Introduction

Wolves Canis lupus Linnaeus, 1758 became ex-tinct in late 1930s from the isolated Peloponnesuspeninsula in southern Greece, while currentwolf distribution covers the majority of conti-nental Greece (Hatzirvassanis 1991, Iliopoulos1999a). Continued wolf presence, resulted in the

maintenance of traditional livestock protectionmeasures like shepherd surveillance, use ofsheepdogs and enclosures, until present times.

In central, northeastern Europe and NorthAmerica wolves feed mainly on wild ungulates,(Pulliainen 1965, Fritts and Mech 1981, Fuller1989, Okarma 1993, Jêdrzejewski et al. 2000,Mattioli et al. 2004, Gazzola et al. 2005, Nowaket al. 2005, Gula 2008). In southern Europe, es-

[11]

Acta Theriologica 54 (1): 11–22, 2009.

PL ISSN 0001–7051

Wolf depredation on livestock in central Greece

Yorgos ILIOPOULOS*, Stefanos SGARDELIS, Vaios KOUTIS

and Dimitrios SAVARIS

Iliopoulos Y., Sgardelis S., Koutis V. and Savaris D. 2009. Wolf depredation onlivestock in central Greece. Acta Theriologica 54: 11–22.

We studied wolf Canis lupus Linnaeus, 1758 – livestock conflict in centralGreece by investigating patterns of 267 verified wolf attacks on livestock for21 months. Wolves attacked adult goats 43% and cattle 218% more thanexpected, whereas sheep 41% less than expected from their availability.Wolves killed less than four sheep or goats in 79%, and one cow or calf in 74% ofdepredation events, respectively. We recorded higher attack rates during wolfpost-weaning season. Wolf attacks on strayed, or kept inside non predator--proof enclosures, sheep and goats, were on average two to four timesrespectively more destructive than those when livestock was guarded by ashepherd. Sheepdog use reduced losses per attack. Optimal sheepdog numberranged from 3 to 9 animals depending on flock size. Losses per attack werepositively related to the number of wolves involved. Total losses per farm werepositively correlated with the size of livestock unit but percentage losses percapita increased with decreasing flock size. Management implications tomitigate livestock depredation are discussed.

Callisto, Wildlife and Nature Conservation Society, Mitropoleos 123, Thessaloniki 54621, Greece(YI, VK, DS); Department of Zoology, School of Biology, Aristotle University of Thessaloniki54124, Greece (YI); Department of Ecology, School of Biology, Aristotle University of Thessaloniki54124, Greece (SS)

Key words: wolf, livestock, depredation, husbandry methods, conservation, Greece

* Present address: Mitropoleos 123, Thessaloniki 54621, Greece, e-mail: yiliop@otenet.gr

pecially in areas with important livestock pro-duction, wolves may depend heavily on livestockas prey (Meriggi et al. 1991, Blanco et al. 1992,Fico et al. 1993, Papageorgiou et al. 1994, Meriggiet al. 1996, Vos 2000, Pezzo et al. 2003, Migli et

al. 2005).Depredation on livestock is a crucial factor

for persecution incentives of wolves (Meriggiand Lovari 1996). Boitani (2000) considers moni-toring of livestock damages as of great importancefor the species’ conservation and management inEurope. Figures on livestock damage are mainlybased on official agencies data of farmer’s com-pensation claims (Blanco et al. 1990, 1992, Ficoet al. 1993, Cozza et al. 1996, Ciucci and Boitani1998, Gazzola et al. 2008).

The compensation scheme in Greece is uni-form for the whole country and covers both dep-redation from wolves and free-ranging dogs(ELGA 2003). Data provided by ELGA refer onlyto damages subject to compensation, usually themore severe incidents, excluding less severe butmore numerous ones. Nevertheless they do notinclude information on attack circumstancesand husbandry methods enforced by the affectedfarmers.

Aims of this study were to: (1) describe ac-tual, independently of their severity, figures onlivestock losses caused by wolves (2) examinefactors associated with the wolf depredation (3)suggest management priorities to mitigate theproblem of wolf depredation.

Study area

Our study area comprises two regions in Central Greece.One region (1200 km

2) is located in the prefecture of Trikala

(39�44’N, 21�38’E) including 36 villages whereas another(1000 km

2) includes 27 villages in the prefecture of Fthiotida

and Magnesia (39�00’N, 22�30’E).Elevations range from 200 to 2300 m a.s.l. Extensive ev-

ergreen oak Quercus coccifera, dominate areas up to 700 ma.s.l. Deciduous oak forests, Quercus spp. dominate the700–1200 m a.s.l. elevation zone. Fir forests, Abies borissii

regis, Abies cephallonica, and black pine forests Pinus nigra

dominate areas above 1000 m a.s.l. In higher elevations andbelow the timberline (1700 m a.s.l.) beech Fagus sylvatica,

form mixed forests with Abies borissi regis stands.Average human population density, excluding cities, is

15 inhabitants per km2

(Ministry of the Interior 1999).

Availability of livestock expressed as the number of headsper species and per village, was provided by the Greek Na-tional Statistical Service and local veterinary offices ofTrikala and Fthiotida. Seven thousand cattle, 119000 sheepand 80 000 goats in total, graze inside the study area. Aver-age summer density of sheep and goats is 90 head per km

2

and 3.5 per km2

for cattle. Sheep and goat flocks graze onlyduring daylight and are guarded by shepherds, with the aidof sheepdogs. Sheep and goat flocks consisted of one or bothspecies (mixed flocks). Cattle herds graze unguarded duringday and night, accompanied or not by sheepdogs.

Concerning availability of wolf natural prey, wild boarSus scrofa is widespread, while roe deer Capreolus cap-

reolus occur in very low densities (Y. Iliopoulos, unpubl.).Balkan chamois Rupicapra rupicapra balcanica are rareand inhabit only alpine or sub-alpine remote areas (Pa-paioannou and Kati 2007). Brown hares Lepus europeus

exist at low densities compared to other European countries(Sfougaris et al. 1999). Winter wolf density in the studyarea has been estimated at 2.6 ± 0.1 (SE) wolves per100 km

2(Iliopoulos 1999b, 2000)

Material and methods

Examination of damage claims

We directly examined damage claims from February1999 through October 2000 every month. Since January1999, a pilot compensation system was initiated in theframework of an EC LIFE project on wolf conservation inCentral Greece. Each verified livestock loss caused by pre-dation, was extra compensated if not covered by the na-tional compensation system.

A trained person (V. Koutis, D. Savaris and Y. Iliopoulos)visited the attack site within 24 hours. We examined attacksites for blood spilled over and close to carcasses, to excludecases of post mortem consumption. We also used the follow-ing secondary criteria: presence of throat bites, presenceand number of injured animals, signs of struggle, draggingof carcasses, predator consumption patterns, presence andlocation of subcutaneous hemorrhages in order to excludefraud claims and identify predator involved (Kaczensky andThomas 1994, Bousbouras 1997). We classified cause oflivestock death into three categories: “predation”, whenblood was found in the attack site and other secondary cri-teria were fulfilled indicating wolf predation, “probable pre-dation” when several of the secondary criteria were fulfilledand “other” when evidence was poor or destroyed. In total,we examined 304 livestock damage claims. Claims for goatand sheep attacks were considered as one category, as inmany cases attacks were on mixed flocks involving bothspecies. We excluded cases classified as “other” cause ofdeath and cases when dogs were suspected or observed tokill livestock from further analysis. Eight more cases wereexcluded as being attacks on dogs or donkeys. Figures onlivestock losses are referred only to killed and seriously in-jured livestock found and examined in the attack site, thusthey represent minimum levels of livestock losses per wolfattack.

12 Y. Iliopoulos et al.

Information on associated factors

During field visits we asked each farmer to report: (1) ifhe was in the vicinity of the attack site and, accordingly, (2)date and hour of attack, (3) livestock flock size during at-tack, (4) number and reaction of sheepdogs present, (5)number of wolves observed, (6) weather conditions, and (7)attack circumstances. Attack circumstances were classifiedin three categories: (a) animals grazed with the rest of theflock guarded by a shepherd, (b) animals strayed away fromthe flock and out of the direct supervision of a shepherd,and (c) animals kept in non predator-proof enclosures in theabsence of a shepherd. We classified weather conditions as(a) foggy and rainy with low visibility and (b) clear withgood visibility. Farmers provided also information concern-ing husbandry methods, size and predominant birth seasonof their livestock flock.

We assessed habitat in the attack site by describingthree basic landscape features inside a radius of approxi-mately 500 meters: (a) visibility according to main tree spe-cies and vegetation structure, (b) vegetation coverage and(c) topography (Appendix 1).

Statistical analyses

We used the �2

goodness-of-fit test to examine: (a) if cat-tle, sheep and goats suffered losses proportionally to theirrelative availability; (b) if the number of attacks on cattlewere equally distributed among different age classes, and(c) if rate of attacks was equally distributed among differentmonths or seasons of the year. In cases, where the �

2-test

showed significant overall differences, we used the Bonfer-roni confidence interval method, eg Meriggi and Lovari(1996), to a) determine which of the three species sufferedsignificantly different losses than expected and b) calculatedeviation percentages from expected attack rates at differ-ent species and amongst seasons.

We performed univariate non-parametric tests (Kruskall--Wallis and Mann-Whitney) to compare the average numberof sheep/goat killed per attack under different circum-stances and seasons, and compare average total losses perfarmer.

We conducted multiple linear regression with stepwisevariable selection for fitting a statistical model to predictthe proportion of sheep and/or goats killed during each at-tack from the following possible predictor variables: num-ber of dogs, season (month), vegetation visibility, forest

cover, slope, weather, time of attack and flock type (sheep,goat, or mixed). Nominal variables were coded into a set ofbinary ones as dummy variables. The dependent variablewas transformed according to Box-Cox family of transfor-mations to select the appropriate scale. Continuous predic-tor variables were also subjected to various transformationsfor selecting the best set to fit the model. We selected the fi-nal model among those leaving normally distributed residu-als. The selection criterion was the maximization of R

2

adjusted for the degrees of freedom. As reliable observa-tions for the number of wolves involved during attacks wereavailable only for a small subset of depredation events (n =75), we fitted a second model for this data subset. We usedthe Spearman rank correlation test to examine relationshipbetween the farm size and amount of losses.

Results

Number of attacks validated

Two hundred sixty seven damage claimswere assigned to “predation” and “probable pre-dation” by wolves. Among them 35 attacks wereon cattle and 224 on sheep and/or goats. We ex-amined 95% of cattle, 88% of sheep and 76% ofgoats from those totally claimed by farmers asbeing killed by wolves.

Wolf selection of livestock species and age

classes

Wolves attacked cattle 218% and goats 43%more often than expected, whereas sheep 41%less often than expected, based on their relativeavailability (�

2= 94.86 df = 2, p < 0.01, Bonferroni

confidence interval, p < 0.01, Table 1). From atotal of 812 sheep and goats killed, 96% wereadults (> 1 year old). In case of cattle, wolvespreyed heavily on calves < 1 year old (�

2= 56.58,

df = 1, p < 0.01) that constituted 77% of all cattle

Wolf depredation on livestock 13

Table 1. Wolf prey selection amongst the three livestock species (Bonferonni intervalanalysis). * – significant at p < 0.01.

Livestock species Expected predationrate (%)

Differences from expected predation (%)

Recorded attackevents

Recorded animalskilled

Cattle 3.4 + 218* + 45*

Goats 38.4 + 43* + 52*

Sheep 58.2 – 41* – 37*

killed. From among 34 calves, 79% were 6months old or younger.

Temporal distribution of attacks

Rate of wolf attacks (expressed as the num-ber of attacks per day per month) on sheep andgoats was not proportionally distributed through-out the year (�

2= 41.6, df = 11, p < 0.01, n = 222)

and peaked in early autumn whereas it was atminimum in winter (Fig. 1). Rate of attacks oncattle did not show any significant monthly dif-ferentiation (�

2= 15.6, df = 11, p > 0.05, n = 35,

Fig. 1).We also evaluated temporal distribution pat-

tern of attacks, amongst the annual biologicalseasons of wolf packs, as proposed by Vila et al.(1995): (1) winter and early spring nomadic sea-son (November–April), (2) denning and wolf pupweaning (May–July), and (3) post-weaning sea-son (August–October). Attack rate to sheep andgoats during the wolf post-weaning season was

by 48% greater than expected, whereas it waslower by 16% and 30% during the denning-weaning season and the winter-early spring sea-son, respectively (�

2= 26.1, df = 2, p < 0.01 and

Bonferroni confidence interval analysis, p < 0.01in all cases, Fig. 2).

Variation of livestock number killed per

attack and associated factors

Wolves killed less than 4 sheep or goats perattack in most cases (79%). Severe losses (> 15animals) occurred only in 3% of all cases, (Fig.3). When wolves killed cattle, 74% of all cases in-volved only one animal and on remaining occa-sions there were two individuals killed duringeach attack. All depredation on cattle occurredon pastures in the absence of a shepherd.

Wolf attacks on strayed sheep and goats (11%of cases), or kept inside non predator-proof, en-closures (3% of cases), were on average, two andfour times respectively more destructive, than

14 Y. Iliopoulos et al.

Fig. 1. Monthly rate of wolf attacks: pooled data from both 1999 and 2000.

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

Attacks

cattle

sheep and goats

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Months

Att

acks

pe

rd

ay

pe

rm

on

th

those cases (86%) when livestock was clumpedtogether and guarded by a shepherd (H = 22.56,df = 2, p < 0.01, Table 2). Most cases of strayedlivestock killed (72%, n = 18) were goats. Wolveskilled more sheep and goats per attack in mixedflocks containing both species, than in sin-gle-species flocks (H = 19.8, df = 2, p < 0.01, Ta-ble 2) and also during the post weaning seasoncompared to other periods (H = 8.47, df = 2, p <0.05, Table 2).

We constructed two models to predict the pro-portion of sheep and goats killed in a livestock

flock after a single attack event. In both modelsthe independent variable was the logarithm ofanimal losses. In Model I, we analyzed 194 at-tack events and we did not include observed wolfnumber as a predictor. In Model II we used asubset of 75 attack events including observedwolf number as a predictor variable. The R

2ad-

justed for the degrees of freedom was 0.453 formodel I and 0.546 for model II.

Model I predicts higher than average lossesper attack for mixed (R

2= 0.407) and sheep

flocks (R2

= 0.457) and when attacks occur in Oc-tober (R

2= 0.470).

The number of dogs involved in protection offlocks affected the losses per attack followingthe formula:

Z1 = 0.0037X2

– 0.774ln(X+1) + 0.601ln(Y+1),

where: X – number of dogs and Y – number ofdogs per 100 animals.

In Model II, losses increase as the number ofobserved wolves increases (R

2= 0.440), while

the effect of dog number is described by the fol-lowing equation:

Z2 = 0.0033X2

– 0.622ln(X+1) + 0.121Y.

Both models I and II indicate that when thenumber of guarding dogs increase, losses aregradually reduced until number of dogs reaches

Wolf depredation on livestock 15

Fig. 3. Number of sheep and goats killed by wolves per at-tack. Percentage distribution of severity classes for 224 at-tack events.

Fig. 2. Temporal distribution of expected and observed attack rates to sheep and goats, amongst the three “wolf seasons”.Black bars represent percentage deviation from expected values.

-30

-20

-10

0

10

20

30

40

50

Winter-breed Den-weaning Post-weaning

Expected

Observed

DeviationPe

rce

nta

ge

Animals killed per attack

>158-155-71-4

80

70

60

50

40

30

20

10

0

Pe

rce

nta

ge

a critical value, (we term it the “optimal” dognumber). When number of dogs exceeds this “op-timal” value, losses gradually start to increase,but dogs still maintain their protective role.When the number of dogs reaches very highnumbers, model I and II predict losses evenlarger than the case when no dogs at all, areused (Fig. 4). In model II, when number of

wolves is used as a predictor variable of animallosses, effect of guarding dogs is more promi-nent: losses are lower for a certain number ofdogs used, compared to those predicted frommodel I. The optimal dog number increases withlivestock flock size from 3–4 in small flocks (n =100) to 7–9 dogs in large flocks ranging from 500to 1000 animals (Fig. 5). Other factors like

16 Y. Iliopoulos et al.

Table 2. Average number of goats and/or sheep killed per attack, according to factors related to severityof losses.

Average loss ± CI (95%) Range, n

Flock type

Goat 3 ± 0.56 1–21 121

Sheep 3.43 ± 1.14 1–26 54

Mixed (sheep and goat) 4.49 ± 1.15 1–21 39

Attack circumstances

Animals within the main flock guarded by shepherd 2.9 ± 0.41 1–21 181

Animals strayed away from the rest of the flock without guarding 6.66 ± 2.59 1–26 25

Animals in non predator-proof enclosure, not guarded 12.3 ± 6.70 2–36 7

Season

Denning-weaning season 3.1 ± 0.31 1–26 72

Winter/wolf breeding season. 3.45 ± 0.97 1–17 53

Post weaning season 4.1 ± 0.95 1–36 97

Number of dogs

181614121086420

0.2

0

-0.2

-0.4

-0.6

-0.8

-1.0

Model 1 flock 300

Model 2 flock 300

Lo

gre

lative

losse

s

Fig. 4. Effect of guarding dogs on the relative animal losses (sheep and goats) killed by wolves per attack for flocks with a sizeof 300 animals.

weather and habitat features (cover, visibility,and topography) did not have any significant ef-fect to the level of livestock losses per attack.

Level of total losses per livestock farm

Most farms (84%) experienced less than 2wolf attacks and only 6% were chronically af-fected (> 3 attacks) during the 21-month period

of the study (Fig. 6). Sixty one percent of allfarmers lost less than 5% of their livestock dur-ing the study, or approximately less than 2.5%per year (Fig. 6).

Total losses averaged 5.8 ± 0.97% (CI = 95%)of sheep and goats (range = 1–38, n = 131), or 2.3± 0.7% (CI = 95%) of cattle (range = 1–8, n = 19).Total number of attacks and animal losses persheep and goat farm were positively correlatedwith the size of the farm (rs = 0.269, p < 0.01 andrs = 0.326, p < 0.01 respectively, n = 131). Pro-portional losses per livestock capita, however,were significantly negatively correlated with thesize of the farm (rs = –0.555, p < 0.01, n = 131).Positive, but not significant trend was found be-tween cattle farm size and total number of at-tacks or overall number of cattle killed duringthe study (rs = 0.274 and rs = 0.204, respectively,p > 0.05, n = 19). As with sheep and goat farms,losses per cattle capita were significantly nega-tively correlated with the size of the farm (rs =–0.675, p < 0.01, n = 19).

No significant differences were found be-tween average total number of attacks and totalanimal losses per farm, among sheep farms, goatfarms or mixed ones (Kruskall-Wallis test: H =4.032 and H = 2.345, respectively, n = 114, df = 2,p > 0.05).

Wolf depredation on livestock 17

Flock size

1000900800700600500400300200100

9

8

7

6

5

4

3

Model 2

Model 1

Op

tim

um

do

gn

um

be

rs

Fig. 5. “Optimum” dog number for different flock sizes as in-dicated from Models I and II.

Fig. 6. Total losses caused by wolf predation per livestock farm during the study. (a) Total number of attacks for sheep andgoats (n = 131) and cattle (n = 19) units. (b) Percentage of livestock killed per flock for sheep and goat units (larger than 30animals, n = 121) and cattle units (n = 19).

Number of attacks

>3321

80

70

60

50

40

30

20

10

0

Sheep/goat farms

Cattle farms

Percentage of livestock capita

>5>1-5>0.5-10.1-0.5

80

60

40

20

0

(a) (b)

Pe

rce

nta

ge

offa

rms

Pe

rce

nta

ge

offa

rms

Discussion

Livestock species and age class selection

Wolves killed more goats and less sheep thanexpected, although overall, the goat farms didnot experience more attacks and losses com-pared to sheep farms. Analysis of wolf scats inpart of the study area, showed also goats as aheavily preyed species (Migli et al. 2005). Vos(2000) in northern Portugal, found goats to bethe main wolf prey, despite abundant sheeppresent. In central Italy instead, sheep was thepreferred livestock prey, but in that case, avail-ability of goats was very low (Ciucci and Boitani1998).

Huggard (1993) suggested that prey selectiv-ity is depended on the degree of habitat overlap,encounter rates between predator and prey, vul-nerability and predictability of prey occurrence.We do not expect sheep and goat predictabilityto differ, as both type flocks graze in steadilywell defined pastures. Considering vulnerabil-ity, sheep should be equally and even more vul-nerable than goats when attacked, as model Ipredicts. We suggest that wolves killed goatsmore often due to higher encounter rates andbetter attack opportunities with goat flocks.Goats utilize denser forested habitat of Quercus

coccifera woodlands and young oak forests, likewolves do while moving during daytime, restingor denning (Ciucci et al. 1997). Gula (2008)found that farms closer to wolf pack rendezvoussites experienced more attacks. Moreover, sur-veillance of goat flocks is more difficult as theyare more scattered than sheep and forage insteeper slopes (Y. Iliopoulos, unpubl.). As goatstend to spread inside the forest, the encounterrate of wolves with isolated individuals may in-crease.

Goats prevailed as the most preferred live-stock species in a study area level, despite thefact that goat farms did not experience more at-tacks and losses compared to sheep farms. Wesuggest this to be a consequence of more goatunits affected than expected, according to theirnumbers in the study area.

Synchronized births in sheep and goat farmsduring winter months reduced losses of lambs

and kids. In periods with higher predation risk(summer-autumn), this age class was almost ab-sent from the pastures.

Cattle predation was by 218% more frequentthan expected and was actually a consequence ofwolves predating mostly calves. Calves aged lessthan 6 months, grazed unattended during nighthours, contrary to sheep and goats that nor-mally stayed inside enclosures and were notavailable. We suggest that increased calf avail-ability and accessibility to wolves was the mainreason for high predation rates recorded. Bradleyand Pletscher (2005) in Montana and Idaho,found no relationship between cattle predationrates amongst farms and calving season or otherhusbandry techniques, but in that case, wolvesfed mainly on elk. Habitat overlap of cattle withwolves and elk was the main predicting factorthat determined loss levels.

Wolf predation on cattle was a serious conser-vation problem, despite the fact that only 19farms were affected during the study. Cattlefarmers were, in general, less tolerant to wolves,compared to sheep/goat farmers, as each adultcattle or calf killed represented an importanteconomic asset. Wolf mortality related with dep-redation on cattle was important in the studyarea, as only a few affected cattle raisers wereknown to have shot or poisoned approximately25% of the wolves totally killed during 1999–2000(Iliopoulos 1999b, 2000)

Seasonal changes in attack frequency

Wolf attacks on livestock occurred all yearround. There was, however, a marked seasonalpattern reported also from other parts of thewolf range (Fritts et al. 1992, Ciucci and Boitani1998, Nowak et al. 2005, Gazzola et al. 2008). At-tacks peak in summer and early autumn, whensheep and goat numbers and availability in pas-tures were relatively stable.

More attacks than expected occurred duringthe post-weaning period (August–October), whenwolf pups require large food intake given theirrelatively high growth rate (Oftedal and Git-tleman 1989). Although growth rate slows downwith pup age, the net amount of food and energyintake is probably much higher in post weaning

18 Y. Iliopoulos et al.

than in the weaning period, imposing a need forincreasing kill rates of livestock (Fritts et al.2003). Treves et al. (2002) found that reproduc-tive wolf packs, rather than lone wolves, causedmost damages on livestock in Wisconsin.

Attacks on cattle did not show a significantseasonal variability (see also Meriggi et al. 1991and Fico et al. 1993). Small sample size mayhave obscured any seasonal trend.

Role of husbandry methods and other factors

Most of the attacks did not result in a severeloss of livestock and were comparable to averagelosses described by Ciucci and Boitani (1998) inTuscany region where livestock production wasalso high. Serious damages happened in the ab-sence of a shepherd, usually after a portion ofthe flock had strayed or was attacked inside nonpredator-proof enclosures. Shepherds can inter-rupt wolf attacks in the approach, attack, killand eating phase (Linnell et al. 1996), althoughin our study area wolves were persistent killersof livestock even in the presence of humans dur-ing daytime. We suggest this is a result of low di-versity and density of wild ungulates that renderlivestock as the only abundant prey for wolves.Moreover, wolves are well adapted to kill over-abundant livestock having done so for centuriesin the humanized environment of southern Eu-rope. Harper et al. (2005) found that learningwas a prime factor that contributed to the in-crease of depredation events in Minnesota.

Sheep dogs generally appeared to reducelosses. Wolves may avoid areas with livestockguarding dogs, as dogs may disrupt depredatorysequences by wolves, enforcing indirect or directaggression (Coppinger and Coppinger 1995).When sheep dog number reached a critical level(“optimum” dog number) their protective rolewas gradually reduced. Large number of sheep-dogs may result in poor nutrition, lack of appro-priate training and development of unsuitablebehavioral traits, like killing of livestock. Train-ing, amongst several other factors, affects sheepdog performance (Coppinger et al. 1983, Hansenand Smith 1999).

Surplus killing of livestock inside enclosureswas rare but very destructive. High density of

livestock, lack of escape and ease of depredationinside enclosures stimulate the triggering of thispredatory behavior (Linnell et al. 1996). More-over, in four of these seven cases, guarding dogswere absent and were used to guard other por-tions of the flock in a different area. Thus, the ef-fectiveness of enclosures may be only enforced orfacilitated by the combined use of sheep dogs.

Larger sheep and goat farms experiencedmore attacks and total animal losses, as also re-ported by Vos (2000) in northern Portugal, Mechet al. (2000) in Minessota and Brandley et al.(2005) in Montana, concerning cattle farms.Larger flocks face higher encounter rates withwolves (Althoff and Gipson 1981), are more dis-persed (Robel et al. 1980) and serve as greaterattractants for wolves, because they containmore individuals at lower condition (Brandley et

al. 2005).The losses in livestock due to depredation

greatly increased with the number of wolves in-volved in the attack. Cooperative hunting bywolves may probably disrupt sheep dog coordi-nation and effectiveness of shepherd surveil-lance. Many shepherds described a commonhunting strategy of wolf packs, where one wolfdistracts the dogs and others scatter the flock.Moreover, larger number of wolves involved alsotranslates into higher energetic needs of the en-tire wolf pack.

Severity of livestock losses at a study area level

Levels of depredation and trophic depend-ence of wolves on livestock, observed in ourstudy area (Migli et al. 2005 and this study)were more severe compared to other areas. Forinstance, livestock losses in the province ofArezzo, Italy, were half the size of that recordedin our study, despite of larger area surveyed,comparable wolf density and high density oflivestock (Gazzola et al. 2008). However, in con-trast to our area, a rich community of wildungulates occurred in Arezzo. In Winsconsin,wolf predation, was negligible if compared tolosses recorded in this study, with only one thirdof wolf packs were involved in killing livestock(Treves 2002) while in our study area all wolfpacks were actually involved. Studies on wolf

Wolf depredation on livestock 19

predation in multi-prey ecosystems has shownthat wolves still prefer wild ungulates despitethe presence of livestock (Meriggi and Lovari1996, Capitani et al. 2004, Gazzola et al. 2005,Nowak et al. 2005, Gula 2008).

Management implications

Efforts to restore ungulate communities inwolf-livestock conflict areas in order to reduce wolfattacks to livestock in Europe have been encour-aged as a very important conservation measure(Meriggi and Lovari 1996, Linnell et al. 1996). Theenforcement of such a measure in Greece shouldbe carefully examined in areas used by livestockas domestic ungulate densities are locally stillhigh. Predation on domestic animals may remainrelatively high, if livestock is locally abundant,even in areas with high densities of wild prey pop-ulations, if protective methods are not effectivelyenforced (Patalano and Lovari 1993, Gazzola et al.2008). Enhancement of natural prey availabilityin selected suitable areas with relatively lesserlivestock densities may be more feasible and effec-tive and should be combined with intensificationof husbandry methods.

Surveillance of livestock is probably the mosteffective way of protecting livestock against wolfattacks. Although this husbandry method is stillwidely used in Greece and southern Europe, itbecomes less and less attractive for youngerfarmers especially in areas recently re-occupiedby wolves in the periphery of wolf distribution(Y. Iliopoulos, unpubl.). This leads to numeroussocially unacceptable severe attack events, jeop-ardizing any other management tool to mitigatewolf-livestock conflicts.

Maintenance of an “optimum” number of welltrained guarding dogs adapted to flock size, in-stead of keeping a large uncontrolled number ofdogs, may result in more effective protection oflivestock and avoidance of unnecessary costs.Use of traditional guarding dog breeds should beencouraged, due to their long history of use, evenfor centuries (Linnell et al. 1996). In Greece,such a breed is the Greek sheepdog Ellinikos

poimenikos, however it is not commonly used byfarmers, as pure descendants of the breed arevery rare (Drivas 1996).

Intensification of husbandry methods shouldfocus particularly during the wolves’ post-wean-ing period (August–October) when the rate andseverity of attacks is higher and at goat farmsthat have a higher probability to be attacked bywolves.

Due to their large body size and lower vulner-ability to wolf depredation cattle have been pro-posed as an alternative for sheep and goatfarming to reduce net number of carnivore at-tacks on livestock (Linnell et al. 1996). We do notrecommend the use of cattle instead of sheepand goats to reduce overall livestock losses, un-less serious improvements in husbandry, birthsynchronization and herding techniques havealso been enforced. Confinement of calves youn-ger than 6 months of age during night could sig-nificantly reduce losses to this age class andincrease the effectiveness of sheepdogs but re-quires substantial effort by farmers.

Although large farms experienced the high-est losses due to depredation, the small farmsshould be prioritized in conservation and man-agement projects, because the economic loss percapita is proportionally higher there, whichgreatly influences the social acceptability ofwolves. Use of predator-proof enclosures com-bined with use of guarding dogs, should be morewidely implemented.

Aknowledgements: This study was part of the LIFE project“Lycos”, NAT97-GR04249, considering wolf conservation inGreece. Study was funded from the EC-DG Env directorate(50%) and Arcturos NGO (50%), former affiliation of Y.I, V.K. and D. S. authors. We greatly thank, Ir. Hatzimichael, P.Menounos, P. Pavlides, S. Tzortzakis, N. Kanellopoulos, G.Giannatos, D. Vassilakis, for contribution on fieldwork, I.Aravidis for helping with GIS work and Dr. Y. Mertzanisfor linguistic help on the manuscript. We also greatly thankDr J. D. C. Linnell for his helpful comments, professors S.Lovari, A. Meriggi, two anonymous referees and especiallyDr K. Schmidt for thoroughly reviewing an earlier draft ofthis manuscript.

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Received 18 March 2008, accepted 18 September 2008.

Associate editor was Krzysztof Schmidt.

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Appendix 1. Landscape features and their given numerical values per class used in analysis of factors as-sociated with wolf depredation on livestock in Greece.

Landscape feature Description Rank classes

Visibility according to main vegetation species and form V0 > V1 > V2

Open pasture or alpine areas High visibility V0

Beech and oak forests in winter Medium visibility forest V1

Beech and oak forests in summer Low visibility forest V2

Fir forest Low visibility forest V2

Black pine forest Low visibility forest V2

Quercus coccifera shrublands Medium visibility forest V1

Quercus coccifera woodlands Low visibility forest V2

Vegetation coverPartially forested 0–40% forest coverage C1

Forested 41–60% forest coverage C2

Dense forested >60% forest coverage C3

TopographyHilly terrain-forest plateau T1

Rugged terrain – steep slopes T2

Gorge-stream T3