impacts of the loss of neotropical highland forests on the species distribution: a case study using...

Impacts of the loss of neotropical highland forests on the speciesdistribution: a case study using resplendent quetzal an

endangered bird species

Sofia Solorzanoa,*, Miguel Angel Castillo-Santiagob,Dario Alejandro Navarrete-Gutierrezb, Ken Oyamaa

aInstituto de Ecologıa, UNAM, Antigua Carretera a Patzcuaro 8701, San Jose de La Huerta, 58190 Morelia, Michoacan, MexicobEl Colegio de la Frontera Sur, Laboratorio de Analisis de Informacion Geografica y Estadıstica, Carretera Panamericana y Periferico Sur,

Barrio de Marıa Auxiliadora, 29290 San Cristobal de las Casas, Chiapas, Mexico

Received 10 July 2002; received in revised form 10 January 2003; accepted 30 January 2003

Abstract

We evaluated the impacts of land-cover changes of evergreen cloud forests on the distribution of quetzals in the four mountainregions of Chiapas, Mexico. The land-cover changes were estimated comparing satellite images of 1970 and 2000. We also simu-lated the amount of remnant forests 50 years in the future. The past and the current distributions of quetzals were based on lit-

erature records and recent field surveys. Our results showed that in 1970 the forests occupied 973 km2, and in 2000, 312 km2, andannual loss from 3.34 to 6.85%. Our simulation suggests that 50 years from now, only one region will maintain evergreen cloudforests. In addition, we documented literature reports of 39 forests inhabited by quetzals, but in 2001 there remained 11 small-

isolated forests. In order to guarantee the survival of this species, conversation efforts must be made to protect the quetzal and itshabitat throughout the entire Mesoamerica region.# 2003 Elsevier Ltd. All rights reserved.

Keywords: Endangered species; Evergreen cloud forests; Mesoamerica; Loss habitat; Resplendent quetzal

1. Introduction

Fragmentation and destruction of forests have beenidentified as the main causes of the decline in biodi-versity around the world (Frankel and Soule, 1981;Soule, 1986; Skole and Tucker, 1993; Cuaron, 2000;Myers et al., 2000). These processes cause destruction ofhabitats, isolation of remnant forests, and edge effects(Lovejoy et al., 1986; Wilcove et al., 1986; Skole andTucker, 1993).

In 1990, 1761 million ha of forest remained in tropicalregions distributed in Latin America and the Caribbean(52%), Africa (30%), Asia and Asian Pacific (18%)regions. These last two zones showed the highest annualrate of forest lost (1.2%), followed by Latin America

and the Caribbean (0.8%) and Africa (0.7%) (FAO,1995).

In Latin America, the annual rate of deforestation inthe highlands (altitude above 1400 m) is 1.1% and inlowlands the loss rate is 0.8%. Cloud forests are inclu-ded within the highland forests and are consideredamong the most threatened ecosystems of the world dueto high biodiversity and endemism (Hamilton et al.,1995; Leo, 1995; Wege and Long, 1995; Rzedowski,1996; Still et al., 1999; Aldrich et al., 2000).

In Latin America, Mesoamerica is an outstandingregion, recognized as a world ‘‘hot spot’’ for biodi-versity in a recent review (Myers et al., 2000). Tropicalhabitats in Mesoamerica contain 4.2% of the world’sendemic vertebrates and 1.7% of all endemic plants. Inthis region, only 20% of the original primary forestremains (231,000 km2). Mesoamerican cloud forestsharbor 9% of the 2534 bird species restricted to cloudforests around the world (Long, 1995; Wege and Long,1995).

0006-3207/03/$ - see front matter # 2003 Elsevier Ltd. All rights reserved.

doi:10.1016/S0006-3207(03)00054-5

Biological Conservation 114 (2003) 341–349

www.elsevier.com/locate/biocon

* Corresponding author: Tel.: +443-322-27-10; fax: +443-322-27-

19.

E-mail address: [email protected] (S. Solorzano).

http://www.sciencedirect.com



http://www.elsevier.com/locate/biocon/a4.3d

mailto:[email protected]

Mexican cloud forests occupy only 0.5–1% of thenational territory and their natural distribution is pat-chy. The isolation of these forests has increased in thelast few decades because of the destruction of bothcloud forests and the connecting lower elevation forests(Rzedowski, 1996). These forests contain 182 bird speciesof which 16% are considered as endemic to Mexico(Escalante et al., 1993), and many of them are recognizedas ‘‘rare, under danger of extinction, or vulnerable’’according to the IUCN (Semarnat, 2002). The Mexicancloud forests harbor 10% (2500 species) of the nationalflora (Rzedowski 1996), and their plant density is 19 timesgreater than in tropical rain forests (Dirzo, 1992).

In southern Mexico, Cuaron (2000) estimated anannual deforestation rate of 3.3% in cloud forests, incontrast with the 1.6–2.1% for tropical rain forestsestimated by Mendoza and Dirzo (1999) and De Jong etal. (2000). In spite of the greater loss rate of cloud for-ests, many authors consider rain forests to be the mostthreatened vegetation type of southern Mexico (Men-doza and Dirzo, 1999).

The effects on biodiversity of this loss of habitat havenot been evaluated, but we may expect a decrease in theabundance and geographic range of many species (e.g.Fuller et al., 1998; Beissinger, 2000; Lunney et al., 2000;Melzer et al., 2000; Penn et al., 2000; Wang and Mos-kovits, 2001). The intensity of endangerment and prob-abilities of extinction may be more severe in speciesrestricted to cloud forests. This is the case of theResplendent Quetzal, Pharomachrus mocinno (Trogoni-dae) an endangered bird (Semarnat, 2002) that onlyreproduces in the small cloud forests of seven countriesof Mesoamerica (Skutch, 1944; Wheelwright, 1983;Powell and Bjork, 1994; Solorzano et al., 2000). Thesecountries contain remnant forests with quetzals:Panama (one area), Costa Rica (four), Nicaragua (two),El Salvador (one that is shared with Guatemala andHonduras), Honduras (four), Guatemala (four) andMexico (six). These 22 sites represent the entire dis-tribution of Pharomachrus mocinno around the world(Sibley and Monroe, 1990; S. Solorzano unpubl. data).

In the last century, the intensification of cattle ranchingand agricultural activities resulted in the loss and frag-mentation of Mesoamerican cloud forests (Bubb, 1991;Hamilton et al., 1995; Aldrich et al., 2000; Nadkarni andWheelwright, 2000). It is likely that this destruction hasreduced the range distribution and the abundance ofquetzals (Hanson, 1982; Powell and Bjork, 1995; Solor-zano, 1995). In the current study we evaluate the effectsof land-cover changes of cloud forests on the currentdistribution of quetzals in southern Mexico. We identifythe past breeding habitats of quetzals based on anextensive literature review and compare this distributionwith the current distribution documented by our recentfield surveys. We estimate the land-cover changes ofcloud forests over the last 30 years, and compare the

changes in forest distribution with quetzal distributionin order to evaluate the impacts of deforestation on thebreeding populations of quetzals.

2. Methods

2.1. Study sites

To evaluate the current distribution of quetzals insouthern Mexico we conducted surveys in the state ofChiapas in the mountain zones of the Central Plateau,the Eastern and Northern Mountains, and the SierraMadre (Fig. 1). Conventionally, in Mexico the repro-ductive habitats of quetzals are named as ‘‘bosquemesofilo de montana’’ (Solorzano, 1995; Avila et al.,2000), or cloud forests (Bubb, 1991; Howell and Webb,1995). Based on the observations obtained during oursurveys we considered that this definition of the quet-zals’ breeding habitat was not appropriate because theterm includes many vegetation types (Breedlove, 1981;Rzedowski, 1996) that correspond to both breeding andmigration sites of quetzals (Solorzano, 1995). Therefore,we adopted the classification proposed by Breedlove(1981) who separated the different vegetation typescontained in cloud forests into evergreen cloud forests(quetzal breeding areas), temperate forests (migrationareas) and elfin forests (not inhabited by quetzals).

In Chiapas, the evergreen cloud forests (ECF here-after) include the wettest habitat found on mountains orhills at elevations between 1600 and 3200 m with canopytrees between 30 and 60 m in height (Breedlove, 1981).The composition of tree species varied in each localityand detailed floristic descriptions of some evergreencloud forests in Chiapas are available from other studies(Breedlove, 1981; Long and Heath, 1991; Breedlove andLaughin, 2000). In these forests the climate is temperate,humid with an annual rainfall ranging from 2500 to4500 mm. The mean annual temperature is 16 �C andthe lowest temperatures (0 to �5 �C) occur in Januaryand February (Solorzano et al., 2000).

2.2. Field surveys

We visited the forests identified in satellite images asECFs. Recently, many of them had been reported asquetzals’ breeding habitats (Bubb, 1991; Howell andWebb, 1995; Solorzano, 1995; Avila et al., 2000;Macıas-Caballero et al., 2000a, b; Tejeda-Cruz et al.,2000). Additionally, we considered the database ofMarch et al. (1995) that contained all quetzals reportedin the literature since 1950. This database includes geo-graphic location of specimens deposited in two nationaland 20 international museums. All localities that corre-sponded to breeding ECF were positioned on satelliteimages from 1970 and 2000 (ESRI, 1996) and visited

342 S. Solorzano et al. / Biological Conservation 114 (2003) 341–349

during the reproductive season of quetzals (late Januaryto June; Solorzano, 1995) during three consecutive years(1999–2001). Additionally we visited six other large(more than 5 km2) ECF detected on satellite images inthe year 2000, but without previous quetzal reports.

We classified all the visited ECF into the followingcategories: (1) breeding areas: if we observed quetzalsexcavating, incubating or chick rearing, (2) extincthabitats: if the original forest had disappeared andinstead we found the area in other land uses, (3) extir-pated populations: those sites with forests where we hadexpected to find quetzals according to recent reports,but none were found, and (4) potential ECF: foreststhat we could not visit because of security reasons (e.g.presence of guerrilla activity), but where there wererecent records of quetzals collected in the region. Wevisited the forests with extirpated habitats in early Feb-ruary, when courtship displays are expected. To assessthe absence of quetzals, we returned in April-May whenincubation or chick-rearing occurs. During the field-work we were able to detect disturbance factors such asthe presence of cattle ranching, tree cutting, or recentfires. We then classified these forests as disturbed orundisturbed.

The classification of each ECF was based on a sys-tematic search of quetzals carried out during the peakhours of feeding or courtship activities from 0600 to1000 and from 1600 to 1800 h (Solorzano, 1995). Wewalked trails of 2 km in length in an effort to obtainsights or sounds of quetzals. To increase the detectionprobability, we used calls recorded in past reproductiveseasons. Once we found a potential nest, we observed itfrom a blind until we could document the reproductivebehavior. The number of days in each locality varied,since in some of them 3 days were enough to detectquetzals, while in other sites we stayed 10 days in orderto document the reproductive behavior of quetzals.

The geographic position of each ECF visited and ofeach quetzal record was taken with a GPS receiver.These positions were projected on to satellite imagesfrom the year 2000, allowing us to compare the currentdistribution of both ECFs and quetzals with thatobtained from 1970 images and the literature database.

We estimated the annual loss rate between 2000 and1970 for each physiographic region and simulated thefuture amount of ECFs for the next 50 years based on alinear model of land-cover change. To obtain the annualloss rate (k) (k=lnAt�lnAo)/t, where At is the land

Fig. 1. Distribution of evergreen cloud forests estimated for 1970. The physiographic regions of Chiapas named according to Mullerried (1957).

S. Solorzano et al. / Biological Conservation 114 (2003) 341–349 343

cover estimated at time t, Ao is the initial area esti-mated, and t is the period of time elapsed between thepoints At and Ao. The remnant amount of forests (Ra)during the interval (t) was predicted as Ra=Ao�ekt,where e is the natural logarithm and k is annual loss rate(Cuaron, 1991).

2.3. Image analysis

In order to determine past and present distribution ofECF in Chiapas, two datasets of satellite images wereanalyzed. For 1970, we used Landsat MSS images (Land-sat Multi Spectral Scanner Images) and for 2000 we usedTM (Land Satellite Enhanced Thematic Mapper Images).All images were georeferenced and visually interpreted.

To obtain the area occupied by ECF we projected onto a satellite image of year 2000 the coordinate dataobtained from the field surveys. With ArcView-GISsoftware and its image analysis extension (ESRI, 1996)we digitized polygons enclosing ECF stands and over-laid ancillary maps and data. To support interpretation,we employed a variety of tools, including, field datataken with GPS, digitized elevation data, and both andhistorical and recent vegetation maps (INEGI, 1984,1985, 1986, 1987, 1988) for the year 2000, respectively(Palacio-Prieto et al., 2000). To determine the positionof ECF in 1970, we overlaid the 1970 images on theforests found in 2000. Therefore, we used the ECF stillpresent in 2000 as a reference in order to search formore ECF that had disappeared during the last 30 yearsand were therefore not present in recent images. We digi-tized the polygons that enclosed ECF and we identifiedthe ECF existing in both periods, we compared the chan-ges in land cover by creating a digital database corre-sponding to 1970 and 2000, and we plotted the changes onmaps of each physiographic region (ESRI, 1996).

3. Results and discussion

3.1. Land-cover changes of ECF

The images of 1970 showed 141 ECF totaling 973km2. The largest extension of ECF was in the Sierra

Madre and Northern Mountains (Table 1). These for-ests were distributed between altitudes from 1800 to2300 m and their size varied from 0.04 to 46 km2. Theseforests showed an almost continuous pattern of dis-tribution inside each of the four regions, thereby con-necting the Central Plateau, Eastern and NorthernMountains (Fig. 1) and the enhancing processes ofcolonization, dispersion and migration of both flora andfauna among these regions. In contrast, in 2000 weestimated the ECF occupied 312 km2, a loss of 67%(Table 1). This included the complete destruction of 48ECF and the fragmentation of 63 other remnant forests.The intensity of loss was different in the four physio-graphic regions of Chiapas (Table 1). The most dra-matic loss was in the Eastern Mountain region whereonly 15% of the original extension remained (Table 1).

During the fieldwork, we detected that the currentthreats to the persistence of ECF are the expansion ofcattle ranching and agricultural activities in the remnantECF. These human disturbances initiated in 1940 insouthern Mexico (Masera et al., 1997), are probably themain causes of land transformation in Chiapas(Cuaron, 2000). If the annual loss rate continues overthe next 50 years, the Sierra Madre (Fig. 2) will containthe last remnant ECF (Fig. 3). A plausible solution tostop or reduce the loss of habitats is to include theremnant ECF located in Central Plateau, EasternMountains and Northern Mountains in the nationalsystem of protected areas. This would increase thechance that some remnant forests might survive, giventhat the rate of habitat loss has decreased in protectedareas compared with unprotected ones (Masera et al.,1997; De Jong et al., 2000). The ECF located in thesethree physiographic regions represent natural corridorslocated in the eastern part of Chiapas probably con-nected to the forests of Central America

3.2. Quetzal distribution and the relationship with land-cover changes of ECF

3.2.1. Breeding forestsBased on data from the literature, we identified 39

breeding ECF existing in 1970, which were distributed inthe four mountain regions of Chiapas (Fig. 2). Of these

Table 1

Land-cover changes (km2) of evergreen cloud forests estimated between 1970 and 2000, and the annual loss rate (%). The area occupied by quetzals

represents the sum of every single ECF inhabited by quetzals

Region
Year 1970 Year 2000 Annual loss rate
ECF
Area occupied by quetzal ECF Area occupied by quetzal
Central Plateau
100 29 46 10 4.89
Eastern Mountains
243 220 36 0 6.85
Northern Mountains
271 207 79 35 4.96
Sierra Madre
359 252 151 99 3.34
Total area
973 708 312 144

39, only five of them presently persist. During the field-work, we found six new sites not previously reported inthe literature (Fig. 2). These 11 ECF represent the cur-rent quetzal breeding area and cover 46% of the totalremnant undisturbed forests in Chiapas (Table 1). These

forests vary in size from 6 to 49 km2. In smaller ECF wedid not detect any quetzals. The remnant-breeding areasare located in the Central Plateau, Northern Mountainsand Sierra Madre. The Eastern Mountains is the onlyregion without any current breeding ECF (Fig. 2b).

Fig. 2. Land-cover changes of evergreen cloud forests in each physiographic region: (a) Northern Mountains, (b) Central Plateau and Eastern

Mountains, (c) North of Sierra Madre, and (d) South of Sierra Madre. The dotted areas correspond to 1970 and the black ones to 2000. The symbol

of the circle indicates the forests that formerly contained breeding quetzal populations and the numbers signify current breeding areas.


Currently, the El Triunfo and La Sepultura BiosphereReserves protect 49.21 and 19.76 km2 of breeding habi-tats, respectively, and the other nine breeding forests areunprotected areas that will very likely be lost during thenext 50 years if conservation efforts are not made(Fig. 3). The results indicate that in the near future, onlythe Sierra Madre will contain ECF with breeding quet-

zals, found at two sites. The 11 current sites do notrepresent a real population because in most of them wedetected only 1–3 individuals along one single transect.In contrast, in the El Triunfo Biosphere Reserve weregistered 2–5 pairs in each transect (seven transects).We can not extrapolate these numbers obtained alongthe transects to estimate a population size since the

Fig. 2. (Continued).


distribution of quetzals does not correspond to ahomogenous pattern (S. Solorzano, pers. obs.), butthese numbers represent an index of relative abundance(Bibby et al., 1992). According to some authors (e.g.Gilpin and Soule, 1986; Sutherland, 2000) to maintain apopulation of quetzals in the long-term it might benecessary to increase the number of quetzals in eachremnant breeding forest, as well as to stop the illegalhunting that occurs in these areas.

3.2.2. Extinct breeding forestsOf the 39 breeding ECF documented in literature, 13

of them were destroyed completely and another 13 per-sist as very small forests (0.09–1.8 km2) with cattleactivities inside of them and with no quetzals. Anotherthree past breeding ECF were burned during the fires of1998. In these altered remnant forests, we did not recordquetzals and their persistence (in the case of smallestforests) or their recovery (the burned ECF) is not likely.These numbers indicate that the distribution of quetzalshas been reduced by 82% during the last 30 years. Ourstudy shows that the main causes of these extinctionshave been the destruction and fragmentation of ECFcaused by land transformation. The size of the ECF andthe presence of perturbation factors (fires, hunting, andcattle) are factors involved in the persistence of quetzalsthat should be considered in conservation programs.

3.2.3. Forest with extirpated populationsIn this category, we include large ECF’s (55.6 km2

that was the minimum size where quetzals wereobserved) that recently were reported as breeding habi-tats (Howell and Webb, 1995). These three ECF’s withextirpated populations are located in the Central Pla-teau near the Montebello Lakes Park (Fig. 2b). Possiblefactors that promoted the extinction of quetzal popula-tions in these ECF’s include the clearing cuttingobserved at these sites and edge effects resulting from

fragmentation processes (e.g., Lovejoy et al., 1986).Another possible explanation is global climate change.It is possible that these ECFs are undergoing the samemicroclimate changes reported for some Costa Ricancloud forests where amphibian species became extinctbecause of local temperature increases (Pounds et al.,1999; Pounds, 2001). Another reason to suspect micro-climate alteration is the changing behavior of lower ele-vation and warmer habitat bird species such as the keel-billed toucans (Ramphastos sulfuratus) which has beeninvading the higher elevation, and colder, cloud forestsof Costa Rica (Pounds et al., 1999). The same phenom-enon of invasion by this bird species was observed inNicaraguan breeding habitats of quetzals (S. Solorzanopers. obs.). A final reason to suspect climate change isthat in our study area of southern Mexico, there werereports that prolonged droughts caused the extinctionof 24 hygroscopic orchids (Soto, 2001) in cloud forestsbordering the breeding habitats of quetzals. Based onthese observations, the effects of local climate change inthe quetzal breeding areas should be considered as acritical factor in future studies.

3.2.4. Potential breeding ECFThe potential nesting ECF category consists of five

forests, three of them located in the Eastern Mountainsand two on Northern Mountains (Fig. 2) near PuebloNuevo. We could not visit these forests but there arerecent observations of quetzals in these forests (Bubb,1991; Macıas-Caballero et al., 2000a, b). In the ECFlocated on slopes of Eastern Mountains, the size is toosmall (3 km2) to contain quetzal populations, making itprobable that these forests already belong to the cate-gory of extinct habitats.

4. Conclusions

In Mexico, Pharomachrus mocinno is a highly threa-tened species that justifiably is considered under dangerof extinction (Semarnat, 2002). Our results from Mexicoshow that the loss and fragmentation of evergreen cloudforests are the main causes of the threat. This situationis similar to that the observed in Nicaragua, El Salva-dor, some forests of Guatemala (S. Solorzano, pers.obs.) and Honduras (Hanson, 1982). Probably onlyCosta Rica (Powell and Bjork, 1995), Panama, Sierra delas Minas in Guatemala and El Triunfo in Mexico havepopulations over 100 nesting pairs, enough pairs toallow for long-term survival (S. Solorzano, pers. obs.).These populations represent the only four populationsin the world large enough to maintain this species tolong term. The other remnant sites with quetzals inMesoamerica are not sites with healthy populationsbecause the number of individuals recorded in most ofthem is very low (S. Solorzano, pers. obs.). The

Fig. 3. Remnant evergreen cloud forests (ECF) simulated for the next

five decades according to the model employed (Cuaron, 1991).


conservation task of quetzals at global level (Mesome-rica region) requires the protection of evergreen cloudforests, as well as the lower forests that serve as naturalcorridors among them. Otherwise the remnant breedingareas will be converted in small isolated patches. Thegenetic effects on the biodiversity contained in theseforests could represent the extinction of local popula-tions and probably species.

At a global level the IUCN considers Pharomachrusmocinno as a species in the lower risk category (Hilton-Taylor, 2000). However, we recommend that the classi-fication of this bird species should be reconsideredbecause the 22 sites with quetzals that represent theirworld distribution are not strictly populations becauseof the low number of individuals contained in each site.Mesomerica must consider the protection of its biodi-versity and habitats as an integrative program thatallows the migration and dispersion process betweenNorth and Central America.

Acknowledgements

We thank R. Solıs, I. Galvez, M. Grosselet and B.Granados for field assistance. The personnel of Con-servation International, Chiapas, and El Triunfo and LaSepultura biosphere reserves helped us to access somelocalities. Laboratory LAIGE, Ecosur, San CristobalChiapas and the I. Geografıa, UNAM provided thesatellite images. A. Sarabia and D. Sanchez providedtechnical support in image analysis. The comments of L.Lopez Hoffman, M. Quesada and K. Stoner improvedthis paper. S. Solorzano was granted by WWF-Pro-grama Corredor Biologico Mesoamericano (PT37),IDEA WILD and CONACyT (No. 93860).

References

Aldrich, M., Bubb, P., Hostettler, S., Van de Wed, H., 2000. Special

supplement. Tropical montane forests. Bulletin Arborvitae of

WWF-IUCN. The Netherlands.

Avila, L., Tejeda-Cruz, C., Cartas-Heredia, G., Jimenez, J., Morales,

E., Solorzano, S., Megchon, R., 2001. El Triunfo. AICA 169. In:

Arizmendi, M.C., Marquez-Valdelamar, L. (Eds.), Areas de Impor-

tancia para la Conservacion de las Aves en Mexico. UNAM-CON-

ABIO, Mexico City, pp. 289–290.

Beissinger, S.R., 2000. Ecological mechanisms of extinction. Proceed-

ings of the National Academy of Sciences, USA 97, 11688–11689.

Bibby, C.J., Burgess, N.D., Hill, D.A., 1992. Bird Census Techniques.

Academic Press, London.

Breedlove, D.E., 1981. Flora of Chiapas. Part 1. California Academy

Press, California.

Breedlove, D.E., Laughin, R.M., 2000. The Flowering of Man. A

Tzotzil Botany of Zinacantan. Smithsonian Institution Press,

Washington, DC.

Bubb, P., 1991. The Current Situation of the Cloud Forest in North-

ern Chiapas, Mexico. Final Report to Pronatura, San Cristobal de

las Casas, Chiapas, Mexico.

Cuaron, A.D., 1991. Conservacion de los Primates y sus Habitats en el

sur de Mexico. MS Thesis, Universidad Nacional, San Jose, Costa

Rica.

Cuaron, A.D., 2000. Effects of land-cover changes on mammals in a

Neotropical region: a modeling approach. Conservation Biology 14,

1676–1692.

De Jong, B.H.J., Ochoa-Gaona, S., Castillo-Santiago, M.A., Ramırez-

Marcial, N., Cairns, M.A., 2000. Carbon flux and patterns of land-

use/land-cover change in the Selva Lacandona, Mexico. Ambio 29,

504–511.

Dirzo, R., 1992. Diversidad florıstica y estados de conservacion de las

selvas tropicales de Mexico. In: Sarukhan, J., Dirzo, R. (Eds.),

Mexico Ante los Retos de la Biodiversidad. CONABIO, Mexico

City, pp. 283–290.

Escalante, P., Navarro-Siguenza, A.G., Towsend, A., 1993. A geo-

graphic, ecological, and historical analysis of land bird diversity in

Mexico. In: Ramamoorthy, T.P., Bye, R., Lot, A., Fa, J. (Eds.),

Biological Diversity of Mexico. Oxford University Press, New York,

pp. 281–307.

ESRI, 1996. Using ArcView-GIS. Environmental Systems Research

Institute Inc, Redlands, CA.

FAO (Food and Agricultural Organization), 1995. Global Forest

Resources Assessment. Forestry Paper 124. Nations United Orga-

nizations, Rome, Italy.

Frankel, O.H., Soule, M.E., 1981. Conservation and Evolution. Cam-

bridge University Press, Cambridge.

Fuller, R.M., Groom, G.B., Mugisha, S., Ipulet, P., Pomeroy, D.,

Katende, A., Bailey, R., Ogutu-Ohwayo, R., 1998. The integration

of field survey and remote sensing for biodiversity assessment: a case

study in the tropical forests and wetlands of Sango Bay. Biological

Conservation 86, 379–391.

Gilpin, M.E., Soule, M.E., 1986. Minimum viable populations: pro-

cesses of species extinction. In: Soule, M.E. (Ed.), Conservation

Biology. The Science of Scarcity and Diversity. Sinauer Associates,

Inc, Massachusetts, pp. 19–39.

Hamilton, L.S., Juvik, J.O., Scatena, F.N., 1995. Tropical Montane

Cloud Forests. Springer-Verlag, New York.

Hanson, D.A., 1982. Distribution of the quetzals in Honduras. Auk

99, 385.

Hilton-Taylor, C., 2000. 2000 IUCN Red List of Threatened Species,

IUCN (Downloaded May 6 2002). Gland, Switzerland and Cambridge.

Howell, S.N.G., Webb, S., 1995. A Guide to the Birds of Mexico and

Northern Central America. Oxford University Press, London.

INEGI (Instituto Nacional de Estadıstica Geografıa e Informatica),

1984. Cartas de vegetacion y uso del suelo (1:250,000), cartas E15-9,

E15-11 y D15-5. 1a edicion. Aguascalientes, Mexico.


1985. Carta de vegetacion y uso del suelo (1:250,000) carta D15-2.

1a edicion. Aguascalientes, Mexico.


1986. Carta de vegetacion y uso del suelo (1:250,000) carta E15-4. 1a

edicion. Aguascalientes, Mexico.


1987. Carta de vegetacion y uso del suelo (1:250,000) carta E15-8. 1a

edicion. Aguascalientes, Mexico.


1988. Carta de vegetacion y uso del suelo (1:250,000). Cartas E15-12

y D15-3. 1a edicion. Aguascalientes, Mexico.

Leo, M., 1995. The importance of tropical montane cloud forest for

preserving vertebrate endemism in Peru: The Rıo Abiseo national

park as a case study. In: Hamilton, L.S., Juvik, O., Scatena, F.N.

(Eds.), Tropical Montane Cloud Forests. Springer-Verlag, New

York, pp. 198–211.

Long, A., 1995. The importance of tropical montane cloud forests for

endemic and threatened birds. In: Hamilton, L.S., Juvik, O., Sca-

tena, F.N. (Eds.), Tropical Montane Cloud Forests. Springer-Ver-

lag, New York, pp. 79–106.


Long, A., Heath, M., 1991. Flora of El Triunfo biosphere reserve,

Chiapas, Mexico: a preliminary floristic inventory and the plant

communities of polygon I. Anales del Instituto de Biologıa, Uni-

versidad Nacional Autonoma de Mexico. Serie Botanica 62, 133–172.

Lovejoy, T.E., Bierregaard Jr., R.O., Rylands, A.B., Malcom, J.R,

Quintela, C.E, Harper, L.H., Brown Jr., K.S., Powell, A.H., Powell,

G.V.N., Schubart, H.O.R, Hays, M.B., 1986. Edge and other effects

of isolation on Amazon forest fragments. In: Soule, M.E. (Ed.),

Conservation Biology. The Science of Scarcity and Diversity.

Sinauer Associates, Inc, Massachusetts, pp. 257–285.

Lunney, D.A., Matthews, C., Moon, C., Ferrier, S., 2000. Incorpor-

ating habitat mapping into practical Koala conservation on private

lands. Conservation Biology 14, 669–680.

Macıas-Caballero, C., Bubb, P., Vidal, R.M., Domınguez-Barradas,

R., 2000a. Cordon Jolvit. AICA 160. In: Arizmendi, M.C., Mar-

quez-Valdelamar, L. (Eds.), Areas de Importancia Para la Con-

servacion de las Aves en Mexico. UNAM-CONABIO, Mexico City,

p. 287.

Macıas-Caballero, C., Bubb, P., Vidal, R.M., Domınguez-Barradas,

R., 2000a. Cordon Jolvit. AICA 160. In: Arizmendi, M.C., Mar-

quez-Valdelamar, L. (Eds.), Areas de Importancia Para la Con-

servacion de las Aves en Mexico. UNAM-CONABIO, Mexico City,

p. 291.

March, I.J., Munoz, A., Navarrete, D.A., Macıas, C., Alba, M.P.,

Fuller, M., Utrera, M.E., Domınguez, R., Vidal, R.M., Bubb, P.,

Reyes, I., Fuentes, I., 1995. Evaluacion y analisis geografico de la

diversidad faunıstica de Chiapas. Primera etapa. El Colegio de la

Frontera Sur-Ecosfera-Pronatura: Chiapas. Informe final para la

Comision Nacional para el Uso y Conocimiento de la Biodiversi-

dad. San Cristobal de las Casas, Chiapas, Mexico.

Masera, O.R., Ordonez, M.J., Dirzo, R., 1997. Carbon emissions from

Mexican forests: current situation and long-term scenarios. Climatic

Change 35, 265–295.

Melzer, A., Carrick, F., Menkhorst, P., Lunney, D., John, B.St., 2000.

Overview, critical assessment, and conservation implications of Koala

distribution and abundance. Conservation Biology 14, 619–628.

Mendoza, E., Dirzo, R., 1999. Deforestation in Lacandonian (South-

east Mexico): evidence for the declaration of the northernmost tro-

pical hot-spot. Biodiversity and Conservation 8, 1621–1641.

Mullerried, F.K.G., 1957. Geologıa de Chiapas. Cultura Editorial,

Mexico City, Mexico.

Myers, N., Mittermeier, R.A., Mittermeier, C.G., da Fonseca, G.A.B.,

Kent, J., 2000. Biodiversity hotspots for conservation priorities.

Nature 403, 853–858.

Nadkarni, N.M., Wheelwright, N.T., 2000. Monteverde. Ecology and

Conservation of a Tropical Cloud Forest. Oxford University Press,

New York.

Palacio-Prieto, J., Bocco, L.G., Velazquez, A., Mas, J.F., Takaki-

Takaki, F., Victoria, A., Luna-Gonzalez, L. Gomez-Rodrıguez, G.,

Lopez-Garcıa, J., Palma-Munoz, M., Trejo-Vazquez, I., Peralta-

Higuera, A, Prado-Molina, J., Rodrıguez-Aguilar, A., Mayorga-

Saucedo, R., Gonzalez-Medrano, F., 2000. La condicion actual de

los recursos forestales en Mexico. Resultados del Inventario Nacio-

nal Forestal 2000. Investigaciones Geograficas. Boletın 43. Instituto

de Geografıa, UNAM. Mexico City, Mexico.

Penn, A.M., Sherwin, W.B., Gordon, G., Lunney, D., Melzer, A.,

Lacy, R.C., 2000. Demographic forescasting in Koala conservation.

Conservation Biology 14, 629–638.

Pounds, J.A.M., 2001. Climate and amphibian declines. Nature 410,

639–640.

Pounds, J.A.M., Fodgen, P.L., Campbell, J.H., 1999. Biological

response to climate change on a tropical mountain. Nature 398,

611–615.

Powell, V.N.G., Bjork, R.D., 1994. Implications of altitudinal migra-

tion for conservation strategies to protect tropical biodiversity: a

case study of the quetzal Pharomachrus mocinno at Monteverde,

Costa Rica. Bird Conservation International 4, 243–255.

Powell, V.N.G., Bjork, R.D., 1995. Implications of intratropical

migration reserve design: a case study using Pharomachrus

mocinno. Conservation Biology 9, 354–362.

Rzedowski, J., 1996. Analisis preliminar de la flora vascular de los

bosques mesofilos de montana de Mexico. Acta Botanica Mexicana

35, 25–37.

Semarnat (Secretarıa de Medio Ambiente y Recursos Naturales),

2002. Norma Oficial Mexicana 059-ECOL- 2001. Diario Oficial de

la Federacion, 6 de marzo del 2002. Mexico City, Mexico.

Sibley, C., Monroe, B.L., 1990. Distribution and Taxonomy of Birds

of the World. Yale University Press, New Haven, MI.

Skole, D., Tucker, C., 1993. Tropical deforestation and habitat frag-

mentation in the Amazon: satellite data from 1978 to 1988. Science

260, 1905–1910.

Skutch, A.F., 1944. Life history of the quetzal. Condor 46, 213–235.

Solorzano, S., 1995. Fenologıa de 22 Especies Arboreas y su Relacion

con la Migracion Altitudinal del Quetzal (Pharomachrus mocinno

mocinno de la Llave 1832) en la Reserva de la Biosfera El Triunfo,

Chiapas, Mexico. Bs Thesis, UNAM, Mexico City, Mexico.

Solorzano, S., Castillo, S., Valverde, T., Avila, L., 2000. Quetzal

abundance in relation to fruit availability in a cloud forest in

Southeastern Mexico. Biotropica 32, 523–532.

Soto, M.A., 2001. Riqueza y Distribucion Taxonomica de Orchida-

ceae en la Meseta Central de Chiapas. Final report (R225) to

CONABIO. Mexico City, Mexico.

Soule, M.E., 1986. Conservation Biology. The Science of Scarcity and

Diversity. Sinauer Associates, Inc, Massachusetts.

Still, C.J., Foster, P.N., Schneider, S.H., 1999. Simulating the effects

of climate change on tropical montane cloud forests. Nature 398,

608–610.

Sutherland, W.J., 2000. The Conservation Handbook: Research,

Management and Policy. Blackwell Science Publ, London.

Tejeda-Cruz, C., Cartas-Heredia, G., Morales, E., Espinoza, E., Gon-

zalez, P., Nunez, H., Altamirano, M., 2000. La Sepultura. AICA

166. In: Arizmendi, M.C., Marquez-Valdelamar, L. (Eds.), Areas de

Importancia Para la Conservacion de las Aves en Mexico. UNAM-

CONABIO, Mexico City, p. 288.

Wang, Y., Moskovits, D.K., 2001. Tracking fragmentation of natural

communities and changes in land cover: applications of landsat data

for conservation in an urban landscape (Chicago Wilderness). Con-

servation Biology 15, 835–843.

Wege, D.C., Long, A.J., 1995. Key Areas for Threatened Birds in the

Neotropics. Bird Life International. The Burlington Press, London.

Wheelwright, N.T., 1983. The ecology and behavior of Resplendent

Quetzal. The Auk 100, 286–301.

Wilcove, D.S., McLellan, C.H., Dobson, A.P., 1986. Habitat frag-

mentation in temperate zone. In: Soule, M.E. (Ed.), Conservation

Biology. The Science of Scarcity and Diversity. Sinauer Associates,

Inc, Massachusetts, pp. 237–256.


impacts of the loss of neotropical highland forests on the species distribution: a case study using...

Documents