Not always, species go extinct all the time. Evolution can get stuck in local optima. Consider the whiptail lizard, which has lost the ability to reproduce sexually. Will they be able to adapt to future changes of the environment? Maybe, but the chips are stacked against them.
No one said that those nooks are not deadly. But evolution will explore them just in case.
Wow what an interesting animal, haven't heard about it before.
> the chips are stacked against them.
Wikipedia says: "This reproductive method enables the asexual desert grassland whiptail lizard to have a genetic diversity previously thought to have been unique to sexually reproductive species."
Doesn't look to bad?