African Study Monographs, Suppl.26: 135-156, March 2001 135 THE MANAGEMENT OF WILD YAM TUBERS BY THE BAKA PYGMIES IN SOUTHERN CAMEROON Edmond DOUNIAS IRD (ex ORSTOM), CEFE - UPR 9056 CNRS ABSTRACT Wild yams (Dioscorea spp.) are primordial sources of carbohydrates for many hunter-gatherers of African forests. Yams play a key role in the symbolic perception of the forest by the Baka Pygmies of Southern Cameroon. The Baka have elaborated an original form of wild yam exploitation that I have termed “paracultivation”. Paraculti- vation defines a set of technical, social and cultural practices aiming at managing wild resources while keeping them in their natural environment. In 1994, I undertook an experimental survey to estimate the effect of paracultivation on survivol and growth of yam plants. Preliminary results presented here demonstrate that paracultivation increases the production of tubers without affecting plant survivorship. Furthermore, it allows a better control of the spatial and temporal availability of yam resources by the Baka. This study has opened up new perspectives on the evolutionary ecology of tuber- producing tropical forest plants. Paracultivation encourages us to reconsider the interac- tive process between forest dwellers and their environment. Key Words: Wild yams; Baka; South Cameroon forest; Paracultivation; Resource man- agement; Ethnoecology INTRODUCTION I. Protocultivation: A Step to Domestication Historical studies of the processes of plant domestication were long dominated by Judeo-Christian bias, persisting in locating the birthplace of the agricultural revolution in the “fertile crescent” of the Near East. The rise of agricultural civil- isations could not be conceived of without seeds. Only in the 1970’s did scientists divorce with classical schemes the emergence of agriculture, by describing the age- old agricultural prehistory which preceded the domestication of barley and wheat by many civilizations in other parts of the world (Harlan et al., 1976; Harris & Hillman, 1989). Interest progressively focused on the Indo-pacific domain, both as the center of origin of a wide range of cultivated plants but also as an ancient locus of domestication. In his innovative work on Melanesia, Barrau (1970) insisted on the interest of analyzing the processes of wild yam harvesting as a demonstration of the major role of vegetative propagation in the domestication of starch-rich perennial crops, which are clonally reproduced. Up to now the observation of such practices among persisting hunting and gathering societies has been generally motivated by the attempt to reconstruct the transition to agriculture in prehistory. 136 E. DOUNIAS The maintenance of wild-yam tuber heads in soil, or their reburial after har- vesting of the fleshy parts, are fairly common practices among hunter-gatherers. I described such practices for the Kubu of Sumatra (Dounias, 1989; submitted), but it is also mentioned in Malaysia among the Orang Asli (Rambo, 1979) and the Batek De’ (Endicott & Bellwood, 1991); in the Philippines among the Batak (Eder, 1988) and the Tasaday (Yen, 1976); in Papua New Guinea (Yen, 1989); in Thailand among the Hoabinhian (Yen, 1977); in India among the Chenchu of the Krishna River (Furer-Haimendorf, 1943); in various locations and ethnic groups in Aus- tralia (Grey, 1841; Jones, 1975; Jones & Meehan, 1989; Yen, 1989; Hallam, 1989); in Tanzania among the Hadza (Vincent, 1985); among the Baka of Cameroon and Congo Brazzaville (Dounias, 1996; Sato, this book), and among the Aka in the Central African Republic (Mouton & Sillans, 1954; Bahuchet, 1985). In several societies, harvesting of tubers of wild yams is regulated by religious prohibitions. Such cases are reported in Western Africa (Coursey & Coursey, 1971), among the Kirdi people of the mountains of northern Cameroon (Seignobos, 1992) and in the Andaman Islands (Burkill, 1953; Radcliffe-Brown, 1964; Coursey, 1972). A related practice is the transplanting of individual wild plants into swiddens or home gardens. Such practice has been described among the Kubu of Sumatra (Sandbukt, 1988), among the Bongo (Chevalier, 1936), and among the sedenta- rized Aka in the Central African Republic (Guille-Escuret, personal communica- tion), and in various groups along the coast of the Guinea Gulf, notably among the Ibo, Yoruba, Ashanti Ewe and Akan (Coursey, 1976). Chevalier (1936) de- scribes such processes as “protocultivation,” meaning that they are performed by “pre”-agriculturalists who are about to adopt full agriculture in a near future. Mouton & Sillans (1954) use the expression “semi-culture” for the same purpose. Braidwood & Reed (1957) propose the neologism “vegecultivation” as a synonym of “specialized foraging” to describe what they consider to be a transitory step between gathering and agriculture. In previous papers (Dounias, 1993; 1996; 1997) I described a set of manipulations performed on wild yams by the Baka hunter-gatherers of rainforests of southern Cameroon. I suggested that these manipulations have an impact on the geographic distribution and seasonal availability of wild yams. My goal was to criticize any linear and stereotyped view of the evolution of human practices concerning plants. Distinctively of “protocultivation” I argued that such processes do not correspond to an intermediate step leading to full domestication, as implied by the term “pro- tocultivation”. I proposed the term “paracultivation” to describe what I consider to be an achieved control of wild resources, which supports the nomadic strategies of hunting and gathering societies. There is no wish nor expressed purpose on the part of the Baka to obtain a complete domestication of these resources. In the present paper, I first summarize what precisely I mean by “paracultiva- tion” and explore the theoretical issues concerning this concept. I then complete the previous descriptions of the tight socio-cultural relationships between the Baka and wild yams. These geophyte vines are not only food resources: they are also keystone elements of Baka cosmogony. Thirdly, I explain how the achieved knowl- edge of the Baka about the ecology and biology of wild yams has influenced new paths of research on these starch-rich tuber plants. Finally, I present some of the results I obtained from a quantitative experimental survey, aimed at testing the effect of “paracultivation” on the productivity of starchy tubers. Management of Wild Yam 137 Fig. 1. What is paracultivation. II. The Concept of Paracultivation “Paracultivation” defines a combination of technical patterns and social rules which structure the exploitation of wild plants. This term characterizes a particular process of wild plant harvesting which aims at encouraging plant reproduction, so that the plant can be repeatedly exploited. Furthermore, the plant is voluntarily kept within its original environment, in order to better respond to the seasonal mobility of forest dwellers. This maintenance of plants in the forest is the key difference between paracultivation and protocultivation (Fig. 1). In addition, paracultivation has shaped the technical design of a specific dig- ging tool. Harvesting patterns are specifically adapted to the paracultivated re- source. Several social rules may codify access to the resource: exclusive rights of ownership with possible inheritance of managed plants, ritual protection, and the specific treatment the resource receives as food (prestige dishes, components of bridewealth). Although such social treatment of wild resources has been little 138 E. DOUNIAS Fig. 2. Study sites on wild yams in Cameroon and their temperature and rainfall profiles. noted by anthropologists working on so-called “egalitarian” societies, I suspect that “paracultivation” may exist or have existed for a wide range of forest resources. Similar controls of plant reproduction should be systematically investigated, in the perspective of proposing realistic scenarii of the historical ecology of interactive processes between forest peoples and their environment. THE USE OF WILD YAMS BY THE BAKA PYGMIES I. Current State of Knowledge Yams (the pantropical genus Dioscorea, of the monocotyledonous family Dioscore- aceae) are vines which store starchy reserves in aerial or underground tubers. Geo- phytes, such as forest species of Diocorea are very uncommon life forms in tropical forest (Richards 1996). The starchy reserves of yams are a primordial source of car- bohydrates for hunter-gatherers. Since 1986 we have conducted systematic censuses of wild yam species in Cameroonian rainforests, estimating densities in different parts of the rainforest zone (Fig. 2). Previous acquired data were published for Central African Republic and Gabon (Hladik et al., 1984). The genus was subse- quently partly revised for Congo Brazzaville (Nkounkou et al.,1993) and Western Africa (Hamon et al., 1995). Cameroon is the African country which retains the Management of Wild Yam 139 highest diversity of rainforest wild yam species, with 17 probably species (Hladik & Dounias, 1996) compared to 12 in Gabon (Hladik et al., 1984), 12 in Congo Brazza- ville (Nkounkou et al., 1993), 11 in Central African Republic (Bahuchet, 1993b), and 9 in Congo Kinshasa (AFlora databank on web). Among the 17 Cameroonian species, 5 which are strictly limited to forest are still not yet described. Five other species are not specific to rainforest habitats, occurring also in sudanian and sub- sahelian savannas. We exclude here 5 to 6 other wild species which grow specifically in edaphic savannas