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Commercial Bryophyte Harvesting in the Monarch Butterfly Biosphere Reserve,

Sierra Chincua, Michoacan, Mexico

Author(s): Marlene Gmez 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

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The Bryologist 104(4), pp. 517 521Copyright 2001 by the American Bryological and Lichenological Society, Inc.

Commercial Bryophyte Harvesting in the Monarch Butterfly Biosphere Reserve,

Sierra Chincua, Michoacan, Mexico

MARLENE GOMEZ PERALTAHerbario de la Facultad de Biologa, Universidad Michoacana de San Nicolas de Hidalgo, Edificio R, Ciudad

Universitaria, C.P. 58030. Morelia, Michoacan, Mexico; e-mail: [email protected]

JAN H. D. WOLFUniversity of Amsterdam, Institute for Biodiversity and Ecosystem Dynamics, Hugo de Vries-laboratory, Kruislaan3181098 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 $3,500USD, leaving behind a mosaic of gaps of bare soil in the mossy layer. The average gap size was

0.48 m2 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 mountainrange of the Neovolcanic Belt. Remnants of the Si-

erra Chincua in the state of Michoacan, 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-San-

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 ofa 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

Calderon de la Barca described a stall in MexicoCity, of which the platform was covered with bryo-

phytes (Gua Mexico Desconocido 1996). The

bryophytes used to date are mostly in the genera

Campylopus, Hypnum, Leptodontium, Polytrichum,

and Thuidium (Delgadillo & Cardenas 1990). He-

patics are hardly taken and the most popular growthforms are wefts and cushions, as defined by Mag-

defrau (1982). In December, bryophytes are regu-

larly for sale in local markets all over the country.

Mexican law (Secretara 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 thispaper 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 MonarchButterfly Biosphere Reserve encompasses several mu-nicipalities of the state of Michoacan and a small sectionwithin the state of Mexico (Fig. 1). The sanctuary com-prises 2,695 ha, situated between 19391942 N and

1001610020 W (Calvert & Brower 1986; InstitutoNacional de Ecologa-Secretara de Desarrollo Social1993). The largest part of the sanctuary is above 3,000 melevation where the daily temperature is 14C and theannual precipitation 1,000 mm, on average, without apronounced dry season. On mountainous slopes the forests


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2001] 519GOMEZ PERALTA & WOLF: BRYOPHYTE HARVESTING

TABLE 1. Characteristics of the removed moss packsat the Sierra Chincua sanctuary during the 1996 harvest-ing season.

Per day(average)

Per season(29 days)

Number

Weight (kg)Volume (m3)Number ofAbies seedlings

218.9

1,716.1 (7.84)10.9 (0.05)

383.0 (1.75)

6,348.1

49,766.9316.1

11,109.1

FIGURE 2. Location of the extraction sites.

TABLE2. Income of the bryophyte gatherers at the Sierra Chincua reserve during the 1996 harvesting season. Valuesare in Mexican Pesos, roughly valued at 10 N$ to 1$ US.

Numberof packs Income

Costs(housing, food) Net gain

GatheredField leader (El Capitn)Adult workerChild worker

810810567

1,820.001,620.001,134.00

1,000.001,000.00

684.00

820.00620.00450.00

Sold at auctionTruck 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 12 ha where adults

cover about 50700 m2, and children 210700 m2

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 thepack measures roughly 50 30 30 cm and the

pack is tied. An adult takes 38 min. to build a

packa 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 m3 (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. Mull.) Ther.

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


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520 [VOL. 104THE 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 m2. The

smallest gap measured 0.026 m2, and the largest

gap measured 305 498 cm or 15.18 m2

.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 Michoacan, and an ad-

jacent area of the State of Mexico. 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, maywell 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 practicesof 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

Abiestrees poses a problem in the reserve (Instituto

Nacional de Ecologa 1996). On the other hand, the

exposure of mineral soil after the removal of the

bryophyte layer may facilitate the establishment ofthe 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 andthe Instituto de Ecologa for granting us access to the re-serve. Also to Fernando Villasenor Gomez for the revi-sions of the manuscript. Our special thanks goes to thegroup of moss gatherers who willingly shared their knowl-edge and experience.

LITERATURE CITED

CALVERT, W. H. & L. P. BROWER. 1986. The locations ofMonarch Butterfly (Danaus plexippus L.) overwinter-ing colonies in Mexico in relation to topography andclimate. Journal of the Lepidopterists Society 40: 164187.

DELGADILLO M., C. & M. A. CARDENAS. 1990. Manual deBriofitas. Instituto de Biologa. Universidad NacionalAutonoma de Mexico. Segunda edicion. Mexico, D.F.

ESPEJO, S. A., J. L. BRUNHUBER M., G. SEGURA W. & J.IBARRA C. 1992. La vegetacion de la zona de hiber-nacion de la Mariposa Monarca (Danaus plexippus L.)


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en la Sierra Chincua. Tulane Studies in Zoology andBotany, Supplementary publications 1: 7999.

GUAM EXICO DESCONOCIDO. 1996. Fiestas navidenas. No.3. Edicion especial, pp. 3039. Editorial Jilguero.Mexico, D.F.

HALE, M. E. 1979. How to Know the Lichens. The Pic-tured Key Nature Series, 2nd ed. Dubuque, IA.

INSTITUTONACIONAL DEECOLOGA. 1996. Programa de ma-nejo de la Reserva Especial de la Biosfera MariposaMonarca. Proyecto de Conservacion de la Biodiver-sidad en Areas naturales Protegidas Selectas de Mex-ico. Instituto Nacional de Ecologa. Documento deTrabajo. Michoacan y Estado de Mexico.

INSTITUTONACIONAL DEECOLOGA INE-SEDESOL. 1993. Pro-grama de manejo. Reserva Especial de la BiosferaMariposa Monarca. Instituto Nacional de Ecologa-Se-cretara de Desarrollo Social. 53 pp. Mexico, D.F.

MADRIGAL-SANCHEZ, X. 1994. Caractersticas ecologicasgenerales de la region forestal oriental del Estado deMichoacan, Mexico. Universidad Michoacana de SanNicolas de Hidalgo. Morelia, Mich. Mexico.

MAGDEFRAU, K. 1982. Life-forms of bryophytes, pp. 4558. In A. J. E. Smith (ed.), Bryophyte Ecology. Chap-man and Hall, London.

PECK, J. E. 1997. The association of commercially har-vestable bryophytes and their host species in north-western Oregon. THE BRYOLOGIST 100: 383393.

SECRETARA DEL MEDIO AMBIENTE, RECURSOS NATURALESYPESCA. 1996. Norma oficial Mexicana NOM-011-REC-NAT-1996, que establece los procedimientos, criteriosy especificaciones para realizar el aprovechamiento,transporte y almacenamiento de musgo, heno y dora-dilla. Diario Oficial de la Federacion. 26 de junio de1996.

SHARP, A. J., H. CRUM & P. M. ECKEL. 1994. The MossFlora of Mexico. Memoirs of the New York BotanicalGarden, Vol. 69. Bronx.

SMITH, A. J. E. (ED.) 1982. Bryophyte Ecology. Chapmanand Hall, London.

ms. received June 12, 2000; accepted May 25, 2001.

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