Learn Portuguese (Portugal): É importante que salves as espécies. - It's important that you save the species.

The phrase starts with É importante que (It's important that). This is an impersonal expression showing an opinion or value judgment, which triggers the present subjunctive (o presente do conjuntivo). For regular -ar verbs like salvar (to save), the subjunctive swaps the characteristic a for an e. So, the tu form becomes salves.

Where is the word for "you" in this sentence?

In Portuguese, subject pronouns are often dropped because the verb ending already tells us who is doing the action. The -s ending on salves tells us this is the tu (informal you) form. If you wanted to emphasize who needs to do the saving, you could add it: É importante que tu salves as espécies.

In English, "species" is the same word whether it's singular or plural. Is it the same in Portuguese?

No, Portuguese distinguishes between singular and plural here. The singular form is a espécie and the plural is as espécies. It is a feminine noun, which is why it uses the feminine plural article as.

Does espécie only refer to biological species of animals or plants?