Hostile Terraforming: In the Worlds, pretty much any straight ecopoesis carried out on a currently life-bearing world is considered this, and even sensible-but-dubious regimes steer clear of it because it is, in effect, burning down an asset. Ecosystems are extremely valuable informational resources, and not to be casually overwritten.
On colony worlds, what you’re supposed to do, ecopoesis-wise, if you need to, is engage in whatever complex bioengineering you have to do to introduce your necessary support species into a successful hybrid or co-existing ecosystem, usually combined with a degree of personal pantropy (adapting yourself to the planet, rather than t’other way around).
This tends to be… tricky, for those without the absolute highest levels of competence in such things, but so it goes. If you can’t manage that and aren’t willing to pay for someone else’s expertise, stick to colonizing barren worlds that you can ecopoese without breaking anything preextant. Or else.