Sentience is like anything else. Just a tool to that makes the species efficient at doing X. When a herd of buffalo gets slightly too efficient at grazing or a a pride of lions gets slightly too efficient at taking down prey things can unravel.
But after the breakdowns and collapses the big mystery is why things reboot.
You don't need sentience to cause imbalance and breakdown - https://www.nature.com/scitable/knowledge/library/trophic-ca...
Sentience is like anything else. Just a tool to that makes the species efficient at doing X. When a herd of buffalo gets slightly too efficient at grazing or a a pride of lions gets slightly too efficient at taking down prey things can unravel.
But after the breakdowns and collapses the big mystery is why things reboot.