Markets, Healers, Vendors, Collectors: The Sustainability of Medicinal Plant Use in Northern Peru

Abstract Northern Peru is the center of the so-called Andean “health axis,” where the continuous use of more than 500 medicinal plants has been documented. Local healers as well as patients purchase a large portion of their plants at local markets. While scientific studies of medicinal plants are under way, concern has arisen over the preservation of both the large diversity of medicinal plants and the traditional knowledge of healing methods that accompanies them. To promote further conservation work, this study attempted to document the sources of the most popular and rarest medicinal plants sold at the markets of Trujillo (Mayorista and Hermelinda) and Chiclayo (Modelo and Moshoqueque), as well as to create an inventory of the plants sold in these markets. The present paper reports on the complete market flow from collection to middlemen to vendor from the perspective of an herb collector/vendor. Although prior studies have indicated that at least some plants, mostly introduced species, are grown in home gardens on the coast, this study shows that increasing plant demand in the large coastal markets has not led to significant cultivation of medicinal plants in home gardens. The vast bulk of the plant material sold in the markets of northern Peru consists of plants collected in the wild. Both collection of plants and their transport to the coastal markets require long-distance travel. Low profit margins indicate that the herb trade is very fragile, since collectors might decide to engage in activities that offer higher income or higher turnover. This, coupled with the fact that most plant material is wild-crafted, could easily lead to overharvesting of rare medicinal species in the region.


Introduction
The study region in northern Peru ( Figure 1) is at the heart of what Peruvian anthropologist Lupe Camino calls the ''health axis'' of the old Central Andean cultural area, which stretches from Ecuador to Bolivia (Camino 1992). The traditional use of medicinal plants in this region, which encompasses in particular the Departments of Piura, Lambayeque, La Libertad, Cajamarca, and San Martín, dates back as far as the first millennium BC (north coastal Cupisnique culture) or at least to the Moche period (AD 100-800), as evidenced by healing scenes and healers frequently depicted on ceramics (Sharon 2000). Early ethnobotanically oriented studies focused mainly on the famous ''magical' ' and ''mind-altering'' flora of Peru (eg Cruz Sánchez 1948;Dobkin de Rios 1968, 1977Bristol 1969;Martin 1970;Rivier and Lindgren 1972;Dobkin de Rios and Cardenas 1980;Naranjo 1981;Plowman 1981Plowman , 1984. General ethnobotany studies in Peru and Bolivia have focused mostly on Quechua herbalism in the Cusco area (eg Larco-Herrera 1940;De Ferreyra 1978Franquemont et al 1990). Other comprehensive studies have centered on the border region of Peru and Bolivia around Lake Titicaca (eg Bastien 1987Bastien , 1992Girault 1987;Roersch 1994) and the Amazon (eg Prance 1972;Rutter 1990). Northern Peru, by contrast, has always been in the shadow of these touristically more important regions, and very few studies have been conducted here to date (Polia 1988;De Feo 1992, 2003Hammond et al 1998). In recent years, the contemporary use of plants by local healers (curanderos) in northern Peru has been well documented Sharon 2006, 2007;Sharon andBussmann 2006a, 2006b;Bussmann et al 2007aBussmann et al , 2007bBussmann et al , 2008Revene et al 2008).
However, as in other areas worldwide, healers as well as the population at large frequently buy their medicinal plants on the local market. In contrast to the wealth of available ethnobotanical information, literature on local markets, market flows, and the value of the plant material traded is rather scarce. Although the value of the international market for medicinals arouses great interest (eg Breevort 1998), and ecosystem services as well as nontimber forest products do receive some attention (Grimes et al 1994;Costanza et al 1997;Godoy et al 2000), studies on the trade volumes of local medicinal markets are rare and focus mostly on the export market (Olsen and Helles 1997;Olsen 1998Olsen , 2005. Latin America is still terra incognita with regard to its medicinal plant markets, and detailed studies are of high importance because even the local health care authorities are beginning to propagate complementary alternative medicine (EsSalud 2000). Macía et al (2005) provided the first study of a high-Andean market, focusing on La Paz, Bolivia. However, that study did not contain any data on plant origin and sales volumes. Very little information exists so far on the composition of the market flora, the origin of the plant material, and the quantities of plant material sold.

Surveys
For this study, surveys focusing on medicinal plants sold and their properties were conducted at the markets in Trujillo (Mayorista and Hermelinda) and Chiclayo (Modelo and Moshoqueque) from 2001 to 2008. Surveys were conducted in Spanish by fluent speakers. Surveyors would approach the vendors and explain the premise for the study, including the goal of conservation of medicinal plants in the area. All vendors were asked to participate, and from those who gave their prior informed consent, information was collected regarding their inventory of medicinal plants. The vendors were also asked to list the ten most commonly sold plants, and ten plants that were disappearing from the market. Of the plants that were most commonly sold and declining, information was also collected on their location (montaña: mountain forest; costa: coast; sierra: highlands; or selva: jungle), origin (pueblo: village), cost per unit sold (soles), units sold per week (bultos: bundles; paquetes: packets), the time when the vendors' suppliers distributed goods, and any other information concerning the popularity of the plant. At each market, the number of medicinal plant vendors was counted in order to estimate how representative the vendors who participated in the study were for the entire market.

Nomenclature
The nomenclature of plant families, genera, and species follows the Catalogue of the Flowering Plants and Gymnosperms of Peru (Brako and Zarucchi 1993). The nomenclature was compared to the TROPICOS database at the Missouri Botanical Garden. Species were identified using the available volumes of the Flora of Peru (McBride 1936(McBride -1981, the work of Ulloa Ulloa and Jørgensen (1993), Jørgensen and Ulloa Ulloa (1994), and Pestalozzi (1998), and reference material in the HUT and HAO herbaria. For a complete overview on traditional uses, recipes, and botanical vouchers collected, see Sharon (2006, 2007).

Markets
The inventory of 54 of 110 vendors on the markets of Mayorista ( Figure 2) and Hermelindas in Trujillo as well as Modelo and Moshoqueque in Chiclayo yielded a total of almost 400 medicinal plants and preparations sold on any given day (Bussmann et al 2007a(Bussmann et al , 2007b. This was expectedly lower than the reported medicinal flora of the region (Bussmann and Sharon 2006, 512 species), because many healers interviewed in earlier studies relied on additional self-collected species or material bought outside the regular market for their treatments. In order to evaluate whether the above sample size of market vendors represented the complete plant inventory on the various markets, species saturation curves were used. A 95% species saturation in comparison to the final number of species observed was reached on all markets with the number of vendors studied. This indicates that the sample size was sufficient to capture the market inventory.
While it was very easy for all vendors to name their most important and frequently sold species, it proved impossible to get detailed information about species that vendors observed as ''rare'' or ''disappearing.'' In most cases, vendors mentioned species as rare based on the fact that they themselves did not sell them, frequently because these plants were very common outside the market (eg Plantago major or common plantain), or because demand was so low that it would not have made sense to carry them in their inventories.

Plant supply
Many plant collectors in northern Peru followed clear harvesting strategies. For example, upon encountering a juvenile specimen of a certain tree that would normally have been partially harvested, informants left it untouched in order to ensure that it would be a more productive and reliable source of plant material in years to come. They also stated that harvesting in the dry season would cause even more damage because trees would have more trouble responding to the physical trauma involved. For small annual plants, conservation strategies seemed to be far less important. Many plants were pulled up completely by the roots. No attention was paid to whether or not a plant had already gone to seed, and in fact, many plants were selected specifically because they were still in flower in order to take advantage of the curative properties inherent in the flower itself (Revene et al 2008).
When asked if they had noticed any decline in the quantity or variety of certain plants in the area, the informants normally responded that the plant populations had always been stable, and that they had always been found in the same areas. It appears that the human impact upon the botanical resources in the area has so far been relatively small.
A network of family and neighbors from whom vendors bought certain plant species proved to be an important component in providing sufficient material for the market. It was this informal network that helped to buffer informants against unusually long treks, and helped to bolster the otherwise dwindling variety that is common during the dry season. The plants that were bought included both cultivated and wild-harvested material.
Another important source of the medicinal plants brokered to the coastal markets was the informal herbal market in the city of Cajamarca. As opposed to formal sales stands where the plants are sold on other markets, the trade here mainly consisted in small-scale suppliers arriving with bundles of 1-7 varieties of plants and selling to the awaiting wholesale buyers. Some collectors came from communities up to 5 hours away. One reason for the long distances that many of these plants traveled was their seasonal scarcity at lower elevations during the dry season. Many of the outlying supply communities are subject to more favorable rainfall conditions, which allows for a longer harvest season (Revene et al 2008). Almost all of the buyers and sellers were women. Each wholesale buyer-of which there was an average of 3-5 during the duration of the study at this specific marketpackaged their wares in large sacks as the morning progressed. Opportunistic sales were sometimes made to passers-by with a specific request, but most of the acquired plants were stowed away, awaiting the more profitable economic gains to be made in the coastal market of Moshoqueque in the city of Chiclayo.

A look at sustainability
Although prior studies have indicated that at least some plants, mostly introduced species, are grown in home gardens on the coast, the origin of the vast bulk of the plants was unclear. Only 76 species (25 introduced, 51 indigenous) were found in local gardens or were cultivated by vendors. Of these, however, only 5 species were commonly cultivated. All but 3 of the commonly cultivated species were introductions. Contrary to the initial assumption, increasing plant demand in the large coastal markets has not led to significant cultivation of medicinal plants in home gardens. The vast bulk of the plant material sold in the markets of northern Peru consists of plants collected in the wild. Moreover, more than two-thirds of all species sold were claimed to originate from the highlands (sierra), above the timberline. These areas are often heavily used for agriculture and livestock grazing.
The overall value of medicinal plants in the coastal markets reaches a staggering US$ 1.2 million per year (Table 1). This figure only represents the share of market vendors, and it does not include the amount local healers charge for their cure. Thus, medicinal plants contribute significantly to the local economy (Bussmann et al 2007b). Such an immense market raises questions regarding the sustainability of this trade, especially because the market analysis does not take into account any informal sales.
Most striking was the fact that 7 indigenous and 3 exotic species (ie 2.5% of all species traded) accounted for more than 40% of the total sales volume (30% and 12%, respectively) ( Figure 3). Moreover, 31 native species accounted for 50% of all sales, while only 16 introduced species contributed to more than one-quarter of all material sold (Figure 4). This means that a little over 11% of all plants on the market accounted for about threequarters of all sales. About one-third of this sales volume includes all exotic species traded. While none of these is rare or endangered, some of the indigenous species traded are threatened by overharvesting. Additionally, the rising market demand might lead to increased production of exotics, which in turn could have negative effects on the local flora (Bussmann et al 2007b).
A look at the indigenous species traded highlights important conservation threats. Croton lechleri (dragon's blood) and Uncaria tomentosa (cat's claw) are immensely popular at a local level, and each contributes to about 7% to the overall market value. Both species are also widely traded internationally. The latex of Croton is harvested by cutting or debarking the whole tree. Uncaria is mostly traded as bark, and again debarking normally involves the whole plant. Croton is a pioneer species, and apart from C. lechleri, a few other species of the genus have found their way onto the market. Sustainable production of this genus seems possible, but the process needs to be closely monitored. The current practice does not appear sustainable, given that the bulk of Croton is wild-harvested. Trade in cat's claw involves such a large volume that, in fact, collectors of this primary forest liana started complaining about a lack of resources years ago. During the study years, other Uncaria species and even Acacia species have appeared on the market under the label of ''cat's claw'' (own observation). These are clear indicators of the fact that trade in Uncaria is not sustainable (Bussmann et al 2007b).
Some of the other ''most important'' species are either common weeds (eg Desmodium molliculum), or have large populations (eg Equisetum giganteum). However, a number of species are very vulnerable. Tillandsia cacticola grows in small areas of the coast as an epiphyte. The habitat, coastal dry forest and shrubs, is heavily impacted by urbanization and mechanized agriculture, and the impact of the latter is worsened by the current biofuel boom. Gentianella alborosea, Gentianella bicolor, Gentianella graminea, Geranium ayavacense, and Laccopetalum giganteum are all high-altitude species with very limited distribution. Their large-scale collection is clearly unsustainable, and, in the case of Laccopetalum collectors, it indicates that supply is harder and harder to find. The fate of a number of species with similar habitat requirements raises comparable concern. The only species under cultivation at this point are exotics and a few common indigenous species (Bussmann et al 2007).

Conclusions
When analyzed, the distances traveled, time spent, and energy expended during the commerce of medicinal Although there were no negative human impacts identified during visits to harvest sites, this does not preclude the possibility that such effects could manifest themselves at the same locations in the future. Data on the medicinal plant selection available from nonspecialized vendors show a prevalence of introduced species in the marketplace. The population of Cajamarca is mostly mestizo, and the belief that ''wild'' plants are more potent than cultivated species, often encountered in indigenous populations, was not observed in the region.
The majority of medicinal plant species sold by nonspecialized vendors were introduced species. Even though a variety of native species were also available among nonspecialized vendors, the medicinal plants that recurred among nonspecialized vendors were Matricaria chamomilla, Origanum vulgare, Petroselinum crispum, and  Coriandrum sativum, all of which are introduced species. Although there is a significant amount of medicinal plant collection in the Cajamarca highlands, introduced species dominate as the ingredients of homemade remedies. While many native species were found in home gardens, it is crucial to note that most of these species grew spontaneously in minute quantities and did not constitute cultivation of significant importance in terms of potential for sale in the marketplace. The selection of medicinal plants and their sale in small quantities by nonspecialized vendors, often alongside other goods of alimentary value, indicate that individuals usually engage in a variety of activities as primary income-generating tactics, incidentally cultivating small amounts of medicinal plants. In other cases, individuals purchase small quantities of medicinal plants from other vendors in the marketplace to diversify product variety. Few individuals, however, cultivate or collect plants; most purchase from others. Overharvesting may become an issue as demand for traditional healing and medicinal plants rises. In addition, pressure on natural resources from activities such as agriculture and mining are issues of escalating concern in Cajamarca. These potentially threaten the habitats of plant species traditionally used for medicinal purposes. To date, there has been little academic research on the habitat requirements and regeneration potential of many plant species of medical value that are native to the Peruvian highlands.