Rewilding with Herbivores

As an Ecological Consultant I didn’t pay too much attention to large herbivores. Often, they would just be present on overgrazed improved grassland, which supported a monotonous sward with very little ecological interest. I only really noticed them to record how little ecology there was, or, in the case of when working in horseshoe bat strongholds in Devon, that they could increase foraging opportunities for this species (oh, and I definitely noticed them when I stumbled across a bull in a field a couple of metres away from me after emerging from a ditch that I was surveying for water voles!). But most of the time, I wasn’t particularly interested in large herbivores – they were usually livestock and just associated with short overgrazed grassland. Even when writing ecological management plans, larger herbivores rarely featured. I was more interested in mechanical ways to manage the environment for nature conservation, in particularly hay meadow cuts, mowing, coppicing etc. I didn’t realise that I was ignoring a crucial part of ecosystem function, and it is one that continues to be absent in our struggling ecosystems. You see, I was writing management plans that just replicated one part of the role of herbivores, one that was probably much more labour intensive, costly, and less efficient. What I should have been looking at was the natural role of larger herbivores in an ecosystem, rather than just viewing them as livestock. It was only when I started studying rewilding that I started to look at landscapes, and the roles of larger herbivores within them, differently.

Many of the livestock that we have today are domesticated versions of the larger herbivores that once roamed in the wild. The only wild herbivores that we have in the UK are deer – some native and some introduced, as well as some ‘wild’ horses. Deer are browsers and intermediate feeders, and often they have big impacts on natural succession through foraging on new samplings and new growth. With no natural predators, deer are often culled in the UK to try to ensure that healthy vegetation can begin to establish, especially natural woodland succession. Take a trip down to Dartmoor and Exmoor and if you are lucky you will also see ponies grazing its heathlands and grasslands, as well as a few other areas around the UK. Horses are grazers – they like to forage on freshly grown meadow grass and newt shoots. The Forest of Dean support a population of wild boar, which open up thickets and dig up soils – this favours natural succession and germination of new plants. But that’s it! That's all we have in the UK, and it’s a really limited picture of wild larger herbivores in this country. We are missing many species, including wild cattle, and it’s the lack of diversity that is affecting the function of many of our ecosystems. Even where herbivores are present, they are often just a single species in high densities. We are ignoring the role that herbivores have in the functioning of our ecosystems, as well as the importance of the combination of different herbivores, and its important that we start to recognise what we are missing.

Large herbivores shape landscapes and change habitats – in dense woodland, they create openings through pushing over trees, debarking species, or in the case of beavers felling them. This in turn creates new habitat for other herbivores to graze – wild boar may dig up the soil to allow new species to germinate, ponies may graze on the freshly grown meadow grass, which eventually will provide forage for deer in the form of tree saplings trying to establish themselves. This may create meadow habitats and attract larger numbers of herbivores, until herbivores move on to another area which may allow it to re-establish as a woodland. I would have previously been shocked at the idea of having herbivores in woodland habitats – and would advise that they are excluded to protect them. But woodlands and herbivores evolved together – without grazing in our woodlands, we wouldn’t see open glades in forests, or meadows, or natural succession. It would essentially be a stagnant system. I was wrong to ignore the role of herbivores when I was an Ecological Consultant – they are so important to the natural functioning of all of our habitats, and diversity of habitats, vegetation and species is what is needed to recover nature in the UK. We can’t afford to continue to ignore them and see the declines in our wildlife and our soil health.

Gabe Brown's book 'Dirt to Soil' says that 'today with grazing animals almost entirely removed from the world’s grasslands, there is much less carbon cycled through the system. It isn’t cattle that’s the problem, its our management of them. Multiple species grazing results in much larger carbon levels in soils. Diversity is key to soil health'

Often, we mimic larger herbivore function with our management plans – coppicing, for example, mimics beavers, felling trees to create openings and thin areas out mimics larger herbivores such as bison. But this takes a lot of effort, and invariably is unlikely to be as efficient as herbivores in achieving our goals. A functioning ecosystem must have a diversity of herbivores to be truly resilient and healthy – we need to have this mix to create a better diversity of habitat, which will create more opportunities for more species and a higher abundance of those species. We have the space for this type of rewilding in the UK – imagine our national parks supporting large numbers of wild boar, deer, cattle and horses grazing extensively across their landscapes. We may not have the predators to control their numbers, but we have the means to do this through hunting groups and park management. This would create not just healthy ecosystems, but also a range of opportunities for other species – bird life, raptors, reptiles, small mammals…the list goes on. It would also create more interesting wild spaces for us to visit and enjoy.

I hope that we can start to change our way of thinking about how we manage and restore our ecosystems in the UK. We need to think about ecosystems as joined up and naturally changing, and the benefits that this change and variety brings. I am planning to start biodiversity monitoring on a range of grazing scenarios this year, including the impact of mob grazing and extensive grazing on biodiversity. I hope this information will contribute to the database of studies that show the importance of wild large herbivores in our environments. Ecologists, biologists and conservationists have already spoken about 2020 being the start of a change in the way that we look at our natural spaces, and the decade of ecological restoration. We have the space and the knowledge of how important herbivores are in our ecosystems, so lets start to change how we all view them – not just as livestock, but as ecosystem engineers. I hope that in 10 years time, I will be writing about the restoration of our ecosystems through larger herbivore introduction to several of our wild spaces!