Conservatism of ecological niches in evolutionary time

Science

Volumn 285, Issue 5431, 1999, Pages 1265-1267

  Peterson, A T ^a   Soberon J ^b   Sanchez Cordero V ^b  

^a UNIVERSITY OF KANSAS   (United States)

^b UNIVERSIDAD NACIONAL AUTÓNOMA DE MÉXICO   (Mexico)

Author keywords

[No Author keywords available]

Indexed keywords

EVOLUTION; NICHE; PALEOECOLOGY;

ARTICLE; BIODIVERSITY; ECOLOGY; ENVIRONMENTAL PROTECTION; EVOLUTION; GEOGRAPHY; MEXICO; NATURAL SELECTION; PREDICTION; PRIORITY JOURNAL; SPECIES DIFFERENTIATION;

EID: 0033588039     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.285.5431.1265     Document Type: Article

References (30)

1. M. L. Rosenzweig, Evol. Ecol. 1, 315.
2. R. D. Holt and M. S. Gaines, ibid. 6, 433 (1992); J. S. Brown and N. B. Pavlovic, ibid., p. 360; A. I. Houston and J. M. McNamara, ibid., p. 243; T. J. Kawecki and S. C Stearns, ibid. 7, 155 (1993).
3. R. D. Holt and M. S. Gaines, ibid. 6, 433 (1992); J. S. Brown and N. B. Pavlovic, ibid., p. 360; A. I. Houston and J. M. McNamara, ibid., p. 243; T. J. Kawecki and S. C Stearns, ibid. 7, 155 (1993).
4. R. D. Holt and M. S. Gaines, ibid. 6, 433 (1992); J. S. Brown and N. B. Pavlovic, ibid., p. 360; A. I. Houston and J. M. McNamara, ibid., p. 243; T. J. Kawecki and S. C Stearns, ibid. 7, 155 (1993).
5. R. D. Holt and M. S. Gaines, ibid. 6, 433 (1992); J. S. Brown and N. B. Pavlovic, ibid., p. 360; A. I. Houston and J. M. McNamara, ibid., p. 243; T. J. Kawecki and S. C Stearns, ibid. 7, 155 (1993).
6. H. H. Ross, Taxon 21, 253 (1972); A. J. Boucot, J. Paleontol. 57, 1.
7. H. H. Ross, Taxon 21, 253 (1972); A. J. Boucot, J. Paleontol. 57, 1.
8. B. Huntley, P. J. Bartlein, I. C. Prentice, J. Biogeogr. 16, 551 (1989).
9. R. E. Ricklefs and R. E. Latham, Am. Nat. 139, 1305 (1992).
10. M. R. Orr and T. B. Smith, Trends Ecol. Evol. 13, 502 (1998).
11. T. P. Ramamoorthy et al., Biological Diversity of Mexico: Origins and Distribution (Oxford Univ. Press, New York, 1993).
12. We obtained distributional data for the bird, mammal, and butterfly species or distinct subspecies involved from label data on specimens in the systematic collections cited in A. T. Peterson et al. [Ibis 140, 288, (1998)] and J. E. Llorente-Bousquets et al. [Papilonidae y Pieridae de México: Distribución Geográfica e Ilustración, Univèrsidad Nacional Autónoma de México, México (1997)] as well as the mammal collection of the University of Kansas Natural History Museum and the Colección Nacional de Mamíferos, Instituto de Biología, Universidad Nacional Autónoma de México. Species pairs were selected according to the following criteria: (1) that they constitute clear examples of sister taxa phylogenetically (for example, the only two species in a genus or the only two well-marked subspecies in a species); (2) that they are separated by the Isthmus of Tehuantepec (with the minor exception of taxon pairs with distinct migratory and resident populations); (3) that distributions of both taxa abut the isthmus fairly directly; and (4) that sample sizes available are sufficient to permit testing.
13. We obtained distributional data for the bird, mammal, and butterfly species or distinct subspecies involved from label data on specimens in the systematic collections cited in A. T. Peterson et al. [Ibis 140, 288, (1998)] and J. E. Llorente-Bousquets et al. [Papilonidae y Pieridae de México: Distribución Geográfica e Ilustración, Univèrsidad Nacional Autónoma de México, México (1997)] as well as the mammal collection of the University of Kansas Natural History Museum and the Colección Nacional de Mamíferos, Instituto de Biología, Universidad Nacional Autónoma de México. Species pairs were selected according to the following criteria: (1) that they constitute clear examples of sister taxa phylogenetically (for example, the only two species in a genus or the only two well-marked subspecies in a species); (2) that they are separated by the Isthmus of Tehuantepec (with the minor exception of taxon pairs with distinct migratory and resident populations); (3) that distributions of both taxa abut the isthmus fairly directly; and (4) that sample sizes available are sufficient to permit testing.
14. The following species pairs and confamilial species were included. Birds: Accipiter striatus + Accipiter chionogaster, Buteo nitidus; Amazilia beryllina + Amazilia devillei, Heliomaster longirostris; A. heloisa + A. ellioti, Hylocharis eliciae; Chlorostilbon canivetii + Chlorostilbon salvini, Tilmatura dupontii; Colaptes cafer + Colaptes mexicanoides, Melanerpes uropygialis; Cyanocitta coronata + Cyanocitta ridgwayi, Cyanocorax beecheii; Cyrtonyx montezuma + Cyrtonyx ocellatus, Colinus virginianus; Doricha eliza + Doricha, sp. nov. (A. T. Peterson et al., unpublished data), Campylopterus excellens; Empidonax occidentalis + Empidonax flavescens, Camptostoma imberbe; Ergaticus ruber + Ergaticus versicolor, Pipilo chlorurus; Eugenes fulgens + Eugenes viridiceps, Campylopterus hemileucurus; Falco sparverius + Falco tropicalis, Falco mexicanus; Icterus pustulatus + Icterus sclateri, Pheucticus melanocephalus; Melanotis caerulescens + Melanotis hypoleucum, Toxostoma redivivum; Mimus polyglottes + Mimus gilvus, Toxostoma bendirei; Pheucticus chrysopeplus + Pheucticus aurantiacus, Lanio aurantius; Picoides jardinii + Pocoides sanctorum, Picoides scalaris; Salpinctes obsoletus + Salpinctes neglectus, Thryothorus maculipectus; Sayornis nigricans + Sayornis acuatica, Mionectes oleagineus; Strix varia + Strix fulvescens, Glaucidium gnoma; and Turdus assimilis + Turdus leucachen, Turdus infuscatus. Mammals: Sorex oreopolus + Sorex sclateri, Megasorex gigas; Sorex oreopolus + S. stizodon, Sorex milleri; Artibeus aztecas aztecus + Artibeus aztecas minor, Chrotopterus auritus; Dasyprocta mexicana + Dasyprocta punctata (no other confamilial species are available in Mexico); Habromys lepturus + Habromys lophurus, Neotoma goldmani; Microtus oaxacensis + Microtus guatemalensis, Peromyscus polius; Microtus umbrosus + Microtus guatemalensis, Peromyscus melanophrys; Peromyscus melanocarpus + Peromyscus zarhynchus, Tylomys nudicaudus; Peromyscus megalops + Peromyscus zarhynchus, Peromyscus merriami; and Sciurus colliaei + Sciurus yucatanensis, Ammospermophilus leucurus. Butterflies: Catasticta nimbice nimbice + Catastica nimbice ochracea, Leptophobia aripa; Dismorphia eunoe eunoe + Dismorphia eunoe chamula, Dismorphia amphione; Pereute charops charops + Pereute charops nigricans, Pyrisitia proterpia; Pereute charops leonilae + Pereute charops nigricans, Ascia monuste; and Pyrrhosticta abderus abderus + Pyrrhosticta abderus electryon, Battus eracon. Species names and taxonomic arrangements followed the American Ornithologists' Union (Check-list of North American Birds, American Ornithologists' Union, Washington, DC, ed. 7, 1998) and A. T. Peterson and A. G. Navarro (unpublished data) for birds, D. E. Wilson and Reeder (Mammal Species of the World, Smithsonian Institution Press, Washington, DC, ed. 2, 1993) for mammals, Tyler et al. (Swallowtail Butterflies of the Americas, Gainesville Scientific Publishers, Gainesville, FL, 1994) for Papilionidae, and I. Vargas et al. (J. Lept. Soc. 50, 97, 1996) for Pieridae.
15. The following species pairs and confamilial species were included. Birds: Accipiter striatus + Accipiter chionogaster, Buteo nitidus; Amazilia beryllina + Amazilia devillei, Heliomaster longirostris; A. heloisa + A. ellioti, Hylocharis eliciae; Chlorostilbon canivetii + Chlorostilbon salvini, Tilmatura dupontii; Colaptes cafer + Colaptes mexicanoides, Melanerpes uropygialis; Cyanocitta coronata + Cyanocitta ridgwayi, Cyanocorax beecheii; Cyrtonyx montezuma + Cyrtonyx ocellatus, Colinus virginianus; Doricha eliza + Doricha, sp. nov. (A. T. Peterson et al., unpublished data), Campylopterus excellens; Empidonax occidentalis + Empidonax flavescens, Camptostoma imberbe; Ergaticus ruber + Ergaticus versicolor, Pipilo chlorurus; Eugenes fulgens + Eugenes viridiceps, Campylopterus hemileucurus; Falco sparverius + Falco tropicalis, Falco mexicanus; Icterus pustulatus + Icterus sclateri, Pheucticus melanocephalus; Melanotis caerulescens + Melanotis hypoleucum, Toxostoma redivivum; Mimus polyglottes + Mimus gilvus, Toxostoma bendirei; Pheucticus chrysopeplus + Pheucticus aurantiacus, Lanio aurantius; Picoides jardinii + Pocoides sanctorum, Picoides scalaris; Salpinctes obsoletus + Salpinctes neglectus, Thryothorus maculipectus; Sayornis nigricans + Sayornis acuatica, Mionectes oleagineus; Strix varia + Strix fulvescens, Glaucidium gnoma; and Turdus assimilis + Turdus leucachen, Turdus infuscatus. Mammals: Sorex oreopolus + Sorex sclateri, Megasorex gigas; Sorex oreopolus + S. stizodon, Sorex milleri; Artibeus aztecas aztecus + Artibeus aztecas minor, Chrotopterus auritus; Dasyprocta mexicana + Dasyprocta punctata (no other confamilial species are available in Mexico); Habromys lepturus + Habromys lophurus, Neotoma goldmani; Microtus oaxacensis + Microtus guatemalensis, Peromyscus polius; Microtus umbrosus + Microtus guatemalensis, Peromyscus melanophrys; Peromyscus melanocarpus + Peromyscus zarhynchus, Tylomys nudicaudus; Peromyscus megalops + Peromyscus zarhynchus, Peromyscus merriami; and Sciurus colliaei + Sciurus yucatanensis, Ammospermophilus leucurus. Butterflies: Catasticta nimbice nimbice + Catastica nimbice ochracea, Leptophobia aripa; Dismorphia eunoe eunoe + Dismorphia eunoe chamula, Dismorphia amphione; Pereute charops charops + Pereute charops nigricans, Pyrisitia proterpia; Pereute charops leonilae + Pereute charops nigricans, Ascia monuste; and Pyrrhosticta abderus abderus + Pyrrhosticta abderus electryon, Battus eracon. Species names and taxonomic arrangements followed the American Ornithologists' Union (Check-list of North American Birds, American Ornithologists' Union, Washington, DC, ed. 7, 1998) and A. T. Peterson and A. G. Navarro (unpublished data) for birds, D. E. Wilson and Reeder (Mammal Species of the World, Smithsonian Institution Press, Washington, DC, ed. 2, 1993) for mammals, Tyler et al. (Swallowtail Butterflies of the Americas, Gainesville Scientific Publishers, Gainesville, FL, 1994) for Papilionidae, and I. Vargas et al. (J. Lept. Soc. 50, 97, 1996) for Pieridae.
16. The following species pairs and confamilial species were included. Birds: Accipiter striatus + Accipiter chionogaster, Buteo nitidus; Amazilia beryllina + Amazilia devillei, Heliomaster longirostris; A. heloisa + A. ellioti, Hylocharis eliciae; Chlorostilbon canivetii + Chlorostilbon salvini, Tilmatura dupontii; Colaptes cafer + Colaptes mexicanoides, Melanerpes uropygialis; Cyanocitta coronata + Cyanocitta ridgwayi, Cyanocorax beecheii; Cyrtonyx montezuma + Cyrtonyx ocellatus, Colinus virginianus; Doricha eliza + Doricha, sp. nov. (A. T. Peterson et al., unpublished data), Campylopterus excellens; Empidonax occidentalis + Empidonax flavescens, Camptostoma imberbe; Ergaticus ruber + Ergaticus versicolor, Pipilo chlorurus; Eugenes fulgens + Eugenes viridiceps, Campylopterus hemileucurus; Falco sparverius + Falco tropicalis, Falco mexicanus; Icterus pustulatus + Icterus sclateri, Pheucticus melanocephalus; Melanotis caerulescens + Melanotis hypoleucum, Toxostoma redivivum; Mimus polyglottes + Mimus gilvus, Toxostoma bendirei; Pheucticus chrysopeplus + Pheucticus aurantiacus, Lanio aurantius; Picoides jardinii + Pocoides sanctorum, Picoides scalaris; Salpinctes obsoletus + Salpinctes neglectus, Thryothorus maculipectus; Sayornis nigricans + Sayornis acuatica, Mionectes oleagineus; Strix varia + Strix fulvescens, Glaucidium gnoma; and Turdus assimilis + Turdus leucachen, Turdus infuscatus. Mammals: Sorex oreopolus + Sorex sclateri, Megasorex gigas; Sorex oreopolus + S. stizodon, Sorex milleri; Artibeus aztecas aztecus + Artibeus aztecas minor, Chrotopterus auritus; Dasyprocta mexicana + Dasyprocta punctata (no other confamilial species are available in Mexico); Habromys lepturus + Habromys lophurus, Neotoma goldmani; Microtus oaxacensis + Microtus guatemalensis, Peromyscus polius; Microtus umbrosus + Microtus guatemalensis, Peromyscus melanophrys; Peromyscus melanocarpus + Peromyscus zarhynchus, Tylomys nudicaudus; Peromyscus megalops + Peromyscus zarhynchus, Peromyscus merriami; and Sciurus colliaei + Sciurus yucatanensis, Ammospermophilus leucurus. Butterflies: Catasticta nimbice nimbice + Catastica nimbice ochracea, Leptophobia aripa; Dismorphia eunoe eunoe + Dismorphia eunoe chamula, Dismorphia amphione; Pereute charops charops + Pereute charops nigricans, Pyrisitia proterpia; Pereute charops leonilae + Pereute charops nigricans, Ascia monuste; and Pyrrhosticta abderus abderus + Pyrrhosticta abderus electryon, Battus eracon. Species names and taxonomic arrangements followed the American Ornithologists' Union (Check-list of North American Birds, American Ornithologists' Union, Washington, DC, ed. 7, 1998) and A. T. Peterson and A. G. Navarro (unpublished data) for birds, D. E. Wilson and Reeder (Mammal Species of the World, Smithsonian Institution Press, Washington, DC, ed. 2, 1993) for mammals, Tyler et al. (Swallowtail Butterflies of the Americas, Gainesville Scientific Publishers, Gainesville, FL, 1994) for Papilionidae, and I. Vargas et al. (J. Lept. Soc. 50, 97, 1996) for Pieridae.
17. The following species pairs and confamilial species were included. Birds: Accipiter striatus + Accipiter chionogaster, Buteo nitidus; Amazilia beryllina + Amazilia devillei, Heliomaster longirostris; A. heloisa + A. ellioti, Hylocharis eliciae; Chlorostilbon canivetii + Chlorostilbon salvini, Tilmatura dupontii; Colaptes cafer + Colaptes mexicanoides, Melanerpes uropygialis; Cyanocitta coronata + Cyanocitta ridgwayi, Cyanocorax beecheii; Cyrtonyx montezuma + Cyrtonyx ocellatus, Colinus virginianus; Doricha eliza + Doricha, sp. nov. (A. T. Peterson et al., unpublished data), Campylopterus excellens; Empidonax occidentalis + Empidonax flavescens, Camptostoma imberbe; Ergaticus ruber + Ergaticus versicolor, Pipilo chlorurus; Eugenes fulgens + Eugenes viridiceps, Campylopterus hemileucurus; Falco sparverius + Falco tropicalis, Falco mexicanus; Icterus pustulatus + Icterus sclateri, Pheucticus melanocephalus; Melanotis caerulescens + Melanotis hypoleucum, Toxostoma redivivum; Mimus polyglottes + Mimus gilvus, Toxostoma bendirei; Pheucticus chrysopeplus + Pheucticus aurantiacus, Lanio aurantius; Picoides jardinii + Pocoides sanctorum, Picoides scalaris; Salpinctes obsoletus + Salpinctes neglectus, Thryothorus maculipectus; Sayornis nigricans + Sayornis acuatica, Mionectes oleagineus; Strix varia + Strix fulvescens, Glaucidium gnoma; and Turdus assimilis + Turdus leucachen, Turdus infuscatus. Mammals: Sorex oreopolus + Sorex sclateri, Megasorex gigas; Sorex oreopolus + S. stizodon, Sorex milleri; Artibeus aztecas aztecus + Artibeus aztecas minor, Chrotopterus auritus; Dasyprocta mexicana + Dasyprocta punctata (no other confamilial species are available in Mexico); Habromys lepturus + Habromys lophurus, Neotoma goldmani; Microtus oaxacensis + Microtus guatemalensis, Peromyscus polius; Microtus umbrosus + Microtus guatemalensis, Peromyscus melanophrys; Peromyscus melanocarpus + Peromyscus zarhynchus, Tylomys nudicaudus; Peromyscus megalops + Peromyscus zarhynchus, Peromyscus merriami; and Sciurus colliaei + Sciurus yucatanensis, Ammospermophilus leucurus. Butterflies: Catasticta nimbice nimbice + Catastica nimbice ochracea, Leptophobia aripa; Dismorphia eunoe eunoe + Dismorphia eunoe chamula, Dismorphia amphione; Pereute charops charops + Pereute charops nigricans, Pyrisitia proterpia; Pereute charops leonilae + Pereute charops nigricans, Ascia monuste; and Pyrrhosticta abderus abderus + Pyrrhosticta abderus electryon, Battus eracon. Species names and taxonomic arrangements followed the American Ornithologists' Union (Check-list of North American Birds, American Ornithologists' Union, Washington, DC, ed. 7, 1998) and A. T. Peterson and A. G. Navarro (unpublished data) for birds, D. E. Wilson and Reeder (Mammal Species of the World, Smithsonian Institution Press, Washington, DC, ed. 2, 1993) for mammals, Tyler et al. (Swallowtail Butterflies of the Americas, Gainesville Scientific Publishers, Gainesville, FL, 1994) for Papilionidae, and I. Vargas et al. (J. Lept. Soc. 50, 97, 1996) for Pieridae.
18. -3 degree and reduced to unique latitude-longitude combinations for each species. The four thematic geographic coverages used (annual mean temperature, annual mean precipitation, elevation, and potential vegetation) consisted of raster grids (7 × 7 km pixels) available from the Comisión Nacional para el Uso y Conocimiento de la Biodiversidad (http:// www.conabio.gob/). Geographic distributional predictions were developed based on algorithms designed to evaluate correlations between distributional occurrences and environmental characteristics (niches). The Biodiversity Species Workshop facility developed by David Stockwell (http://biodi.sdsc.edu/) provides an implementation of the Genetic Algorithm for Rule-Set Prediction [GARP; D. R. B. Stockwell and I. R. Noble, Math. Comp. Simul. 33, 385, (1992); D. R. B. Stockwell and D. Peters, Int. J. Geogr. Inf. Sci. 13, 143 (1999)]. GARP works in an iterative process of rule selection, evaluation, testing, and incorporation or rejection: first, a method is chosen from a set of possibilities (logistic regression, bioclimatic rules), and then it is applied to the data and a rule is developed. Predictive accuracy is then evaluated based on 1250 points resampled from the test data set and 1250 points sampled randomly from the study region as a whole. The change in predictive accuracy from one iteration to the next is used to evaluate whether a particular rule should be incorporated into the model. The algorithm runs either 1000 iterations or until convergence. Distributional predictions from GARP may often include areas not inhabited, an effect of the modeling being focused on ecological niches instead of geographic distributions; these commission errors in some cases may be reduced by inclusion of additional ecological dimensions or may require consideration of historical factors that lead to the absence of species from habitable areas.
19. -3 degree and reduced to unique latitude-longitude combinations for each species. The four thematic geographic coverages used (annual mean temperature, annual mean precipitation, elevation, and potential vegetation) consisted of raster grids (7 × 7 km pixels) available from the Comisión Nacional para el Uso y Conocimiento de la Biodiversidad (http:// www.conabio.gob/). Geographic distributional predictions were developed based on algorithms designed to evaluate correlations between distributional occurrences and environmental characteristics (niches). The Biodiversity Species Workshop facility developed by David Stockwell (http://biodi.sdsc.edu/) provides an implementation of the Genetic Algorithm for Rule-Set Prediction [GARP; D. R. B. Stockwell and I. R. Noble, Math. Comp. Simul. 33, 385, (1992); D. R. B. Stockwell and D. Peters, Int. J. Geogr. Inf. Sci. 13, 143 (1999)]. GARP works in an iterative process of rule selection, evaluation, testing, and incorporation or rejection: first, a method is chosen from a set of possibilities (logistic regression, bioclimatic rules), and then it is applied to the data and a rule is developed. Predictive accuracy is then evaluated based on 1250 points resampled from the test data set and 1250 points sampled randomly from the study region as a whole. The change in predictive accuracy from one iteration to the next is used to evaluate whether a particular rule should be incorporated into the model. The algorithm runs either 1000 iterations or until convergence. Distributional predictions from GARP may often include areas not inhabited, an effect of the modeling being focused on ecological niches instead of geographic distributions; these commission errors in some cases may be reduced by inclusion of additional ecological dimensions or may require consideration of historical factors that lead to the absence of species from habitable areas.
20. -3 degree and reduced to unique latitude-longitude combinations for each species. The four thematic geographic coverages used (annual mean temperature, annual mean precipitation, elevation, and potential vegetation) consisted of raster grids (7 × 7 km pixels) available from the Comisión Nacional para el Uso y Conocimiento de la Biodiversidad (http:// www.conabio.gob/). Geographic distributional predictions were developed based on algorithms designed to evaluate correlations between distributional occurrences and environmental characteristics (niches). The Biodiversity Species Workshop facility developed by David Stockwell (http://biodi.sdsc.edu/) provides an implementation of the Genetic Algorithm for Rule-Set Prediction [GARP; D. R. B. Stockwell and I. R. Noble, Math. Comp. Simul. 33, 385, (1992); D. R. B. Stockwell and D. Peters, Int. J. Geogr. Inf. Sci. 13, 143 (1999)]. GARP works in an iterative process of rule selection, evaluation, testing, and incorporation or rejection: first, a method is chosen from a set of possibilities (logistic regression, bioclimatic rules), and then it is applied to the data and a rule is developed. Predictive accuracy is then evaluated based on 1250 points resampled from the test data set and 1250 points sampled randomly from the study region as a whole. The change in predictive accuracy from one iteration to the next is used to evaluate whether a particular rule should be incorporated into the model. The algorithm runs either 1000 iterations or until convergence. Distributional predictions from GARP may often include areas not inhabited, an effect of the modeling being focused on ecological niches instead of geographic distributions; these commission errors in some cases may be reduced by inclusion of additional ecological dimensions or may require consideration of historical factors that lead to the absence of species from habitable areas.
21. 2 approach described above.
22. 2 = 5.10, df = 1, P = 0.0239.
23. T. Wendt, Anales Inst. Biol. UNAM 58, 29 (1989); A. Graham, in Biological Diversity of Mexico: Origins and Distribution, T. P. Ramamoorthy et al., Eds. (Oxford Univ. Press, New York, 1993), p. 109.
24. T. Wendt, Anales Inst. Biol. UNAM 58, 29 (1989); A. Graham, in Biological Diversity of Mexico: Origins and Distribution, T. P. Ramamoorthy et al., Eds. (Oxford Univ. Press, New York, 1993), p. 109.
25. A. Cooper and D. Penny, Science 275, 1109 (1997); T. Stidham, Nature 396, 29 (1998).
26. A. Cooper and D. Penny, Science 275, 1109 (1997); T. Stidham, Nature 396, 29 (1998).
27. D. J. Futuyma, Evolutionary Biology (Sinauer Associates, Sunderland, MA, ed. 3, 1997); E. Mayr, Animal Species and Evolution (Harvard Univ. Press, Cambridge, MA, 1963).
28. D. J. Futuyma, Evolutionary Biology (Sinauer Associates, Sunderland, MA, ed. 3, 1997); E. Mayr, Animal Species and Evolution (Harvard Univ. Press, Cambridge, MA, 1963).
29. A. D. Bradshaw, Philos. Trans. R. Soc. London Ser. B 333, 289 (1991).
30. Supported by the National Science Foundation, Kansas EPSCor, Dirección General de Asuntos del Personal Académico de la Universidad Nacional Autónoma de México, Consejo Nacional de Ciencia y Tecnología, and the National Geographic Society. We thank the Comisión para el Uso y Conocimiento de la Biodiversidad for making geographic coverages available; the curators of scientific collections for providing access to species occurrence data; R. Holt and E. Wiley for discussions; and A. Navarro Sigüenza, J. Llorente Bousquets, D. R. B. Stockwell, R. M. Timm, and H. Benítez Díaz for assistance and access to data.