How do brambles, jays, thrushes and squirrels contribute to land restoration? In this interview about passive rewilding, British ecologist Richard Broughton explains  

Left to their own devices, wild animals and plants have repeatedly shown an unparalleled ability to heal human-scarred land. Yet too often we don’t have the patience to give them that chance. In studies at two very different sites in England—one near an ancient woodland and another in an urban, open landscape—ecologists have documented how quickly nature can reclaim and restore degraded places.

At the first site, Monks Wood National Nature Reserve in Cambridgeshire, new forest patches called “wildernesses” have approached the height and structure of their centuries-old counterpart in less than 60 years. At the second site, Noddle Hill Nature Reserve in East Yorkshire, shrubland, wetland and grassland have meandered their way back onto the scene in only 30 years since the former grazing lands were left fallow.

Both of these areas are thriving in part due to a key, often forgotten habitat layer: brambles and other shrubs, which feed wildlife while also protecting trees from being overbrowsed. What lessons can we learn from such findings to apply in our own communities here in the U.S.? In the process of researching my next book, Wildscape, due out in March, I reached out to the lead author of the studies, Richard Broughton of the UK Centre for Ecology and Hydrology, to find out. Here is our full written interview.

What do you think about passive rewilding of land that has been covered in turfgrass for decades? Has anyone studied this? How might it differ from passive rewilding of farmlands?

By turfgrass, do you mean lawns, city parks and public sports fields (soccer)? I don’t think anyone has studied this, although much will depend on the same things as for farmland—such as distance to seed sources and the species of animals and plants that are around. In the UK, there is a thing called “No Mow May,” which encourages people to not mow their garden lawns (or parks not to mow public amenity grass/turf) during May to allow wildflowers and insects to have a chance. I suppose that is a very gentle way of “wilding” turfgrass, even if only temporarily.

Can you speak to the benefits of passive rewilding and land abandonment versus active tree planting?

Planting provides a greater control over the outcome, such as which trees are present and how closely together they will grow—this is useful if the trees and woodland are expected to produce timber or other wood products. The emphasis here will generally be to achieve closed-canopy woodland as quickly as possible, composed of preferred species of a preferred form (trees good for making products). That might not necessarily have the best outcome for biodiversity—plantations tend to have a simplified age structure and species composition. However, all of that relies on continued management.

Plantings that are not managed (or are abandoned) will be less predictable. Passive rewilding is different in that it prioritizes the “self-willed” aspect, without a narrowly defined objective. It is a more naturalistic way of creating woodland, but it has unpredictable outcomes in terms of timescale and composition. However, this is how natural woodlands establish themselves, and so it creates more opportunities for biodiversity, which are naturally adapted to live in the various stages of the process. For example, tree planting skips the initial pioneer stage of thorny shrubs and brambles (Rubus species), which are considered undesirable in forestry management. These species produce lots of blossom and berries, and protective thickets for nesting birds. Passive rewilding also results in patchy mosaics of trees, thickets and open areas, which a range of species can exploit, whereas planting tends to be more uniform.

I loved this quote from you in the Guardian: “We call it scrub like it should be scrubbed away but it’s shrubland. It’s like a wildlife fest—covered in blossom, full of warblers. It’s just a really nice place to be.” Following up on that, I wondered if you could describe some of the animals and plants you were surprised or delighted to see at the Noddle Hill site? How different was it from the Monks Wood sites, and what was special about it to you after three decades of passive rewilding there?

Monks Wood and Noddle Hill are at opposite ends of a spectrum— the former being close to seed sources (ancient woodland) and dispersers (especially Eurasian jays, which hide acorns). By contrast, Noddle Hill is far from woodland seed sources and lacks some key seed-dispersers (jays). So they developed along very different trajectories. At Monks Wood, the shrubland stage is shorter and the woodland develops more quickly—and with more tree species, especially oaks, planted by the jays. At Noddle Hill, the thorny shrubland stage will last many decades, until more trees eventually arrive and start seeding themselves. Jays may then arrive with them and speed things up.

The special, distinctive feature of Monks Wood after 20 to 30 years was how quickly it had become dominated by trees and shrubs. Meanwhile, after three decades, the shrubland stage at Noddle Hill was notable for the abundance of blossoms on the shrubs, but also the mosaic of grassland, thickets and small ponds that appeared, giving a light, sunny, open feeling to the landscape. The long blossom season on the hawthorns from April to May and bramble from May to August, [along with] the long grassland, supports lots of insects, such as butterflies, bees and grasshoppers, and the ponds support lots of dragonflies. As such, the site is very insect-rich and is literally buzzing with life—there is no mowing and no chemicals are sprayed.

Dominating the soundscape are the songbirds—the mosaic of habitats and the thorn thickets are perfect for many songbird species that sing from March to June. Noddle Hill is an oasis of life in an otherwise relatively hostile landscape of intensive agriculture and urbanization. The songbirds include resident song thrushes, European blackbirds, European robins and wrens, which are all renowned songsters. Summer migrants from African wintering grounds include the warblers, a large group of quite plain-looking small birds, but which have a fantastic array of songs—nine species of warbler arrive to sing and breed in the thickets of Noddle Hill: reed warbler, sedge warbler, blackcap, common whitethroat, lesser whitethroat, garden warbler, chiffchaff, willow warbler and the resident Cetti’s warbler (which stay all year round). The reed warblers are hosts for the common cuckoos, which also come from Africa to breed.

A calm, still early morning from mid-April to mid-May is when the dawn chorus is at its peak, with all of the birds in full song at full volume. The sound is spectacular, a medley all around you in the stillness of the morning, as a light mist lifts with the rising sun. The birds sing throughout the day, but it is at its most intense and magical in the early morning.

People generally don’t call such habitat “scrub” here in the U.S., but of course we have other derogatory terms for it: wasteland, waste spaces, overgrowth. The word “bramble” is synonymous with “weed.” These types of areas aren’t even respected by a lot of nature-oriented people. Why do you think that is? Are there historical and cultural reasons for this, aside from people wanting a savanna view of their estate lawns? I get the sense that people here and in the U.K. share similar sensibilities about this.

Brits use the term “wasteland” too for abandoned land. Brambles here refer specifically to the plant Rubus fruticosus, which is extremely common and grows almost anywhere in the lowlands where it can get a toehold. The fruits are called “blackberries,” but around Noddle Hill in the city of Kingston-upon-Hull, aka Hull, the locals call the fruits “brambles” too, and “brambling”—picking blackberries—is a common pastime. My mum took me brambling when I was a kid, and she still does it, collecting berries with her grandchildren and great grandchildren. She collects the brambles/blackberries from Noddle Hill to bake a dessert called “Bramble and Apple Crumble,” which everyone loves as a seasonal treat.

Scrub has negative connotations also for some conservationists, such as those conserving delicate grasslands and wildflower meadows. So some other conservationists are trying to “rebrand” it as “shrubland,” akin to woodland or grassland, to help change perceptions and increase appreciation for what it really is: a valuable habitat in its own right, but also a transition on the way to woodland—although that transition might be sooner or later, depending on the location!

I guess for many people, scrub/shrublands are a sign of abandonment, dereliction and economic failure—farmland that a farmer couldn’t make a living from, or industrial land after the major industry has collapsed (such as docks, mines, quarries—with the collapse often leaving the local communities broken and abandoned too). A cultural reason in Britain may be rooted in the World War 2 generation, when Britain was blockaded and food was running out nationally—every scrap of land was needed for food production, even in gardens and parks, and efficiency and productivity of all land was essential to staying in the war during the “Dig for Victory” era. This outlook of production and efficiency set the scene for land use for the generations that followed—land was micro-managed.

As such, shrublands are rarely deliberate or planned. Only now with the rewilding movement are sites being deliberately abandoned for a purpose, even if that purpose is open-ended and self-willed.

You also told the Guardian that “the thing which really stood out is unlike with planting, natural regeneration creates this essential first stage of shrubby development—a thicket of brambles and hawthorn sown by thrushes and a natural tree-guard against the browsers such as deer.” Can you talk a bit about your findings that herbivory by deer, rabbits and squirrels didn’t negatively affect plant growth at the Monks Wood sites? People get very upset with deer and rabbits here in the U.S., but many landscapes—and even many of our more natural areas—lack this middle shrubby layer. The natural caging effect of these plants is so amazing.

Herbivores undoubtedly had some effect on the growth of trees and shrubs, and signs of nibbling are plain to see here and there, but the main point is that they did not prevent the trees and shrubs from becoming established across the sites. They may have modified the vegetation somewhat (not possible to say how much), but natural regeneration was still hugely successful and quite rapid. That was something of a surprise, especially for the younger plot that was established in the late 1990s, as by then there was a large population of invasive muntjac deer in the region—a small deer from Asia that reaches high densities and is considered very damaging to woodland vegetation.

It was revealing to see how the thorny vegetation was able to deter the muntjac enough to allow tree saplings to establish in the thickets. Last year we set trail cameras and found that there are at least two deer per hectare in this plot (about one per acre), comprising muntjacs and also the larger roe deer. They make trails through the shrubs and thorns and browse around the edges, but they don’t get everywhere, and so plenty of young trees escape their attention. It’s the pioneers of thorny hawthorn and bramble that make this possible, establishing first and growing quickly. If the deer keep some areas open by more intensive browsing, that will create some sunny glades in the maturing woodland, which should benefit sun-loving insects, such as butterflies.

Squirrels (another invasive species in England—they’re American Eastern grey squirrels) are considered a pest for forestry, eating bark and tree shoots, making them more gnarled and creating cavities—not good for timber production. But in these natural new woodlands they may have actually been a benefit, by burying some of the tree seeds in the open grassland (like the jays). We often saw them out there—and still do on the cameras—burying acorns that they collected in the adjacent wood. They are reported to nibble the growing point out of many of the acorns, so they cannot germinate, but enough may not be damaged, and can grow. If they strip some bark off some of the growing trees, that is not a problem; they could create tree cavities that birds will nest in, and the trees are not destined to be felled for timber.

So it was interesting, and a little surprising, to see how the natural regeneration could still happen despite moderate numbers of herbivores.

Other than your studies and the ones you cited in your references—and also what I’ve read in Isabella Tree’s Wilding—I wasn’t aware of research showing the protective power of brambles. I’ve seen nurse plants in our desert Southwest and read about protective acacia trees in Kenya. But I haven’t really seen an interest in the safeguarding concept of brambles in the U.S. yet. Have seen any research or interest from colleagues here?

No, I have not been contacted by US researchers. In the UK, and Western Europe, the scale is perhaps different to the USA, as parcels of land and field sizes tend to be much smaller, and ownership is very fragmented, so doing anything on a large scale is difficult. Although there is quite a large literature on farmland abandonment (“old field” research), especially from the eastern USA, where it is returning to forest.

It seems to me that people in the U.S. are quite reluctant to try passively rewilding on any type of site—semi-natural areas or private properties with sizeable acreage where it is possible to experiment. They believe they’ll become overrun with invasives, and while it’s true that invasives do show up, over time the natives do too—at least in my limited experience both at my 2.25-acre place and while volunteering on local public lands. I’ve met so many interesting native plants I’d never even heard of before, just by letting things be for a while. And your research is showing that even in spots where woodland seed sources are scarce, the animals can help create new shrubland through seed dispersal. How can we get people more interested in this and/or less afraid to try it?

I think that question is largely for social scientists and policy-makers, as it’s a very complex one. As ecological scientists, we can provide the information to underpin policy, and can advocate for it on a personal level, but there are many competing interests. Campaigns like “No Mow May” and inspirational books such as Wilding can help change public perception. Although to become more widespread or viable, the economics need to work for land owners, and that means underpinning within the wider regulatory framework (e.g., land use subsidies and grants, planning regulations). Promoting these areas can also help local people appreciate them—Noddle Hill has been designated as a “Local Nature Reserve” by the city council, giving it a positive “official status” that can counter any negative connotations of it being a wasteland.

I thought it was interesting that the wetlands at Noddle Hill expanded a bit and then seemed to contract back to original size. Would you expect them to fill in in the future or continue to shift? That’s just something I have really wondered about in relation to passive rewildling. Here the beavers are slowly starting to come back, and I dream of what this land might have looked like long ago and what it would be again without all the stream diversion and road engineering.

Noddle Hill is very low lying, only about three to five feet above sea level. Originally it would have been quite marshy woodland and wetlands (a type called “carr” woodland, a Viking word—the area was settled by Norse Vikings a thousand years ago, and many of their words persist in the language and dialect). So it would be expected that wetlands and ponds would persist and reemerge once the drainage ditches fell into disrepair, especially after wet winters. However, climate change means that the region is experiencing more summer droughts, and that might explain some of the shift in the wetland extent. The wetter hollows would limit some of the shrubs from colonizing (like hawthorn, which doesn’t like having wet feet!), helping to keep them open or favoring wet-loving willows instead.

Beavers would have lived here originally—indeed, about 4 miles away is the town of Beverley—the name literally means Beaver Stream (“Beaver Lea”). Beavers became extinct in England hundreds of years ago but are being reintroduced in some places. What’s fascinating about Noddle Hill is that abandonment has allowed a fragment of the lost landscape of the carr woodland to start returning—the low-lying patchwork of shrubs, trees and wetlands, before it was cleared for wet grazing land for cattle and sheep. Maybe one day, the beavers will also return.

[Photos by Richard Broughton]

For More Information:

“When Plants Protect Plants,” HumaneGardener.com: Thorny shrubs and brambles have helped trees escape browsing in my habitat too. Learn more about what happens when we allow plants to become partners.

“Long-term woodland restoration on lowland farmland through passive rewilding,” PLOS One: Read the original paper on rewilded sites at Monks Wood by Richard Broughton and his colleagues.

“Monks Wood Rewilding,” UK Center for Ecology and Hydrology: Read a summary of the Monks Wood experiment that explains how the research was conducted.

“Rewilding Bransholme: success at Europe’s ‘biggest council estate,’” Yorkshire Bylines: Learn more in this article about the research study at Noddle Hill, which is due to be published in a few weeks.