I'm talking about the possessive form of the word. This is my opinion only.

Whatever the text books and the Internet sites say, it is my own experience as an English speaker that nobody ever says or writes something like "species's".

We just don't talk like that in the UK. It's too risky, especially if one's false teeth don't fit too well.

The only time I can think of a plural apostrophe being tolerated in daily speech is "Jones's" because it is easy to say.

The natural thing to do - and the way, indeed, that the language has evolved to avoid the above problem - is to say species' in conversation, whether or not the additional 's is added in written English.