Ecological consequence of predator removal
"a one-way system for biodiversity loss, as once an animal ceases to appear in the wild, it ceases to be native"
Such was the opinion of Baroness Parminter in seeking amendment of Part 2 of the Infrastructure Bill on Invasive non-native species. Another of her criticisms was that it would “interfere with important future reintroduction programmes”
You can read why I think she is wrong here
In thinking last time about the lack of natural control mechanisms in Britain, I stressed the importance of large carnivores in natural processes, especially their function in trophic cascades (1). I also noted that you would be hard pressed to find someone in the conservation industry here that has a real grasp on this, and I could also have added amongst environmental journalists as well, their engagement with the subject rarely getting much above churning out the latest press release from the conservation industry. In reality, it took a radio comedian to write something that was comprehensible about trophic cascades in the Observer last September, and he was only standing in that day for another comedian who has a regular column (2,3). What was impressive was that John Finnemore used the analogy of the trophic cascade initiated by sea otters on the Pacific Coast of California to question the ecological illiteracy of the delayed badger cull that had just got underway in Somerset and Gloucestershire (4,5).
In a light hearted way, Finnemore explained the results of a 50-year study that sought to understand why endangered seagrass beds have been expanding in recent years in estuaries on the Californian coast when the nutrient load in effluent run off from agricultural fields was known to encourage the growth of algal blooms on the seagrass, blocking sunlight and knocking back seagrass growth (6). Eelgrass (Zostera marina) is the dominant seagrass along this coast, providing an important coastal ecosystem as nursery habitat for juvenile shellfish and finfish, especially salmonids; supporting the foundation of the detrital food web through its decaying leaves being consumed by bacteria, worms, and young crabs; as well as helping to prevent erosion and maintain shoreline stability by anchoring seafloor sediment with its spreading roots and rhizomes (7,8). In addition, its leaves, floating in the water column, absorb wave energy thus slowing water flow, which promotes deposition of suspended particles and stabilization of sediments.
What the study provided was evidence that an unusual four-level trophic cascade was occurring, whereby a top predator was mitigating the bottom-up influences of the nutrient loading. In an area of sea-grass beds in an estuarine ecosystem exposed to extreme nutrient loading, the study demonstrated that the growth and expansion of the eelgrass beds fluctuated with the fluctuations in the sea otter (Enhydra lutris) population; the study areas initial recolonizing population of sea otters in 1984 of about 15 declined in the late 1980s, then grew to nearly 100 in the 1990s before declining again, followed by a recovery over the past decade. What follows is the chain of events that explain how a carnivore can influence the growth of an aquatic flowering plant, but without having any direct effect on it – a sequence and characteristic that is defining of a trophic cascade. Sea slugs are the grazing herbivores that eat the algae that block light from the eel grass. However, the sea slugs in turn are eaten by crabs. In the absence of sea otter, the crabs reduce the population of sea slugs to the point where they cannot deal with the flush of algae promoted by eutrophication from the run-off. Since sea otters eat the crabs, using a stone to break into their shells, they then keep the population of this middle or mesopredator in check, freeing up the sea slugs to graze off the algae.
What Finnemore found interesting about this research was the unpredictability of the linkage between the sea otter and the fate of the eelgrass, noting that it was unlikely that the hunters that had nearly brought the sea otter to the brink of extinction a hundred years ago, would have imagined what the consequences of their actions could have been (3). The lesson Finnemore took from this was that it could move him past his unease at the badger cull being just his personal distaste at the slaughter, and on to him questioning whether DEFRA really knew what the effect of the badger cull would be, especially when there seemed to him to be a great deal of disagreement among experts about whether a badger cull would slow the spread of bovine TB, leave it unaffected, or indeed make it worse.
I have seen groups of sea otters floating on their backs in kelp beds off the California coast at Santa Cruz, which is at the northern end of Monterey Bay, the study area being 25 miles further down the bay. There is no denying their apparent charm, nor that Finnemore in wishing to scratch an itch about the badger cull, showed a remarkable level of engagement and ingenuity, especially when his blog shows that he is not a frequent nature writer. I left a comment on his Observer article, praising its description of a trophic cascade as a rare example of ecological literacy, not often seen in the UK. As I also remarked, if only there was more commentary on the natural world we have left, that shows this level of understanding.
Evolution of ecological principles
I leave to others a condemnation of badger
culling in pursuit of propping up an overweening farming industry, but
there are more lessons and observations that can be extracted from this
sorry tale. Before coming to those, it’s worth looking back in time to see
the early milestones in our understanding of trophic function, the species
interaction between trophic levels. While Charles Darwin is remembered for
his theories on the evolution of species, a preceding chapter in his book
from 1859 - The Origin of Species - focuses on the “struggle for
existence ….with the physical conditions of life” (Chapter 3 (9)).
Here, Darwin gave his observations on the relations between species, be it
the limits or competition for food, the vagaries of reproduction, or
falling prey to other species:
This perhaps constitutes an early understanding of the dynamics of predator-prey interactions, Darwin recognising that it was not only resource limitation that determined the populations of herbivores, but also that they served as prey for other animals. This is the timescale of survival, a more immediate concern for wild nature than the much longer term of the evolutionary development of species, but which directs, as Darwin wrote, “the whole economy of nature, with every fact on distribution, rarity, abundance, extinction, and variation”
The whole economy of nature soon found description in the term ecology (oecologie) invented by German zoologist Ernst Haeckel. He was greatly influenced by Darwin, with many references in his book from 1866 to Darwin’s struggle for existence - “Kampf ums Dasein” (10). It was in a chapter about ecology and the biogeographical distribution of living organisms entitled Oecologie und Chorologie that we find a definition that it is “the whole science” of the relations of the organism to the surrounding outside world, and where we can expect all the "conditions of existence"
The interrelationships in communities attracted mathematicians in the early 20th century, who began to develop models for the population dynamics of biological systems. One of these was Vito Volterra, an Italian mathematician. In 1926, Volterra took the earlier work on human population dynamics by Pierre Verhulst of the University of Ghent, himself influenced by the earlier work of Malthus (11) and developed it further to produce one of the first models that considered food sufficiency and the herbivore-carnivore relationship: the three trophic levels of carnivore, herbivore and plants (12). The periodical fluctuations in population abundance that his equations predicted, allowed him to deduce three laws, and for which he sought confirmation in observations from natural systems, including noting that Charles Darwin had shown a perception of these phenomena in relation to the struggle for existence.
Charles Darwin had noted, in his description of the struggle for existence, the effect of grazing on the growth of regenerating conifers, judging from the rings of growth that, even after 26 years, one tree had failed to advance in height above the dwarf shrubbery surrounding it (9). He had also observed that when that area of heathland near Farnham in Surrey was fenced to exclude grazing, it became thickly clothed with vigorously growing young conifers. In the logic of predator-prey dynamics, the outcome of this exclusion fencing is the equivalent of a density-mediated effect in a trophic cascade between predators and plants that results from a reduction in the number of herbivores feeding on the plants. This had been at the heart of Vito Volterra’s equations on the abundance of species, the interplay between the three trophic levels of carnivore, herbivore and plant species, “the first eats the second, which in turn eats the third” (12).
While Volterra was working on the
mathematical relationships between trophic levels, Charles Sutherland
Elton, English zoologist and animal ecologist, was working on the
functional attributes of animals, the niches they occupied on the basis of
their prey, and their corresponding trophic position. His book, Animal
Ecology, published in 1927, described an animal's place in its
community, its relations to its food and enemies, as well as the pyramid
of numbers in a community, with a greater abundance of animals at the base
of food-chains, and the comparative scarcity of animals at the top (13):
Elton used examples from around the world as
the canvas on which to make his observations. He had to, if he wanted to
write about the position and function of large carnivores in food chains
and cycles, because he only had a mesopredtaor in the fox as an example he
could use from England. Thus he noted that on Vancouver Island, cougar
(mountain lion) prey on deer, lynx upon snowshoe rabbits; arctic fox subsist
on guillemot eggs when available, while in winter they rely partly on the
remains of seals killed by polar bears; spotted hyaena in tropical Africa
destroy large numbers of ostrich eggs, but also gorge on the remains of
zebras killed by lions; and the Tibetan wolf eats small gazelles. As he
His example of the consequences of when
carnivores were missing came from a deer sanctuary in Arizona. He did not
name the sanctuary, but it was the Grand Canyon National Game Preserve
on Arizona's Kaibab Plateau, a million-acre refuge created in 1906 to
protect 3,000 endangered Rocky Mountain mule deer (14,15). Hunting was
prohibited in the Preserve, but agents of the Forest Service killed off
the deer's main predators: wolves, mountain lions, bobcats, and coyotes.
Because the Kaibab Plateau is surrounded by deep canyons and hostile
deserts, it functions like a biological island and thus resisted the
migration in of new predators to replace those extirpated. Thus the deer
population boomed, the Preserve hailed as a success, but as Elton noted,
without their usual “carnivorous enemies” they increased so much
that they began to over-eat their food-supply. Between 1906 and 1924 the
herd increased to perhaps as many as 100,000 animals, the resulting
degradation of the landscape vegetation not only leaving the deer
malnourished and susceptible to disease, but also resulting in changes to
birds, other mammals and reptiles. An official visit to the area by a
committee of experts in 1924 brought forth a recommendation that to avoid
disaster, the deer population should be cut immediately by 50 percent. It
was a tough decision to make at that time, resisted for four years, by
which time the starved herd had plummeted to 15,000. However, the cull
proceeded because the range had deteriorated so much by then that the herd
had to be cut far below even its original numbers in order to give the
vegetation an opportunity to recover. The lesson was clear for Elton (13):
Elton also gave an example of where man was in competition with a large predator. He described the intensive hunting of the great bearded seal (Erignathus harhatus) killed for its skin and blubber by Norwegians venturing into the outer fringes of the ice-pack around Spitsbergen, the largest island of the Svarlbard archipelago. The rate of slaughter - 5,000 skins or more brought back by just one of the small sealing-sloops over the course of a summer – could have resulted in a plummeting seal population, especially since the seal was a staple food of polar bears: they stalk and kill the seals as they lie out on the pack-ice. However, the Norwegian sealers also hunted and killed large numbers of polar bears for their hides, sometimes reaching 900 in any one year (16). As to the supply of seals, Elton noted that “a balance happens to have been struck”, but it was of course to the detriment as well of the polar bears. Fortunately, Polar bear hunting was banned in Svalbard in 1973 (16).
As with Haekel and Volterra, Elton took inspiration from Charles Darwin, except that he referenced an earlier work of Darwin’s on the structure and distribution of coral reefs (17). Elton quotes a passage about the browsing of coral-reefs by sea cucumbers (Holothuria spp) that Darwin saw as the “living checks to the growth of coral-reefs” and giving further evidence of the “almost universal law of ' consume and be consumed'”. Elton regarded this passage as evidence that the coral-eating niche had a geological significance, but that it also illustrated the “wide grasp of ecological principles possessed by Darwin”
Ecological consequences of badger removal
There are two references to badgers in
Elton’s book: once in relation to effects of weather cycles on animals, in
that most avoid rain as their wetted fur loses its properties of
insulation, but that badgers lie in the sun to dry themselves if they get
wet. It is the second reference that brings me back to the lessons to be
learnt from the sorry tale of the badger cull. Elton was developing his
idea of the niches of animals, their place in the biotic environment, and
their relations to food. He argues that the ecologist should not just
describe what an animal looks like, but also what it is doing in its
I wonder if John Finnemore was aware, when he wrote his article for the Observer, that the Randomised Badger Culling Trial (RBCT) that kicked off 15 years ago was used as an opportunity to study the very thing that Elton recommended, the ecological consequences of removing a predator like badgers from an ecosystem. The trial ran from 1998 to 2007, taking place in replicate 100 square kilometre areas of England, the culling operations lasting for between four and seven years, and with 11,000 badgers cage-trapped and killed (18). The incidence of bovine tuberculosis (bTB) was studied in control areas of no culling, areas of repeated culling across all accessible land, and areas where culling was in response to bTB outbreaks in cattle. The incidence of bTB was also monitored around the outside of the trial areas. The outcome in terms of transmission of the disease is lost through years of constant self-interested bickering, but the report of the findings warned of a "perturbation effect" in which culling leads to disruption in the badgers’ territorial system, causing any surviving badgers to range more widely, which itself led to a substantial increase in the incidence of the disease, and its wider dispersal.
For the ecological study, DEFRA contracted the Central Science Laboratory to monitor the populations of species that may have been affected by badger removal and, where possible, determine the underlying ecological processes driving any observed population responses (19). A clear result of the eight-year-long study was a significant increase in the number of foxes, the likeliest explanation for this effect being a reduction in competition for similar dietary components as well as for space, in particular breeding den availability, caused by badger removal. There were variations across the study areas in what happened to rabbit numbers, which might have been expected to fall in number with the rise in foxes, and which would have had knock-on effects for the prey base of species such as stoats and weasels. Hedgehog numbers more than doubled, which was to be expected as the badger is a predator of the hedgehog, and the removal of badgers would also have favoured the hedgehog in release of the competition between them for earthworms and beetles. However, while the numbers of two ground nesting birds vulnerable to badger predation declined in control areas, the skylark and meadow pipit, they were maintained where badgers were removed. The authors were not able to resolve this when the expectation may have been no change where there was no culling, and a rise in numbers where there was.
The authors concluded that badger removal had a range of ecological consequence. They were very keen for a continuation of the monitoring program so that the recolonization of the repeatedly culled areas with badgers could be followed – in effect, a reversal of the experiment. The response of various populations to this recolonization would have added a greater understanding about the nature of the relationship between badgers and these species. This recommendation was not taken up, but the authors were able to publish their findings, and in a context and terminology that is rarely applied in England, of carnivores, trophic cascades and ecosystem processes. Thus the findings on badgers and foxes gave experimental support for competitive release in sympatric carnivores (carnivores that exist in the same geographic area and thus regularly encounter one another (20)) and the findings on badgers and hedgehogs provided experimental evidence for mesopredator release, a situation where removal of a higher predator results in an increase in the population of a middle predator (21).
There have been two more reports commissioned on the potential ecological consequences of badger removal through culling. In October 2009, an order came in to force in Wales that allowed the Welsh Assembly Government to authorise a non-selective badger cull (22). This was before it had even received the report commissioned to assess the consequences of badger removal in areas of Pembrokeshire, Cardigan and Carmarthenshire (23). The section of the report on the possible ecological changes drew heavily on the results of the RBCT in the report from the Central Science Laboratory, but with also a focus on species in the Welsh counties that were not considered for the English study. It was from this focus that the authors concluded that it was the impact on the chough, a bird that is associated with the coastal clifftops bordering the cull areas, that was the most important consequence of badger removal. The chain of events was the expected rise in foxes leading to a decline in rabbits, and which would reduce herbivore activity on these coastal clifftops. This would reduce the area of short grass produced by grazing, making the chough more dependent in finding their prey of soil living insects in the lesser area of natural, maritime grasslands kept short by coastal exposure.
In what had portent for the proposed cull, the authors asserted that many of the results of their impact assessment were “unavoidably inconclusive”. They recommended that a responsible approach to these uncertainties would have been to implement a scheme to monitor the effects of the badger removal on the most vulnerable of the species and sites that might have been affected, as was carried out alongside the RBCT. The Badger Trust applied through judicial review to have the Tuberculosis Eradication (Wales) Order 2009 quashed, and had to go to appeal before it was (24). In 2011, the Welsh Assembly replaced proposals for a cull with a five year vaccination programme (25).
For the third report, DEFRA had commissioned
FERA (the new organisation that absorbed the Central Science Laboratory)
for another look at the ecological impacts that might result from culling
badgers in England, but this time the delivery date of January 2011 was in
advance of the proposals for a cull (26). The timing was a significant
issue for the authors. DEFRA gave guidance on the potential areas of the
culling based on a schedule for testing intervals derived from the annual
incidence of bTB. This resulted in a very large ‘Area of Interest’ that
covered much of south west England and the West Midlands. With that large
size and lack of information on the location, number and size of any
potential culling areas, it made it impossible for the authors to follow a
conventional Ecological Impact Assessment (EcIA) process, as was carried
out for the Wales report:
The authors relied again on the research carried out during the RBCT, succinctly summarising its results, before feebly justifying the existence of their report as an aid to Natural England, who as the competent authority for issuing culling licences, would make the decision on whether to conduct such an EcIA before the determination of an individual licensing decision. On 14 December 2011, the Government announced that it intended to go forward with trial badger culls in two 150 square kilometre pilot areas in West Gloucestershire and West Somerset with the aim of reducing the badger population by 70% in each area (27). Farmers and land-owners would be licensed to control badgers by shooting and would bear the costs of any culls. Natural England issued culling licences for the two areas in September and October 2012 (28,29) without any evidence that the consequences of ecological impact formed any part of the process (30). DEFRA then postponed the pilot culls until summer 2013, as the farming groups holding the licences were ill-prepared (31).
This brings us up to date with the article by John Finnemore, but there is one more aspect of this sorry tale still to cover, and that is the challenge to the remaining three years of the cull in England brought by the Badgers Trust, along with others, on the basis of a breach in the Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention). In a complaint under the Convention, the Badgers Trust assert that while the UK identified “ecosystem perturbation” from its large-scale predator removal programmes in the RBCT, the UK “has failed to correctly carry out a self-regulatory duty to determine and to act on any negative impacts from such removals both within and outside designated international sites, upon species and habitats, contrary to the Articles of the Bern Convention including Articles 2-11”(32).
The complaint identifies the shrugging off of a responsibility to consider changes in ‘sympatric meso-predator abundance’ and its implications, and of the further need of a EcIA, as identified in the FERA report. A supplement to the complaint goes into greater detail on the impact of ‘meso-predator release’ upon the species and habitats protected under the Convention, and reveals that Natural England had dispensed with the requirements of an EcIA for license applicants by carrying out their own assessment internally, and limited to just one site in Somerset – as exposed in information released by Natural England under a Freedom of Information request (33,34).
The process of reinstating top carnivores
It seems we are condemned ever to be thoughtless in consideration of ecological processes in our own land, the fluffy world of the conservation industry getting away with concentrating on their favoured species without having to take responsibility for reversing the degradation caused by the ruthless ecological simplification of our landscapes over the millennia. Would you trust Natural England to carry out a candid assessment of the ecological consequences of the loss from England of large predators like the lynx around 1,700 years ago and the wolf around 500 years ago? More importantly, what faith would you have in Natural England, or any of the statutory nature organisations in the UK, responding maturely to the consequences and processes of reinstating those top carnivores?
In effect we are held hostage by these statutory nature organisations in our aspirations for that reinstatement because we are an island. Being an island creates a barrier to voluntary reinstatement, as I noted when writing about the reinstatement of beaver (35). In continental Europe, beaver could restore itself just by crossing a national boundary under its own volition, and it would be protected under EU law, whereas beaver reinstatement here requires our active involvement. It is this active involvement that comes up against legislation in Section 14 of the Wildlife and Countryside Act 1981 that prohibits introduction of a new species that is “not ordinarily resident in Great Britain and is not a regular visitor in a wild state” (36). In the case of England, licences can be issued by Natural England, on behalf of the Secretary of State, to permit actions that would otherwise be an offence under this section, effectively making Natural England gatekeepers for that licensing, as they are for the badger culling, which is an offence under Section 1 of the Protection of Badgers Act 1992 (37).
I also noted that this lack of ability for voluntary reinstatement applied to the wolf as well, the paper by Dutch environmental lawyer Arie Trouwborst rightly identifying our and Ireland’s predicament as islands separated from the rest of continental Europe (35). I met Arie last October in Tilburg in the Netherlands, at a gathering of contributors for a forthcoming book on European wilderness. The wolf was never far away from our discussions, with Arie kindly drawing me a wolf swimming the English Channel – I asked for a second wolf, as we really need a breeding pair! We also talked about a wolf that only months before had been found dead by the side of the road in Luttelgeest, about 20km from the Dutch coast - maybe the voluntary reinstatement of wolf by swimming across the English Channel is not that far fetched? Wolf were lost to the Netherlands in 1897, and so any evidence of their return excites speculation, except that this wolf was killed twice – an autopsy revealed that it had been shot before it was hit by a car, and the likely origin was that this wolf had been killed in Poland and dumped in the Netherlands (38).
Wolves have a great ability for dispersal through hostile terrain with a seeming adaptability to habitat conditions and human presence (39). This is a function of their very nature, as territoriality, social behaviour and dispersal are the intrinsic mechanisms regulating wolf density. Having settled in eastern Germany after crossing over from Poland (40) wolves are gradually moving west across Europe, with sightings and probably the first breeding pack in Denmark after an absence of 200 years (41,42) as well as sightings in the Netherlands (43). The likelihood is that wolves in Denmark crossed over from Germany, and so in anticipation of this becoming a more common event, an evaluation was carried out in early 2013 of potential breeding areas in Denmark for wolf (44). The evaluation was based on the distribution of sufficiently large enough patches of inter-connected forest and heath, and with those having good populations of Red and roe deer. The outcome was the identification of 10 breeding areas in Denmark for packs consisting of about eight wolves, including pups (see Fig. 7 in (44)). In addition, there will likely be an unknown number of strays as young wolves looking to disperse away from the pack when they reach maturity. Denmark has accepted the wolf as having been reinstated, giving it protection by amending its Nature Protection Act to include protection of the wolf, and adopting a first national wolf plan in June this year (45,46). The plan describes a compensation system for livestock losses, and how in the future wolves in Denmark can be protected and managed along with other endangered species.
Two spatial studies were also carried out in the Netherlands in 2012, again in anticipation of the arrival of wolves. The first to report was based on prey distribution and abundance, habitat suitability, and areas with low human disturbance (47). The north-eastern part of the Netherlands gave the largest suitable area, with 16 wolf packs being considered as an ecological minimum, but with the potential of up to 44 packs if wolves ranged wider for their prey. The second report found that prey availability was more limiting for carrying capacity than the size of suitable habitat, and with the north east again showing the largest potential (48). This study predicted a carrying capacity of 343 wolves, based on pack sizes of 8-10 wolves. The prospect of the return of wolves to the Netherlands was matched by a process in civil society that involved initially qualitative and quantitative research among Dutch people about their reaction to that return (49). Almost half of the Dutch (45%) believed that the wolf was welcome in the Netherlands, a third were against the arrival of the wolf, and the rest were undecided. What is encouraging is that the main argument given for welcoming the wolf was that nature itself would determine whether or not the animal comes back to the Netherlands. This was followed by a fact finding study (50) a workshop (51) and a legal study commissioned from Arie to assess policy options (52). This process culminated in late 2013 with a report that was a proposal for a wolf plan for the Netherlands (53). The proposal had guidelines on information and communication, monitoring and research and the prevention and compensation of damages to livestock. It also had a discussion of the applicable legislative framework for wolves, including the species’ generic protection through various prohibitions, the designation of protected areas and transboundary cooperation with neighbouring states.
It was on the basis of the information in that proposal that the Netherlands has very recently decided that the wolf is a protected native species living in its natural range, amending their regulations for designating animal and plant species by adding the wolf to the list of protected native species in Annex 2 (54,55). The designation since the I July means that the killing, capture or deliberate disturbance of wild wolves – “animals in their natural habitat” (dieren in hun natuurlijke leefomgeving) is prohibited under Articles 9 and 10 of the Flora and Fauna Act (56) and that the Wildlife Fund is authorized to decide on applications for compensation for damage caused by wolves. This shows remarkable prescience, since it is an acceptance of the wolf returning to its natural range, a key consideration for the legal reinstatement and protection of species, and given that the wolf has yet to have a regular presence, or has settled in the Netherlands.
A readjustment in the way nature conservation is viewed
You can sense my absolute frustration that we are not getting the opportunity here to prepare for the return of the wolf. We desperately need a readjustment in the way nature conservation is viewed, so that we break away from the crushing lack of aspiration of the conservation industry, its epitome being the landscape scale approach of networking agro-ecological habitats, as characterised by the Government inspired Nature Improvement Areas (57,58). Nature doesn’t need improvement – it needs setting free! We do not need the conservation industry seeking to cement their agri-environment subsidy funded business model in legislation, a fake “recovery of nature” through their NIA-alikes, feebly justified on the back of health improvements for society, as envisaged in its proposed Nature and Wellbeing Act (see response to Q11 in (59)).
At present, there is no terminology in our
nature conservation legislation that is descriptive of natural systems
or processes, unlike in the national protected area legislation of many
continental European countries allowing freedom to natural processes (see
section 5.4.4 in (60)). Thus what is needed is a review of that
terminology with the aim that it better reflects the reality of natural
systems, rather than the utilitarian approach that it embodies at present,
and which avoids any distinction between natural and agricultural
landscapes. France has recently recognised this as an omission in its
legislation, and in its draft law on biodiversity intends to amend the
Environmental Code to introduce a dynamic view of ecosystems by adding the
concepts of "biological processes" and of biodiversity integrating all
living beings, recognising that biodiversity is part of the common
heritage of the Nation (61). Perhaps we need to understand more clearly
and reflect on what Elton meant when he wrote (13):
Mark Fisher 28 July 2014
(1) Lack of natural control mechanisms - the missing lynx, Self-willed land June 2014
(2) Two things, Forget What Did. Sunday, 1 September 2013
(3) Could otters be the key to bovine TB? John Finnemore, Observer 1 September 2013
(4) Badger cull: environment secretary defends move on 'dark day', Adam Vaughn, Guardian 27 August 2013
(5) Badgers: animal lovers to patrol hunting zone as second cull begins, John Vidal 3 September 2013
(6) Hughes, B.B., R. Eby, E. Van Dyke, M.T. Tinker, C.I. Marks, K.S. Johnson, K. Wasson. 2013. Recovery of a top predator mediates negative eutrophic effects on seagrass. Proceedings of the National Academy of Sciences 110:15313-15318
(7) Sea otters promote recovery of seagrass beds. Recolonization of Elkhorn Slough by sea otters led to recovery and expansion of seagrass beds due to cascading effects on the food web, study finds. Tim Stephens, UCSC News August 26, 2013
(8) California Eelgrass. National Oceanic and Atmospheric Administration Fisheries Service West Coast Region
(9) Darwin, C. (1859) The Origin of Species - by means of natural selection or the preservation of favoured races in the struggle for life. London: John Murray 1859
(10) Haeckel, E. (1866) Generelle Morphologie der Organismen : allgemeine Grundzüge der organischen Formen-Wissenschaft, mechanisch begründet durch die von Charles Darwin reformirte Descendenz-Theorie. Berlin: Georg Reimer
(11) Verhulst, P.H. (1838) Notice sur la loi que la population poursuit dans son accroissement. Corresp. mathématique et physique 10, 113–121
(12) Volterra, V. (1926) Fluctuations in the abundance of a species considered mathematically. Nature 118: 558–560
(13) Elton, C. (1927) Animal Ecology. Sidgwick and Jackson, London
(14) Flader, S. (1994) Thinking Like a Mountain: Aldo Leopold and the Evolution of an Ecological Attitude toward Deer, Wolves, and Forests. University of Wisconsin Press. ppg 84-91
(15) Binkley, D., Moore, M.M., Romme, W.H. and Brown, P.M. (2006) Was Aldo Leopold Right about the Kaibab Deer Herd? Ecosystems 9: 227–241
(16) Polar Bears in Svalbard, Norwegian Polar Institute 2005
(17) Darwin, C. (1842) The structure and distribution of coral reefs, Being the first part of the geology of the voyage of the Beagle, under the command of Capt. Fitzroy, R.N. during the years 1832 to 1836. London: Smith, Elder and Co.
(18) Research into Bovine TB, DEFRA
(19) Project ZF0531: Ecological consequences of removing badgers from an ecosystem. Research project final report. DEFRA 2007
(20) Trewby ID, Wilson GJ, Delahay RJ, Walker N, Young R, et al. (2008) Experimental evidence of competitive release in sympatric carnivores. Biology letters 4: 170–172. doi: 10.1098/rsbl.2007.0516
(21) Trewby ID, Young R, McDonald RA, Wilson GJ, Davison J, et al. (2014) Impacts of Removing Badgers on Localised Counts of Hedgehogs. PLoS ONE 9(4): e95477. http://www.plosone.org/article/fetchObject.action?uri=info%3Adoi%2F10.1371%2Fjournal.pone.0095477&representation=PDF
(22) Tuberculosis Eradication (Wales) Order 2009 No. 2614 (W.212)
(23) Potential ecological consequences of a badger removal operation (BRO) in the ‘Intensive Action Pilot Area’ (IAPA), South-west Wales. Ecological Impact Assessment (EcIA). Welsh Assembly Government Report no: C1314/V6/Doc.1. December 2009
(24) Badger Trust v The Welsh Ministers  EWCA Civ 807
(25) Badger vaccination in the Intensive Action Area, Welsh Government
(26) Evaluation of the Potential Consequences for Wildlife of a Badger Control Policy in England, Food and Environment Research Agency, January 2011.
(27) Badger control – culling of badgers, DEFRA
(28) Badger Control Licence issued in West Gloucestershire, Natural England 17 September 2012
(29) Badger Control Licence issued in West Somerset, Natural England 4 October 2012
(30) Guidance to Natural England: Licences to kill or take badgers for the purpose of preventing the spread of bovine TB under section 10(2)(a) of the Protection of Badgers Act 1992. DEFRA 2011
(31) Badger cull to proceed next year, DEFRA Press release 23 October 2012
(32) Convention on the Conservation of European Wildlife and Natural Habitats. COMPLAINT FORM, Humane Society International/UK, The Badger Trust, Care for the Wild International, 16 June 2014 http://mb.cision.com/Public/9005/9604606/82ef5461d6241929.pdf
(33) Bern Convention Complaint June 2014 United Kingdom. Ecological perturbation and failure to conduct Impact Assessments. FURTHER INFORMATION: United Kingdom failure to conduct sufficient assessment of potential disturbance and damage to Bern Convention Appendix II species and their habitats
(34) Badger Cull Breaches International Wildlife Convention, Say Charities, Badger Trust 19 June 2014
(35) The Tayside beavers - living wild and free in Scotland, Self-willed land January 2011
(36) Wildlife and Countryside Act 1981, CHAPTER 69
(37) Protection of Badgers Act 1992 c. 51
(38) Kogelresten gevonden in wolf Luttelgeest, NU.nl 24 October 2013
(39) Boitani, L. (2000) Action Plan for the conservation of the wolves (Canis lupus) in Europe. Council of Europe. Nature and environment
(40) Managementplan für den Wolf in Brandenburg 2013 – 2017. Ministerium für Umwelt, Gesundheit und Verbraucherschutz, Brandenburg Dezember 2012
(41) Ulve-sensation: Danmark har sandsynligvis første ulvekobbel i mindst 200 år. Laura Juul, DR:DK 25 March 2014
(42) Ulven, Miljøministeriet Naturstyrelsen
(43) Wolf spotted in the Netherlands, Maxime Mech, NL Times 18 June 2014
(44) Madsen, A.B., Andersen, L.W. & Sunde, P. (2013) Ulve i Danmark – hvad kan vi forvente? Notat fra DCE – Nationalt Center for Miljø og Energi, Aarhus Universitet
Bekendtgørelse om fredning af visse dyre- og plantearter og pleje af
tilskadekommet vildt, BEK nr 330 af 19/03/2013
(46) Forvaltningsplan for ulv i Danmark Miljøministeriet Naturstyrelsen June 2014
(47) Lelieveld, G. (2012) Room for wolf comeback in the Netherlands: A spatial analysis on the possibilities of settlement of wolves from European populations in the Netherlands. Internship for MSc Ecology, Vrije Universiteit, Amsterdam 6 May 2012
(48) Potiek, A., Wamelink, G.W.W, Jochem, R. and van Langevelde, F. (2012) Potential for Grey wolf Canis lupus in the Netherlands, Effects of habitat fragmentation and climate change on the carrying capacity. Wageningen, Alterra, Alterra Report 2349. July 2012
(49) Appreciatie-onderzoek naar de komst van de wolf. Kwalitatief en kwantitatief onderzoek onder de Nederlandse bevolking. Uitgevoerd voor het Ministerie van Economische Zaken, Landbouw en Innovatie. February 2012
(50) Groot Bruinderink, GWTA, Jansman, HAH, Jacobs, MH and M Harms, M (2012) De Komst van de Wolf (Canis lupus) in Nederland: Een ‘Factfinding Study. Wageningen, Alterra, Alterra-Rapport 2339 June 2012
(51) Groot Bruinderink, G.W.T.A., Lammertsma, D.R., Hoon, C., Kruft, A. en Lanters, R. (2013) De komst van de wolf in Nederland; Verslag van de workshop gehouden op 8 november 2012. Wageningen, Alterra, Alterra-rapport 2403 januray 2013
(52) Trouwborst, A. and Bastmeijer, CJ., m.m.v. Backes, CW (2013) Wolvenplan voor Nederland: Naar een Gedegen Juridische Basis: Een juridisch onderzoek ter ondersteuning van de opstelling van een Nederlands wolvenplan. Tilburg University and Maastricht University, Juli 2013
(53) Groot Bruinderink, G.W.T.A. en. Lammertsma, D.R. (2013) Voorstel voor een wolvenplan voor Nederland; versie 2.0. Wageningen, Alterra Wageningen UR (University & Research centre), Alterra rapport 2486
(54) Regeling van de Staatssecretaris van Economische Zaken van 25 juni 2014, nr. 13107468, tot wijziging van de Regeling aanwijzing dier- en plantensoorten Flora- en faunawet (Aanwijzing van de wolf als beschermde inheemse diersoort)Staatscourant 2014 nr. 18306 30 juni 2014
(55) Regeling aanwijzing dier- en plantensoorten Flora- en faunawet 2002
(56) Wet van 25 mei 1998, houdende regels ter bescherming van in het wild levende planten- en diersoorten (Flora- en faunawet)
(57) Nature improvement and restoration areas - are they a step towards rewilding? Self-willed land June 2011
(58) The neoliberalisation of nature conservation, Self-willed land February 2013
(59) Oral evidence: An environmental scorecard, HC 215 Environmental Audit Committee House of Commons 9 July 2014
(60) Fisher, M. and others (2010). Review of Status and Conservation of Wild Land in Europe. Project commissioned by the Scottish Government.
(61) Projet de loi relatif à la biodiversité, N° 1847, Enregistré à la Présidence de l’Assemblée nationale le 26 mars 2014