Or can we get rid of it?
Poison ivy is very useful in propogating poison ivy. That’s all the more reason any organism exists in the biosphere.
Your question is, really, “what good is it to me”.
Poison ivys (Toxicodendron radicans,Toxicodendron rydbergii, as well as other members of the genus Toxicodendron) are part of the sumac family and are a source of fruit for many birds, foraging mammals, and other animals, as well as pollinators where it serves the function of providing a food source by flowering out of season with most other angiosperms.
Stranger
Vines are ground cover and prevents erosion.
Unfortunately for humans; Poison oak, Poison Sumac, and Poison Ivy have powerful defense mechanisms.
Can any herbivore safely eat these vines?
Leaves of Three, Leave Them Be
goats do a number on them.
Poison Ivy Got Your Goat? Call Goat Girls! - Western Massachusetts Master Gardener Association.
My father was never bothered by Poison Oak.
He pulled vines from my backyard without any problem. He bagged them for me and put on the curb.
That much exposure would have nearly killed me. Even his clothes and gloves were a hazard and thrown out.
Poison Ivy gets everybody. Never, ever, ever put it in a burn pile. The smoke will get you.
I hate that stuff. Stinging Nettles are almost as bad. Except the pain goes away much quicker.
Nettles (after processing) are an important herbal medicine used for centuries.
Don’t forget those marvelous medicinal uses of poison ivy.
“There is evidence that the Meskwaki, Ojibwe, and Potawatomi made a poultice from the plant to be used to treat swelling. Ramah Navajos used a mix of poison ivy sap, deer blood, and charcoal to make poison for arrowheads. Indigenous Americans on the west coast used poison oak leaves in cooking and in addition to using the sap to treat warts, rattlesnake bites, and ringworm.”
Poison ivy has been grown as an ornamental in Europe, to which it was transported in the 1800s. I recall hearing about British gardeners who valued it for its attractive red fall foliage. Probably the same Brits who grow pokeweed for its ornamental qualities (one hopes that neither plant is as rampant a pest in British climates as they are in the U.S.).
Goats will get into and eat damn near anything, much to the surprise of hobby farmers who think they are getting a few cute pets and then find their garden, trees, shrubs, flowers, and unprotected hoses and tubing nibbled down to the dirt. A little bit of allergenic oleoresin isn’t going to put them off of available feed.
Stranger
Rabbits can eat poison ivy.
Most ornamental ivy is poisonous to rabbits.
Weird.
::::shudder::::
When I was in 4th grade, I picked up a large, pretty leaf that had fallen. Most of it had gone a shade of yellow, with one small green patch.
I held it up to my face, clowning around.
The next month was… not fun.
More to the point of the original question: if the stuff were nuked from orbit, is there anything else less vile that might take its place in the ecosystem?
I understood the question to be exactly what it said in the title. Before getting rid of it, it is essential to know what part it plays in the ecosystem.
Well, I guess technically humans don’t count as herbivores.
https://www.wsj.com/style/eat-poison-ivy-oak-immunity-3207ec3c
Yes. She introduced novelty records and rockabilly to the punk rock scene and kept Lux out of trouble.
I’ve never seen poison ivy cover ground. Maybe if it took over some other ground cover.
I’ve only seen in crawling up trees, fences and walls.
Technically it could, I guess. I’ve walked a million miles in the woods. Seen lots of it.
I’ve seen it climbing in kudzu vine. Never on its own, on the ground.
Not apt to do the research for the root either.
But, yeah it’s an important pollinator.
And the namesake to my Ivy. 
As a volunteer Ranger in San Jose we had Poison oak- Toxicodendron diversilobum, and yes it will grow as a sort of shrubby ground cover. Many species eat it.
Whatever you do- do NOT burn it. The smoke can irritate lungs and even kill.
Oh, I know about the burning.
Wisteria will cause the same kind of problem, I found out the hard way.
Good to know, I see bunnies in my chaos garden where undoubtedly there’s PI vines sneaking around. As well as wild grapevine.
I’ve also seen poison hemlock on roadsides in the neighborhood. I’ve looked it up but there are no sources that claim any benefits to hemlock in a habitat.
I’m cautious, but often cannot avoid it. I rarely get affected, and it clears up quickly. My gf is the opposite. When we’ve both done yard work involving the vine, she will end up with a severe case while I might have some around an ankle.
When I was a kid, a farmer down the road always talked about his immunity. Each year he’d make a sandwich using bread, butter, and poison ivy. He claimed that was how he avoided getting it. He was also kinda crazy and beat his wife and kids with impunity.
I don’t have time to search YouTube right now, but @Mangetout has a cool video on his atomic shrimp channel on making nettle soup. It’s the most beautiful soup, and you can imagine the silky texture.
My sister volunteers at the local forest preserves. The staff put in considerable effort to control invasives. But they have an ongoing dilemma w/ poison ivy. It is a native, and the only species that reacts negatively to it is humans. As others have noted, birds and some mammals eat the leaves and berries.
I had a skin tag on my inner arm once that poison ivy landed on. The skin tag swelled up turned black then fell off. Painless all around.no scar nothing.