Managing wildlife to conserve amazonian forests: Population biology and economic considerations of game hunting

Biological Conservation 67 (1994) 29-35

M A N A G I N G WILDLIFE TO CONSERVE A M A Z O N I A N FORESTS: POPULATION BIOLOGY A N D ECONOMIC CONSIDERATIONS OF GAME H U N T I N G Richard E. Bodmer* Departamento de Zoologia, Museu Paraense Emilio Goeldi, CP 399, Bel~m 66.040 Pa, Brazil

Tula G. Fang Facultad de Biologia, UniversidadNacional de la Amazonia Peruana, Plaza Serafin Filomeno, lquitos, Peru

Luis Moya I Direcci6n Regional de Recursos Naturales y Medio Ambiente, Casilla 621, Iquitos, Peru

&

Robin Gill Wildlife and Conservation Research Branch, Forestry Commission, Alice Holt Lodge, Wrecclesham, Surrey, UK, GUIO 4LH (Received 1 July 1992; revised version received 15 February 1993; accepted 4 March 1993)

Abstract Rural inhabitants in Amazonia can overexploit many mammalian species by game hunting, and tropical forests lose their value as a source of game meat when mammal populations decline. Implementing a sustainable hunt should reduce overexploitation of animals, and therefore help retain the value of intact Amazonian ecosystems. Rural folk in the Tahuayo region of the Reserva Comunal Tamshiyacu--Tahuayo of northeastern Peru appear to be overharvesting primates and lowland tapir Tapirus terrestris, but are apparently not overexploiting artiodactyls and large rodents. Converting the current overhunting in Tahuayo to a more sustainable harvest would require cessation of hunting of overexploited species and the setting of artiodactyl and large rodent harvests at or below current levels. Costs of implementing a more sustainable hunt in Tahuayo would incur a 26% reduction of economic benefits for hunters and reduce the extraction of mammalian biomass by 35%.

INTRODUCTION

Local inhabitants of Amazonia value intact forests for the market and consumption benefits obtained from hunting (Redford & Robinson, 1987) and from extraction of non-timber plant products (Vasquez & Gentry, 1989). However, rural households can clearly overexploit some species (Bodmer et al., 1990b), and deforestation often occurs when inhabitants no longer gain sufficient economic benefits from game and non-timber plant products (Browder, 1992). The sustainable use of animals and plants should halt the progression towards overexploitation and therefore help to retain the value of intact Amazonian ecosystems (Ehrlich & Wilson, 1991). However, local inhabitants will incur short-term economic costs if sustainable harvests are implemented through resource management. These costs might be alleviated either by subsidizing social services or by developing alternative economic activities. In this paper we present studies on game hunting in the lowland Amazonian forests of the Reserva Comunal Tamshiyacu-Tahuayo situated in northeastern Peru (Fig. 1). We calculated costs of converting an overhunted forest to a more sustainably used one, and developed a management model that considers population biology of game with economic cost/benefit analysis, and income distribution from game hunting. The local inhabitants of the Reserva Comunal Tamshiyacu--Tahuayo practise hunting, fishing, shifting agriculture, and gathering of non-timber plant

Keywords: Loreto Peru, game hunting, sustainable uses, mammals, economics.

* Present address for correspondence: Tropical Conservation and Development Program, Center for Latin American Studies, University of Florida, 319 Grinter Hall, Gainesville, Florida, 32611 USA Biological Conservation 0006-3207/93/$06.00 © 1993 Elsevier Science Publishers Ltd, England. Printed in Great Britain 29

30

R. E. Bodmer, T. G. Fang, L. Moya I. R. Gill

°Ta

xlO

!m, 25

Fig. 1. Location of the Tahuayo and Yavari Miri study sites. products. The management programmes in the reserve intend to conserve Amazonian forests by working with, not against, the local economic and social environment. METHODS The biology and harvest of mammals were researched in two study sites within the reserve, one the Tahuayo region, which experiences persistent hunting pressure, and the other the Yavari Miri region, with slight hunting pressure. The reserve is located between the Tamshiyacu, Tahuayo and Yavari Miri rivers and is predominantly non-flooded forest (over 75%) (Bodmer et al., 1988a). It was formed by the communities of the Tamshiyacu and Tahuayo rivers, the Proyecto Peruano de Primatologia 'Manuel Moro Sommo', and the Ministerio de Agricultura in Iquitos, Peru (legislated in June 1991;' Resoluci6n Ejecutiva Regional No. 080-91CR-GRA-P) (Bodmer et al., 1990c). The reserve covers an area of 322 500 ha, has no permanent settlements, and is divided into two zones: (1) a fully protected core area; and (2) a buffer zone of subsistence use. A zone of permanent settlements along the Tamshiyacu and Tahuayo rivers is adjacent to the reserve, comprising 30 villages with about 4229 people. This area was not officially incorporated into the reserve to avoid conflict over land-use practices, but is a vital part of the management programmes. The Tahuayo study site was located in both the buffer and permanent settlement zones, and there were 34 extended families (family units) who collected wildlife

products in this area. In contrast, the Yavari Miri site had approximately eight family units collecting wildlife products. Two methods were used to evaluate whether mammals were overhunted, causing or threatening population declines. First, we compared animal biomass between the slightly hunted Yavari Miri and the persistently hunted Tahuayo sites, which were only 40 km apart and within the same continuous forest. Biomasses were determined by multiplying the average body weight of a species by the density of individuals. Body weights of mammals were determined from hunted samples. Densities of mammals were estimated using Fourier series expansion of line transect sightings. A total of 150 km of line transects were laid in seven trail systems in a 200-km 2 section of the Tahuayo site and 170 km of line transects in four trail systems in a 180-km 2 section of the Yavari Miri site. Individual transects ranged from 1 to 7 km in length and each trail was surveyed several times. Transects were censused in the morning from 0500 to 1100 h and in the evening from 1500 to 1900 h, and perpendicular distance of the first animal sighting to the trail was measured to within 1 m. Secondly, we compared the age structure of several mammalian populations at the Tahuayo site and a site at Taperinha, which had had persistent hunting pressure since the 1850s and is situated 40 km east of Santar6m in the eastern Brazilian Amazon (see Roosevelt et al., 1991). Both areas have the same composition of ungulates, including two species of

Game hunting and conservation of Amazonian forests brocket deer (Mazama americana and M. gouazoubira), two species of peccaries (Tayassu pecari and T. tajacu) and the lowland tapir Tapirus terrestris. Age of hunted ungulates was estimated by tooth wear from skulls of animals. Samples were pooled into four age categories. Animals in the 0-1 year range were not evenly sampled and were omitted from life table calculations. The number of years per age category was estimated by the oldest life expectancy for each species. Both species of brocket deer had an estimated two years per age category with the oldest individuals living to six+ years, and both species of peccaries had an estimated three years per age category with the oldest individuals living to nine+ years (Nowak & Paradiso, 1983; Sowls, 1984). Lowland tapir had an estimated 10 years per age category with the oldest individuals reaching 30+ years (Nowak & Paradiso, 1983). Most mortality between age categories 1-2 and 2-3 was of adults, and hunting was likely to affect the adult age categories more than most other causes of death. Indeed, in most unhunted mammalian populations the mortality rate is low in adults, but high in juveniles and old animals (Caughley, 1966). The skulls from Tahuayo were collected by local inhabitants from October 1990 to October 1991, and are housed at the Proyecto Peruano de Primatologia 'Manuel Moro Sommo'. The skulls from Taperinha were collected by Prof. G. Hagmann from 1912 to 1942, and are housed in the Departamento de ZooIogia, Museu Paraense Emilio Goeldi. The number of mammals hunted at Tahuayo was determined from October 1990 to October 1991. From interviews with hunters it was estimated that we obtained data on 95% of the harvested mammals. The economic value of game mammals was determined from market surveys and interviews with hunters (Bodmer et al., 1990a). We visited the Bel6n market in lquitos and observed the price of game meat sales. Local currency values were converted to US$. We determined which animals were sold to market and which ones were used for consumption by directly observing market transactions and food habits of local inhabitants, and from interviews with hunters. The value of meat used for consumption was estimated from the price local inhabitants would pay for 1 kg of meat brought from the city or brought from neighbours. The distribution of economic benefits obtained from game animals was determined by recording the harvests of each family unit. RESULTS Excluding small rodents, 1278 mammals were harvested during one year in a 500-km 2 area of the Tahuayo site (Table 1). This hunting pressure resulted in the extraction of 22 136 kg of animal biomass. Ungulates represented 78% of this biomass, and were harvested in greater numbers than primates, marsupials, edentates, large rodents, and carnivores. The biomass data for artiodactyl (deer and peccaries)

31

Tapirus terrestris 1000

_

nTah = 58

750 IX

500

250

1

2

3

4

X

Fig. 2. Age structure curve of the lowland tapir from Tahuayo, where x denotes age categories estimated from tooth wear. Survivorship is given as 1x, which represents the number of individuals surviving to age x from a cohort of 1o. 1x is scaled so that 1o = 1000. Table 1. Number of mammals hunted in Tahuayo from October 1990 to October 1991 Latin names a

Common names

Number hunted

Artiodactyls

Tayassu pecari Tayassu tajacu Mazama americana Mazama gouazoubira

White-lipped peccary Collared peccary Red brocket deer Grey brocket deer

166 165 60 28

Perissodactyls

Tapirus terrestris

Lowland tapir

38

Tamarins Pygmy marmoset Common squirrel monkey White-fronted capuchin Brown capuchin Titi monkey Night monkey Monk saki monkey Uakari monkey Red howler monkey Black spider monkey Common woolly monkey

11 1 9 20 46 76 4 57 23 22 8 58

Bicolour-spined porcupine Capybara Paca Black agouti Green acouchy Squirrels

8 10 174 97 13 15

Primates

Saguinus spp. Cebuella pygmaea Saimiri sciureus Cebus albifrons Cebus apella Callicebus cupreus Aotus nancymae Pithecia monachus Cacajao calms Alouatta seniculus Ateles paniscus Lagothrix lagothrica Rodents

Coendou bicolor Hydrochaeris hydrochaeris Agouti paca Dasyproctafuliginosa Myoprocta pratti Sciurus spp. Marsupials and edentates Dideiphidae

Myrmecophaga tridactyla Tamandua tetradactyla Bradypus variegatus Priodontes maximus Dasypus novemcinctus Carnivores Canidae Nasua nasua

Potos flavus Eira barbara Lutra longicaudis Felis spp. Puma concolor

Oppossums Giant anteater Collared anteater Three-toed sloth Giant armadillo Nine-banded armadillo

25 5 17 4 1 19

Free-ranging dogs South American coati Kinkajou Tayra Southern river otter Ocelot/margay

2 49 4 14 1 25

Puma

a Nomenclature follows Nowak and Paradiso (1983).

3

R. E. Bodmer, T. G. Fang, L. Moya L R. Gill

32

Tayassupecad

Tayassu tajacu nTa h = 137

nTah = 151

100C

750

Ix

500

250

1000

-,

75O Ix

250

0

'

1

5OO

2

3

0

4

1

2

Mazama gouazoubira

nTah = 63

n T ~ = 29

nTap= 56

= 19

1000

750

750

Ix

500

250

0

4

Mazama amedcana 1000

Ix

3 X

X

500

250

I

1

'

2

3

4

X

0

1

2

3

4

X

Fig. 3. Age structure curves of Amazonian peccaries and brocket deer from Tahuayo ( ) and Taperinha (. . . . ), where x denotes age categories estimated from tooth wear, nTah the sample size for Tahuayo, and nTap the sample size for Taperinha. Survivorship is given as Ix, which represents the number of individuals surviving to age x from a cohort of Io. lx is scaled so that 1o = 1000. and large rodent species from the persistently hunted Tahuayo site were similar to those of the lightly hunted Yavari Miri site (Xa = 3-1; d.f. -- 3; p = 0-38, and X2 = 1.3; d.f. = 2; p = 0.51; respectively) (Table 2), suggesting that these groups were not greatly affected by hunting. In contrast, the biomass of primates in Tahuayo was considerably less than in Yavari Miri ( ~ = 60.7; d.f. = 9; p < 0.001), which suggests that this group was being overhunted in Tahuayo. Lowland tapir biomass was also lower in Tahuayo than in Yavari Miri. The age structure curve of lowland tapir in Tahuayo supported the results of the biomass comparison. It declined rapidly in the second and third age categories, which is unusual for such a long-lived species, and suggests overhunting (Fig. 2). Likewise, lowland tapir were prevalent in Taperinha during the 1850s (Smith, 1879), but were virtually absent from this site between 1912 and 1942, presumably because of overhunting. The age structure curves also indicate that increasing current hunting levels in Tahuayo might have an adverse effect on artiodactyl populations. Indeed, overhunting may have caused artiodactyl age structure

curves to be lower at Taperinha than at Tahuayo for the second ( ~ = 220; d.f. = 3; p < 0.001) and third (A,2 = 50; d.f. = 3; p < 0.001) age categories (Fig. 3). Hunters in Amazonia obtain economic benefits from market sales and consumption of game mammals. For example, hunters in Tahuayo received cash for meat of ungulates and two of the large rodents (Hydrochaeris hydrochaeris and Agouti paca) in city markets of Iquitos. These mammals were hunted for their market value, and animal parts of these species were only occasionally consumed by hunters. Peccary hides also had a market value for hunters. Mammals not having market potential had consumption value and substituted for purchases of animal protein. Commercial sale of meat during the one-year study in Tahuayo earned US$17 270 for all hunters combined and was 82% of the total economic benefits obtained from mammalian game (Table 3). In addition, hunters received US$662 from the 331 peccary pelts extracted. A total of 3008 kg of game meat was not suitable for commercial use, and had a consumption value of US$1/kg. In Tahuayo, economic benefits obtained from

Game hunting and conservation o f Amazonian forests 30

Table 2. Mammalian biomass extracted in Tahuayo from October 1990 to October 1991, and biomass of mammals in the persistently hunted Tahuayo site and the slightly hunted Yavari Miri site

Mammals

Biomass Estimated biomass extracted (kg/km2) in in Tahuayo (kg) Tahuayo Yavari Miri

Ungulates Deer and peccaries Lowland tapir Primates Large rodents Marsupials and edentates Carnivores

11 977 5 320 1 419 2 345 409 666

202-7 64-0 183.8" 55.7" NA NA

~n 2 0 -

°5 Zw.

10-

223.2 96.0 440.9" 63.2" NA NA

Cebuella pygmaea, Aotus nancymae, Hydrochaeris hydrochaeris and Coendou bicolor are absent from biomass values, because densities of these species were not available. NA, data not available.

33

I 0-500

5001000

10001500

Table 3. Economic benefits of the current harvest in Tahuayo and costs of converting the overhunting in Tahuayo to a more sustainable harvest Values are in US$ over a one-year period.

Commercial meat value Tayassu pecari 7". tajacu Mazama americana M. gouazoubira Tapirus terrestris Hydrochaeris hydrochaeris Agoutipaca Total commercial meat value Commercial pelt value Total commercial value for hunters Direct consumption value Total direct benefits of mammalian harvests for hunters

Price per animal

n

$30 $30 $30 $20 $80 $20 $10

166 165 60 28 38 10 174

$2

331

Total

$4 980 $4 950 $1 800 $560 $3 040 $200 $1 740 $17 270 $662 $17 932

$1 per kg 3 008 kg $3 008 $20 940

Economic costs of prohibiting hunting on overharvested species Tapirus terrestris $3 040 Primates (1 419 kg) $1 419 Edentates and carnivores (1 075 kg) $1 075 Total costs

20002500

25003000

Benefits of Meat Sales in US$

"

mammals with market value were substantially greater than benefits obtained from mammals used for consumption (FL32 = 43.2; p < 0.001). Likewise, harvests of m a m m a l s having commercial value were greater than those with consumption value (FL32 = 17.2; p < 0.001). Population analyses for T a h u a y o suggest that artiodactyls and large rodents are not currently overhunted in Tahuayo. Populations of primates and tapirs are probably overhunted, and we assume populations of marsupials, edentates and carnivores cannot sustain current hunting levels, because of their apparently low densities. Thus, a more sustainable hunt would require cessation of hunting on primates, tapirs, marsupials, edentates, and carnivores, and the setting of artiodactyl and large rodent harvests at or below current levels.

15002000

20

15.

0 0-50

50100

100150

150200

200250

250300

300350

Benefits of C o n s u m p t i o n V a l u e in US$

Fig. 4. The distribution of economic benefits obtained by family units for meat sales and consumption value in the 500-km2 Tahuayo site.

Hunters would incur a 26% reduction of economic benefits if they ceased to harvest primates, tapirs, marsupials, edentates, and carnivores. This restricted hunt would reduce the extraction of m a m m a l i a n biomass by 35%. The economic costs of implementing a more sustainable hunt would not be evenly distributed between family units. In T a h u a y o there was an average of 1.7 hunters per family unit (range 1 ~ ) , with the majority of families obtaining less than US$500 for annual meat sales and less than US$50 for annual consumption value (Fig. 4). There was an obvious gap in benefits earned from meat sales, with two families gaining over US$2500 in revenue while all other families earned less than US$1500. The benefits obtained by families for consumption value was more evenly distributed and did not show a gap between the upper and lower levels of benefits.

$5 534

DISCUSSION

$1 l/km 2

H o w then could a sustainable hunt be managed that combined biological and economic considerations to

or

34

R. E. Bodmer, T. G. bang, L. Moya L R. Gill

conserve Amazonian ecosystems? One possible management programme would be to cull a greater proportion of males of species that are not currently overharvested, and to cease hunting overexpioited animals. Implementing a male-directed hunting programme should maintain a harvest that does not degrade the game resources. Reductions in the harvest of female moose Alces alces have been found to result in increased recruitment (Myberget, 1979), and male-directed hunting has been widely introduced for ungulate management in North America and Scandinavia to minimize the impact of hunting (Gill, 1990). Indeed, in many mammals lifetime reproductive success of males is determined by access to females, but female reproductive success is limited more by resources than by the number of males (Clutton-Brock, 1988). Recruitment in such mammalian populations is therefore relatively unaffected by a reduction in the proportion of adult males if the population is not near its carrying capacity, which appears to be the case for Amazonian ungulates and large rodents (J. Terborgh, pers. comm.). Age structure curves of deer and peccaries in Tahuayo and Taperinha suggest that current harvests of artiodactyls should not be increased, and we assume that this is also the case for large rodents. An increase in the proportion of males taken is likely to increase recruitment only if it involves an actual reduction in females harvested. Thus, one way to manage a male-directed hunt without increasing the current harvests of artiodactyls and large rodents would be to implement a system which requires that market benefits be obtained only from male artiodactyls and large rodents and consumption benefits from female artiodactyls and large rodents. This would produce a male-directed harvest of species that are not currently overhunted, which concurs well with predictions based on production models (Robinson & Redford, 1991). We do not propose a management programme that only permits the harvest of males, because this might have repercussions on recruitment, by altering too drastically the ability of females to find mates. Interestingly, economic considerations of this management programme complement its biological justification. First, hunters will become more selective in harvesting male animals in order to maximize commercial benefits. Secondly, meat from females used for consumption will substitute for meat lost from prohibited species. Indeed, hunters will have less incentive to harvest primates, marsupials, edentates, or carnivores for consumption when meat from female artiodactyls and large rodents is available. Finally, benefits of the peccary hide trade will not be affected by this management scheme. A management programme which only permits male artiodactyls and large rodents to be sold at market would decrease the total commercial meat benefits by 54% of the present hunt, if we use the sex ratio of the current harvest. Meat available for consumption would

increase by 2.4 times the current level, and harvests of mammals with commercial value would be similar to those with consumption value. However, by implementing a male-directed management programme, the harvested sex ratio should become male-biased, and increase the proportion of commercial benefits. As far as we are aware, this is the first quantitative analysis of the costs of implementing a more sustainable hunt for the conservation of tropical forests. Annual costs to local inhabitants of Tahuayo would amount to US$11/km 2. However, the costs of implementing this management programme would not be evenly distributed between family units and programmes replacing losses should be directed more to the families incurring greater costs. Both private and public organizations appreciate that conserving tropical forests will have immediate costs, and these will be outweighed by future benefits (Morowitz, 1991). Thus, costs to local inhabitants of implementing a wildlife management programme should be replaced. However, these losses should probably not be reimbursed directly with cash, but indirectly through social services or by developing alternative economic activities. Inhabitants of Tahuayo often use revenue obtained from game to purchase health, education, and transportation services, and subsidies of these social services might replace losses incurred from a management programme. Alternative economic activities such as agricultural and agroforestry assistance, or developing the extraction of non-timber plant products, might also replace economic losses of a wildlife management programme. However, rural inhabitants are likely to lose interest in maintaining intact forests if alternative activities do not utilize the sustainable exploitation of forest resources. Unfortunately, many alternative economic activities might encourage rural development schemes that lead to deforestation. In addition to the costs incurred by rural inhabitants, implementing a wildlife management programme will require managing costs in the form of extension officers and inspectors. However, these costs can be minimized if incentives are given for a community-based management. Indeed, many communities throughout Latin America are beginning to implement wildlife, forestry, and fisheries management systems that require little or no input from city-based authorities (Penn & Alvarez, 1990; Wells & Brandon, 1992). There is a true social benefit in changing an unsustainable hunting system to a sustainable one, because the opportunity cost to society (the sum of subsidy and management costs) would be outweighed by the benefits incurred from future hunting revenue. Indeed, if the unsustainable system is maintained one would expect hunting revenues to fall over time as populations of game animals decline to numbers too small to make hunting worthwhile. Economic considerations of minor forest products have in the past calculated solely the benefits obtained from non-timber plant products, and have not included

Game hunting and conservation o f Amazonian forests economic benefits from game (Peters et al., 1989). However, the valuation of minor forest products must include the economic value of animals together with non-timber plant products. As with game, non-timber products bring economic benefits to rural households, and have been used as an argument for conserving tropical forests (Peters et al., 1989). However, the most valuable non-timber plant products are often overexploited (Vasquez & Gentry, 1989; Bodmer et al., 1990b; Browder, 1992), and local inhabitants would incur economic costs to produce a more sustainable harvest. These costs would be determined using an analysis similar to the one presented above, which combines population biology of exploited species with economic considerations. ACKNOWLEDGEMENTS We thank P. Puertas, I. Vilchez, D. Leal Rodrigues, J. J. da Silva, J. Moro, F. Encarnaci6n, and E. Montoya for their kind assistance. Logistical and financial support was provided by the Proyecto Peruano de Primatologia 'Manuel Moro Sommo', Peruvian Ministry of Agriculture, Museu Paraense Emilio Goeldi/CNPq, the Chicago Zoological Society, Wildlife Conservation International and Conservation International. Drs Kent Redford and Clyde Kiker are thanked for reviewing the manuscript. REFERENCES Bodmer, R. E., Fang, T. G. & Moya, I. L. (1988a). Ungulate management and conservation in the Peruvian Amazon. Biol. Conserv., 45, 303-10. Bodmer, R. E., Fang, T. G. & Moya, I. L. (1988b). Primates and ungulates: A comparison in susceptibility to hunting. Primate Conserv., 9, 79-83. Bodmer, R. E., Benday~in, N. Y., Moya, I. L. & Fang, T. G. (1990a). Manejo de ungulados en la Amazonia Peruana: An~ilisis de la caza de subsistencia y la comercializaci6n local, nacional e internacional. Bol. Lima, 70, 49-56. Bodmer, R. E., Fang, T. G. & Moya, I. L. (1990b). Fruits of the forest. Nature, Lond., 343, 109. Bodmer, R. E., Penn, J., Fang, T. G. & Moya, I. L. (1990c). Management programmes and protected areas--the case of

35

the Reserva Comunal Tamshiyacu-Tahuayo, Peru. Parks, 1, 21-5. Browder, J. O. (1992). The limits of extractivism: Tropical forest strategies beyond extractive reserves. BioScience, 42, 174-82. Caughley, G. (1966). Mortality patterns in mammals. Ecology, 47, 906-18. Clutton-Brock, T. H. (1988). Reproductive Success: Studies of Individual Variation in Contrasting Breeding Systems. University of Chicago Press, Chicago. Ehrlich, P. R. & Wilson, E. O. (1991). Biodiversity studies: Science and policy. Science, N. Y., 253, 758~2. Gill, R. (1990). Monitoring the Status of European and North American Cervids. United Nations Environment Programme, Nairobi. Myrberget, S. (1979). The Norwegian moose population 1945-77. Meddelelser fra Norsk Viltforskning, 3, 18-33. Morowitz, H. J. (1991). Balancing species preservation and economic considerations. Science, N. Y., 253, 752-4. Nowak, R. M. & Paradiso, J. L. (1983). Walker's Mammals of the WorM, 4th edn. John Hopkins University Press, London. Penn, J. W. & Alvarez, J. (1990). Manejo racional del recurso pesquero: Comunidad campesina protege sus cochas. Kanatari, 7, 10-11. Peters, C. M., Gentry, A. H. & Mendelsohn, R. O. (1989). Valuation of an Amazonian rainforest. Nature, Lond., 339, 655-6. Redford, K. H. & Robinson, J. G. (1987). The game of choice: Patterns of Indian and colonist hunting in the neotropics. Amer. Anthropol., 89, 650-67. Robinson, J. G. & Redford, K. H. (1991). Sustainable harvest of Neotropical forest mammals. In Neotropical Wildlife Use and Conservation, ed. J. G. Robinson & K. H. Redford. University of Chicago Press, Chicago, Illinois, pp. 415 29. Roosevelt, A. C., Housley, R. A., Imazio da Silveira, M., Maranca, S. & Johnson, R. (1991). Eighth millennium pottery from a prehistoric shell midden in the Brazilian Amazon. Science, N. Y., 254, 1621-4. Smith, H. H. (1879). Brazil: the Amazons and the Coast. Charles Scribner's Sons, New York. Sowls, L. K. (1984). The Peccaries. University of Arizona Press, Tucson, Arizona. Vasquez, R. & Gentry, A. H. (1989). Use and misuse of forest-harvested fruits in the Iquitos area. Conserv. Biol., 3, 350-61. Wells, M. & Brandon, K. (1992). People and Parks." Linking Protected Area Management with Local Communities. World Bank, Washington, DC.