What does the cryptic crossword clue "Critical of population growth: wild animals taking over next (10)" mean?

The wordplay uses an anagram. anagram of THU (synonym="‘next’…") + MALSIAN (synonym="MALSIAN") = MALTHUSIAN The answer is MALTHUSIAN.

Critical of population growth: wild animals taking over next (10)

Guardian Cryptic #29565 | 11 Across | 2024-12-13 flower