Commercial Bryophyte

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BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. Commercial Bryophyte Harvesting in the Monarch Butterfly Biosphere Reserve, Sierra Chincua, Michoacan, Mexico Author(s): Marlene Gómez Peralta and Jan H. D. Wolf Source: The Bryologist, 104(4):517-521. 2001. Published By: The American Bryological and Lichenological Society, Inc. DOI: http://dx.doi.org/10.1639/0007-2745(2001)104[0517:CBHITM]2.0.CO;2 URL: http://www.bioone.org/doi/full/10.1639/0007-2745%282001%29104%5B0517%3ACBHITM %5D2.0.CO%3B2 BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. 0007-2745/01/517–521$0.65/0 The Bryologist 104(4), pp. 517 521 Copyright ᭧ 2001 by the American Bryological and Lichenological Society, Inc. Commercial Bryophyte Harvesting in the Monarch Butterfly Biosphere Reserve, Sierra Chincua, Michoacan, Mexico MARLENE GO ´ MEZ PERALTA Herbario de la Facultad de Biologı ´a, Universidad Michoacana de San Nicola´s de Hidalgo, Edificio ‘‘R’’, Ciudad Universitaria, C.P. 58030. Morelia, Michoaca´n, Me´xico; e-mail: [email protected] JAN H. D. WOLF University of Amsterdam, Institute for Biodiversity and Ecosystem Dynamics, Hugo de Vries-laboratory, Kruislaan 3181098 SM Amsterdam, The Netherlands Abstract. Each Christmas season, the abundance of terrestrial bryophytes in the Abies-dom- inated forests of the Sierra Chincua, part of the Monarch Butterfly Biosphere Reserve, attracts moss gatherers. Bryophyte mats are harvested as ornamentals, packed, and sold at the central auction of Mexico City. In 1996, we followed a group of about 10 family members in this activity and documented economic and ecological aspects. During the season they removed in total nearly 50 tons of fresh weight of bryophytes from the forest floor that was sold for approximately $3,500 USD, leaving behind a mosaic of gaps of bare soil in the mossy layer. The average gap size was 0.48 m 2 and extraction intensity varied between 0.5 and 4.1% of the total surface area (2.14% on average). In addition, over 11,000 Abies seedlings were unintentionally removed. We are conceive that the Mexican norm for bryophyte harvesting is not in line with current practices and we recommend the inclusion of guidelines for patch size, and that harvesters pay attention to accidental removal of tree seedlings. In Mexico, the largest remaining extensions of Abies religiosa forest can be found in the mountain range of the Neovolcanic Belt. Remnants of the Si- erra Chincua in the state of Michoaca´n, are well known as hibernating grounds for migrant monarch butterflies, which has resulted in the creation of the ‘‘Monarch Butterfly’’ Biosphere Reserve (Calvert & Brower 1986). In this region the Abies forest is common at elevations ranging from 2,700 to 3,600 m, on slopes between 10 and 30% (Madrigal-Sa´n- chez 1994). Abies-dominated forests are character- ized by a well developed bryophytic layer, covering some 70% of the forest floor. A constant high hu- midity, relatively low temperatures, and absence of a great deal of seasonal smothering of the bryo- phytes due to the linear, small leaves and the ev- ergreen habit of Abies, are all likely to contribute to the great abundance of terrestrial bryophytes (Smith 1982). The high abundance of large-mat forming bryo- phytes has attracted commercial interests. Bryo- phytes are traditionally used as ornamentals in fam- ily Christmas stalls. This usage of bryophytes is not just a recent phenomenon. In 1840, the marquis Caldero´n de la Barca described a stall in Mexico City, of which the platform was covered with bryo- phytes (Guı ´a Me´xico Desconocido 1996). The bryophytes used to date are mostly in the genera Campylopus, Hypnum, Leptodontium, Polytrichum, and Thuidium (Delgadillo & Ca´rdenas 1990). He- patics are hardly taken and the most popular growth forms are wefts and cushions, as defined by Ma¨g- defrau (1982). In December, bryophytes are regu- larly for sale in local markets all over the country. Mexican law (Secretarı ´a del Medio Ambiente, Recursos Naturales y Pesca 1996) provides mini- mal guidelines for the exploitation of natural pop- ulations of bryophytes: harvesting should be con- ducted in patches of no more than two meters wide and not exceed 50% of the coverage. Enforcement is virtually non-existent. At present there are no data about the intensity of this activity and its im- pact on both the bryophytes and the forest. In this paper we document the kind and extent of com- mercial moss harvesting within the Abies forest of the ‘Monarch Butterfly’ Biosphere Reserve. METHODS The Sierra Chincua sanctuary within the ‘‘Monarch Butterfly’’ Biosphere Reserve encompasses several mu- nicipalities of the state of Michoacan and a small section within the state of Mexico (Fig. 1). The sanctuary com- prises 2,695 ha, situated between 19Њ39Ј–19Њ42Ј N and 100Њ16Ј–100Њ20Ј W (Calvert & Brower 1986; Instituto Nacional de Ecologı ´a-Secretarı ´a de Desarrollo Social 1993). The largest part of the sanctuary is above 3,000 m elevation where the daily temperature is Ͻ14ЊC and the annual precipitation Ͼ1,000 mm, on average, without a pronounced dry season. On mountainous slopes the forests 518 [VOL. 104 THE BRYOLOGIST FIGURE 1. Location of the study area. are dominated by Abies religiosa and on the plains Juni- perus monticola is also present. Fieldwork was carried out in two stages. During the entire harvesting period, November 20, until December 20, 1996, one of us (Marlene Go´mez Peralta) accompa- nied a group of moss gatherers to document socio-eco- nomic aspects and their daily non-authorized activities in the field. Individual gatherers bundle collected newspaper sheet-size moss carpets into ‘packs’ of handling weight and leave behind a mossy layer dotted with gaps of barren soil. Data were compiled on the characteristics of the site, the preferred species, the moss weight removed from the forest floor and the number and size of the gaps in the mossy layer. In addition, the number and size of acciden- tally removed Abies seedlings were recorded. Collected cryptogamic species (mosses and lichens) were identified using Delgadillo and Ca´rdenas (1990), Hale (1979), and Sharp et al. (1994). Afterwards the area was revisited to estimate the cleared surface per unit area. RESULTS Some 10 yr ago, a single rural family started dedicating themselves to the gathering of bryo- phytes in the Chincua area during the Christmas season. The group leaders are the owner of a small truck and another person that is the driver both share the profits. The number of adult workers varies annually between four and six, and the num- ber of child workers, 9–16 yr old, between three and seven. All are male and members of the same family. During the 27 d long harvesting season, the group stays in a shack near the reserve and makes daily collecting trips into the Reserve. The group field leader, ‘‘El Capita´n’’ decides the area to be 2001] 519 GO ´ MEZ PERALTA & WOLF: BRYOPHYTE HARVESTING TABLE 1. Characteristics of the removed moss packs at the Sierra Chincua sanctuary during the 1996 harvest- ing season. Per day (average) Per season (29 days) Number Weight (kg) Volume (m 3 ) Number of Abies seedlings 218.9 1,716.1 (7.84) 10.9 (0.05) 383.0 (1.75) 6,348.1 49,766.9 316.1 11,109.1 FIGURE 2. Location of the extraction sites. TABLE 2. Income of the bryophyte gatherers at the Sierra Chincua reserve during the 1996 harvesting season. Values are in Mexican Pesos, roughly valued at 10 N$ to 1$ US. Number of packs Income Costs (housing, food) Net gain Gathered Field leader (El Capitn´) Adult worker Child worker 810 810 567 1,820.00 1,620.00 1,134.00 1,000.00 1,000.00 684.00 820.00 620.00 450.00 Sold at auction Truck owner and truck driver 6,350 37,147.00 12,700.00 (pay field group) 13,500.00 (transport) 500.00 (others) 10,447.00 visited based on seclusion and the abundance of the bryophytic layer, avoiding areas that were visited during recent years. Each day the group members work spread over an area of 1–2 ha where adults cover about 50–700 m 2 , and children 210–700 m 2 surface area, to build their packs. First, two strings are laid out on the ground with two twigs on top. Then moss carpets are added manually until the pack measures roughly 50 ϫ 30 ϫ 30 cm and the pack is tied. An adult takes 3–8 min. to build a pack—a child may need over 20 min.—for which they are paid N$ 2.00 Mexican pesos (some 0.20 $ U.S.). Per day, adults build an average of 30 packs; children 21 packs. The packs are brought to a cen- tral area, accessible for the truck. On average, 219 packs are harvested by the group per day. The av- erage weight is 1,716.65 kg per day (wet weight) and the average size is 10.9 m 3 (Table 1). The truck is loaded late at night, and the packs are taken di- rectly to the Central de Abastos in Mexico City for auctioning early in the morning. Late in the after- noon, the truck driver initiates the journey back to the Chincua area. In total, nearly 50 tons of bryo- phytes were removed in 1996. The moss gathering operation is mostly a lucra- tive activity for the two organizers (truck owner and truck driver), who earn over 5,000.00 Mexican pesos each during the season, some eight times the amount of an adult field worker who collects 620.00 Mexican pesos, the equivalent to about one month of minimal wage in Mexico (Table 2). Even though field workers are paid with disre- gard to the species gathered, at the market Hypnum amabile (Mitt.) Hampe and Thuidium delicatulum (Hedw.) B.S.G. var. delicatulum are valued higher. Both species are also the most abundant in the Si- erra Chincua reserve. In addition, the herbaceous angiosperm Sibothorpia repens (L.f.) O. Kuntze with its dime-like leaves is a sought-after species of the mossy layer. Other common species in the packs are the acrocarpic mosses Bryum procerum Besch. and Morinia ehrenbergiana (C. Mu¨ll.) The´r. and the lichens Cladonia furcata (Huds.) Schrad., Leptogium corticola Tayl., Peltigera canina Willd, and P. polydactyla (Neck.) Hoffm. Finally, over 11,000 Abies seedlings were unin- tentionally removed together with the mosses (Ta- ble 1). Removed seedlings were 8.7 cm tall, on av- erage. The removal of Abies seeds is of minor im- portance, since tree cones ripen several months af- ter the moss harvesting season. In total, the field group visited 17 different sites within the boundaries of the reserve (Fig. 2); one site was situated within the core area, six within the zone of restricted exploitation (buffer zone), and the remaining ten within the zone of influence. Ex- traction intensity at 13 of these sites varied between 0.5 and 4.1% of each hectare studied, and was 2.14% on average. Four of these sites are owned 520 [VOL. 104 THE BRYOLOGIST by the federal government and 13 are owned by local communities. Most forests were dominated by Abies religiosa, but at some sites Juniperus mon- ticola was also abundant. The average gap size in the mossy layer after extraction was 0.48 m 2 . The smallest gap measured 0.026 m 2 , and the largest gap measured 305 ϫ 498 cm or 15.18 m 2 . According to the information obtained in the Central de Abastos in Mexico City, within the re- serve area three similar groups operate during the November-December period each year. Another three groups of harvesters, collect mosses in neigh- boring areas, also in eastern Michoaca´n, and an ad- jacent area of the State of Me´xico. In general, all harvesters collect and pack the mosses in the same way, and the studied group could be considered typical in this sense. DISCUSSION It is debatable if moss gathering within a pro- tected area should be allowed. Since many aspects of the ecology of the monarch butterfly remain un- known (Espejo et al. 1992) human activity in the core area of the ‘‘Monarch Butterfly’’ Biosphere Reserve should especially be discouraged. It should be recognized, however, that the economic viability of harvesting of bryophytes will make bryophyte exploitation likely to continue. In a positive note, bryophytes as a non-timber forest product, may well contribute to economic growth and forest con- servation under proper management. An attempt should be made to better regulate the harvesting of bryophytes. Interestingly, despite the fact that the studied ac- tivities are not officially allowed, the practices cur- rently applied by this group of harvesters are less intense and appear more rational than the kind of bryophyte exploitation permitted under Mexican law. The official norm allows the removal of up to two m wide strips and an extraction of 50% of the total surface area. Probably for fear of detection, the gaps made by the group were narrower, 67 cm on average and the maximum total surface area cleared was 4.1%. According to our observations, recovery of the bryophyte layer occurs mainly through re-growth from the margins as opposed to recruitment. A high margin/area ratio i.e., many small gaps as opposed to few large gaps, would enhance recovery capacity. On the basis of our findings, we recommend Mexican authorities bring the national norm for harvesting bryophytes in line with current practices of moss gatherers. The norm should include guide- lines for patch sizes, and although it indicates a larger surface than that removed in this study (and then, can be reduced) it lacks a timeframe for the recovery of the harvested areas. Special care should be taken to avoid the accidental removal of Abies seedlings, since the slow natural regeneration of the Abies trees poses a problem in the reserve (Instituto Nacional de Ecologı ´a 1996). On the other hand, the exposure of mineral soil after the removal of the bryophyte layer may facilitate the establishment of the seedling radicle. Considering that environmental factors differ in different sites, and also that species composition varies, we suggest that further studies need to be made in order to determine rates and times of re- growth and maximum area to harvest, because ex- tant Mexican guidelines at present are of very gen- eral application. Among the mitigation measures to be included in the Mexican guidelines that should be considered is the maintenance of seeds and seed- lings of forest trees and fungal mycelia. This means that the harvest must be carried out in areas of low seed and seedling densities. Fungal mycelia can be maintained by harvesting thinner layers of mosses, and leaving, as much as possible, the thicker humus layer in place. On the other hand, there is no spec- ification of the species allowed to be collected (it mentions species of the genus Polytrichum, of ac- rocarp growth). It should stress the use of pleuro- carp species, that have higher capacities of recov- ery in harvested areas. In conclusion, however, we reiterate the final re- mark by Peck (1997), based on a study in north- western Oregon, ‘‘investigations of the impact of commercial moss harvest, on not only moss species richness and composition, but on ecosystem func- tions ranging from invertebrate habitat to nutrient cycling will ultimately be necessary before this in- dustry can be regulated in a sustainable manner’’. ACKNOWLEDGMENTS We thank Claudio Delgadillo, Xavier Madrigal San- chez, and Carlos Tena for their valuable comments and suggestions during various stages of this investigation and the Instituto de Ecologı ´a for granting us access to the re- serve. Also to Fernando Villasen˜or Go´mez for the revi- sions of the manuscript. Our special thanks goes to the group of moss gatherers who willingly shared their knowl- edge and experience. LITERATURE CITED CALVERT, W. H. & L. P. BROWER. 1986. 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