Rewilding in the Knepp Wildland

by Anangi  Sumalde

Last summer I read a copy of Wilding: The Return of Nature to a British Farm by Isabella Tree. This book recounts how twenty years ago Isabella and her partner Charlie Burrell turned their traditional dairy farm (located on the 3,500-acre Knepp estate in southern England) into a thriving eco-tourism business. At the heart of this land lies the Knepp Wildland, which has become one of the U.K.’s most renowned and inspirational rewilding projects. 

“Rewilding” is a holistic form of land restoration that looks at the entire landscape of a given site rather than focusing on the conservation of just a few species. This allows natural processes to takeover and create a highly complex ecosystem that has the ability to reverse biodiversity loss and habitat fragmentation. Rewilding helps the ecosystem build a better resilience towards the effects of climate change.

The opportunity to gain a first-hand experience of the Knepp Wildland arose when I discovered an organisation called Operation Wallacea. It is composed of a network of academics, scientists and field biologists who organise biodiversity research expeditions, field training courses, and wildlife holidays. The residential field course, located at a camping facility onsite at Knepp, is designed to teach participants essential ecology training skills such as: field surveying methods, habitat classification and identification of a range of taxa, all while gaining an appreciation for the Wildland. 

Isabella and Charlie’s daughter, Nancy, led one of the surveys which involved walking the lengths of selected fields in search of young English oak trees. Specifically, we were looking for trees of approximately two metres in height that had developed without the protection of a nurse species (for example a surrounding crown of brambles) in order to assist Nancy in quantifying the survival rate of exposed young oak trees. Nancy’s research has shown how exposed oaks tend to gain more mass on their root systems, perhaps as a way of helping to develop their resilience against herbivory. Evidence of herbivory came in the form of ‘topiary’ executed on some of the tree and shrub species by deer, who as browsers, prefer to do their munching above ground. 

“Rootling encourages opportunistic annual plants to colonise these bare patches and creates hollows that fill up with water, attracting wildlife to the disturbed area.”

Pivotal to the Knepp Wildland is the rewilding practise of ‘grazing ecology’. Knepp’s “Big Five” species consist of Tamworth pigs, red deer, fallow deer, Exmoor ponies and old English longhorn cattle. The Big Five is a set of free-roaming, large mammals that have been adopted by the estate to intentionally disturb the process of vegetation succession. They mimic the herbivory patterns of some of the extinct, wild, megafauna species of temperate-zone Europe, such as the wild horse, ox and boar, through behaviours such as trampling, browsing and rooting.

The result is that rather than reaching its climax as a closed canopy forest system, Knepp has become a dynamic and open wood pasture instead, composed of interconnected microhabitats of grassland, hedgerow, scrubland, wood groves and free-standing trees. More habitat variety has led to more ecological niches for species to inhabit, resulting in a surge in plant and animal life on the estate. For example, during a plant quadrat survey, we found abundant numbers of several grass species, including Yorkshire Fog, Creeping Bent, Rough Meadow-grass and Timothy, all nestled within a haze of native wildflowers.

In addition to their grazing and browsing behaviours, Knepp’s Big Five facilitate disturbance by their ability to disperse seeds and transfer nutrients in their manure. Since the project avoids the use of pesticides, their dung serves as a microhabitat for invertebrates, such as the eponymous dung beetle. Our guide mentioned how dung sampled at Knepp belonging to horses merely passing through the estate with their riders was found to contain far fewer dung beetle species than dung sampled from the Big Five, possibly due to being contaminated with pesticide residues. 

During a continuous distance sampling survey of large mammals, we saw Tamworth pigs a few metres away, foraging in a grassland habitat with their snouts to the ground. Evidence of their rootling behaviour was present in the form of distinct, bare patches of earth. Rootling encourages opportunistic annual plants to colonise these bare patches and creates hollows that fill up with water, attracting wildlife to the disturbed area. 

“I found there to be an interesting irony in how all meals served on the course were fully plant-based and made by the same kitchen that processed the meat obtained from the animals at Knepp”

I admired the longhorn cattle at dusk one day from a treehouse at the camp site. The herd was making its way across a field. Their presence was known again when my surveying group was out looking for somewhere close to water to set up our pitfall traps. These traps aim to catch ground-level insects in saucers filled with water. A drop of biodegradable soap is added to the water to break its surface tension, which causes any insect that lands in it to drown. As we approached a nearby stream, we passed a previously installed Malaise trap; a tent-like structure used for catching Diptera and Hymenoptera invertebrate orders. However, we found that it had been utterly destroyed. Besides the wreckage, we spotted some tell-tale hoof prints, all the more impressionable in the heavy clay soil that characterises this part of West Sussex. 

My first observation of Knepp’s deer was when I saw a pair of fallow deer resting beside a lake, basking in the midday sun. Without the presence of apex predators such as the wolf or the lynx, they have the luxury of being able to remain relaxed for long periods of time. To maintain optimal levels of species richness and to prevent the open wood pasture from developing into grassland through overgrazing, excess numbers of deer and livestock are removed and processed into organic, pasture-fed meat. Therefore, I found there to be an interesting irony in how all meals served on the course were fully plant-based and made by the same kitchen that processed the meat obtained from the animals at Knepp. Reflections on my time spent on the course evoke the vivid, the unexpected and the wondrous. There were cold nights shivering under a sleeping bag while listening to the sound of a nearby shrew and hot days battling the effects of heatstroke from long days out in the field during a summer heatwave.

There was the disconcertment felt with intentionally catching invertebrates in nets, gassing them with ethyl acetate and pinning them through the thorax in the name of science, and a feeling of relief when my overnight-soaked oats, chocolate brownies and sweet potato shepherd’s pie were all 100% plant-based. I think about the micromoth species I examined up close while they rested on egg boxes inside a moth trap I had helped to install and the Purple Emperor butterfly that had to be enticed down from its dwelling quarters in the heights of the sallow scrub. Midnight conversations with fellow course participants under a moonlit marquee brought a sense of comfort and comradery that made waking up at the crack of dawn to join a bird mist netting session more manageable. Operation Wallacea’s field course in the Knepp Wildland has served me up a generous portion of newfound skills, knowledge and friendships.

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