Mountain lion depredation in southern Brazil
Transcrição
Mountain lion depredation in southern Brazil
Biological Conservation 105 (2002) 43–51 www.elsevier.com/locate/biocon Mountain lion depredation in southern Brazil Marcelo Mazzollia,*, Mauricio E. Graipelb, Nigel Dunstonec a Projeto Puma, R. J. Pio Duarte Silva, 535 Horto Florestal, 88037-000, Florianópolis-SC, Brazil Departmento de Ecologia e Zoologia-CCB, Universidade Federal de Santa Catarina-UFSC, 8804- 900, Florianópolis-SC, Brazil c Department of Biological Sciences, University of Durham, South Road, Durham City, DH1 3LE, UK b Received 6 July 2000; received in revised form 5 July 2001; accepted 27 July 2001 Abstract Mountain lion (Puma concolor) depredation incidents on livestock herds were recorded at 15 ranches in southern Brazil from 1993 to 1995. Maximum losses to mountain lions were 78% for goats, 84% for sheep, and 16% for cattle. Cattle mortality arising from causes other than depredation assumed a greater importance in herd productivity. In contrast, attacks on sheep and goats were more frequent than losses to other causes, but could be reduced to acceptable levels when flocks were corralled at night. Most depredation incidents occurred when weather and light conditions were unfavorable to human activity. We explain these patterns and inter-ranch variation in depredation rates on the basis of a risk-avoidance strategy by the mountain lions. Stock losses can be minimized by understanding these patterns and by applying appropriate herd husbandry, thus reducing the urge to persecute this protected species. # 2002 Elsevier Science Ltd. All rights reserved. Keywords: Mountain lion; Livestock depredation; Puma concolor 1. Introduction Globally, large felid predators face three major threats: a diminishing prey base, direct persecution by man, and habitat modification and fragmentation (Nowell and Jackson, 1996). These three factors are likely to operate together since they are predominantly products of anthropogenic disturbance. The predominance of any one factor over the other will vary according to local culture, economy, and land tenure system. In areas where ranching predominates predators may suffer more from direct persecution following attacks on livestock. Livestock loss is the greatest source of conflict between humans and large cats, and the major cause underlying their disappearance from considerable areas of their former range [e.g. tiger Panthera tigris from most of China; lion Panthera leo from north Africa and southwest Asia; and the mountain lion or puma Puma concolor from most of eastern North America (Nowell and Jackson, 1996)]. Weaver et al. (1996) estimated from several studies that the greater proportion (75%) * Corresponding author. E-mail address: [email protected] (M. Mazzolli). of adult mountain lion mortality resulted from conflict with humans. In Brazil the mountain lion is currently considered endangered (Bernardes et al., 1990), although it cannot be considered so under IUCN criteria (IUCN, 1994; Nowell and Jackson, 1996). The global range of the mountain lion is estimated to be 17,120,00 km2 (Nowell and Jackson, 1996). Hence, Brazil,with a land area of 8,547,403 km2, could host half the global population (Mazzolli, 2000). Although there is currently no indication that mountain lion populations are declining in Brazil their lethal removal by hunting or other means is prohibited by law. Although its threatened status is controversial this does not imply that mountain lions should not be protected as they have, for example, restricted their range mainly to mountainous areas in southern Brazil (Ihering, 1892; Mazzolli, 1993). While the current high rate of deforestation occurring in the lowland rainforests of the Amazon Basin of northern Brazil is a cause for concern (Collins, 1990; Reading et al., 1995), and may eventually lead to widespread fragmentation, the Moist Ombrofilous (Atlantic forest; GAPLAN, 1986; IBGE, 1992) and Mixed Ombrofilous (Araucaria angustifolia pine forest, hereafter Araucaria forest) forests of eastern and southern Brazil, respectively, are already fragmented 0006-3207/02/$ - see front matter # 2002 Elsevier Science Ltd. All rights reserved. PII: S0006-3207(01)00178-1 44 M. Mazzolli et al. / Biological Conservation 105 (2002) 43–51 to a large extent. About 5–12% of the Atlantic Forest remains (Brown and Brown, 1992), and of the Araucaria forest only 3% was left in 1978, of which 0.6% was primary forest (IBDF/FUPEF, 1978). Deforestation continues with 11% of the remaining Atlantic Forest areas destroyed between 1985 and 1990 (SOS Mata Atlântica and INPE, 1993). In southern Brazil, livestock husbandry is commonly practiced on a small scale with mixed species herds of cattle, goats, sheep and swine. Farming of livestock and the fodder crops (e.g. corn Zea mays) grown to supplement livestock diet have fragmented forests considerably. The consequences of forest fragmentation include the decline of prey refugia and increased conflict between wildlife and humans, particularly near habitat edges where wild ungulates such as deer (e.g. Mazama spp.) and rodents such as capybara (Hydrochaeris hydrochaeris) are attracted to crops and from where they are easily poached. Chiarello (1999) found that small, isolated reserves in south-eastern Brazil lacked both large predators and their prey base (e.g. agoutis Dasyprocta leporina, pacas Agouti paca, peccaries Tayassu tajacu and T. pecari, and deer). Under these circumstances, poaching of wildlife has been shown to exacerbate the effects of forest fragmentation with direct effects on population genetic structure and demography (Glanz, 1991; Robinson, 1996; Turner and Corlett, 1996; Cullen et al., 2000). In all cases, the degree to which predator and prey are affected will depend not only on the type of disturbance but also on how it is implemented and whether procedures are adopted to reduce crop damage and livestock depredation. Despite the fact that depredation incidents have been widely reported and documented for mountain lions (e.g. in Chile: Yáñez et al., 1986; Iriarte et al., 1991; in: Arizona, Cunningham et al., 1995), little is known of the factors affecting depredation success under these circumstances. Also within the context of predatorhuman interaction, few studies have dealt with the issue of large felids living entirely within productive agricultural and ranching systems (e.g. Schaller and Crawshaw, 1980; Van Dyke et al., 1986; Mazzolli, 2000), and it is still unclear whether long term habitat suitability for large carnivores can be maintained in such areas even with the incorporation of alternative regimes of forest management and land use. The consideration of this issue is crucial to determine which development models can be recommended and implemented in the vicinity of suitable large carnivore habitat. The present study aims to contribute to the understanding of such predator–livestock and predator– human interactions by attempting to establish the relationship between livestock losses and husbandry methods in southern Brazil; to identify some of the factors that limit or encourage livestock attacks; to identify local constraints to the instigation of mitigating procedures; and to compare the extent of mountain lion depredation with losses due to other causes. Such information on predator–livestock interactions should ultimately help to prevent or diminish livestock losses and hence persecution of large felids. This information is especially important in areas where these predators are found at low density and where there is interest in protecting their populations and avoiding conflict with ranching enterprises. 2. Study area The study area is located in the coastal mountains of southern Brazil, from approximately 49 W to 51 W and from 26 500 S to 28 500 S (Fig. 1), and comprises two areas, distinguished by vegetation and landscape features. The southern area is located near the Serra Geral which in southern Brazil is characterized by a series of plateaus rifted by steep cliffs, with the easternmost slopes covered with Atlantic forest up to 700 m, and cloud forest from 700 to 1600 m (Falkenberg and Voltolini, 1995). Extensive steppe (‘‘campos de altitude’’) cover the plateaus above and westward of the cliffs, where, as a consequence of anthropogenic fires set to expand livestock grazing areas, most Araucaria forest has given way to the steppe with scattered fragments of cloud forest and/or other shrub associations (Safford, 1999). The northern part of the study area consists of a mountain range with climate, geomorphology, and phytophysiognomy characteristic of the ‘‘Serra do Mar’’, a mountain chain that harbors much of the remaining Atlantic forest in southern and southeastern Brazil. There is a predominance of Atlantic Forest and mountainous terrain with valleys, which are not so abruptly cut as the canyons in the southern area. At higher altitudes small patches of steppe and Araucaria forest also occur. 3. Methods Livestock depredation surveys were conducted from 1993 to 1995, and earlier information regarding mountain lion poaching incidents are included where available. Poaching records were based on analysis of mountain lion skulls and pelts (n=25) from animals killed whilst attacking livestock. In some cases, records are derived from information gathered during interviews (n=5). In order to determine the sex ratio of these mountain lions their skulls were collected, compared, and classified according to strong dimorphic features (Mazzolli, 1992). Individuals were classified as adult, subadult or young according to cementation of fissures M. Mazzolli et al. / Biological Conservation 105 (2002) 43–51 45 Fig. 1. The study areas are represented by county limits: Lages (Cochilha Rica-Rincão do Perigo, Bocaina do Sul-Mineiros, Capão Alto-Sto Cristo, Capão Alto/Capão Verde), Rancho Queimado (Alto da Boa Vista), Dr. Pedrinho (Bom Sucesso and Rio do Cedro), Bom Retiro (Campo dos Padres) and Itaiópolis (Toldo). Grey areas represent primary remnant vegetation above 800 m. Numbers indicate mountain lion locations from Mazzolli (1993): 1, Praia Grande (Pedras Brancas); 2, Meleiro (foothill zone of Serra Geral); 3, São Joaquim (River São Mateus/Chapada Bonita/ Colégio); 4, Urupema (Morro do Capote); 5, Urubici (River Baiano); 6, Bom Retiro (Paraı́so da Serra); 7, Alfredo Wagner (Caeté); 8, Anitápolis (Maracujá); 9, São Bonifácio (Neeketer ranch); 10, Antônio Carlos (Santa Maria/Faxinal); 11, Blumenau (Source of the Garcia River); 12, Brusque (Limeira Alta); 13, Rio dos Cedros (Alto Palmeiras); 14, Rio Negrinho; 15, Joinville (D.Francisca Road/Waterfall 1 of River Cubatão); 16, Campo Alegre; 17, Garuva (plains and foothill zone of Serra do Mar); 18, Itapoá (plains of Bom Futuro and Barra do Saı́-Mirim); 19, Rio do Campo (Azul River); 20, Curitibanos (das Pedras River); 21, Agua Doce; 22, Ponte Serrada (between rivers Chapecó and Chapecozinho). and skull size (Mazzolli, 1992). We only attributed kills to mountain lion depredation in those cases where the rancher or one of the authors had inspected the carcass(es) and its location. Some could not be inspected owing to difficult terrain and were included in losses attributed to other causes. Several neighboring ranches were also surveyed to allow consistency of depredation incidents to be checked. This allowed us to evaluate whether a depredation incident on one ranch was supported by others occurring on neighboring properties. Since we did not wish to rely on anecdotal accounts, we also looked for evidence of recent kills (carcasses), and skins and skulls of killed mountain lions kept as trophies. No other major predator, e.g. jaguar (Panthera onca), inhabited the study area, which might otherwise have increased the possibility of predator misidentification. We compared depredation losses of sheep between managed herds (i.e. confined within a corral during the night) and free-ranging herds. We also compared the mortality arising from depredation with that attributable to other causes, which may include theft, disease, and falls from cliffs, in all herds on an annual basis. We compared losses between mortality factors and between managed and non-managed sheep herds by summing the values for each factor across ranches (i.e. number of ranches involved and the value for each factor on each ranch). We also compared the average loss per ranch by applying a Mann–Whitney U test. In the latter comparison, only those cases where mortality occurred were included unless otherwise mentioned. Means were compared as percentages to allow comparison of data from ranches with different herd sizes at the same scale, i.e. larger herd sizes will tend to have higher losses. Livestock units were standardized by converting livestock head units to US Dollars/head to avoid underestimating cattle losses. Because there were insufficient data available on age class composition of herds, we assumed, for calculation purposes, that all animals within a particular herd belonged to the same weight or price class. The following cost/head estimates which were based on local market value were applied: cattle $210, goat $50, sheep $50, swine $60. 4. Results Fourteen of the 15 ranches surveyed within mountain lion range were located at altitudes above 800 m, one at 46 M. Mazzolli et al. / Biological Conservation 105 (2002) 43–51 650 m. The average size of ranches was 840 ha, ranging from 40 to 2500 ha (see Table 1). These were categorized into three size classes: small (five ranches from 40 to 100 ha in extent); medium (four ranches, 150–400 ha) and large (six ranches, 500–2500 ha). Twelve of these ranches reared cattle, 12 reared sheep, six reared goat and seven reared swine. Most livestock births occurred during spring to protect newborn livestock from winter stress, when temperatures may drop to 10 C. Of 37 recorded depredation incidents, 15 occurred in winter (June–September), 11 in spring (September– December), nine in autumn (March–June), and two in summer (December–March). Most attacks (92%) were recorded at night. For those incidents when weather conditions were recorded (n=13), 62% were in rainy weather (including drizzle) associated or not with fog, 31% in good weather, and 7% under fog. In addition, there were several alleged incidents of mountain lion attacks during foggy conditions only, some of which were not verified. Table 1 Details of ranches visited during the study, including number of head of livestock at each rancha Ranch name Area (ha) Year Livestock Total Losses lions Losses other Managementa Obs. date Cabanha Sto. Cristo Boa Vista Cerro Azul Do Aleixo Judas Tadeu Mineiros Palmeira Velha Cabanha Sto. Cristo São Domingo Saulo Yung Sı́tio São Pedro Sta. Cruz Judas Tadeu Sı́tio Ruck Sı́tio São Pedro Estância S.F. Rio Perdido Saulo Yung Judas Tadeu Boa Vista Mineiros Judas Tadeu Sı́tio Ruck Dona Olindina Judas Tadeu Do Aleixo Judas Tadeu Mineiros Palmeira Velha Potreiro Velho Cabanha Sto. Cristo São Domingo Sta. Cruz Sta. Cruz Judas Tadeu Cabanha Sto. Cristo Saulo Yung Sı́tio Ruck Sı́tio São Pedro Boa Vista Do Aleixo Judas Tadeu Mineiros Potreiro Velho São Domingo Judas Tadeu Sı́tio Ruck 2000 500 400 70 2500 150 350 2000 70 2500 100 522 2500 40 100 400 2500 2500 500 150 2500 40 2500 2500 70 2500 150 350 50 2000 70 522 522 2500 2000 2500 40 100 500 70 2500 150 50 70 2500 40 1995 1994 1994 1994 1994 1994 1994 1994 1994 91-94 1994 1994 1995 1995 1995 1993 1991 1993 1994 1994 1995 1995 1992 1992 1994 1994 1994 1994 1994 1994 1994 1994 1994 1995 1995 1991 1995 1995 1994 1994 1994 1994 1994 1994 1995 1995 Cattle Cattle Cattle Cattle Cattle Cattle Cattle Cattle Cattle Cattle Cattle Cattle Cattle Cattle Cattle Goat Goat Goat Goat Goat Goat Goat Sheep Sheep Sheep Sheep Sheep Sheep Sheep Sheep Sheep Sheep Sheep Sheep Sheep Sheep Sheep Sheep Swine Swine Swine Swine Swine Swine Swine Swine 1000 400 19 25 600 80 70 1000 25 840 86 150 600 32 86 80 14 28 11 28 14 62 25 25 17 25 12 120 34 42 9 65 65 25 60 20 6 14 8 6 35 18 9 7 35 39 1 0 3 0 0 2 0 2 0 1 0 0 0 0 0 28 7 4 1 22 0 22 0 13 1 8 8 45 1 12 1 1 18 0 0 6 0 2 0 0 3 0 1 0 1 0 22 8 4 0 4 6 1 12 0 20 11 10 3 8 3 0 0 0 0 0 2 2 0 0 7 0 0 2 1 0 0 0 0 0 5 0 0 0 1 0 0 4 0 1 0 0 no no no no no no no no no no no no no no no no no no no no no no yes no no no no no yes no no no no no no no yes yes no no no no yes no no no Aug 95 Apr 95 Apr 95 Nov 94 Apr 95 Nov 94 Nov 94 Aug 95 Nov 94 – Aug 95 Nov 94 Apr 95 Apr 95 Aug 95 Apr 95 – Apr 95 Apr 95 Nov 94 Apr 95 Apr 95 Jan 93 Apr 95 Nov 94 Apr 95 Nov 94 Nov 94 Aug 95 Aug 95 Nov 94 Nov 94 Nov 94 Apr 95 Aug 95 – Apr 95 Aug 95 Apr 95 Nov 94 Apr 95 Nov 94 Aug 95 Nov 94 Apr 95 Apr 95 a The management column indicates whether the livestock were corralled at night or not. 47 M. Mazzolli et al. / Biological Conservation 105 (2002) 43–51 Table 2 Records of mountain lions killed at ranches from 1988 to 1995 #Colec. Procedence Sex Age Record UFSC-0320 UFSC-0381 UFSC-0351 UFSC-s/n FURB-s/n UFSC-0352 UFSC-0605 UFSC-0333 UFSC-0397 UFSC-0396 UFSC-0373 None None UFSC-0344 UFSC-0387 UFSC-0559 M.M. FURB-s/n UFSC-0318 UFSC-0557 UFSC-0319 UFSC-0606 UFSC-0745 UFSC-0323 None None None A. Palmeiras-Rio dos Cedros-SC D. Francisca-Joinville-SC Urupema-SC Curitibanos-SC A. Palmeiras-Rio dos Cedros-SC Alto Palmeiras-Rio dos Cedros-SC Tainhas-Cambará do Sul-RS Ponte Serrada-SC Jaquirana-RS Alfredo Wagner-SC Bom Jesus-RS Rincão do Perigo-Lages-SC Rincão do Perigo-Lages-SC Bom Jesus-RS Urubici-SC Joinville-SC Alfredo Wagner-SC A. Palmeiras-Rio dos Cedros-SC A. Palmeiras-Rio dos Cedros-SC Alfredo Wagner-SC Siderópolis-SC São Joaquim-SC Rancho Queimado-SC A. Palmeiras-Rio dos Cedros-SC Afredo Wagner-SC Dr. Pedrinho-SC Bocaina do Sul-SC Female Female Female Female Female Female Female Female Female Female Female Female Female Male Male Male Male Male Male Male Male Male Male Unknown Male Unknown Male Adult Adult Adult Adult Adult Subadult Subadult Subadult Subadult or adult Subadult or adult Subadult or adult Unknown Unkonwn Adult Adult Adult Adult Adult Subadult Subadult Subadult Subadult Subadult Young Young Young Unknown Skull Skull Skull Skull and skin Skull Skull Skull Skin Skin Skin Skin Interview Interview Skull and skin Skull and skin Skull Skull Skull Skull Skull Skull Skull and skin Skull Skull Interview Interview Interview Mountain lions killed by ranchers were categorized by age and sex whenever possible. Adults were from 3 to 5 years old, and all young were killed when in attendance with the mother at sheep and goat kills (Table 2). The sex ratio of adults and sub-adults was 1.2 M:1 F, comprising five adult males, five adult females, five subadult males, three sub-adult females, and three young (< 1 year old). 4.1. Cattle Attacks on cattle occurred in only four out of 12 ranches with cattle herds, although mountain lions were present and actively depredating other herd types in ten of these ranches. Cattle herds were not put into corrals at night. Three of the four ranches with cattle depredation had losses ranging from 0.1 to 2.5% of their herd value, and also had depredation of other livestock types; the other ranch, which experienced a 16% loss, did not maintain other types of livestock, and had the smallest cattle herd size of all ranches, suggesting a relationship between these variables and the higher mountain lion attack rate. As a result of a generally low loss per ranch and low number of cattle ranches affected, it can be seen from Fig. 2 that depredation represented only 0.27% (US$ 1,890) of the summed value of all cattle herds from all ranches (US$ 699,670). In contrast, cattle losses to other causes occurred on 10 ranches, and were 12 times greater than those to depredation, representing 3.37% (US$ 23,520) of the total value of all cattle herds. The difference in financial loss between the two mortality factors is mainly a consequence of the larger number of ranches with losses to other causes, which sum to a higher value. Nonetheless, on an individual basis, ranches that have suffered attacks generally lost less to mountain lions than to other causes, as percentages of their stock (Mann–Whitney U=10, df=12, P=0.16). 4.2. Sheep Sheep were attacked at 10 of the 12 ranches with flocks, accounting for 32% (US$ 5,900) of the summed value of all flocks from all ranches (US$ 18,600) (see Fig. 2). Four ranches managed their sheep herds, corralling them at night. Of these, only two suffered losses to depredation, which amounted to 3 and 14% of their value. All eight ranches that left sheep to graze extensively had depredation losses. From these, seven had losses to mountain lions ranging from 24 to 84% of their flock value (mean=43,%, S.D.=23). The remaining ranch, which suffered a 6% depredation loss, was the only one with losses within the same range of values reported for managed flocks. A large difference was found in depredation between managed and non-managed ranches where losses 48 M. Mazzolli et al. / Biological Conservation 105 (2002) 43–51 occurred (Mann–Whitney U=15, df=10, P=0.07). This difference is even larger when managed ranches with no losses to depredation are included in the analysis (Mann–Whitney U=31, df=12, P=0.01). Mountain lions often killed several free-ranging sheep and/or goats in a single attack, but would take only a single animal from a corral. We witnessed two cases of massive depredation on free-ranging flocks, with 25 goats and sheep killed in the southern area and 12 sheep near the northern area, within a 2-week period. Among the managed sheep flocks, the highest loss (14%) was sustained where sheep were penned farthest from the main house (about ca. 60 m) and very near a deep and forested canyon (about ca. 40 m). One ranch, which recorded no sheep losses, sustained high goat losses, which probably reduced attacks on the small sheep flock. These ranches also had dogs near the house, which might have helped to reduce depredation. Only four of the 12 ranches with sheep sustained losses to other causes, less than half the number of ranches affected by depredation, accounting for 4% (US$ 744) of the summed value of all sheep flocks from all ranches (US$ 18,600) (see Fig. 2). In three of the four cases, losses to other causes were < 10% per ranch, although the other ranch recorded 41% losses. The economic impact of mountain lion depredation on sheep farming is mostly due to the higher number of ranches suffering attacks, although the average losses to mountain lions were, in most cases, higher than to other causes (Mann– Whitney U=29.5, df=14, P=0.18). Differences between mortality factors are even larger when only those depredation cases at non-managed ranches are included in the analysis (Mann–Whitney U=25, df=10, P=0.126). 4.3. Goat All six goat flocks were free-ranging and sustained depredation, ranging from 9 to 78% of their value. Fig. 2. Livestock losses to mountain lions (in% of US$) from all studied ranches (n=number of sampled ranches) to mountain lions compared to losses due to other factors. Depredation losses from combined flocks was 38% (US$ 4332) of the summed value of all goat flocks from all ranches (US$ 11,150), while that attributable to other causes accounted for < 2% (US$ 205) of this value (see Fig. 2). Two of the goat ranches had losses to other causes (3 and 7% of the herd), this was lower than that caused by depredation (range 9–78%, mean=37, S.D.=25). 4.4. Swine Seven ranches raised swine, the total value of the herd amounted to US$ 7,320. Two ranches reported losses to mountain lions (11% loss each) amounted to only US$ 300. Losses of swine to other causes were reported on three ranches, ranging from 13 to 22% (US$360) (see Fig. 2). Some of the losses attributed to other causes may have been in fact a product of depredation. 5. Discussion 5.1. Livestock depredation Free-ranging flocks of goats and sheep suffered more losses to mountain lions than to causes other than depredation. However, those ranches that corralled flocks at night were able to maintain a productive stock, providing evidence that with relatively little management effort small ranching enterprises are able to coexist with mountain lions. Whereas all free-ranging sheep and goat flocks sustained depredation losses, managed flocks may avoid losses. There is evidence that differences found in predation rates on managed and non-managed sheep flocks are related to risk-aversion by the mountain lion. Depredation rates were influenced by environmental factors, which reduced visibility of prey and human activity. Mountain lion predation was modified by the proximity of human habitation and fencing in two ways. First, attacks did not occur on successive nights as was frequently the case with free-ranging flocks; and when mountain lions did enter a corral, the damage inflicted, commonly killing only one or two sheep, was lower than in the case of a single attack on free-ranging flocks. Other evidence of stress is found by the way mountain lions handled livestock kills. The wild prey of mountain lions is usually dragged away after a kill, and covered with leaves following feeding (Hornocker, 1970). However, when mountain lions killed many free-ranging sheep or goats during a single attack they left most of them uncovered where they fell. Within a corral, mountain lions were reported dragging sheep up to the fence and attempting to jump over. Where fencing was sufficiently high to prevent jumping, mountain lions ate the prey in the corral. On one occasion a mountain lions M. Mazzolli et al. / Biological Conservation 105 (2002) 43–51 was observed vomiting following such a meal presumably as a result of feeding under stress (Mazzolli, pers. obs.). Cattle herds suffered more losses to diseases, falls from cliffs, and theft, than to depredation. Similarly low levels of cattle depredation (0.4, 0.15 and 1.5%) by jaguar and mountain lions were also estimated at three ranches in Venezuela by Hoogesteijn et al. (1992). Cattle ranchers would benefit by adopting strategies to minimize such losses, including fencing, adequate drug administration, and herd security, than by attempting to eliminate mountain lions. Additional methods that could be adopted to deter predators include the use of guard dogs (Andelt, 1999; Hansen and Smith, 1999), and aversion conditioning, such as electric fences and use of nauseating substances (Gustavson et al., 1976; Andelt et al., 1999; Huygens and Hayashi 1999; Ternent and Garshelis, 1999). It is possible that some unknown number of cases of cattle falling from cliffs could be an indirect result of mountain lion attack. Typically, fencing was inadequate, and pastures frequently included forested patches that provided suitable places of concealment for predators. Adequate fencing would prevent cattle from approaching large forested patches and very steep slopes where large prey is known to be more vulnerable to predators (e.g. Hornocker, 1970; Schaller 1972; Courtin et al., 1980, Deutsch and Weeks, 1992; Hoogesteijn et al., 1992; Cunningham et al., 1995). Only one cattle herd scored a high depredation loss (16%), and possible explanations are speculative in this case. This ranch had the smallest cattle herd among ranches and the only one that lacked more vulnerable alternative livestock such as goats and sheep. The size of the herd (e.g. Schell, 1993), learning by young mountain lions prior to independence (Leyhausen, 1979; Rabinowitz, 1986; Quigley and Crawshaw, 1992), and injuries (Rabinowitz, 1986) are all reasons that may lead a felid to depredate a herd intensively. Size and sex of the mountain lion also may play its role; for example, male mountain lions which are considerably larger than females (Anderson, 1983; Mazzolli, 1992; Gay and Best, 1995), have been found to take larger wild prey (Jalkotzy et al., 1992), and are more commonly involved in cattle predation than females (Cunningham et al., 1995). 5.2. Local issues concerning depredation incidents Meetings were held with a local ranching association in the southern zone of our study area to discuss solutions to the widespread loss of sheep. The government has subsidised sheep and goat ranching since 1990, although no consideration of the predation by mountain lions had been made. This resulted in a fast growth of the number of free-ranging herds, which was then followed by an increase in mountain lion depredation 49 incidents. Depredation may also have increased indirectly as a result of the rigorous enforcement of environmental laws, which might have lead to increased mountain lion populations. Although illegal, ranchers still kill mountain lions following livestock depredation incidents. They also alleged that attacks had recently become more intense and they believed (incorrectly) that the environmental agency [IBAMA (Instituto Brasileiro de Meio Ambiente)] had released mountain lions in the area, and was therefore to blame for predator attacks. We observed three main reactions from the sheep and goat ranchers who sustained the highest levels of losses: abandonment of ranching of their most vulnerable stock (sheep/goat/ pigs), but retaining cattle; attempting to eliminate the predators or confining stock to a corral at night. The latter was the least frequently implemented option although this had been advocated as early as 1820 (Saint-Hillaire, 1978). There seems to be a reluctance to adopt alternative husbandry strategies, as has been reported in other investigations of felid depredation incidents (Oli et al., 1994; Weber and Rabinowitz, 1996). The reluctance to adopt appropriate stock management techniques may be reduced by appointing a local environmental officer to implement and supervise changes in herd management on some ranches and possibly,by subsidising the cost of fencing, as a way to stimulate the changes. Such methods are commonly used in Brazil to increase crop and meat production. In conclusion, our investigation suggests that the predation strategy of the mountain lion when hunting domestic livestock in southern Brazil is predominantly cautionary. Preference is shown for attacking free-ranging flocks of goats and sheep and with only occasional incidents occurring near households. In addition, predation on livestock is influenced by weather condition, time of day, physical (declivity) and biotic (forest cover) characteristics of the terrain, and the predator’s physical condition. By attacking at night under conditions of low visibility (rain and fog) mountain lions not only avoid instant retaliation from ranchers, but their prey are also less likely to recognise predation risk (Vasquez, 1994), thereby minimizing any prey reaction or struggle that may result in injury to the predator. Ranchers and wildlife managers should use this knowledge and avoid leaving domestic stock in conditions favorable to attacks, thus minimizing livestock losses, and persecution of mountain lions. Acknowledgements We like to thank the staff of the Department of Ecosystems at IBAMA-Santa Catarina, especially to biologists Américo Ribeiro Tunes and Marlise Becker for their continuous support. IBAMA partially funded the 50 M. Mazzolli et al. / Biological Conservation 105 (2002) 43–51 trips to check incidents, and on several occasions made vehicles available for field trips. Ana Cimardi has given unconditional support to the surveys, and some of the early field trips were only possible due to FATMA funding obtained with her help. Ivo Ghizoni Junior (Paraná) helped by participating on several of the most recent expeditions, while Marcos Da-Ré participated in the early stages. Thanks also to Kristin Nowell and Peter Jackson of the IUCN Cat Specialist Group for recognizing Projeto Puma as a valuable initiative, and their willingness to provide help. Appreciation is also due to The UK CommonWealth Office and the British Council which provided a MSc scholarship to Marcelo Mazzolli. References Andelt, W.F., 1999. Relative effectiveness of guardian-dog breeds to deter predation on domestic sheep in Colorado. Wildlife Society Bulletin 27, 706–714. Andelt, W.F., Philips, R.L., Gruver, K.S., Gutrie, J.W., 1999. 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