This thread was split off in the second page of a topic that began here:
It may have been wise to do it because worms and ants are steadily bringing up a lot of soil. I will probably do this next time.
I have found that the ants will just cut holes through landscape fabric. It is not horribly destructive, but they do bring up their diggings into the gravel. The holes made by the ants are small, however there can be a large number. The ants make trails from their nest under the fabric to distant locations, which means there is a hole where ever a little trail comes up from under the fabric.
Worms have been less of a problem. The worms largely avoid my dry gravel beds. Maybe the landscape fabric also has something to do with the lack of worms in my gravel beds. I don't know. Although, they do like to hang out just below the landscape fabric.
I really think it is a good idea to place a barrier down when gravel is spread over soil. If a gardener decides to rearrange a garden this will make life so much easier. It is an unbelievable amount of work to sieve gravel from soil. It is so much work a gardener is probably better off having the mix carted off and start over with fresh soil and clean gravel. A barrier eliminates a huge amount of work if one ever changes his/her mind.
It also helps prevent the gravel from sinking into the soil thereby eliminating the necessity to constantly add more gravel to the bed. Holes can be cut through the fabric for deeply rooted plants. This will allow the soil and gravel to mix, but it minimizes mixing as much as possible.
Even with gravel incorporated into soil, overly moist conditions can still be a problem. In many situations a raised bed should be considered first and the addition of gravel should be a secondary measure.
Of course you know all this, I am mentioning it for all the people that are still learning like myself.