Adolfo Navarro-Sigüenza | Universidad Nacional Autónoma de México (original) (raw)
Papers by Adolfo Navarro-Sigüenza
Ornithology research, Mar 4, 2024
Research Square (Research Square), Dec 16, 2019
Background: Mesoamerica is a remarkable region with a high geological and ecological complexity. ... more Background: Mesoamerica is a remarkable region with a high geological and ecological complexity. Within northern Mesoamerica, the biotic province of the Sierra Madre del Sur (SMS) in southwestern Mexico harbors exceptionally high avian endemism and diversity. Herein, we searched for spatially and temporally concordant phylogeographic patterns, in four bird genera from three distinct avian orders co-distributed across Mesoamerica and investigated their causes through hypothesis testing regarding historical processes. Selected species include endemic and differentiated populations across the montane forests of Mesoamerica, and particularly within the SMS. Results: We gathered mitochondrial DNA sequences for at least one locus from 177 individuals across all species. We assessed genetic structure, demographic history, and defined a framework for the coalescent simulations used in biogeographic hypothesis testing temporal and spatial co-variance. Our analyses suggested shared phylogeographic breaks in areas corresponding to the SMS populations, and between the main montane systems in Mesoamerica, with the Central Valley of
Biota Neotropica, 2004
Patterns of differentiation and geographic variation among populations of the Rhodinocichla compl... more Patterns of differentiation and geographic variation among populations of the Rhodinocichla complex are described. We document the existence of a heretofore unreported population in the vicinity of Acapulco, Guerrero, Mexico. The species occurs in 4-6 allopatric populations, each of which has unique characters that make it diagnosable. We recommend that the complex be considered a single biological species, but at least five phylogenetic species.
Journal of Field Ornithology, Mar 28, 2016
Mexico holds a megadiverse avifauna that includes many endemic elements, as well as rich sets of ... more Mexico holds a megadiverse avifauna that includes many endemic elements, as well as rich sets of species from both farther north and farther south in the Americas. This avifauna, nonetheless, has suffered considerable losses as a consequence of long-term, intensive human activity across the landscape. We review what is known about the Mexican avifauna, specifically its diversity and endemism, and how that knowledge has and has not turned into effective conservation measures to assure the long-term integrity of the avifauna. RESUMEN. Conservación e investigación de biodiversidad sobre las aves de México: Estatus y prioridades México tiene una avifauna megadiversa que incluye muchos elementos endémicos, además de muchas especies que provienen de más al norte o más al sur en las Américas. No obstante, esta avifauna ha sufrido pérdidas considerables debido a la actividad humana intensa a largo plazo a través del país. En esta contribución, resumimos el estatus de conocimiento de la avifauna de México, en particular su diversidad y endemismo, y como estos conocimientos se ha traducido (o no) en medidas eficaces hacia su conservación para asegurar su integridad a largo plazo.
Molecular Phylogenetics and Evolution, Mar 1, 2012
Ibis, Sep 30, 2022
Mining is present in all major biomes worldwide and overlaps strongly with areas of importance fo... more Mining is present in all major biomes worldwide and overlaps strongly with areas of importance for bird conservation. Mining causes multiple types of environmental disturbance, including habitat alteration, increased human presence and persistent heavy metal pollution. Feather coloration and fluctuating asymmetry (random deviation from perfect symmetry between the two sides of the body), especially of elaborate or ornamental characters, have been proposed as potentially useful biomarkers of anthropogenic stress in birds. However, there has been virtually no research on their responses to mining disturbance. Here, we use colour and morphometric measurements and collection location data from museum specimens of the Russet‐crowned Motmot Momotus mexicanus to evaluate how their proximity to mining concessions in south‐central Mexico (Morelos, Guerrero and Oaxaca states) relates to: (1) structural and melanin‐based plumage coloration, and (2) size and fluctuating asymmetry of their distinctive racket‐shaped tail. As a resident, philopatric bird that has been observed nesting directly in contaminated mining waste, motmots may be particularly well suited for addressing this question. In birds collected closer to metal mines, the violet under‐eye spot had decreased UV‐blue chroma and the black eye streak was paler, and there was weaker colour contrast between these adjacent conspicuous facial plumage patches. Body, tail and crown colour and tail length and asymmetry were unaffected by metal mine distance, and no variable was affected by distance to mines extracting non‐metals. Overall, our findings show that aspects of motmot coloration are affected by mining disturbance, probably more from heavy metal contamination rather than other aspects of mine‐related anthropization. Further research is needed to determine whether these effects are due to direct toxicity or to ecological effects such as decreased food availability and to discern whether altered colour of conspicuous patches affects social processes such as mate choice and territorial interactions in populations exposed to mining.
Methods in Ecology and Evolution, Apr 27, 2022
Journal of Biogeography, Mar 20, 2017
Aim Understanding patterns of endemism is a key to deciphering the history of biotas and setting ... more Aim Understanding patterns of endemism is a key to deciphering the history of biotas and setting conservation priorities, but resolving the complexity of distributional patterns quantitatively into areas of endemism is often a difficult task. We report here an analysis of a comprehensive biodiversity dataset for the study of endemism, including virtually all vouchered records available for resident land birds of Mexico (> 100,000 georeferenced data points for all 780 species). Location Mexico. Methods The dataset was analysed with methods that recover areas without assuming prior endemic status for any species. This grid-based method for detecting areas of endemism considers co-occurrence and exclusiveness of species in alternative sets of geographic cells at different spatial resolutions, and finds optimal sets using heuristic, computationally intensive searches. Results We provide the most detailed study of endemism in Mexico to date. Our analysis recovered 17 of 18 previously recognized areas of endemism for Mexican birds, plus many additional areas clearly supported by distributional data totalling 33 areas of endemism at different spatial scales. These areas cover 70% of the country's surface and form a network of nested and partially overlapping regions, some of which are also disjoint. Main conclusions This picture contrasts strongly with previous conceptions of areas of endemism as non-overlapping and spatially simple in terms of scale. Our results reveal that endemism may be spatially complex and shed new light on its role as a key manifestation of biodiversity. Species identified as endemic to these areas comprise > 30% of the land birds of Mexico, with a disproportionately large fraction endangered according to IUCN or SEMARNAT.
Biological Conservation, May 1, 2021
Abstract Increasing evidence indicates that distribution of Neotropical seasonally dry forests (N... more Abstract Increasing evidence indicates that distribution of Neotropical seasonally dry forests (NSDFs) and the survival of the species and communities that inhabit them have been negatively affected by land-use modifications and global climate change (GCC). Protected Areas (PAs) in the region are inefficient and insufficient, and these human-driven threats are expected to further diminish their effectiveness. Research on the long-term effectiveness of these areas for NSDFs protection is therefore a high priority. Here, using birds as a study group, we combined both species distribution modelling and systematic conservation planning techniques to delineate priority areas where species are predicted to persist into the 2050's in the face of GCC and land conversion across the NSDFs distribution. These analyses showed an imperative need to improve the performance of PAs, which covered only ~11% of the NSDFs area and included on average just 13% of species' remaining distributions in the 2050's. The most important opportunity for improving NSDFs conservation status is provided by protecting ~6% more surface area, which could increase the level of protection in the near future: 24.8–28.2% of species distributions on average and 36.9–39.5% for those threatened and Data Deficit species. Besides, 21.6% for these proposed areas coincide with areas currently defined as priority for NSDFs, and 22.8% coincides with priority areas for conservation and research of terrestrial vertebrates. The priority areas identified are mainly distributed in Mexico (70.8%). Our findings pinpoint major opportunities for efficient conservation planning in the region, if there is political will to do so.
Journal of Avian Biology, Dec 31, 2012
Speciation may be influenced by geographic variation in animal signals, particularly when those s... more Speciation may be influenced by geographic variation in animal signals, particularly when those signals are important in reproductive decisions. Here, we describe patterns of geographic variation in the song of rufous-naped wrens Campylorhynchus rufinucha. This species complex is a morphologically variable taxon confined to tropical dry forest areas from Mexico to northwestern Costa Rica. Morphological and genetic analyses suggest that there are at least three partially isolated groups within the complex, including a secondary-contact zone in coastal western Chiapas between the subspecies C. r. humilus and C. r. nigricaudatus. Based on recordings throughout their geographic range, we investigate the effects of historical isolation on song structure and analyze whether genetic differences or climatic conditions explain observed patterns of variation. Our findings, based on a culturally-transmitted and sexually-selected trait, support the hypothesis that three evolutionary units exist within this taxon. Our results suggest that song differences between genetic groups were influenced by historical isolation. We report a strong relationship between vocal dissimilarity and genetic distance, suggesting that differences in vocal characteristics are probably affected by the same factors that drive genetic divergence. We argue that the evolution of song in this taxon is influenced by vicariant events, followed by accumulation of changes in song structure due to several possible factors: cultural drift in song structure; genetic drift in features related to song production; or natural selection acting on features that influence songs, such as body and beak size.
Cladistics, Dec 11, 2018
Neotropical seasonally dry forests (NSDFs) are widely distributed and possess high levels of spec... more Neotropical seasonally dry forests (NSDFs) are widely distributed and possess high levels of species richness and endemism; however, their biogeography remains only partially understood. Using species distribution modelling and parsimony analysis of endemicity, we analysed the distributional patterns of the NSDF avifauna in order to identify their areas of endemism and provide a better understanding of the historical relationships among those areas. The strict consensus trees revealed 17 areas of endemism for NSDFs, which involve four large regions: Baja California, Caribbean-Antilles islands, Mesoamerica and South America. These well-resolved clades are circumscribed by geographical and ecological barriers associated with the Gulf of California, the leading edge of the Caribbean plate, the Tehuantepec Isthmus, the Polochic-Motagua fault, the Nicaragua Depression, the Choc o forest, the Amazon basin and the Andean Cordillera. Relationships among groups of NSDFs found here suggest that evolution of their avifauna involved a mixture of vicariance and dispersal events. Our results support the idea of independent diversification patterns and biogeographical processes in each region, including those previously associated with the Pleistocene Arc Hypothesis for NSDFs of southeastern South America. This study provides a biogeographical framework to open new lines of research related to the biotic diversification of NSDFs.
Molecular Phylogenetics and Evolution, 2014
Among-species phylogeographic concordance provides insight into the common processes driving line... more Among-species phylogeographic concordance provides insight into the common processes driving lineage divergence in a particular region. However, identifying the processes that caused phylogeographic breaks is not always straight forward, and inferring past environmental conditions in combination with documented geologic events is sometimes necessary to explain current patterns. We searched for concordant phylogeographic patterns and investigated their causes in three bird species (Momotus mexicanus, Melanerpes chrysogenys, and Passerina leclancherii) that belong to three different avian orders and are endemic to the northernmost range of the Neotropical dry forest. We obtained mitochondrial DNA (ND2 and COI or cyt b) and nuclear DNA (20454, GAPDH, MUSK, and TGFB) sequences for at least one locus from 162 individuals across all species and defined climatically stable areas using environmental niche model projections for the last 130,000 years to have a paleoenvironmental framework for the phylogeographic results. All three species showed marked phylogeographic structure, with breaks found in roughly similar areas, such as the border between the Mexican states of Guerrero and Oaxaca, and between southern Jalisco and Michoacán. Both of these regions are known biogeographic breaks among other taxa. Patterns of genetic diversity and differentiation were partially compatible with climatically stable areas. Coalescent analyses revealed recent population growth and estimated the deeper haplogroup divergence of all three taxa to have occurred within the last 600,000 years. The phylogeographic patterns found are noteworthy because they are maintained in a relatively small area for bird species with continuous ranges, and highlight a unique situation when compared to phylogeographic patterns found in other studies of Neotropical birds that have stressed the role of geographic barriers to explain intraspecific differentiation. Our results point to a scenario of population isolation resulting in the present phylogeographic structure, likely a result of historical climate fluctuations that have fragmented and reconnected the Neotropical dry forest. This study contributes to a growing body of evidence indicating active diversification of endemic lineages in the northern Neotropical dry forest region.
Biota Neotropica, 2004
Extensive debate has surrounded the application of alternative species concepts in Ornithology. T... more Extensive debate has surrounded the application of alternative species concepts in Ornithology. The biological species concept (BSC) and phylogenetic species concept (PSC) have typically been set in opposition, with extensive debate on the relative merits of each. An alternative is the evolutionary species concept (ESC), which offers a perspective similar to that of the PSC, yet with several significant differences. To date, no major avifauna has been examined and compared among taxonomic viewpoints. Herein, we develop an alternative phylogenetic/evolutionary species taxonomy to the current BSC treatment for the more than 1000 bird species of Mexico. A total of 135 biological species was divided to produce a total of 323 phylogenetic/evolutionary species, 122 of which represent "new" endemic forms in Mexico.
cliffs. Cheng et al. (1983) reported that this species occurs at 2,900-3,900m, but I found them u... more cliffs. Cheng et al. (1983) reported that this species occurs at 2,900-3,900m, but I found them up to 4,500m. Grimmett et al. (1998) gives 3,000-5,200 m (occasionally to 5,700 m) as the altitude in summer for this species. A nesting attempt was recorded in Xiong Se valley (29º27´N 91º40´E), 30 km from Lhasa city. The nest-site was located at 4,020 m on a low cliff, 2.5 m above the ground, next to a stream. On 6 May 2001, I discovered an almost-complete nest, and saw both parents collecting nest material 50 m from the nest-site. The nest was simply constructed from thin roots lined with grass stems, and measured 23.5 cm in diameter, 13.0 cm in depth and 10.5 cm in height. I returned on 29 May and found two chicks, with yellow down and open eyes, being brooded. I measured and weighed them, and repeated this on 4 June (Table 2). On 5 June, the two chicks were found dead below the nest-site having fallen out during a storm the previous night.
InTech eBooks, Nov 14, 2011
Ornithology research, Mar 4, 2024
Research Square (Research Square), Dec 16, 2019
Background: Mesoamerica is a remarkable region with a high geological and ecological complexity. ... more Background: Mesoamerica is a remarkable region with a high geological and ecological complexity. Within northern Mesoamerica, the biotic province of the Sierra Madre del Sur (SMS) in southwestern Mexico harbors exceptionally high avian endemism and diversity. Herein, we searched for spatially and temporally concordant phylogeographic patterns, in four bird genera from three distinct avian orders co-distributed across Mesoamerica and investigated their causes through hypothesis testing regarding historical processes. Selected species include endemic and differentiated populations across the montane forests of Mesoamerica, and particularly within the SMS. Results: We gathered mitochondrial DNA sequences for at least one locus from 177 individuals across all species. We assessed genetic structure, demographic history, and defined a framework for the coalescent simulations used in biogeographic hypothesis testing temporal and spatial co-variance. Our analyses suggested shared phylogeographic breaks in areas corresponding to the SMS populations, and between the main montane systems in Mesoamerica, with the Central Valley of
Biota Neotropica, 2004
Patterns of differentiation and geographic variation among populations of the Rhodinocichla compl... more Patterns of differentiation and geographic variation among populations of the Rhodinocichla complex are described. We document the existence of a heretofore unreported population in the vicinity of Acapulco, Guerrero, Mexico. The species occurs in 4-6 allopatric populations, each of which has unique characters that make it diagnosable. We recommend that the complex be considered a single biological species, but at least five phylogenetic species.
Journal of Field Ornithology, Mar 28, 2016
Mexico holds a megadiverse avifauna that includes many endemic elements, as well as rich sets of ... more Mexico holds a megadiverse avifauna that includes many endemic elements, as well as rich sets of species from both farther north and farther south in the Americas. This avifauna, nonetheless, has suffered considerable losses as a consequence of long-term, intensive human activity across the landscape. We review what is known about the Mexican avifauna, specifically its diversity and endemism, and how that knowledge has and has not turned into effective conservation measures to assure the long-term integrity of the avifauna. RESUMEN. Conservación e investigación de biodiversidad sobre las aves de México: Estatus y prioridades México tiene una avifauna megadiversa que incluye muchos elementos endémicos, además de muchas especies que provienen de más al norte o más al sur en las Américas. No obstante, esta avifauna ha sufrido pérdidas considerables debido a la actividad humana intensa a largo plazo a través del país. En esta contribución, resumimos el estatus de conocimiento de la avifauna de México, en particular su diversidad y endemismo, y como estos conocimientos se ha traducido (o no) en medidas eficaces hacia su conservación para asegurar su integridad a largo plazo.
Molecular Phylogenetics and Evolution, Mar 1, 2012
Ibis, Sep 30, 2022
Mining is present in all major biomes worldwide and overlaps strongly with areas of importance fo... more Mining is present in all major biomes worldwide and overlaps strongly with areas of importance for bird conservation. Mining causes multiple types of environmental disturbance, including habitat alteration, increased human presence and persistent heavy metal pollution. Feather coloration and fluctuating asymmetry (random deviation from perfect symmetry between the two sides of the body), especially of elaborate or ornamental characters, have been proposed as potentially useful biomarkers of anthropogenic stress in birds. However, there has been virtually no research on their responses to mining disturbance. Here, we use colour and morphometric measurements and collection location data from museum specimens of the Russet‐crowned Motmot Momotus mexicanus to evaluate how their proximity to mining concessions in south‐central Mexico (Morelos, Guerrero and Oaxaca states) relates to: (1) structural and melanin‐based plumage coloration, and (2) size and fluctuating asymmetry of their distinctive racket‐shaped tail. As a resident, philopatric bird that has been observed nesting directly in contaminated mining waste, motmots may be particularly well suited for addressing this question. In birds collected closer to metal mines, the violet under‐eye spot had decreased UV‐blue chroma and the black eye streak was paler, and there was weaker colour contrast between these adjacent conspicuous facial plumage patches. Body, tail and crown colour and tail length and asymmetry were unaffected by metal mine distance, and no variable was affected by distance to mines extracting non‐metals. Overall, our findings show that aspects of motmot coloration are affected by mining disturbance, probably more from heavy metal contamination rather than other aspects of mine‐related anthropization. Further research is needed to determine whether these effects are due to direct toxicity or to ecological effects such as decreased food availability and to discern whether altered colour of conspicuous patches affects social processes such as mate choice and territorial interactions in populations exposed to mining.
Methods in Ecology and Evolution, Apr 27, 2022
Journal of Biogeography, Mar 20, 2017
Aim Understanding patterns of endemism is a key to deciphering the history of biotas and setting ... more Aim Understanding patterns of endemism is a key to deciphering the history of biotas and setting conservation priorities, but resolving the complexity of distributional patterns quantitatively into areas of endemism is often a difficult task. We report here an analysis of a comprehensive biodiversity dataset for the study of endemism, including virtually all vouchered records available for resident land birds of Mexico (> 100,000 georeferenced data points for all 780 species). Location Mexico. Methods The dataset was analysed with methods that recover areas without assuming prior endemic status for any species. This grid-based method for detecting areas of endemism considers co-occurrence and exclusiveness of species in alternative sets of geographic cells at different spatial resolutions, and finds optimal sets using heuristic, computationally intensive searches. Results We provide the most detailed study of endemism in Mexico to date. Our analysis recovered 17 of 18 previously recognized areas of endemism for Mexican birds, plus many additional areas clearly supported by distributional data totalling 33 areas of endemism at different spatial scales. These areas cover 70% of the country's surface and form a network of nested and partially overlapping regions, some of which are also disjoint. Main conclusions This picture contrasts strongly with previous conceptions of areas of endemism as non-overlapping and spatially simple in terms of scale. Our results reveal that endemism may be spatially complex and shed new light on its role as a key manifestation of biodiversity. Species identified as endemic to these areas comprise > 30% of the land birds of Mexico, with a disproportionately large fraction endangered according to IUCN or SEMARNAT.
Biological Conservation, May 1, 2021
Abstract Increasing evidence indicates that distribution of Neotropical seasonally dry forests (N... more Abstract Increasing evidence indicates that distribution of Neotropical seasonally dry forests (NSDFs) and the survival of the species and communities that inhabit them have been negatively affected by land-use modifications and global climate change (GCC). Protected Areas (PAs) in the region are inefficient and insufficient, and these human-driven threats are expected to further diminish their effectiveness. Research on the long-term effectiveness of these areas for NSDFs protection is therefore a high priority. Here, using birds as a study group, we combined both species distribution modelling and systematic conservation planning techniques to delineate priority areas where species are predicted to persist into the 2050's in the face of GCC and land conversion across the NSDFs distribution. These analyses showed an imperative need to improve the performance of PAs, which covered only ~11% of the NSDFs area and included on average just 13% of species' remaining distributions in the 2050's. The most important opportunity for improving NSDFs conservation status is provided by protecting ~6% more surface area, which could increase the level of protection in the near future: 24.8–28.2% of species distributions on average and 36.9–39.5% for those threatened and Data Deficit species. Besides, 21.6% for these proposed areas coincide with areas currently defined as priority for NSDFs, and 22.8% coincides with priority areas for conservation and research of terrestrial vertebrates. The priority areas identified are mainly distributed in Mexico (70.8%). Our findings pinpoint major opportunities for efficient conservation planning in the region, if there is political will to do so.
Journal of Avian Biology, Dec 31, 2012
Speciation may be influenced by geographic variation in animal signals, particularly when those s... more Speciation may be influenced by geographic variation in animal signals, particularly when those signals are important in reproductive decisions. Here, we describe patterns of geographic variation in the song of rufous-naped wrens Campylorhynchus rufinucha. This species complex is a morphologically variable taxon confined to tropical dry forest areas from Mexico to northwestern Costa Rica. Morphological and genetic analyses suggest that there are at least three partially isolated groups within the complex, including a secondary-contact zone in coastal western Chiapas between the subspecies C. r. humilus and C. r. nigricaudatus. Based on recordings throughout their geographic range, we investigate the effects of historical isolation on song structure and analyze whether genetic differences or climatic conditions explain observed patterns of variation. Our findings, based on a culturally-transmitted and sexually-selected trait, support the hypothesis that three evolutionary units exist within this taxon. Our results suggest that song differences between genetic groups were influenced by historical isolation. We report a strong relationship between vocal dissimilarity and genetic distance, suggesting that differences in vocal characteristics are probably affected by the same factors that drive genetic divergence. We argue that the evolution of song in this taxon is influenced by vicariant events, followed by accumulation of changes in song structure due to several possible factors: cultural drift in song structure; genetic drift in features related to song production; or natural selection acting on features that influence songs, such as body and beak size.
Cladistics, Dec 11, 2018
Neotropical seasonally dry forests (NSDFs) are widely distributed and possess high levels of spec... more Neotropical seasonally dry forests (NSDFs) are widely distributed and possess high levels of species richness and endemism; however, their biogeography remains only partially understood. Using species distribution modelling and parsimony analysis of endemicity, we analysed the distributional patterns of the NSDF avifauna in order to identify their areas of endemism and provide a better understanding of the historical relationships among those areas. The strict consensus trees revealed 17 areas of endemism for NSDFs, which involve four large regions: Baja California, Caribbean-Antilles islands, Mesoamerica and South America. These well-resolved clades are circumscribed by geographical and ecological barriers associated with the Gulf of California, the leading edge of the Caribbean plate, the Tehuantepec Isthmus, the Polochic-Motagua fault, the Nicaragua Depression, the Choc o forest, the Amazon basin and the Andean Cordillera. Relationships among groups of NSDFs found here suggest that evolution of their avifauna involved a mixture of vicariance and dispersal events. Our results support the idea of independent diversification patterns and biogeographical processes in each region, including those previously associated with the Pleistocene Arc Hypothesis for NSDFs of southeastern South America. This study provides a biogeographical framework to open new lines of research related to the biotic diversification of NSDFs.
Molecular Phylogenetics and Evolution, 2014
Among-species phylogeographic concordance provides insight into the common processes driving line... more Among-species phylogeographic concordance provides insight into the common processes driving lineage divergence in a particular region. However, identifying the processes that caused phylogeographic breaks is not always straight forward, and inferring past environmental conditions in combination with documented geologic events is sometimes necessary to explain current patterns. We searched for concordant phylogeographic patterns and investigated their causes in three bird species (Momotus mexicanus, Melanerpes chrysogenys, and Passerina leclancherii) that belong to three different avian orders and are endemic to the northernmost range of the Neotropical dry forest. We obtained mitochondrial DNA (ND2 and COI or cyt b) and nuclear DNA (20454, GAPDH, MUSK, and TGFB) sequences for at least one locus from 162 individuals across all species and defined climatically stable areas using environmental niche model projections for the last 130,000 years to have a paleoenvironmental framework for the phylogeographic results. All three species showed marked phylogeographic structure, with breaks found in roughly similar areas, such as the border between the Mexican states of Guerrero and Oaxaca, and between southern Jalisco and Michoacán. Both of these regions are known biogeographic breaks among other taxa. Patterns of genetic diversity and differentiation were partially compatible with climatically stable areas. Coalescent analyses revealed recent population growth and estimated the deeper haplogroup divergence of all three taxa to have occurred within the last 600,000 years. The phylogeographic patterns found are noteworthy because they are maintained in a relatively small area for bird species with continuous ranges, and highlight a unique situation when compared to phylogeographic patterns found in other studies of Neotropical birds that have stressed the role of geographic barriers to explain intraspecific differentiation. Our results point to a scenario of population isolation resulting in the present phylogeographic structure, likely a result of historical climate fluctuations that have fragmented and reconnected the Neotropical dry forest. This study contributes to a growing body of evidence indicating active diversification of endemic lineages in the northern Neotropical dry forest region.
Biota Neotropica, 2004
Extensive debate has surrounded the application of alternative species concepts in Ornithology. T... more Extensive debate has surrounded the application of alternative species concepts in Ornithology. The biological species concept (BSC) and phylogenetic species concept (PSC) have typically been set in opposition, with extensive debate on the relative merits of each. An alternative is the evolutionary species concept (ESC), which offers a perspective similar to that of the PSC, yet with several significant differences. To date, no major avifauna has been examined and compared among taxonomic viewpoints. Herein, we develop an alternative phylogenetic/evolutionary species taxonomy to the current BSC treatment for the more than 1000 bird species of Mexico. A total of 135 biological species was divided to produce a total of 323 phylogenetic/evolutionary species, 122 of which represent "new" endemic forms in Mexico.
cliffs. Cheng et al. (1983) reported that this species occurs at 2,900-3,900m, but I found them u... more cliffs. Cheng et al. (1983) reported that this species occurs at 2,900-3,900m, but I found them up to 4,500m. Grimmett et al. (1998) gives 3,000-5,200 m (occasionally to 5,700 m) as the altitude in summer for this species. A nesting attempt was recorded in Xiong Se valley (29º27´N 91º40´E), 30 km from Lhasa city. The nest-site was located at 4,020 m on a low cliff, 2.5 m above the ground, next to a stream. On 6 May 2001, I discovered an almost-complete nest, and saw both parents collecting nest material 50 m from the nest-site. The nest was simply constructed from thin roots lined with grass stems, and measured 23.5 cm in diameter, 13.0 cm in depth and 10.5 cm in height. I returned on 29 May and found two chicks, with yellow down and open eyes, being brooded. I measured and weighed them, and repeated this on 4 June (Table 2). On 5 June, the two chicks were found dead below the nest-site having fallen out during a storm the previous night.
InTech eBooks, Nov 14, 2011