The effects of herbivores on the landscape were often overlooked by the early conservation movement. Fortunately, we are now starting to see a return of this free and arguably infinitely better labour, for free-ranging herbivores smashing and crashing their way through habitat do a far better job of replicating just this than humans with scythes and secateurs.
The holy trilogy of herbivorous engineers are cattle, horses and boar. Combined, their feeding habits create almost every micro-niche available in woodland and grassland. Both Isabella Tree in Wilding and Benedict MacDonald in Rebirding make this case emphatically. When they are allowed to join forces with deer - much maligned in the UK as they are often present in far too high densities - and beavers, the resulting mosaic of grasslands, wood pasture, disrupted ground, fragmented woodland and wet coppice meadows that they create fuels the European biodiversity engine.
On smaller reserves where livestock just aren't possible, I like the idea of teams of volunteers working in small groups, each labelled as a specific disruptor for the day. 'Team Boar' would be armed with small spades and shovels, tasked with stripping back the surface few inches of soil in random marginal patches. 'Team Deer' would seek out young saplings self seeding in meadows, and remove the top two thirds of them. 'Team Aurochs' would have to shuffle around as a Roman-esque testudo, keeping a close formation to create cow-sized breakages through the undergrowth. You get the idea.
Here in the Dordogne, a healthy population of wild boar, alongside a high demand for local beef, well-managed wild deer stocks and the odd farm pony have ensured that most of the vital ecological roles provided by these large herbivores are still present.