We need to translate visible text to Japanese, preserving HTML tags exactly. Ensure not to alter tags, attributes, URLs remain unchanged. Translate text inside tags. Let's go through:

keystone species

=>

キーストーン種

maybe "キーストーン種" or "キーストーン・種". Use "キーストーン種".

... text ... Continue Reading

Need translate the paragraph content, keeping the tag unchanged except its inner text "Continue Reading" to Japanese "続きを読む" likely. Also preserve the
tag unchanged. Then

Source: https://www.nationalgeographic.org/encyclopedia/keystone-species/

Need translate "Source:" to Japanese "出典：" maybe. Keep link unchanged. Also a self-closing

tag at end; preserve. Now translate paragraph: Original: "A keystone species is an organism that helps define an entire ecosystem. Without its keystone species, the ecosystem would be dramatically different or cease to exist altogether. Keystone species have low functional