Voles! can they climb/jump?

[PHAT]

I'm in the later planning stages of making some raised beds.  The problem is our neighbourhood has a TON of voles.  They seem to not have discovered our yard yet, but probably just because we don't really have a garden.  The neighbours all say their gardens get destroyed by them, and their yards are all full of tunnels. 

My one gardening neighbour told me that I need to make my raised beds at least 18" high (or more, some websites say 24"!), and line them with hardware cloth (wire mesh).  I have found a supply for my materials, but they aren't cheap!  Do they really need to be 18" high?  I could do it for much cheaper if they were only about 12-16" (yard is sloped).  BUT some websites say as long as the mesh goes 4-8" above ground, that is sufficient...so I'm so confused about what I need to do!

Or do I just make them lower for now, and build another layer later on top if it becomes a problem? 

I am in Southern interior of BC (Canada) if that matters.

[slackmax]

Don't know. But I can commiserate about the voles. My lawn is lumpy with vole tunnels. My echinacea patches along my fence have been getting smaller each year.

I am trying pouring caster oil and urine around my echinaceas. Only started it a few days ago. We'll see. 

I read that you can set mouse traps for voiles, and eventually kill them all off (or just keep killing them as new ones arrive, but at least limit the numbers?)

I don't think they have been eating anything in my garden, though. I had tomatoes every year, and they were OK.