Where have all the woodland flowers gone?
Freelance Scottish nature writer Gordon Eaglesham put his finger on a bugbear. In writing about the turbulent nature of the discourse on rewilding, he noted that much is left unresolved and hanging in the ether when exchanges of ideas and rhetoric between advocates and critics take place on social media – “At worst, these debates stoke tensions, breed further division and fortify barriers” (1). He believes the “point-scoring from behind a screen” erodes trust, whereas a face-to-face forum, where these exchanges can be explored in more depth, would accomplish much more – “Tweets are not a friend of nuance; social media posts are more of a transaction than a conversation”
He struck a chord - I'm fed up with the influencers not just on Twitter but every media platform, who play to the gallery by backing soft messages so that they win approval. It is a churning of seemingly received wisdoms that is gauged to invoke plaudits, rather than being a reasoned observation – the latter would anyway be utterly unproductive in upping the fawning quotient for these influencers, as would also be a trenchant defence of wild nature rather than just a nod to it that is often given. Thus I am fed up with all the influencers playing to the gallery in decrying tree planting in favour of natural regeneration (i.e. (2, 3)) when the latter is better termed a natural colonisation that faces huge obstacles in landscape traps devoid of most of its potential natural vegetation (4). Moreover, critiques of tree planting also come at it from the angle of carbon sequestration, leaping on the succession of papers that throw suspicion on the efficacy of carbon capture through planting trees by monitoring or modelling changes in soil versus biomass carbon: two recent studies are based on Scotland (5,6). I refuse to take studies like these seriously when wild nature doesn’t care about soil or biomass carbon. It’s an anthropocentric obsession born out of misuse of planetary resources, with wild nature seemingly having to bear the burden of mitigating human stupidity as well as its depauperation in our landscapes. This depauperation includes the extirpation of native tree species at every scale from where they could be growing, leading to landscape traps (4).
Return of native tree species
Self-willed land has no past, only a future of its own volition (7). It’s the reasoning that says given all the pieces, wild nature will have the ability to reassemble, to recover. So I have been watching my local moor for the seventeen years since sheep grazing ceased to see what trees would return in the absence of their destroying effect (8). It has shown me the high impact of birds as long distance vectors in facilitating natural tree colonisation in what was a tree-less landscape, a process of seed dispersal by birds from trees at the fringes of the moor that I find has a term – ornithochory (9). Most successful of these has been the seeds of rowan excreted by birds after ingesting the berry, and which usefully will even come up in the shade of bracken stands that patch the moor. Seed from holly and hawthorn berries take the same route and there is a scattering of these across the moor. Oak coming up from acorns hidden by blackbirds and possibly jays (synzoochory) are more likely in bracken-free areas. Wind dispersal (anemochory) is much, much less successful - willow, ash and birch are really hard, except in a few places where there are stands around the edge of the moor because the seed will not travel very far downwind, falling close to the tree. Moreover, birch struggles to come up naturally in the shade of bracken cover, and will not establish on the wetter areas of the moor. Water (hydrochory) doesn't travel upstream, excluding one form of tree dispersal and the seeds that may use it; and mammals as vectors (epizoochory) through inadvertent translocation of seeds with spines, hooks, bristles, or barbs, have probably had little effect as their numbers are sorely few on the moor, and likely to get fewer in general according to the Mammal Society Redlist for British Mammals that indicates that 11 of 47 mammals native to Britain are classified as being at imminent risk of extinction (10). I applaud the Mammal Society for including the European wolf, albeit shown as regionally extinct in Britain, in its listing of vulnerable mammal species, as well as in its infographics (10,11).
This gradient of return on the moor is thus selective of tree species, and which is why supplementary tree planting is needed for those species that may never make it back if the moor is to realise its true natural potential for woodland. If you think about it, reinstating a tree species missing from a landscape is as important as reinstating a former native mammal species like the beaver or wolf. It’s relatively easy to check what this unfulfilled potential is because of missing tree species by using the Forestry Commission’s Ecological Site Classification Decision Support System (12). This matches key site factors with the ecological requirements of different tree species and woodland communities that distribute along environmental gradients of climatic and edaphic factors, such as soil type, moisture, aspect, and disturbance (13). It shows that oak, ash and alder will have an uneasy but not impossible time in the climatic conditions at the highest point of the moor, the summit plateau at ~900ft asl (275m) being the driest and most compacted area, but will thrive on the lower slopes and down to the fringes at ~560ft asl (170m) whereas rowan, downy and silver birch, and surprisingly also aspen, will flourish across all the moor (enter SE141399 in (12)). Rowan and oak have made it onto the summit of the moor, but it took around 14 years before they did so, the lower slopes colonising much, much earlier. Sources of birch seed are some distance from the summit and will take a long time to regain a position if it is based on small, year-on-year incremental movements downwind that even then depend on conditions that break the dormancy of the seed. In terms of potential woodland communities, the phytosociological associations that characterise native woodland, the strongest indication on the summit is for a birch woodland with an understorey of willows and purple moor grass (see NVC W4 in (14)). The situation is less clear cut for the various broadleaved woodland communities that could form on the lower slopes, but the strongly emergent rowan, oak, and holly are suggestive.
Alder has been the best success in supplementary planting, mostly thriving in the wetter areas and seemingly able to find the nitrogen-fixing bacteria that live in symbiosis with actinorhizal plants like alder (15). We have now seen alder seedlings for the last three years in a row, arising from early tree plantings. Birch plantings have produced strong trees but no natural colonisation arising from them yet, although the established birch on the fringe of the moor continues to slowly spread. Birch has been a constant disappointment in how it does so poorly in naturally spreading up the moor compared to other upland areas nearby that have less bracken cover, and it’s certainly not going to disperse against the prevailing wind. However, sometimes you can be taken by surprise when a recent walk revealed an overlooked area of dense birch establishing higher than we had seen before, although being an obvious downwind extension, and we determined to go back and have a close look. It was quite something – salmon-russet bark and sufficient numbers and canopy size for the shade to knock back the surface growth of grass, bracken and heather. The lower branches of the birch inside the stand were dying back in that shade, so starting the creation of a woodland interior space under the canopy. It is at a stage now where woodland plants could take hold, such as if a few fern spores turned up.
We feared that bark stripping by roe deer would be a problem for all the trees developing on the moor - tree guards could not be used for the planted trees as the agri-environment agreement on the moor does not permit tree planting (16) but it hasn't proven as damaging as we feared for our and wild nature's trees. In fact the worst damage has come from sub-humans who have deliberately persecuted and degraded the trees over the years by pulling or cutting off branches so that they eventually deaden the tree (see photo above). My understanding is that this resentful, mutilating behaviour is carried out by horse riders; bird watchers who claim trees and scrub harbour predators of ground nesters; and dewy-eyed people who claim the moor was once covered in heather when it’s been bracken infested for probably centuries. The wide albeit scattered distribution of trees and the exponential growth now of the early-established trees has made that persecution a much harder task.
Smashing up woodland
Grazing of woodland is another bugbear. The Woodland Trust are always keen to defend their planting of trees, depressingly though in the context of carbon sequestration (17) but what really annoyed me was the announcement that it was dumping cows into a woodland it had planted on arable land in 2000, allegedly to structure it – the cows would “bash their way through, creating new paths and keeping glades clear of shrubs” – so that it “adds a whole new layer in the ecosystem and is expected to have dramatic benefits for wildlife” (18). This is the onerous subjectivity that says wild nature can’t be allowed its own volition in its own timescale, that it has instead to be diversified through manufacturing, but we also get the twee hyperbole that the cows will “bring a wild influence to this landscape which will evolve as they browse, roam, and make it their home” their “moovements” tracked through satellite positioning collars that can be live-checked (19) but then the “wild influence” is surely destroyed by knowing that the cows are named Denzil, Bisy Backson, Dumbledore, June, Bella and Berry.
Similar hyperbole is rumbling from a project in Kent for European bison to smash up woodland in a fenced off area in the Blean Woods, the aim being to “restore the ecosystem of the area’s renowned ancient woodlands …. Their ability to fell trees by rubbing up against them, and eating the bark, creates space for a wide range of other species to thrive. No other species can perform this job in quite the same way” (20,21). So I wonder why the bison will be accompanied by other grazing animals - cows, horses and pigs (22)? It’s an outrageous assertion to imply that a biodiversity crisis will be averted by this woodland bashing, virtue signalling that it is better done by the bison than by the usual practice of human intervention. I just see this as playing to the gallery of fashionable safari park rewilding (23) when the claim is that the bison will give people “a truly wild experience” (20,21) presumably from the viewing platforms that are to be built along with the necessary fencing and water holes (22). Fundamentally, though, it is no different from conservation grazing - using an animal as a tool for species gardening, just like the use of cattle in mainstream nature conservation in Britain – but with the difference that the perpetrators of this project have been seduced by seeing the greater destructive ability of bison compared to cattle in fenced-off enclosures in the Netherlands like the Kraansvlak (22,24). Would the bison be so apparently destructive if they weren’t trapped in such small enclosures, imposing an unnatural level of grazing, an over grazing, rather than being able to disperse freely into a wider landscape? That bison are not a domesticated animal should ring warning bells about this hyperbole - fencing these animals merely creates an open-air zoo that cuts across the animal’s life history, its habitat selection, movement ecology and home range size (25). It’s an awful manifestation of human perversity to trap wild animals like bison behind a fence to use as a tool in the same way that so many beaver trapped from the wild and then enslaved behind fences in England are used as tools in safari park rewilding (23) (see also this critique of the bison project by collbradán (26)).
The hyperbole of the Blean project in justification says that the European bison (Bison bonasus) would be a substitution for the functions of the extinct steppe bison (Bison priscus) that once existed in Britain (22). Does that mean we have to find analogues for every animal that roamed our land mass but went extinct? How about dinosaurs? It is my understanding that our jurisdictional systems on nature assume a species to be native to Britain if had an unassisted presence before the land bridge to continental Europe disappeared through sea level rise, as well as making a judgement call that rules out consideration of species that became extinct without the involvement of human agency, like the dinosaur in the unlikely event that we could recreate them, from being classified as former native species. Thus former natives are species that once were native in a location, but the population has died out and the species no longer has the potential to re-colonise naturally. These species are considered worthy of reinstatement.
I can’t easily find an official document that confirms all these points. Nevertheless, I see no evidence that indicates human agency in the extinction of the steppe bison: a newspaper article about the project claims that the “steppe bison is thought to have roamed the UK until about 6,000 years ago, when hunting and changes in habitat led to its global extinction”(27) implying human agency for its loss from Britain, but that claim is not supported by the literature which indicates the steppe bison disappeared from the fossil record of Western Europe at the end of the Pleistocene, around 12–10,000 years ago and therefore not 6,000 years ago (28-30). Nor is the claim in the article that the “European bison….is a descendant of [the steppe bison] and its closest living relative”(27) supported, as the phylogenetic relationships between European bison, steppe bison and the wood bison (Bison schoetensacki) another extinct bison, are unclear especially since there is a lack of genomic data for the wood bison, and a recent study rejected the European bison being a descendant of the steppe bison (30). Unsurprisingly, the steppe bison is not shown as an extinct former native species in Britain (31). Thus there can be no justification for presuming a need for a replacement of the ecological functions of that steppe bison, even if it could be certain that the European bison has similar ecological function (32).
Further, and at least this is admitted, there is no evidence that European bison has ever had a presence here, although there are others who would want to argue this (24,31). There have been murmurings of observing the impact of the bison in this project (33) and encouraging the public to do so as well, probably so that it can be contended that the jurisdictional system needs changing, but currently introducing "animals which are not ordinarily resident in and are not regular visitors to Great Britain in a wild state" (see s14 in (34) would require a licence application to Natural England (see s16 in (34)). Thus any rhetoric about this project being a preliminary to introduction of European bison to free living would be a translocation OUTSIDE of their natural range, which under international guidance would be classified as a conservation introduction, an Ecological Replacement allegedly to restore the ecological function provided by a lost species. It does, however, have to be a close equivalence in ecological function, which is unproven and unneeded (see above) and the guidance cautions that such translocations may potentially bring high risks that are often difficult or impossible to predict with accuracy (35).
Rammed with spring flowers
I have my own observations on the impact of grazing in woodland. Some years ago, I wrote about the impact of grazing at the western end of Hawksworth Spring Wood, and where cattle had already "trodden out the bugle, bluebells, dog’s mercury, wood anemone, wild garlic and ferns. These woodland plants barely remained in refuge around the base of the larger trees, or where the cows could not squeeze, but they could be seen to gloriously carpet the ungrazed, eastern half of the wood” (36). I also noted a lot of structural damage in two small adjacent woods open to rough pasture where ponies had been introduced, and which had cleared through the bramble undergrowth that roe deer rely on during the winter. We haven’t walked these woods in the last few years as we got fed up having to traipse through cow fields to get to them. Needs must during the anthropause, and we worked out a way just to go through some horse livery fields. We had forgotten how rammed the eastern end of the wood is with spring flowers – wood anemone, bluebells, wild garlic, woodruff, moschatel, winter heliotrope. We looked in vain for the remnant marsh marigold in the grazed woodland areas, and which is abundant in the flushed areas of the ungrazed wood, but it had been completely trodden out. However, at our coffee spot surrounded by flowers next to the beck in the ungrazed woodlands, I suddenly realised I was looking at some deadwood sticks of hazel hanging at crazy angles across live branches – it was glue fungus (Hymenochaete corrugata) sticking them together! We first saw this fungus in woodlands in Argyll five years ago where it is recognised as occurring only when woods are undisturbed – for obvious reasons due to the fragility of the coupling (37). We realise now that we haven’t been back to Hawksworth Spring since walking the Argyll woods, so we wouldn’t have recognised it there until now. Wonderful. It is a diminishing return that something new will turn up in places you have known for many years, but sometimes they do!
Herbivory is a natural process, but the dogma for every situation says that it has to be applied by fenced-in livestock if there is to be high biological diversity, irrespective of any consideration of whether this imposed herbivory is at a level that would constitute over grazing. It is, anyway, not the case that my local woods lack herbivorous action, as roe deer have a presence in all of them. I don’t see them every time, but they are evident from the narrow trails they wear in the ground layer where you can also see hoof prints; from the scrapes they make for overnight resting places; and the roe rings in the ground cover relating to male behaviour during the rutting season. Their browsing impact is difficult to discern when the ground flora of these woodlands is so abundant. It is probably due to their freedom of movement and low numbers. However, I did see significant evidence of the impact of deer when visiting those Argyll woodlands (37). Thus a high-fenced deer exclosure in Glen Nant had lush and varied growth, including bilberry, mosses and ferns, compared to the poor ground flora dominated by grass outside of the exclosure.
The impact of a higher density of deer in Scotland was described in an article by Kate Holl and Helen Armstrong in the journal Scottish Forestry that reflected on the implications for Scotland’s native woodlands from the Forestry Commission’s Native Woodland Survey of Scotland. Holl and Armstrong cautioned that deer grazing was putting a considerable constraint on woodland regeneration, the fear being that the small amount of native woodland was "at imminent risk of disappearance through senescence and a lack of regeneration" (38). Moreover, it was considered species poor in terms of its tree composition and shrubs, and the ground flora was almost completely lacking climbing and trailing species, such as bramble, wild raspberry, ivy and honeysuckle. Only rarely, where grazing pressure was reduced for at least the required ten or twenty years, could trees regenerate successfully and, even then, usually only the pioneer species of birch or Scots pine were able to establish because of a constraint on the establishment of the more palatable or susceptible tree species, such as rowan, hazel, oak, elm, ash, willow, aspen, gean or holly. These had a greater ability to regenerate in partial shade and could gradually replace the dominance of birch or Scots pine, and so produce woodlands diverse in both structure and tree species.
Thus high grazing impact was altering tree species composition and age structure, as well as causing a loss of structural and species diversity. The authors believed that to “truly regenerate our native woodlands requires grazing pressures to be brought down to the point here the whole suite of trees, shrubs, ground flora and climbing plants can regenerate and the woodlands can start to expand into open areas”. In another article, the authors bemoaned that they had “become so used to seeing woodlands grazed to the bone that many people think that woodland ‘should’ have no understorey and no young trees or shrubs”(39). Working through a litany of examples of grazing impact from a varying range of herbivore pressure, they noted that “different people looked at different things” as indicators of herbivore impact, that they “do not always look carefully enough at the right indicators”, so that there was a lack of objectivity in assessment. This argued for a standard approach for assessing herbivore impact on woodland, and which they described. The assessment method is now more comprehensive and forms part of the woodland grazing toolbox provided by Scottish Forestry (40).
Woods free of grazing for the longest appeared to be the most flower-ful and biodiverse
Kate Holl, a woodland adviser with Scottish Natural Heritage, and one of those authors, had been thinking about grazing impacts on woodlands for a number of years. It was during a visit to the island of Mull in 2012 that she noticed that the grassland fenced off around an old house was a carpet of flowers, whereas there were none outside the fence where sheep grazed (41,42). On the same trip, she went to a woodland that had been protected from grazing by sheep and deer since the 1980s – “This small wood was like a little bit of paradise. Here there was an understorey of shrubs and young trees, and a profusion of flowers. The sound of birds and insects filled the air”. All of a sudden, Holl realised that something was missing from most Scottish woods – “Several hundred years of deer and sheep browsing has left our woods without their “filling” – there is the canopy and the ground, but everything in between – especially the flowers – has been eaten out. Our woods are like the “sandwich without the filling”!” She asked herself “Where have all the flowers gone?”
She found on a later return to the island that the fencing had been taken down as it was considered that it was time to reinstate grazing – “In the space of less than 2 years, much of that ecological richness that had taken over 30 years to develop had been completely wiped out. Apart from a few sapling trees, you would have never known what abundance of flowering plants this wood had come to support, for they had all been eaten or trampled into oblivion” (42). This moved her to apply for a Fellowship that would fund her in 2017 to gather information about the understorey and flowering plants in ungrazed (or little grazed) woods in other parts of Europe where the climate and geology is comparable to Scotland. She wanted to “experience what it feels like to be in a wood that has not been ecologically depleted by centuries of overgrazing” – and to find out whether there would be “more flowers, more insects, birds and mammals?” Holl visited ungrazed woodlands in SW France, SW Norway, and Iceland, as well as surprisingly on the Isle of Wight as it has no wild deer. All these woods, like Scottish woods, have an oceanic influence so that they are wet and temperate. Her report, and a presentation and article on her findings, all have photos of these woodlands showing the astonishing abundance of wildflowers, and with well-developed understoreys having shrubs such as dog rose or low shrubs such as blaeberry, stone bramble and northern bilberry; trailing and climbing species such as honeysuckle and bramble; and luxuriant with ferns (41,42,43). The woods appeared to be self-regenerating and had high ecological productivity in terms of their ability to generate biomass.
Holl says that her findings “did not support the received wisdom of many ecologists in this country, which is that without grazing, woodland ecosystems become rank and species poor” (42). On the contrary, “woods that had been free of grazing for the longest appeared to be the most flower-ful and biodiverse”. Her main conclusions were that Scottish woods should have more flowers; that the understorey was missing from most woods; and because there were so few flowers, there were also few woodland berries such as raspberries, blaeberries, rosehips and brambles. The implications were that due to the flowers being preferentially browsed, few were able to complete their reproductive cycle and so had to propagate vegetatively, so breaking the evolutionary advantage of new genotypes arising from cross pollination; many dependent species (insects, birds and mammals) were missing from Scottish woods because there was not enough food for them to eat and few places for them to live; and that the extent and composition of species-rich woodland communities characterised by palatable and grazing-sensitive species had been greatly altered in landscapes that have a long history of supporting large numbers of herbivores. Additionally, in the wider Scottish landscape, Holl noted that due to grazing by domestic stock and the imbalance between wild herbivores and predators (i.e. lack of large predators) habitats in Scotland had been depleted over hundreds of years by overgrazing, and were now functioning at a very low level of ecological productivity; and that whole habitats comprising palatable species were missing from the Scottish landscape, or like tall herb communities, had retreated to inaccessible places like cliff ledges. In the other countries she had visited, where grazing pressure was much lower, these vegetation communities were much more frequent and extensive, and not confined to inaccessible places. Her main recommendation was that "there is now an urgent need to significantly reduce large herbivore numbers across Scotland in order to allow ecological restoration of over-grazed habitats", this recommendation strengthened by a recent study that showed that tall herb communities were released from refuge after grazing by sheep and deer was excluded from a Scottish hillside by fencing (44).
At the end of her report, Holl notes that while sharing her findings on returning to stimulate a discussion about re-flowering Scotland, she was pleased to be made aware of wood on a tiny island off the west coast of Scotland where a photo showed it to be carpeted with flowers, just like the woods she had seen in Iceland (42). She visited this island of Eilean nam Meann, off Port Ramsay on the Isle of Lismore off the Argyll coast in the summer of 2018 (45,46). It’s an offshore rock in the intertidal zone so that it can only be visited at low tide. This is a sufficient limitation to discourage deer, and the local sheep are kept away from it. The woodland can be seen crowning the island, the woodland edge having what Holl describes as an almost impenetrable mantel of thorn scrub (bramble, hawthorn and dog rose) encircling and protecting it. Past that, the interior of the woodland was carpeted with wild flowers - bluebell, pignut, wood anemone, sanicle, primrose, bugle, yellow pimpernel, herb robert, wild garlic, stitchwort, and twayblade orchids - and climbing plants such as ivy and honeysuckle, had grown up in the canopy where they can flower and fruit, the trees being hazel with ash, and occasional oak, and with holly and hawthorn. It was a joy for her to discover this wood, and to see the proof again that, where herbivore numbers were low enough or absent, the flowers and the understorey can develop just like those woods in Iceland, Norway, France and the Isle of Wight that she had visited – “There could indeed be “flowerful” woods in Scotland. It’s just that most don’t ever get the chance, but really, how much more enjoyable would a walk in your local wood be if there were just some more flowers….?”
I am fortunate that I can enjoy the abundance of wild flowers in the eastern end of Hawksworth Spring Wood (see above) as well as in other ancient woods near me like Walker, Hirst and Middleton, all of which have a presence of roe deer albeit at low density, but there is no access for livestock grazing in these woods. It is painfully obvious which of my local ancient woods have a history of sheep grazing, since Deep Cliff Wood is unenclosed from Harden Moor, and Broadstone Wood in Shipley Glen is unenclosed to Baildon Moor, and both woods are lacking in woodland flowers (47). I can also point to the abundance of wild flowers in the almost inaccessible woodlands, like those on coastal slopes such as Goultrop Roads on the Pembrokeshire coast (37) and Little Cliff at Hayburn Wyke on the N Yorkshire coast (48) as well as in a narrow limestone ravine like Ling Gill a few miles north of Horton in Ribblesdale (49). I trust the evidence of my eyes for the reason why I am seeing this abundance of wild flowers. It’s what I seek out, and I believe it is an expression of wild nature comparable to that which does arise if all the pieces are there, if herbivory is constrained through the natural process of predation. We can only know if I am wrong, determine which the unnatural aberration really is, if all the pieces are there, that former native carnivore species like the wolf and lynx are reinstated. Is it the floristic abundance of a woodland that is not overgrazed, or the smashed up, overgrazed woodland lacking many of its woodland species?
Mark Fisher 4 August 2020
(1) A forum for rewilding after coronavirus, Gordon Eaglesham, Ecologist 9 July 2020
(2) Isabella Tree (@isabella_tree) Twitter 26 November 2018
(3) Peter Smith (@PeetaSmith) Twitter 6 July 2020
(4) Watching the naturalness return to the Carrifran Valley, Self-willed land April 2015
(5) Matthews, K.B., Wardell-Johnson, D., Miller, D., Fitton, N., Jones, E., Bathgate, S., Randle, T., Matthews, R., Smith, P. and Perks, M., (2020) Not seeing the carbon for the trees? Why area-based targets for establishing new woodlands can limit or underplay their climate change mitigation benefits. Land Use Policy, 97: p.104690
(6) Friggens, N. L., Hester, A. J., Mitchell, R. J., Parker, T. C., Subke, J. A., & Wookey, P. A. (2020). Tree planting in organic soils does not result in net carbon sequestration on decadal timescales. Global Change Biology 00: 1–11.
(7) Wild Park, Brighton - not so wild now, Self-willed land December 2013
(8) The continuing destruction of our native trophic pyramid, Self-willed land February 2018
(9) Agents of Dispersal, Seed, Encyclopædia Britannic
(10) One quarter of native mammals now at risk of extinction in Britain, Mammal Society 30 July 2020
(11) Red List for Britain’s Mammals, Mammal Society
(12) Ecological Site Classification Decision Support System, Forestry Commission
(13) Species distribution mapping and its insights on the self-assembly of wild nature, Self-willed land October 2017
(14) Hall, J.E., Kirby, K.J. & Whitbread, A.M. (revised 2004) National vegetation classification field guide to woodland, JNCC, Peterborough
(15) Santi, C., Bogusz, D., & Franche, C. (2013). Biological nitrogen fixation in non-legume plants. Annals of botany, 111(5), 743-767
(16) The moral corruptness of Higher Level Stewardship, Self-willed land August 2013
(17) Tackling climate change with the right trees in the right place, Karen Hornigold, Woodland Trust 27 July 2020
(18) “Track and trace” of cows introduced in woods to boost biodiversity, Andy Bond, Woodland Trust 5 June 2020
(19) Cattle Tracking in the Woods at Woodleigh, Cows in Clover, Digitanimal
(20) Bison to help bring back UK wildlife, Wildwood Trust
(21) Bison to help bring back UK wildlife, The Wildlife Trusts 10 July 2020
(22) Wilder Blean, Wildwood Trust
(23) Faking the wild – safari park rewilding, Self-willed land May 2020
(24) Bison habitat preference becomes a pawn in the disputed natural vegetation cover of Europe, Self-willed land November 2015
(25) Movement ecology and rewilding, Self-willed land September 2019
(26) collbradán (@collbradan) Twitter 13 July 2020
(27) Wild bison to return to UK for first time in 6,000 years, Damian Carrington, Guardian 10 July 2020
(28) Marsolier-Kergoat, M.C., Palacio, P., Berthonaud, V., Maksud, F., Stafford, T., Bégouën, R. and Elalouf, J.M., (2015) Hunting the extinct steppe bison (Bison priscus) mitochondrial genome in the Trois-Freres Paleolithic Painted Cave. PLoS One, 10(6), p.e0128267
(29) Massilani, D., Guimaraes, S., Brugal, J.P., Bennett, E.A., Tokarska, M., Arbogast, R.M., Baryshnikov, G., Boeskorov, G., Castel, J.C., Davydov, S. and Madelaine, S. (2016) Past climate changes, population dynamics and the origin of Bison in Europe. BMC biology, 14(1), pp.1-17.
(30) Palacio, P., Berthonaud, V., Guérin, C., Lambourdière, J., Maksud, F., Philippe, M., Plaire, D., Stafford, T., Marsolier-Kergoat, M.C. and Elalouf, J.M. (2017) Genome data on the extinct Bison schoetensacki establish it as a sister species of the extant European bison (Bison bonasus). BMC evolutionary biology, 17(1), pp.1-11.
(31) Montgomery, W. I., Provan, J., McCabe, A. M., & Yalden, D. W. (2014). Origin of British and Irish mammals: disparate post-glacial colonisation and species introductions. Quaternary Science Reviews, 98, 144-165
(32) Яшина, O. & Цветкова, T.B.(2006) Кирилловский бизон, Вестник Кирилло-Белозерского музея. Вестник 9 (Май 2006)
(33) Paul Whitfield (@FoxWhitfield) Twitter 14 July 2020
(34) Wildlife and Countryside Act 1981 c.69
(35) IUCN/SSC (2013) Guidelines for Reintroductions and Other Conservation
Translocations. Version 1.0. Gland, Switzerland: IUCN Species Survival Commission
(36) The craze for conservation grazing, Self-willed land May 2009
(37) Coastal temperate rainforest - in Britain?! Self-willed land June 2015
(38) Holl, K. Armstrong, H. (2014) Deer and livestock impacts on native woodlands in Scotland re-visited. Scottish Forestry 68(2): 32-36
(39) Assessing the impact of deer on woodlands: a new method Helen Armstrong & Kate Holl explain the need for a standard approach when assessing deer impacts and introduce the Herbivore Impact Assessment method. Reforesting Scotland # 52 (AUTUMN/WINTER 2015) 11-13
(40) Assessing Herbivore Impact in Woodlands: An Observation-based Method, Helen Armstrong, Bob Black, Kate Holl, Richard Thompson. Revised 4 March 2020
(41) Where have all the flowers gone? Scotland's Nature 12 October 2017
(42) Where have all the flowers gone? Kate Holl, Churchill Fellow of 2017, Churchill Memorial Trust
(43) Where have all the flowers gone? A perspective on flowering plants in Scottish semi-natural woods. Findings from Kate Holl’s Churchill Fellowship, June 2018
(44) Grazing exclusion and
vegetation change in an upland grassland with patches of tall herbs, Sarah H.
Watts, Anna Griffith & Lindsay Mackinlay, Vegetation Science Blog 1 April 2019
(45) A trip to a wooded rock off the west of Scotland where the herbivores don’t go! Scotland’s Nature 7 September 2018
(46) In search of Scotland’s secret rainforest, Richard Baynes, The Herald 11 January 2020
(47) Leaky dams - preciousness, vanity and tree persecution, Self-willed land April 2019
(48) Rare and precious – words devalued by the conservation industry, Self-willed land May 2011
(49) Walking the wild places, Self-willed land September 2010