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W estern Mexico: a significant centre of avian endem ism and challenge for conservation action A. Townsend Peterson and Adolfo G. Navarro-Sigüenza Cotinga 14 (2000): 42–46

El endemismo de aves en México está concentrado en el oeste del país, pues entre el 40 al 47% de las aves endémicas de México están totalmente restringidas a la región. Presentamos un compendio de estos taxones, tanto siguiendo el concepto biológico de especie como el concepto filogenético de especie, documentando la región como un importante centro de endemismo. Discutimos estrategias de conservación en la región, especialmente la idea de ligar reservas para preservar transectos altitudinales de hábitats continuos, desde las tierras bajas hasta las mayores altitudes, en áreas críticas.

Introduction and Transvolcanic Belt of central and western Mexico has been identified as a megadiverse coun­ Mexico were identified as major concentrations of try, with impressive diversity in many taxonomic endemic . This non-coincidence of diversity groups20. Efforts to document the country’s biologi­ and endemism in Mexican biodiversity has since cal diversity are at varying stages of development been documented on different spatial scales13,17 and in different taxa17,19,20 but avian studies have ben­ in additional taxonomic groups17. efited from extensive data already accumulated18 In prior examinations, however, western Mexico and have been able to advance to more detailed lev­ (herein defined as the region from Sonora and Chi­ els of analysis6,12,17. huahua south to , including the coastal In the only recent countrywide survey of avian lowlands, the and Sierra diversity and endemism6, the south-east lowlands Madre del Sur, and Pacific-draining interior basins were identified as important foci of avian species such as the Balsas Basin) has not been appreciated richness. In contrast, the Sierra Madre Occidental sufficiently as a centre of endemism. Our ongoing

Figure 1. Map of Mexico, showing the region here treated as western Mexico, with elevations marked as increasingly darker shades of grey by 1000s of metres of elevation. The three reserve systems discussed in the text are indicated with squares, triangles and circles.

42 Cotinga 14 Western Mexico: a significant centre of avian endemism systematic studies of Mexican birds3,5,9,14–16, as well endemic to Mexico, 99 of which are endemic to west­ as our re-examination of Mexican ern Mexico — 29 in montane regions, 55 in the from alternative viewpoints10, have led us to appre­ lowlands, and 15 in the interior. Twenty-two ciate western Mexico as the primary focus of avian phylogenetic species are restricted to north-west endemism in Mesoamerica. Although the region has Mexico, whereas 42 are restricted to south-west been mentioned as important by previous authors4,7, Mexico. the purpose of the present contribution is to em­ Overall, western Mexico supports a substantial phasise the biological uniqueness of the region and portion of Mexican bird diversity. In all, 45% of the to explore the implications of this for conservation 100 endemic biological species and 40% of the 250 strategies. endemic phylogenetic species in the country are found only in the west of the country. Indeed, three Endemism in biological and phylogenetic genera —Euptilotis , Deltarhynchus, and Philortyx— species are endemic to the region, as well as two others The dominant taxonomic viewpoint for has sometimes considered separate genera (Neochloe = long been the Biological Species Concept8, as exem­ , Aechmolophus = ). Other regions, plified in North America by the American such as the Sierra Madre Oriental, the Yucatán Ornithologists’ Union’s check-list series2, and has Peninsula, and the southern tip of Baja California11, been the basis for previous examinations of Mexi­ hold smaller concentrations of endemic species. can bird endemism6. Under this concept, 101 species Patterns of endemism in other taxonomic groups are endemic to Mexico, 46 of which are restricted to generally appear to parallel those of birds2,3, sug­ western Mexico — 13 in montane regions, 20 in the gesting that the patterns outlined herein may be lowlands, and 13 in the interior of southern Mexico quite general for Mexican biodiversity. (Table 1). Eleven of these species are restricted to north-west Mexico (south to ), whereas 20 Conservation challenges occur only in south-west Mexico (Jalisco south to The enormous concentration of endemic birds in Oaxaca). western Mexico represents both a challenge and an Alternative taxonomic viewpoints, such as the opportunity for conservation efforts in Mexico. The Phylogenetic Species Concept and the Evolution­ challenge results from the paucity of reserves es­ ary Species Concept21, are beginning to acquire tablished in the region. Presently, the only greater significance in . These concepts large-scale, effective reserves in western Mexico, emphasise monophyly as a base criterion for iden­ north to south, are El Carricito del Huichol (moun­ tifying potential species taxa. The Phylogenetic tains of northern Jalisco), Chamela/Cuixmala Species Concept then focuses on diagnosability — (coastal lowlands of Jalisco) and the Sierra de distinct populations that are essentially 100% Manantlán (mountains of western Jalisco)1. Large identifiable and distinguishable from other groups. areas of important rich in endemic species The Evolutionary Species Concept refers to the idea both north and south of this limited zone remain of identifying populations that have taken independ­ either unprotected or poorly protected. ent evolutionary trajectories as species; we have The western Mexican centre of endemism also implemented this concept in similar manner as the represents an opportunity. If biologically unique Phylogenetic Species Concept — evolutionary inde­ elements were scattered randomly, without geo­ pendence is signalled by the fixation of distinct graphic foci, development of cost-effective character states. Hence, we applied the two alter­ conservation strategies would be extremely diffi­ native concepts under a single decision rule: we cult13. Rather, given clear concentrations, those same sought sets of populations that exhibit unique areas can represent priority areas for conservation phenotypic character suites that distinguish them attention. from other populations. We detected potential al­ In the present case, we recommend three lati- ternative species units via the scientific literature tudinally separated sets of reserves linked to cross and via inspection of specimens, and checked our altitudinal gradients in western Mexico. In the hypotheses in at least one additional scientific col­ north, perhaps in and northern Jalisco, link­ lection based on an independent series of specimens. age of El Carricito del Huichol with coastal slope Although these approaches have been applied sites and coastal sites (e.g. Marismas Nacionales in to several avian clades, they have not yet been ap­ coastal and Nayarit) would be an ideal start­ plied to an entire region; we are presently preparing ing point. A nearby, but more southerly reserve a revision under these concepts for Mexican birds10. assemblage could link Sierra de Manantlán with Based on this information, we have been able to the coastal Chamela/Cuixmala complex. The com­ assess levels of endemism across the country11, and bination of these two mega-reserves would summarise species endemic to western Mexico (Ta­ effectively protect habitat appropriate for almost ble 1). Under this view, c. 250 bird species are all of the ‘northern’ species endemic to the region,

43 Cotinga 14 Western Mexico: a significant centre of avian endemism

T a b l e 1 . Summary of distributions of 99 bird species spadiceus), W hite-bellied Becard Pachyramphus albiventris endemic to western Mexico, divided by geography. For (Pachyramphus aglaiae), S inaloa B ecard Pachyramphus uropygialis names representing recognisable phylogenetic species, (Pachyramphus major), W e s te rn T ity ra Tityra griseiceps ( Tityra names of associated biological species taxa recognised by semifasciata), San Blas sanblasianus, W e ste rn A O U 2 are given in parentheses. Com m on names are G re e n Jay Cyanocorax speciosa (Cyanocorax yncas), Happy W ren prelim inary in nature. Thryothorus felix, Sinaloa W ren Thryothorus sinaloa, Rufous-backed R obin Turdus rufopalliatus (Turdus rufopalliatus), G o ld e n V ireo Vireo hypochryseus, W estern Parula Parula pulchra (Parula pitiayumi), Red-breasted Chat Granatellus venustus, Pale-vented Euphonia S p e c ie s Euphonia godmani (Euphonia affinis), W estern Ant-Tanager Habia affinis (Habia rubica), M exican T h ru s h Ta n a g e r Rhodinocichla Northern Mountains: schistacea (Rhodinocichla rosea), W estern Saltator Saltator vigorsii Thick-billed Rhynchopsitta pachyrhyncha, M exican (Saltator coerulescens), Yellow Grosbeak Pheucticus chrysopeplus, W o o d n y m p h Thalurania ridgwayi ( Thalurania colombica), E ared Pacific Bunting Cyanocompsa indigotica (Cyanocompsa parellina), Q u e tz a l Euptilotis neoxenus, Arizona W oodpecker Picoides Orange-breasted Bunting Passerina leclancherii, W estern Olive arizonae (Picoides stricklandii), Imperial W oodpecker Campephilus Sp a rro w Arremonops sumichrasti (Arremonops rufivirgatus), imperialis†, Sinaloa Martin Progne sinaloae, Tufted Jay Cyanocorax Rusty-crowned Ground-sparrow Melozone kieneri, Cinnamon- dickeyi, Olive Nightingale-Thrush Catharus olivascens (Catharus rumped Seedeater Sporophila torqueola (Sporophila torqueola), occidentalis), M oore’s Red Warbler melanauris (Ergaticus Russet-tailed Sparrow Aimophila acuminata (Aimophila ruficauda), ruber), Five-striped Sparrow Amphispiza quinquestriata Yellow-winged Cacique Cacicus melanicterus, Scarlet-headed O rio le Icterus pustulatus (Icterus pustulatus)

Northern and Southern Mountains: W hite-naped Swift Streptoprocne semicollaris, Red-headed Southern Lowlands: T anager Piranga erythrocephala, Flame-colored Tanager Piranga W est Mexican Chachalaca Ortalis poliocephala (Ortalis bidentata (Piranga bidentata) poliocephala), W est Mexican Bobwhite Colinus coyolcos (Colinus virginianus), Lamb’s Screech-Owl Otus lam bi (Otus cooperii), Cinnamon-sided Amazilia wagneri (Am azilia Southern Mountains: Salle’s Quail Cyrtonyx sallei (Cyrtonyx montezumae ), W hite-fronted viridifrons), Doubleday’s Hummingbird doubledayi Sw ift Cypseloides storeri, W hite-tailed Hummingbird (Cynanthus latirostris), Short-crested Coquette Lophornis poliocerca, Blue-capped Hummingbird Eupherusa cyanophrys, brachylopha (Lophornis delattrei), Golden-cheeked W oodpecker Melanerpes chrysogenys, W estern W ren Campylorhynchus humilus Margarita’s Hummingbird Lampornis margaritae (Lampornis amethystinus), W agler’s Toucanet Aulacorhynchus wagleri (Campylorhynchus rufinucha), C o lim a W r e n Uropsila pacifica (Uropsila leucogastra) (Aulacorhynchus prasinus), Grey-crowned W oodpecker Piculus auricularis, W oodhewer Xiphocolaptes omiltemensis (Xiphocolaptes propmeropirhynchus), Mexican Antpitta Grallaria Southern Interior: ochraceiventris (Grallaria guatimalensis), G uerrero Jay Aphelocom a Banded Quail Philortyx fasciatus, Balsas Screech-Owl Otus guerrerensis ( unicolor), S u m ic h ra st’s Jay Aphelocom a seductus, Balsas Pygm y-Owl Glaucidium griscomi (Glaucidium sumichrasti (Aphelocoma coerulescens), W hite-throated Jay minutissimum ), Green-fronted Hummingbird Amazilia viridifrons mirabilis, G uerrero Bush-Tanager Chlorospingus albifrons (Amazilia viridifrons), Dusky Hummingbird Cynanthus sordidus, (Chlorospingus ophthalmicus), Michoacán Towhee Pipilo nigrescens Beautiful Hummingbird Calothorax pulcher, Grey-breasted (Pipilo ocai), Slate-blue Seedeater Amaurospiza relicta W oodpecker Melanerpes hypopolius, (Amaurospiza concolor), D ick ey ’s O rio le Icterus dickeyae (Icterus Xenotriccus mexicanus, B o u ca rd ’s W r e n Campylorhynchus jocosus, graduacauda) Slaty V ireo Vireo brevipennis, Dwarf Vireo Vireo nelsoni, W h ite - throated Towhee Pipilo albicollis, Bridled Sparrow Aimophila m ystacalis, Black-chested Sparrow Aimophila humeralis, O a x a c a Northern Lowlands: W a g le r’s C h ac h alac a Ortalis wagleri (Ortalis poliocephala), M asked S p a rro w Aimophila notosticta † B o b w h ite Colinus ridgwayi (Colinus virginianus), Elegant Quail Callipepla douglasii, Brewster’s Parakeet Aratinga brewsteri † extinct. (Aratinga holochlora), Mexican cyanopygius, Sinaloa Crow sinaloae (Corvus imparatus), Black-throated -Jay Calocitta colliei, Purplish-backed Jay Cyanocorax beecheii, Black-capped Gnatcatcher Polioptila nigriceps, Palm er’s T h ra s h e r Toxostoma palmeri (Toxostoma curvirostre), Sinaloa Vireo including habitat critical to the survival of narrow- Vireo paluster ( Vireo pallens) range endemics such as Mexican Thalurania ridgwayi, Sinaloa Martin Progne Northern and Southern Lowlands: sinaloae and Tufted Jay Cyanocorax dickeyi. Lilac-crowned Parrot Amazona finschi, Mexican Squirrel Cuckoo Perhaps most important — and least protected — Piaya mexicana (Piaya cayana), C o lim a Pygm y-Owl Glaucidium is the southern part of the region. An ideal site palm arum (Glaucidium minutissimum ), Eared Poorwill would be the coastal and interior slopes of the Si­ m cleodii, H a r te r t’s H e rm it Phaethornis mexicanus (Phaethornis erra Madre del Sur, where the southern faunas are superciliosus), Golden-crowned Emerald Chlorostilbon auriceps best developed. Here, appropriate and indeed criti­ (Chlorostilbon canivetii), Citreoline Trogon citreolus, Thick ­ billed Kingbird Tyrannus crassirostris, Flammulated Flycatcher cal habitat is present from near the coast, in the Deltarhynchus flammulatus, Pacific Attila Attila pacificus (Attila vicinity of Atoyac de Alvarez, up into the Sierra de

44 Cotinga 14 Western Mexico: a significant centre of avian endemism

Atoyac to Cerro Teotepec (including the paper park References Parque Nacional Cerro Teotepec), along the Sierra 1. Aid, C. S., Carter, M. F. & Peterson, A. T. (eds.) Madre del Sur to the Parque Ecológico Estatal de (in press) Protected areas of Western Mexico: Omiltemi, and the interior slopes into the Balsas status, management, and needs, with recom­ Basin (Cañon del Zopilote Biosphere Reserve and mendations for potential reserves. Brighton, Reserva Biológica Sierra de Huautla). These areas CO: Colorado Bird Observatory. include the entire geographic distribution of the rare 2. American Ornithologists’ Union (1983) Check­ Short-crested Coquette Lophornis brachylopha and list of North American birds. Sixth edition. Guerrero Jay Aphelocoma guerrerensis, perhaps the Washington, DC: American Ornithologists’ only viable known populations of White-throated Union. Jay Cyanolyca mirabilis and White-tailed Hum­ 3. Benítez-Díaz, H. (1993) Geographic variation in m ingbird Eupherusa poliocerca, and known coloration and morphology of the Acorn Wood­ populations of rarities such as Balsas Screech-Owl pecker. Condor 95: 63–71. Otus seductus, Pileated Flycatcher Xenotriccus 4. Ceballos, G. & Garcia, A. (1995) Conserving mexicanus and Slaty Vireo Vireo brevipennis. This Neotropical biodiversity: The role of dry for­ mega-reserve, including at least four linked areas, ests in western Mexico. Conserv. Biol. 9: 1349– would effectively protect much of the southern com­ 1356. ponent of the western Mexican endemic avifauna. 5. Escalante P, P. & Peterson, A. T. (1992) Geo­ The reserve systems outlined above are in­ graphic variation and species limits in the tended as a framework for bird conservation in hummingbird Thalurania. Wilson Bull. western Mexico. Although they include most of the 104: 205–219. endemic forms in the region, several taxa would 6. Escalante P., P., Navarro S., A. G. & Peterson, A. remain unprotected, including Masked Bobwhite T. (1993) A geographic, historical, and ecologi­ Colinus ridgwayi (Sonora), Brewster’s Parakeet cal analysis of avian diversity in Mexico. In: Aratinga brewsteri (Sonora, Sinaloa and Durango), Ramamoorthy, T. R, Bye, R., Lot, A., & Fa, J. Blue-capped Hummingbird Eupherusa cyanophrys (eds.) The biological diversity of Mexico: ori­ (Sierra de Miahuatlán, Oaxaca), Lamb’s Screech- gins and distribution. New York: Oxford Uni­ Owl Otus lambi (coastal Oaxaca), Cinnamon-sided versity Press. Hummingbird Amazilia wagneri (Sierra Madre del 7. ICBP (1992) Putting biodiversity on the map: Sur, Oaxaca), Balsas Pygmy-Owl Glaucidium priority areas for global conservation. Cam­ griscomi (upper Balsas Basin), and Oaxaca Spar­ bridge, UK: International Council for Bird row Aimophila notosticta (interior Oaxaca). These Preservation. forms are either located in areas that do not present 8. Mayr, E. (1963) species and evolution. opportunities for cross-habitat reserve complexes Cambridge, Mass: Harvard University Press. (e.g. Durango), or are in regions too poorly explored 9. Navarro S., A. G., Peterson, A. T., Escalante R, to permit ready identification of priority areas. P. & Benitez D., H. (1992) Cypseloides storeri: a new species of swift from Mexico. Wilson Bull. Conclusions 104: 55–64. Western Mexico, though long an attraction for or­ 10. Navarro, A. G. & Peterson, A. T. (submitted) An nithologists and birdwatchers, has been alternative species taxonomy for the birds of under-appreciated as a centre of endemism. A sig­ Mexico. nificant portion of Mexican bird diversity is 11. Peterson, A. T. & Navarro, A. G. (1999) Conser­ represented there and indeed almost half of the bird vation priorities depend on taxonomic view­ species unique to the country are restricted to the point: avian endemism in Mexico. Conserv. region. We propose this area as a critical priority Biol. 13: 427–431. for conservation action in the country and suggest 12. Peterson, A. T. & Robbins, M. B. (1999) The im­ that broad strategies for achieving these conserva­ portance of Mexico to North American grass­ tion goals need to be outlined. land bird conservation: a preliminary assess­ ment. Studies in Avian Biol. 19: 258–262. Acknowledgements 13. Peterson, A. T. & Salazar, R. M. (in press) Pro­ We thank our many colleagues for discussions of tected areas of Oaxaca. In: Aid, C. S., Carter, these ideas, in particular Hesiquio Benítez-Díaz and M. F. & Peterson, A. T. (eds.) Protected areas of Octavio Rojas. Thanks to the National Science Foun­ Western Mexico: status, management, and dation, Comisión Nacional para el Uso y needs, with recommendations for potential re­ Conocimiento de la Biodiversidad, Consejo Nacional serves. Brighton, CO: Colorado Bird Observa­ de Ciencia y Tecnología, National Geographic Soci­ tory. ety, and Dirección General de Asuntos del Personal 14. Peterson, A. T. (1992) Phylogeny and rates of Académico de la Universidad Nacional Autónoma molecular evolution in the jays of the genus de México for providing funding. Aphelocoma (). Auk 109: 134–148.

45 Cotinga 14 Western Mexico: a significant centre of avian endemism

15. Peterson, A. T. (1993) Species status of Geotrygon 19. Ramamoorthy, T. R, Bye, R., Lot, A., & Fa, J. carrikeri. Bull. Brit. Orn. Club 113: 166–168. (1993) The biological diversity of Mexico: ori­ 16. Peterson, A. T., Escalante P., P. & Navarro S., A. gins and distribution. New York: Oxford Uni­ G. (1992) Genetic differentiation among Mexi­ versity Press. can populations of Chestnut-capped 20. Wilson, E. O. (1988) Biodiversity. Washington Brush-Finches (Atlapetes brunneinucha) and DC: National Academy Press. Common Bush-Tanagers (Chlorospingus 21. Zink, R. M. & McKitrick, M. C. (1995) The de­ ophthalmicus). Condor 94: 242–251. bate over species concepts and its implications 17. Peterson, A. T., Flores V., O. A., Leon P., L. S., for ornithology. Auk 112: 701–719. Llorente B., J. E., Luis M., M. A., Navarro S., A. G., Torres C., M. G. & Vargas F., I. (1993) A. Townsend Peterson Conservation priorities in northern Middle Natural History Museum, The University of Kan­ America: moving up in the world. Biodiversity sas, Lawrence, Kansas 66045 USA. E-mail: Letters 1: 33–38. [email protected]. 18. Peterson, A. T., Navarro-Sigüenza, A. G. & Benítez-Díaz, H. (1998) The need for contin­ Adolfo G. Navarro-Sigüenza ued scientific collecting: a geographic analy­ Museo de Zoología, Facultad de Ciencias, sis of Mexican bird specimens. Ibis 140: 288– Universidad. Nacional Autónoma de México, 294. México, D.F. 04510 México. E-mail: [email protected].

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