CDPNews No 7 / July2004
CDPNews No 7 / July2004
Notes
from the Editors
Recovering the Use of Livestock Guarding Dogs in Portugal: Results of a Long-Term Action
Influence of Large Carnivores on the Distribution of Excreta by Sheep on a Summer
Pasture, in NW-Italian Alps
King Collar: Predator Protection Collars for Small Livestock
Bringing Insight into Livestock Depredation by Wolves in Southwestern Alberta, Canada
Reduced Wolf Attacks on Sheep in
Østfold, Norway, using Electric Fencing
A Simple Carnivore Improvement of Existing Sheep Fencing
Back to archive
The show must go on!
During the last meeting of the core group of the Large Carnivore Initiative for Europe LCIE, we discussed on how to go on with the Carnivore Damage Prevention Newsletter. CDPNews is meant to be a forum to discuss practical problems, experiences and solutions. It is an interface between the research and the application, a place to promote measures that work and attempts that failed. The basic idea was that there are many people across the world trying to mitigate the carnivore-livestock-human conflict, and that not everybody should be forced to make the same mistakes and to re-invent the wheel. The problem with such an interface tool is however the communication. To distribute information in English through the World Wide Web is the easiest, fastest and cheapest way of communication today. However, we know that many of the practicians across the world do not communicate that way. We have therefore produced and distributed a printed version in addition to the PDF version available on the internet. But we were never able to produce CDPNews in a different language than English. Also we hope that part of the information provided may have been translated to and spread in other languages, there was never such a feedback. We want to continue CDPNews, but give it a somewhat different shape. We intend to produce two issues a year, but this depends on funding available. We will however strengthen the internet presence of CDPNews, and this is already done for the present issue. All articles will be available as HTML documents in addition to the PDF versions of all issues, and rubrics such as news, address lists, providers etc., requiring frequent changes will be delegated to the websites. Furthermore, we want to produce fact sheets and topical brochures featuring damage prevention. These, as they go beyond actualities, may even be translated into several languages. Whatever we, the editors, plan to do – whether CDPNews is a lively tool or not depends mainly on you, the reader, on your feedback, your comments and your contributions. CDPNews should not compete any scientific publication. We will feature new publications (e.g. by publishing abstracts), but we all know that there is a wealth of important practical intelligence available that will never make it into a scientific journal. That’s exactly what we are looking for. Please report also your negative experience and your problems, to ask other CDPNews readers for their help and opinion, and do not hesitate to write us in other languages than English.
The Editors
Recovering the Use of Livestock Guarding Dogs in Portugal: Results of a Long-Term Action
by Silvia Ribeiro & Francisco Petrucci-Fonseca
Wolf
predation on livestock is one of the major threats to wolf conservation
worldwide. Included in this conflict are more than just economic issues.
Wolf damages are often perceived as being higher than real damages and
as having a larger economic impact than livestock losses due to other
factors such as disease. In some areas of Portugal mortality of goat
kids due to the lack of disease prevention can reach more than 50 % of
the yearly production, per flock, while maximum wolf predation
registered was around 5 %. Therefore, despite the use of compensation
measures, their effectiveness at increasing tolerance may be limited.
Besides
the financial losses that result directly from wolf predation, other
costs must also be considered. Wolf presence also implies changes in
livestock husbandry, management and protection techniques that involve
additional work and extra costs. These
changes are difficult for livestock producers to accept. Therefore we
could therefore expect the imposition of adequate husbandry and
protection measures to actually increase animosity towards the wolf and
the agencies responsible for its protection in the short term. The
answer may be implementing long-term awareness and cooperative actions
to improve husbandry and livestock protection practices thus reducing
the potential for conflict. In our experience, in wolf areas where the
damages on livestock are low, tolerance is recognisably higher. Besides
damage’s reduction those actions would also result in establishing a
direct working partnership with the rural community leading to a more
trusting relationship that seems to be important when dealing with
tolerance issues.
In
the scope of wolf conservation efforts, several techniques are being
developed and implemented to reduce predatory impact on livestock. One
of the most widespread and successful is the use of Livestock Guarding
Dogs (LGDs). LGDs are part of the traditional husbandry system used in
Europe and Asia, where dogs were selected to protect livestock from
several predators. In recent decades the use of these dogs was gradually
abandoned due to socio-economical reasons (mainly related to the
depreciation of the traditional livestock production and the reduction
of predators). With the new policies on wildlife restoration and
revitalisation of traditional livestock production, there is the need
for tools that could prevent conflicts and make coexistence possible.
This will enable the wolf to live in areas where its presence would not
otherwise be acceptable.
Recovering the use of LGDs
In
Portugal, Grupo Lobo initiated a programme aiming to contribute
to the conservation of the endangered Iberian wolf through the
development and implementation of practical measures to reduce livestock
predation. This programme has been ongoing since 1997 and will be
briefly presented here.
The
first action was to help recover the use of native breeds of
LGDs. In
Portugal three[1]
breeds of LGDs (Cão de Castro Laboreiro, Rafeiro do Alentejo
and Cão da Serra da Estrela, that has both long and short hair
varieties) were selected to protect livestock from predators. A total of
75 pups (38 males and 37 females) from these breeds were selected and
given to shepherds (Fig.1).
[1] A fourth LGD breed named Cão de Gado
Transmontano (originated in the Northeast of Portugal) is
currently under recognition by the Portuguese Kennel Club.
Fig.
1: A shepherd holding its new
Cão de Castro Laboreiro pup, before
placing it with the flock.
They were integrated into goat and/or sheep flocks, ranging from 50-700 animals, in the North and Centre of the country. The progenitors of the dogs were preferentially working dogs that presented no physical abnormalities or health problems. Criteria for flock selection were based on:
(1)
the amount of damages,
(2)
the existence of conditions to receive a dog and,
(3) the shepherd’s motivation to cooperate in the project.
Before
delivering the pup, the shepherd had to sign a cooperation contract with
the entity coordinating the programme. The contract established the
education and raising conditions/rules the shepherd should comply in
order for the dog to become a good working dog and was valid until the
animal reached adulthood. During this period the dog belonged to the
entity implementing the action and thus could not be given away or sold
if the shepherd sold the flock. The project team was responsible for
replacing the dog in case of its death (only if the shepherd was not
directly responsible) or if it was considered inefficient by researchers.
We found this contract to be very useful, because it would enable the
exclusion of the shepherd if he was not raising the dog according to the
conditions previously defined (thus risking its future success) as well
as the dog transfer to other shepherd. Also it contributed to increase
the shepherd responsibility towards the dog and thus the success of the
action.
The
pups were integrated in the flocks after weaning
(around 7-8 weeks old),
during the socialization period. After a short period of 2-3 weeks, of
strict confinement in the stables/corral (where the livestock was kept
during the night), the pup would then start to accompany the flock to
the pasture/mountain during grazing periods. Limited contact with other
livestock, dogs or people (apart from the strictly necessary contact for
the pup to know the shepherd and its family) was observed. As soon as
the pup started to go with the flock to the pasture an member of the
project team would regularly accompany the flock to monitor the dog’s
behavioural development. The periodicity ranged from 15 to 30 days,
respectively for pups younger or older than 6 months. Dog monitoring was
maintained until they reached adulthood (12-18 months). This schedule
was followed as much as possible and intended also to control the
shepherd’s behaviour towards the dog and allow the prompt correction
of undesirable behaviour (whether by the dog or the shepherd). During
the visits the general condition of the dog was verified and any health
problems were treated. The shepherds were also requested to contact the
project team in case the dog was sick or behaving strangely, and if they
needed any other help or advise. The project team provided the food for
the dogs until they reached adulthood as well as the veterinary care. In
spite of the extra care devoted to these dogs, a mortality rate of 24 %
was observed, with disease as the main cause of death (n=8), followed by
poison (n=2), while 4 dogs died from other causes (run over by car, shot
by hunters, blow to the head, attacked by a wolf) and 4 dogs disappeared.
The
evaluation of the dogs’ efficiency was based on three different types
of analysis: damages reduction, dog’s behaviour, and owners’
satisfaction. This evaluation was done only for adult dogs (>18
months). For each flock we compared the mean number of damages in the
three years before the integration of the dog with the number of damages
that occurred in the year after the dog filled 12 months of age. We
observed a general reduction in the number of damages, ranging from 33 %
to 100 %. Nevertheless, there was a considerable variability in the
number of damages throughout the years, suggesting that other factors
unrelated to the dog’s action (e.g. fluctuations in predators density,
availability of alternative prey, changes in flock management, and in
habitat conditions affecting the efficiency of the attacks) could also
be responsible for the observed changes. When analysing the number of
damages relative to the total damages in the nearby flocks, we observed
a reduction from 10 - 40 % in 60 % of the cases. This indicates that
there was a reduction in the number of damages in the studied flocks
compared to the predatory impact in the region. As stated before, this
could result from the presence of the dog or from other factors. In some
flocks, where there was no change or a small reduction in the relative
damages, there was nonetheless a significant increase in the number of
attacks that were efficiently prevented by the dogs (Petrucci-Fonseca et
al., 2000).
The
behaviour of adult dogs was evaluated according to the three behavioural
components defined by Coppinger & Coppinger (1978) for this type of
dogs: attentiveness, trustworthiness and protectiveness. Attentiveness
refers to the dog maintaining its proximity to the flock and following
its daily movements during grazing as well as exhibiting social
behaviours towards the animals in the flock. Trustworthiness implies the
dog not disturbing flock’s activity or chasing/injuring animals in the
flock. Protectiveness refers to the dog being alert to any new or
strange situation or intruder (barking) and actively preventing a
potential attack.
Almost
90 % of the adult dogs were attentive to the flock. Most dogs displayed
adequate investigatory and submissive behaviours towards the animals in
their flock (Fig.2). However, during monitoring seven juvenile dogs were
identified as not behaving correctly, mostly due to incorrect behaviour
by the shepherds that were reinforcing their own bond with the dog or
limiting their contact with livestock. After some actions were initiated
to correct these situations, 4 dogs died soon after (disease, run over).
In 2 other cases the shepherds did not change their conduct and the dogs
were transferred to other flocks; one was recovered and the other died
soon after (disease). One dog was definitely removed.
Regarding trustworthiness, although it is fairly common for juvenile dogs to
chase/injure (rarely kill) kid goats or lambs during play sequences only one adult
dog attacked and killed flock animals and was immediately removed.
Excessive play behaviour in juvenile dogs can become a real problem and
was thus immediately corrected to prevent it from being reinforced. This
was facilitated since most of the flocks were shepherded. The permanent
presence of a shepherd and the continuous monitoring of the dogs’
behaviours by the work team could account for the high percentage of
attentive and trustworthy dogs when compared to other studies. All adult
dogs exhibit protective behaviours (alert to the flock activity and
movements, barking in strange situations, placing themselves between
intruders and the flock, chasing and occasionally fighting intruders)
and actively preventing wolf attacks. Shepherds were generally satisfied
with their dogs: 95 % consider them very effective and 60 % say the dogs
were responsible for the observed damage reduction.
The
analysis of the amount of damages before and after the introduction of
the dog is the method generally used to assess LGDs’ efficiency.
Nevertheless, since the amount of damage can be influenced by several
factors difficult to assess, an alternative would be to focus on the
number of attacks prevented by the dog as well as on the behaviour
exhibited by the dog in specific situations. According to Lorenz &
Coppinger (1986), the development of protective behaviour is a result of
good trustworthy and attentive behaviours. Attentiveness is also
considered to be a key indicator of success because most predation
problems are associated with low attentiveness (Coppinger et al.,
1983) (Fig.3).
Alternative
protection methods
Raising a LGD requires a great commitment by an inexperienced shepherd and some requirements must be met for a LGD to become an efficient guardian (e.g. gregarious livestock, the absence of potential causes of death like the illegal use of poison). Moreover, more than a year is necessary to evaluate the dog’s efficiency, since the dog may not be fully effective until after reaching adulthood. Taking this into account, a new project (AGRO 311 – INIAP-Ministry of Agriculture) has been initiated in 2001 that aims to test the efficiency of alternative or complimentary methods to LGDs, namely electric fences and fladry, as well as to recover other traditional protection methods. Preliminary inquiries (n=74) on traditional techniques of livestock protection conducted in Central Portugal, led to interesting findings on the use of different light-mobile barriers (at least until 1950), some similar to fladry, to protect sheep flocks kept in small enclosures (corrals) overnight. The gathering of information is still underway and the test of the effectiveness of these methods will be conducted this year. Although testing the long-term efficiency of fladry to protect livestock from wolf predation in natural environments is still underway, the use of similar barriers by Portuguese shepherds increases our confidence in this technique. The success of livestock protection measures necessarily requires the implementation of new and traditional methods that best complement and adapt to each situation.
Fig. 2:
A juvenile Cão
de Castro Laboreiro dog displaying submissive behaviours towards an
animal from its flock.
Fig. 3: An adult short-haired Cão da Serra da Estrela dog perfectly integrated in the flock.
Importance of long-term support actions
After the initial scepticism showed by shepherds, this long-term action resulted in an increasingly positive acceptance of LGDs. Participating shepherds can now recognize a good working LGD and are aware of the conditions necessary for raising one. They frequently ask for supplementary dogs to substitute their other dogs and improve flock protection. There is also a good receptivity from other shepherds that learn about the dog’s efficiency and increasingly ask for LGDs descending from those dogs. This flow of information between shepherds from the same and neighbouring villages seems to be very effective at a local scale and contributes to enhance their confidence in LGDs and their willingness to use them. Once livestock producers are satisfied with the use of LGDs the mere presence of a good working dog in the flock can contribute to reduce conflicts with the wolf and put damages in a real perspective.
Almost 90 % of the adult dogs were attentive to the flock. Most dogs display adequate investigatory and submissive behaviours towards the animals in their flock (Fig. 2). However, during monitoring seven juvenile dogs were identified as not behaving correctly, mostly due to incorrect behaviour by the shepherds that were reinforcing their bond with the dog or limiting the contact with livestock. After some actions were initiated to correct these situations, 4 dogs died soon after (disease, run over). In 2 other cases the shepherds did not change their conduct and the dogs were transferred to other flocks; one was recovered and the other died soon after (disease). One dog was definitely removed.
Regarding trustworthiness, although it is fairly common for juvenile dogs to chase/injure (rarely kill) kid goats or lambs during play sequences only one adult dog attacked and killed flock animals and was immediately removed. Excessive play behaviour in juvenile dogs can become a real problem and was thus immediately corrected to prevent it from being reinforced. This was facilitated since most of the flocks were shepherded. The permanent presence of a shepherd and the continuous monitoring of the dogs’ behaviours by the work team could account for the high percentage of attentive and trustworthy dogs when compared to other studies. All adult dogs exhibit protective behaviours (alert to the flock activity and movements, barking in strange situations, placing themselves between intruders and the flock, chasing and occasionally fighting intruders) and actively prevent wolf attacks. Shepherds were generally satisfied with their dogs: 95 % consider them very effective and 60 % say the dogs were responsible for the observed damages’ reduction.
The analysis of the amount of damages before and after the introduction of the dog is the method generally used to assess LGDs’ efficiency. Nevertheless, since the number of damages can be influenced by several factors difficult to assess, an alternative would be to focus on the number of attacks prevented by the dog as well as on the behaviour exhibited by the dog in specific situations. According to Lorenz & Coppinger (1986), the development of protective behaviour is a result of good trustworthy and attentive behaviours. Attentiveness is also considered to be a key indicator of success because most predation problems are associated with low attentiveness (Coppinger et al., 1983) (Fig. 3).
Alternative protection methods
Raising a LGD requires a great commitment by an inexperienced shepherd and some factors must be met for a LGD to become an efficient guardian (e.g. gregarious livestock, the absence of potential causes of death, like the illegal use of poison). Moreover, more than a year is necessary to evaluate the dog’s efficiency, since the dog may not be fully effective until reaching adulthood. Taking this into account, a new project (AGRO 311 – INIAP-Ministry of Agriculture) has been initiated in 2001 that aims to test the efficiency of alternative or complimentary methods to LGDs, namely electric fences and fladry, as well as to recover other traditional protection methods. Preliminary inquiries (n=74) on traditional techniques of livestock protection conducted in Central Portugal, lead to interesting findings on the use of different light-mobile barriers (at least until 1950), some similar to fladry, to protect sheep flocks kept in small enclosures (corral) overnight. The gathering of information is still underway and the test of the effectiveness of these methods will be conducted this year. Although testing on the long-term efficiency of fladry to protect livestock from wolf predation in natural environments is still underway, the use of similar barriers by Portuguese shepherds seems to increase the trust on the use of this technique. The success of livestock protection measures necessarily requires the implementation of new and traditional methods that best complement and adapt to each situation.
Importance of long-term support actions
After the initial scepticism showed by shepherds, this long-term action resulted in an increasingly good acceptance of LGDs. Participating shepherds can now recognize a good working LGD and are aware of the conditions necessary for raising one. They frequently ask for supplementary dogs to substitute their other dogs and improve flock protection. There is also a good receptivity from other shepherds that learn about the dog’s efficiency and increasingly ask for LGD descending from those dogs. This flow of information between shepherds from the same and neighbouring villages seems to be very effective at a local scale and contributes to enhance their confidence on LGDs and their willingness to use them. Once livestock producers are satisfied with the use of LGDs the mere presence of a good working dog in the flock can contribute to reduce conflicts with the wolf and put damages in a real perspective.
References
Coppinger, R. & L. Coppinger (1978). Livestock guarding dogs for U.S. Agriculture. Hampshire College, Amherst, MA.
Coppinger, R., J. Lorenz & L. Coppinger (1983). Introducing livestock guarding dogs to sheep and goat producers. In D. Decker (Ed.), Proceedings of the First Eastern Wildlife Damage Control Conference (pp. 129-132) (September 27-30, Ithaca, New York).
Lorenz, J. & R. Coppinger (1986). Raising and training a livestock-guarding dog. Extension Circular, 1238/April, Oregon State University Extension Service.
Petrucci-Fonseca, F., S. Ribeiro, A.E. Pires & C. Cruz (2000). Contributo para a minimização do impacto económico dos predadores sobre os animais domésticos. Technical Report, Programme PAMAF-IED. Lisbon: Faculty of Sciences of Lisbon University.
Influence of Large Carnivores on the Distribution of Excreta by Sheep on a Summer Pasture, in the NW-Italian Alps
by Davide Cugno & Giampiero Lombardi
Introduction
The
presence of large carnivores in the Alps has caused great changes in
sheep pastoral systems: the traditional grazing management (exploitation
of summer pastures by free ranging flocks) has been replaced by a
non-traditional one, with constant shepherd supervisoin and the use of
night-time enclosures. As a consequence of the changes in flock
distribution and movements, the distribution of animal excreta has been
affected, with possible effects on vegetation and pastoral quality.
To
evaluate the consequences of the non-traditional grazing management, the
distribution of excreta was surveyed in an Alpine summer pasture and
related to vegetation types, flock movements, stocking density, and
efficiency of grazing. The results concerning dung distribution are
presented in this paper.
Interactions between domestic animals and predators, and consequences for grazing management
In
Valle Stura of Demonte (NW Italian Alps, province of
Cuneo), sheep
breeding is a traditional activity (still important for the economy of
the valley), based mainly on the exploitation of summer pastures. At the
same time, it is an important area for the conservation of the alpine
environment. Until a few years ago, because of the absence of large
carnivores and the lack of labour, shepherds used to drive their flocks
to mountain pastures and leave them alone for the whole summer: free
ranging flocks used to exploit even the remote areas of summer pastures,
spending the night outdoors without protection.
Recently,
in relation to the increasing presence of Canis
lupus, Vulpes vulpes and stray dogs, the risk of losses due to
depredation has affected alpine grazing
management; discouraging the
exploitation of more remote and inaccessible pastures, and forcing
shepherds to guard flocks during the day and fence them in protected
enclosures during the night. Even the distribution of excreta on
rangelands has been affected by changes in grazing management, with
transfer of nutrients from the rangeland to paddocks, which was
evaluated in an alpine pasture and related to vegetation types,
stocking-rates and grazing efficiency.
The
situation on the “Alpe Ischiator”
Studies
have been carried out during 2001, at the Ischiator summer pasture (1800
- 2830 m a.s.l.), grazed by a flock of 500 Sambucana sheep.
Vegetation, morphological characteristics of the grazing areas and sheep
solid excreta distribution were surveyed. The vegetation composition was
determined with the Daget-Poissonet method (1969), along 32 transects.
To
estimate the quantity and distribution of faeces, so to detect possible
gradients from shelters outwards, 52 sample areas (20 x 0.80
m) were located over the rangeland (243 ha of herbaceous surface
out of 824 ha of total surface), inside which faeces were counted after
the sheep had been grazing there. The length of exploitation inside each
sector of the pasture, as well as the intensity of grazing were also
surveyed. To assess the transfer of organic matter and nutrients from
the rangeland due to the actual grazing management, faeces samples were
collected, oven-dried (40°C) to determine dry weight, and analysed for
N, P, K, Na, and Ca content.
The quantity of nutrients supplied by urine was assessed on the base of literature (Barrow, 1987; Barrow and Lambourne, 1962; Lancon, 1978a, 1978b).
Fertility
management
The
rangeland was characterized mainly by Festuca paniculata (45% of
the surface) and Nardus stricta (34%) dominated swards. The
pastoral value (Daget & Poissonet, 1972) was on average low (12-15
compared to 30 for a good quality pasture in those conditions), but
higher forage values (up to 38) were computed for less extended types.
As
an effect of actual grazing management (sheep grazing for no more than
12 h d-1 and night sheltering in 2 areas of approx.
1 ha each, near the shepherds buildings), the flock brought to the
rangeland about 13.1 t y-1 (55 kg ha-1y-1)
of faeces (table 1), which is less then 50% of the supply with
traditional management (26.8 t y-1 over a 243 ha
surface).
Because
of the wide variability of faeces distribution within the same
vegetation type (even if the sheep were herded an uniform grazing
pressure was not
maintained), a significant effect of vegetation
composition on excreta distribution could not be identified in the
analysis of variance (P = 0.26 ns). Furthermore, as the
shepherd used to guide the flock during the day all over the grazing
area, no correlation was found between the quantity of dung and the
distance from the night shelters (r = -0.01 ns, n = 44).
Instead,
the quantity of dung distributed on the rangeland was linearly related
to the stocking-rate, expressed as live-weight
(figure 1), and well
correlated to the intensity of defoliation by sheep (r = 0.62 ++,
n = 44).
Among morphological
factors, the dung distribution
was mainly determined by the slope, to which it was inversely correlated
(r = -0.45 ++, n = 44), in agreement to what
was found by Lombardi (1997), with cattle.
Tab.
1: Solid
excreta and nitrogen distributed on the rangeland during the grazing
season.
Fig
1:
Relationship between stocking-rate and quantity of dung.
With
regard
to
nitrogen, 2.6 kg ha-1y-1 returned
to the rangeland (35% of the amount with traditional mangement), of
which 1.2 kg ha-1 y-1 with faeces,
with a wide variability among vegetation types (from 1 to 4 kg ha-1y-1)
confirmed also in literature (Whitehead, 1995; Lancon, 1978a).
The
quantity of dung concentrated inside night
shelters, assessed on the
basis of stocking-rate and daily distribution of defecations, was 13.7 t y-1
of dry faeces and 1200 kg y-1 of N (faeces + urine).
As a consequence, since 1996, 275 kg ha-1 of faeces
and 25 kg ha-1 of N have been transferred from the
rangeland and concentrated into the two small corrals (1 ha each)
used during the night. In spite of the little
amount per hectare and per year, N and organic matter removal from the
grazing area might affect the nutrient budget of this fragile alpine
ecosystem, and facilitate the spreading of non-pastoral species, even in
a short time period, as reported by Cugno (2001) in a similar
environment of the same valley.
Conclusion
According to Vidrih (2002) the corrals, surrounded
by permanent electric fences, seem to be an interesting solution (in
terms of cost and feasibility) to prevent livestock depredation.
Nevertheless, with the actual grazing management, excreta are excessively
concentrated in the areas where flocks are sheltered. In fact, in the
summer pasture where the experiment was carried out, about 50% of
seasonal faeces production was released in the shelters, with
unfavourable effects on the nutrient budget. An important nutrient and
organic matter transfer may create conditions for the deterioration of
the pastoral quality of vegetation, especially in the more remote areas.
As a perspective, this may make it impossibile to carry on sheep grazing,
and may be detrimental for the production of high quality lamb meat, on
which the local breeding system is based (Sambucano heavy lamb meat is
well appreciated not only at a regional scale). Consequently, the
presence of large carnivores might be indirectly detrimental not only to
the ecosystem, but also to the economic system, if management changes to
integrate them will not be put into practice. The long term effects of
an integration of predators, which are an important element in food
chain and might be a tourist attraction (especially wolves), have to be
further investigated.
References
Barrow,
N.J., 1987. Return of nutrients by animals. In: Ecosystems of the world,
Managed Grasslands -Analytical Studies-, R.W. Snaydon Edition, Elsevier,
Amsterdam, Oxford, New York, Tokyo, 1987. 285 pp.
Barrow,
N.J., & Lambourne, L.J., 1962. Partition of excreted nitrogen,
sulphur and phosphorus between the faeces and urine of sheep being fed
pasture. Australian Journal of Agricultural Research, 13(3): 461-471.
Cugno,
D., 2001. Analisi gestionale del sistema
pastorale ovino con la razza Sambucana in Valle Stura di Demonte, a
fronte delle predazioni di canidi. PhD
thesis, Torino. 143 pp.
Daget,
PH., & Poissonet, J., 1969. Analyse
phytologique des prairies. Application agronomiques. CNRS - CEPE
Montpellier,
document n. 48.
Daget,
Ph., & Poissonet, J., 1972. Un procédé
d'estimation de la valeur pastorale des pâturages. Fourrages,
49: 31-39.
Lancon, J., 1978a. Les restitutions du bétail au pâturage et leur effets-1. Fourrages, 75: 55-88.
Lancon, J., 1978b. Les restitutions du bétail au pâturage et leur effets-2. Fourrages, 76: 91-122.
Lombardi,
G., 1997. Prelievo
di erba e distribuzione delle deiezioni in relazione al comportamento
degli animali su di un pascolo alpino. Rivista di Agronomia 31(1):
306-309.
Vidrih, A., 2002. Electric fencing and carnivore damage prevention. Carnivore Damage Prevention News, n° 5, May 2002: 10-12.
Whitehead,
D.C., 1995. Grassland nitrogen. CAB International – Wallingford. 397 pp.
King Collar, Predator Protection Collars for Small Livestock
by Larry King
Introduction
Predation
on small stock in South Africa is widespread. Many graziers will lose up
to 30 % and even 40 % of their lamb crop from birth to adulthood, to
predation by wild animals. Over 90 % of the predation is by caracal and
black-backed jackal. Depending on age, the breed of animal and how the
value is calculated, the loss of a lamb will imply a direct loss to the
grazier of between R140 (1 Rand = 0.15 US$) and R275. Typical ewe flock
size will range between 500 and 1’000 animals. The average number of
lambs dropped per flock of 2’000 animals will be about 700 for animals
used in fibre production (wool sheep and Angora goats) and perhaps 1’400
in meat producing animals. There are in excess of 30 millions small
stock in South Africa. 1990 estimates are 29,9 million sheep and 2.8
million goats. Traditional control measures have almost exclusively
concentrated on the elimination of the predator. Methods used include:
hunting by means of dog packs, by means of rifle, leg-hold trapping,
poison baits, baited cages, poison collars placed on lambs’ necks and
poisonous explosive baits. A small number of farmers attempt to exclude
predators with electrified fencing. Some farmers attach bells to the
lambs’ necks, and others slip pieces of old inner tube over the neck.
Both caracal and black-backed jackal use very specific methods of
killing prey. Both suffocate their prey by biting the windpipe from the
underside. Caracal will stabilise their prey while biting by using their
claws behind the head and on the back of the neck. Jackal will bite on
the cheek, injuring a nerve running down the side of the face. This
injury apparently causes a degree of paralysis. The jackal then changes
its grip to the windpipe. Very occasionally jackals have been known to
bite in the hindquarters and attempt to kill in this way.
Innovation
We believe
that no amount of hunting will eliminate the predation problem. There
will always be predators that will elude eradication. Many small stock
graziers border cattle farmers, game farmers or game reserves, none of
whom have an interest in eradicating caracal or jackal. However,
accepting a permanent predator presence implies a preventative approach.
Our device attempts (successfully) to ARMOUR stock against attack (see
figure 1). It is important to note that the bells and inner tubes
mentioned above attempt to repel predators. They are also not successful
for more than short periods as the predators soon adapt to the strange
sounds and strange appearance/texture.
Fig.
1: King Collar on sheep: it can be
nicely how they protect the side of the cheek.
Use of quality materials, manufacture and assembly
The collars are manufactured out of black 1mm HDPE sheet. The collars are pressed out using a die-knife and a mechanical press. We have purchased our own press and manufacture the collars on the farm. The collars require no assembly. They are flat, shaped plastic sheet with various slits and holes in them. They are smooth and do not irritate the lambs they are fitted to.
Safety and Ergonomics
The plastic used is inert and contains no poison. The collars are adjustable in size, and so may be “let out” as the lamb grows. Once the lamb has outgrown the small collar, the large one is fitted. The collars do not damage wool or mohair. The collars allow free movement of the neck and head, and do not interfere with suckling or grazing. The collars have several small holes in them in order to allow for the release of moisture. Wet wool would attract blow-fly infestations.
Affordability
We sell our
collars at R4.00 each for the small size and R5.50 for the large, VAT
included. The collars, being made of UV resistant high density
polyethylene, should last at least 5 years. They are re-usable and the
cost of protecting a lamb to adulthood will therefore be R4.00 + R5.50
divided by the 5 years, totalling R1.90.
Presume a lamb crop of 100, a predation rate of 10 %, a collar
protection success of 90 % and a lamb value of R200. An unprotected crop
will result in a loss of R2000 to predation. Protection will reduce this
by R1’900, at a cost of R160. The only other successful preventative
measure – electric fencing – will cost from R10’000 to up to R80’000,
depending on the area to be fenced.
We must point out, that while success in preventing attacks by jackal is
reported to us by users to be almost 100 %, against caracal predation,
the collar is effective but not as successful. Users have described it
as “65 %” effective against caracal. We suspect that the caracal is
able to hold its prey still with its claws and thus find the small
unprotected area of neck, this area is necessary in order to allow the
lamb sufficient mobility to eat and drink.
Environmental impact
The collars
can be manufactured from “regrind” – recycled plastic, which has
the added advantage of being cheaper. The small amount of waste plastic
can be recycled.
However, the major environmental impact will result from the cessation
of attempts at killing jackal and caracal. These attempts are very often
indiscriminate and can impact very heavily on non-target animals.
Leg-hold traps are not humane and eliminate many innocent animals. Only
the very best packs of hunting dogs can be dissuaded from attacking
animals other than jackal and caracal. But it is the (usually
indiscriminate) use of poison that causes very significant environmental
damage. Many farmers become so desperate that they distribute unsuitable
poisons in baits and carcasses, and fail to monitor or clear up the
poison afterwards. Other carrion feeders then become targets and
significant losses of particularly vultures have occurred in this way.
Some poisons do not break down and by remaining in the food chain can
continue killing for long periods. The widespread use of the collars can
do much to obviate this damage.
Ease of maintenance and installation
The collars can be fitted and removed in less than a minute per sheep by farm labourers. Adjusting the collars for growth is equally quick and needs to be done every third week in young lambs and perhaps every 3 months in weaned lambs. The collars require no maintenance. This must be contrasted with traditional control methods, all of which require significant and regular time inputs, as well as varying degrees of skill.
Social acceptance
Our sales to date are just over 270’000 collars, the first sale having taken place in October of 1997. We have been somewhat surprised that acquaintances particularly, in spite of appreciating the advantages outlined above and in the face of proof of efficacy, have been reluctant to use the collars. In spite of being farmers ourselves, we have come to the conclusion that farmers are a very conservative and suspicious lot. And secondly, that they have come to hate predators so much that it is hard for them come to terms with control methods that do not result in dead jackals and caracals.
More information on:
There is currently a small trial under way at one of the SA agricultural colleges, but no results are available yet. CDPNews intends to keep you updated.
Bringing Insight into Livestock Depredation by Wolves in Southwestern Alberta, Canada.
by Tyler Muhly, C. Cormack Gates, Carolyn Callaghan, Charles Mamo, Shelley Alexander, Elisabetta Tosoni and Marco Musiani
Conflict between the livestock industry and wolves
has been ongoing in southwestern Alberta, Canada since settlement of the
area, because of wolf depredation on domestic livestock (Gunson 1992,
Musiani et al. 2003, Musiani and Paquet 2004). Although impacts of
depredation on the livestock industry in Alberta as a whole are very
small, costs to individual ranchers can be high, as depredation events
often re-occur in the same area. The common management practice in
response to depredation, both in the past and present, is to cull wolves,
affecting the viability of wolf populations in this portion of the
province (Gunson 1992, Musiani et al. 2003, Musiani and Paquet 2004). It
is in the interest of many segments of the general public, including
ranchers, to reduce depredation (Gunson 1992, Kellert et al. 1996,
Musiani et al. 2003, Musiani and Paquet 2004). Benefits to the rancher
are obvious, with the potential for additional benefits to all concerned
stakeholders, including increased tolerance for wolves in the area
leading to a probable reduction of culling, resulting in more stable
wolf populations in the southwest portion of Alberta.
Some studies in other parts of the world have used a spatial approach to
model and predict areas of livestock depredation (Mech et al. 2000,
Treves et al. 2004). In southwestern Alberta, depredations tend to
re-occur in the same areas; therefore we used a similar approach, using
Geographic Information Systems (GIS) to model spatial factors we thought
had an impact on depredation events in southwestern Alberta. We used
multivariate statistics to determine what variables could be used to
predict areas of livestock depredation risk. Some of the factors we
looked at included: human disturbances (e.g. buildings and roads),
habitat (e.g. vegetative cover, riparian areas and terrain ruggedness)
and wild prey distribution (elk density). Our goal is to provide
information to ranchers in southwestern Alberta on what defines areas of
livestock depredation, and thus help them better manage their livestock
to reduce depredation risk when wolves are in the area.
Methods
We contacted ranchers along the foothills of southwestern Alberta to determine locations of depredation sites. We visited these depredation sites with the ranchers to record GPS locations. We established the relationship of these depredation locations to roads, buildings, vegetative cover, riparian areas, and prey density in comparison to random points on the landscape available to wolves using multivariate statistics.
Depredation Risk Factors
Some
of the parameters we tested had a nominal relationship to depredation
risk. These parameters indicated that depredation risk was related to
cattle distribution. For example, contrary to what was expected,
depredation risk was higher closer to paved roads and buildings but
lower closer to remote areas and dirt roads. This is because we looked
at depredation risk across a large scale. In relation to habitat
available to wolves, depredation happens in areas where humans are
located, as this is where cattle are located. If we examined depredation
at a smaller scale (e.g. at the individual ranch) we believe depredation
risk would be lower where human presence is high. However, it is also
possible that human disturbance levels in southwestern Alberta are not
high enough to deter wolves from attacking cattle. Regardless, these
parameters had a weak relationship to depredation risk and are not the
most useful for predicting areas susceptible to depredation.
Conversely, the elk density and distance to vegetative cover parameters
had the greatest ability to predict depredation risk. Depredation events
occurred in locations where elk density was higher and in closer
proximity to vegetative cover when compared to available sites. Wolves
likely use cover to avoid detection of prey (Kunkel et al. 1999) and
cover likely decreases detection of wolves by humans, important in areas
where culling of wolves is practiced. Depredation risk is higher where
elk density is higher, potentially because these areas are expected to
be colonized and hunted by wolves (Mech 1970, Jedrzejewski et al. 2000
and Carroll et al. 2003). When livestock are put into these areas,
chance encounters with wolves are higher (Linnell et al. 1999) and
depredation events may be more likely to occur.
Implications for Ranchers and Wildlife Managers
Proximity
to vegetative cover is an important indicator of where depredation
events occur in southwestern Alberta. This is a variable we believe can
be managed by ranchers and wildlife managers when depredation becomes a
problem on a given ranch. Movement of cattle away from forested areas
will result in decreased risk of depredation to that livestock and will
potentially result in fewer depredation events. Ranchers and managers
should focus anti-depredation strategies to areas where vegetation cover
is substantial (when livestock are located there) to deter wolves from
preying on livestock.
Elk density is a factor that would be difficult for wildlife managers
and ranchers to manage. However, at the very least, wildlife managers
and ranchers may be able to determine the vulnerability of an area where
cattle are grazed to depredation by understanding the density of wild
prey in the area. Eliminating wild prey in an area will not necessarily
decrease depredation risk and may in fact increase reliance of wolves on
livestock (Meriggi and Lovari 1996, Meriggi et al. 1996) and is unlikely
a management tool available to ranchers or wildlife managers. Public
support for removal of big game species, such as elk, to reduce
depredation risk would likely be very low if it existed at all. Improved
understanding on the finer scales of the relationship of wild prey
density to livestock depredation will provide further insight into what
drives livestock depredation by wolves in southwestern Alberta.
Acknowledgements
We would like to thank the following for their support of the project. The ranching community of southwestern Alberta, Alberta Beef Producers, Alberta Conservation Association, Alberta Ecotrust, University of Calgary Faculty of Environmental Design, the Alberta Government, and the Calgary Zoo.
References
Gunson, J.R. 1992. Historical and present management of wolves in Alberta. Wildlife Society Bulletin. 20:330-339.
Jedrzejewski, W. B., H. Jedrzejewska, K. Okarma, K. Schmidt, K. Zub, and M. Musiani. 2000. Prey selection and predation by wolves in Bialowieza Primeval Forest, Poland. Journal of Mammalogy. 81:197-212.
Kellert, S.R., M. Black, C.R. Rush, and A.J. Bath. 1996. Human culture and large carnivore conservation in North America. Conservation Biology. 10:977-990.
Kunkel, K.E., T.K. Ruth, D.H. Pletscher and M.G. Hornocker. 1999. Winter prey selection by wolves and cougars in and near Glacier National Park, Montana. 63:901-910.
Linnell, J.D.C., J. Odden, M. E. Smith, R. Aanes, and J.E. Swenson. 1999. Large carnivores that kill livestock: Do "problem individuals" really exist? Wildlife Society Bulletin. 27:698-705.
Mech, L.D. 1970. The wolf: the ecology and behaviour of an endangered species. The Natural History Press. Garden City, NY.
Mech, L.D., E. K. Harper, T. J. Meier, W. J. Paul. 2000. Assessing factors that may predispose Minnesota farms to wolf depredations on cattle. Wildlife Society Bulletin. 28:623-629.
Meriggi, A. and S. Lovari. 1996. A review of wolf predation in southern Europe: does the wolf prefer wild prey to livestock? Journal of Applied Ecology. 33:1561-1571.
Meriggi, A., A. Brangi, C. Matteucci and O. Sacchi. 1996. The feeding habits of wolves in relation to large prey availability in northern Italy. Ecography. 19:287-295.
Musiani, M., C. Mamo, L. Boitani, C. Callaghan, C.C. Gates, L. Mattei, E. Visalberghi, S. Breck, and G. Volpi. 2003. Wolf depredation trends and the use of fladry barriers to protect livestock in western North America. Conservation Biology 17: 1538-1547.
Musiani, M., and P.C. Paquet. 2004. The practices of wolf persecution, protection and restoration in Canada and the USA. Bioscience 54: 50-60.
Treves,
A., L. Naughton-Treves, E. K. Harper, D. J. Mladenoff, R. A. Rose, T. A.
Sickley, and A. P. Wydeven. 2004. Predicting Human-Carnivore Conflict: a
Spatial Model Derived from 25 Years of Data on Wolf Predation on
Livestock. Conservation Biology. 18:114-125.
Abstract
Contact:
Tyler Muhly, Faculty of Environmental Design, University of Calgary,
2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4 (email: tmuhly@ucalgary.ca;
phone: (403) 220-2475)
Reduced Wolf Attacks on Sheep in Østfold, Norway, using Electric Fencing
by
Hilde
K. Wam, John Gunnar Dokk and Olav Hjeljord
Short summary: Improving traditional fencing with electric wires significantly protected sheep from wolf attacks in an area experiencing high losses in Norway 2002. The attack frequency on pastures with traditional fencing was 5-6 times higher than on pastures with improved fences. Also, attacked pastures lay farther from houses than pastures not attacked, which supports the use of night closures near farmyards.
Wolves returned to the county of Østfold, Norway in 1997 after being
absent for almost 150 years. With traditional fencing and no shepherd
guarding, the wolves then had free access to grazing livestock, and the
number of attacks rapidly increased (Fig. 1). In the majority of cases
sheep were attacked (i.e. 31 out of 35), but also some cattle were
involved. One wolf territory in particular became a “problem area”.
Of the 35 attacks reported until 2002, 29 occurred within this territory,
called Moss-Våler.
Fig.
1. Number of wolves and
attacks on
sheep pastures in Østfold, Norw
The
territory covered approximately 600 km2 across 8 different
municipalities. The density of winter-fed livestock varied locally from
3.0 to 10.2 animals per km2, of which one fifth were sheep or
goats, and the rest beef cattle, diary herds and a few horses. Most
livestock in Østfold graze in pastures for parts of the year, mainly in
May-Sept. Sheep are traditionally fenced off with a non-electric 15x20
cm mesh wire 90-100 cm in height, while an electric one- or two-wired
fence is used for cattle and horses. Østfold does not have the
extensive free-ranging of livestock common elsewhere in Norway, and most
pastures lie within 1 km from the farmyard.
From
2000 and onwards, farmers could apply for financial support to improve
their fences through the scheme “Preventive measures against livestock
depredation”. By 2002, 17 % of all farms with grazing livestock within
the county had applied, and a total of 182 km of fences had been
improved for the cost of € 325'000 (US$ 400'000). Within the Moss-Våler
territory,
the figure was 60 %. Those who received financial support had to follow a
given standard, i.e. minimum height: 100 cm; maximum distance from
ground to first wire: 20 cm; maximum distance between wires: 20 cm (30
cm in upper half). In the end of 2002, the minimum height was raised to
120 cm.
In
the summer 2002 the losses were higher than ever, and 40 % of all
registered sheep farmers within the territory had one or more wolf
attack on their pastures. This was a valuable opportunity to test the
preventive effects of the improved fences. Roughly half the sheep
pastures had experienced losses, while the other half had not. Which
factors differed between the two?
Methodology
A field survey of all registered sheep pastures within the territory was conducted in the spring 2003. The following were registered at each site;
a.
Fence type
•
Improved or not
•
Mesh wire vs. fully electric
b.
Fence parameters
•
Minimum height
•
Number of electric wires
•
Largest distance from ground to 1.wire
•
Largest distance between wires
•
Number of “weak” points along fence
c.
Position of pasture
• nearest distance to houses
• nearest distance to roads
The
data obtained from the survey was treated statistically with
non-parametric methods, where pastures with and without attacks were
compared with a Wilcoxon rank sum test. Despite the data being
non-normal, we here present the mean (not the median) of parameters,
since the mean is more familiar to most people.
Results
Of the 15 wolf attacks on grazing sheep within the Moss-Våler territory in 2002, only 3 occurred on pastures with improved fences (Fig. 2). Since there were a total of 27 pastures with improved fences, the attack frequency on these pastures were 11 %. In contrast, there were a total of 15 registered pastures with traditional fencing, which makes an attack frequency of 80 % 1.
Fig.
2. Attacked and not attacked sheep
pastures within the Moss-Våler territory 2002.
Of
all the 15 attacks, 14 occurred on pastures with mesh-wire fences (of
which two were improved), while one attack was registered on a pasture
with both improved mesh-wire and stretches of fully electric fence. The
sample size is too small, however, to say anything about the relative
preventive effect of improved mesh-wire vs. fully electric fences.
The
attacked pastures had fences with lower height (N=37, W=185, P=0.001)
and fewer electric wires (N=37, W=111, P=0.015) than pastures not
attacked (Table 1). Also the attacked pastures had larger maximum
distances between fence wires (N=17, W=42; P=0.034), a slightly larger
distance from ground to the first wire (not significant, N=37, W=160,
P=0.256) and more weak points along the fence (N=37, W=73, P=0.006).
Pastures
not attacked by wolves were closer to houses than the attacked ones,
i.e. 76 ± 30 metre vs. 203 ± 71 metre (N=37, W=137, P=0.013). The
proximity to roads, however, did not affect the chance of being
attacked:
the distance to nearest road was 53 ± 33 metre for attacked pastures,
and 44 ± 24 metres for pastures not attacked (N=37, W=102, P=0.476).
Tab.
1. Fence parameters for pastures with and without wolf attacks on
sheep in Østfold, Norway 2002.
Discussion
Clearly the improvement of traditional fences was preventive against wolf attacks in Moss-Våler 2002. What the Østfold experience cannot tell us so far is to what extent the preventive effects will last. The improved fences are mainly psychological, not physical, barriers for wolves.
Aalong
with this survey, we also checked the general condition of one third of
all improved fences in Østfold (N=29, randomly chosen). This revealed
that there were deviations from the given standard along the fences at
28 out of 29 farms. A highly adaptive species like the wolf may quickly
learn about these weak points in the fence, and then gradually loose the
wariness it originally had against the improved fences.
The
most prevailing deviation in Østfold was too high distances from the
ground to first wire. This was also reflected in the farmers’ own
comments. The remark most often made was how time consuming it is to
have the first wire only 20 cm above the ground (vegetation underneath
the wire has to be frequently removed not to shortcut the electricity).
It might be socio-economically viable to compensate farmers for doing
this job. A fence with weak points not only increases the risk of attack
on that particular pasture, but it may also lower the protective effect
of all similar fences in the area.
The study was financially supported, and conducted on behalf of the county government of Østfold. The full report can be found at: http://skandulv.nina.no/ (in Norwegian only).
1
There
might have been some additional sheep pastures within the territory, as
e.g. sheep kept as pet are not registered. Therefore, the attack
frequency of pastures with un-improved fences is likely to be slightly
over-estimated.
A Simple Carnivore Improvement of Existing Sheep Fencing
by Hilde K. Wam, John Gunnar Dokk and Olav Hjeljord
Summary: We
present technical specification for a simple way of securing sheep
pastures against large carnivore attacks. The method was originally
planned to suit pastures already fenced off with a mesh-wire, i.e. the
traditional fence used for sheep in Norway.
In
2000-2002, the Norwegian government spent € 325'000 (US$ 400'000) on securing
livestock fences against large carnivores in the county of Østfold.
Sheep owners had two options; either they could improve an existing
mesh-wire fencing (Fig. 1a) by adding 1-3 electric wires, or exchange
the whole fence with a fully-electric wire fence (Fig. 1b). Most sheep
owners chose the first option. However, due to low height of their
existing fences several owners also chose the latter option. Thereby
long stretches of high-quality sheep mesh-wire was taken down, and
exchanged with fully-electric fencing.
Although
immediate preventive effects of the improved Østfold fences have been
documented (see this issue of CDPN), their long-term effects are
uncertain since they predominantly work as psychological barriers. The
most prevalent argument for not building fences with stronger physical
effects has been high material costs.
We present a fence alternative that represents more of a physical barrier, but still lies within the cost range of improved fences in Østfold.
Technical specifications
We
assume that the pasture is already fenced off with a traditional sheep
mesh-wire fence. The challenge with such a fence is to get
sufficient height to prevent carnivores from jumping in. The posts
usually stand 100-120 cm above the ground. On sloping ground this means
the effective height can be very low on the outside.
The
distance between posts in the traditional fence is normally 1.5-2 m.
Along with the mesh-wire this makes them very rigid. They can easily
withstand the pressure of adding extra height without any of them being
exchanged. This may of course be done in several different ways, not all
equally robust. We suggest that higher fence posts are added for every
third existing one (Fig.
2). This means that no parts of the original fence have to be removed (although
it may be a good idea to simultaneously tighten up the mesh-wire).
Fig. 1 Sheep fencing used in Østfold: a. traditional mesh-wire, and b. a fully-electric “carnivore” fence.
Tab. 1. Alternative carnivore improvement of sheep fencing in Norway, their cost and subjectively estimated barrier effects (based on the Østfold experience and present knowledge on carnivore behaviour, not tested). Costs include the labour needed to build the fence (for details, please contact the corresponding author).
Although
immediate preventive effects of the improved Østfold fences have been
documented (see this issue of CDPN), their long-term effects are
uncertain since they predominantly work as psychological barriers. The
most prevalent argument for not building fences with stronger physical
effects has been high material costs.
We
present a fence alternative that represents more of a physical barrier,
but still lies within the cost range of improved fences in Østfold.
Technical specifications
We
assume that the pasture is already fenced off with a traditional sheep
mesh-wire fence. The challenge with such a fence is to get
sufficient height to prevent carnivores from jumping in. The posts
usually stand 100-120 cm above the ground. On sloping ground this means
the effective height can be very low on the outside.
The
distance between posts in the traditional fence is normally 1.5-2 m.
Along with the mesh-wire this makes them very rigid. They can easily
withstand the pressure of adding extra height without any of them being
exchanged. This may of course be done in several different ways, not all
equally robust. We suggest that higher fence posts are added for every
third existing one (Fig.
2). This means that no parts of the original fence have to be removed (although
it may be a good idea to simultaneously tighten up the mesh-wire).
Fig. 2. A simple way of securing sheep mesh-wire fences against attacks from large carnivores.
Conclusion
The cost of the described fence alternative is intermediate compared to the improved fencing in Østfold (see Table 1). Though, without a mesh-wire fence present, it will become the most expensive alternative with the present cost-regime in Norway. However, if one considers the potentially higher preventive effects of such a fence, it may still be the best option. A cheaper fence with mainly psychological effects may turn out to be more expensive over time.