Bird conservation and biodiversity research in Mexico: status and priorities

This is the peer reviewed version of the following article: Peterson, A. T. and Navarro-Sigüenza, A. G. (2016), Bird conservation and biodiversity research in Mexico: status and priorities. J. Field Ornithol.. doi:10.1111/jofo.12146, which has been published in final form at doi:10.1111/jofo.12146. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.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

Assumption- versus data-based approaches to summarizing species’ ranges

This is the peer reviewed version of the following article: Assumption- versus data-based approaches to summarizing species’ ranges, which will be published in final form in Conservation Biology at http://dx.doi.org/10.1111/cobi.12801. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving: http://olabout.wiley.com/WileyCDA/Section/id-828039.html#termsSpecies’ geographic distributions are mapped using various approaches for use in conservation decision-making. Some such mapping efforts have relied on modifications of coarse-resolution extent-of-occurrence maps to downscale them to fine resolutions for conservation planning. This contribution examines (1) the quality of the extent-of-occurrence maps as range summaries, and (2) the utility of refining those maps into fine-resolution distributional hypotheses. In both cases, we found significant problems: the extent-of-occurrence maps are overly simple, omit many known and well-documented populations, and likely frequently include many areas not holding populations. Refinement steps involve typological assumptions about habitat preferences and elevational ranges of species, which can introduce significant error in anticipating species’ true distributional areas; however, as no model evaluation steps are taken to assess predictive ability of models, “bad” models are not noticed. Whereas range summaries derived by these methods may be useful in coarse-grained, global-extent studies, their continued use in on-the-ground conservation challenges at fine resolutions is not advisable. On the other hand, data-driven techniques that integrate primary biodiversity occurrence data with remotely sensed data summarizing environmental dimensions, termed ecological niche modeling or species distribution modeling, with rigorous and quantitative testing of model predictions prior to any use. These data-driven approaches constitute a well-founded, widely accepted alternative with a minimum of assumptions

A Mexican case study on a centralised database from world natural history museums

The present contribution is a case study of the possibilities of using data from world scientific collections to understand the distribution and conservation of Mexican birds. Information was gathered on specimens from Mexico housed in 40 scientific collections in Mexico, the United States, Canada, and Europe. This information was compiled in a centralized database and various analyses were developed to address historical patterns of ornithological investigations in Mexico: current and potential distribution areas of the species; patterns of species richness, endemism and seasonality; and conservation applications

Genetic Variation and Differentiation in Mexican Populations of Common Bush-Tanagers and Chestnut-Capped Brush-Finches

Genetic differentiation among four Mexican populations each of Common Bush-tanagers (Chlorospingus ophthalmicus) and Chestnut-capped Brush-finches (Atlapetes brunneinucha) was evaluated using allozyme electrophoresis. In both species, although levels of within-population variation are moderate, among-population variation is extreme, including fixed differences among populations. Genetic variation is significantly reduced in some populations on the smallest habitat islands. Differentiation is apparently unrelated to geographic distance among populations, and effects of habitat island size and isolation on genetic differentiation are not clear. Populations of the Sierra de los Tuxtlas in Veracruz, however, are strongly differentiated in both species

Molecular systematics and evolution of the Cyanocorax jays

Phylogenetic relationships were studied in the genus Cyanocorax (Aves: Corvidae) and related genera, Psilorhinus and Calocitta, a diverse group of New World jays distributed from the southern United States south to Argentina. Although the ecology and behavior of some species in the group have been studied extensively, lack of a molecular phylogeny has precluded rigorous interpretations in an evolutionary framework. Given the diverse combinations of plumage coloration, size, and morphology, the taxonomy of the group has been inconsistent and understanding of biogeographic patterns problematic. Moreover, plumage similarity between two geographically disjuct species, the Tufted Jay (Cyanocorax dickeyi) from western Mexico and the White-tailed Jay (C. mystacalis) from western Ecuador and Peru, has puzzled ornithologists for decades. Here, a phylogeny of all species in the three genera is presented, based on study of two mitochondrial and three nuclear genes. Phylogenetic trees revealed the non-monophyly of Cyanocorax, and the division of the whole assemblage in two groups: “Clade A” containing Psilorhinus morio, both species in Calocitta, Cyanocorax violaceus, C. caeruleus, C. cristatellus, and C. cyanomelas, and “Clade B” consisting of the remaining species in Cyanocorax. Relationships among species in Clade A were ambiguous and, in general, not well resolved. Within Clade B, analyses revealed the monophyly of the “Cissilopha” jays and showed no evidence for a sister relationship between C. mystacalis and C. dickeyi. The phylogenetic complexity of lineages in the group suggests several complications for the understanding biogeographic patterns, as well as for proposing a taxonomy that is consistent with morphological variation. Although multiple taxonomic arrangements are possible, recommendations are for recognizing only one genus, Cyanocorax, with Psilorhinus and Calocitta as synonyms. Se estudiaron las relaciones filogenéticas en los géneros Cyanocorax, Psilorhinus y Calocitta (Aves: Corvidae), un grupo diverso de urracas del Nuevo Mundo cuyas especies se distribuyen desde el sur de los Estados Unidos hasta Argentina. Aunque la ecología y el comportamiento de algunas especies en el grupo han sido estudiadas extensamente, la falta de una filogenia molecular ha impedido la interpretación rigurosa de estos estudios en un marco evolutivo. Dadas las diversas combinaciones de coloración de plumaje, tamaño y morfología presentes en las especies del grupo, su taxonomía ha sido inconsistente y la interpretación de sus patrones biogeográficos ha sido problemática. Mas aún, la similitud de plumaje en especies que están geográficamente distantes, como Cyanocorax dickeyi del oeste de Mexico y C. mystacalis del oeste de Ecuador y Perú, ha sido difícil de interpretar. Se presenta una filogenia para todas las especies en los tres géneros, basada en el estudio de dos genes nucleares y dos genes mitocondriales. Los árboles filogenéticos mostraron la parafilia de Cyanocorax y la división de todas las especies en dos grupos: “Clado A” en el cual se encuentran Psilorhinus morio, ambas especies Calocitta, Cyanocorax violaceus, C. caeruleus, C. cristatellus, y C. cyanomelas, y “Clado B” en el cual se encuentran el resto de las especies de Cyanocorax. Las relaciones entre especies del Clado A fueron ambiguas y, en general, poco resueltas. En el Clado B, los análisis mostraron la monofilia de las especies en “Cissilopha”, pero no indicaron la monofilia de C. mystacalis + C. dickeyi. La complejidad filogenética de los linajes en el grupo sugiere varias complicaciones en el entendimiento de su biogeografía y taxonomía. Con base en los resultados filogenéticos se reconoce un solo género, Cyanocorax, con Psilorhinus y Calocitta como sinónimos

Constructing check-lists and avifauna-wide reviews: Mexican bird taxonomy revisited

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Hidden endemism, deep polyphyly, and repeated dispersal across the Isthmus of Tehuantepec: Diversification of the White-collared Seedeater complex (Thraupidae: Sporophila torqueola)

© 2018 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. Phenotypic and genetic variation are present in all species, but lineages differ in how variation is partitioned among populations. Examining phenotypic clustering and genetic structure within a phylogeographic framework can clarify which biological processes have contributed to extant biodiversity in a given lineage. Here, we investigate genetic and phenotypic variation among populations and subspecies within a Neotropical songbird complex, the White-collared Seedeater (Sporophila torqueola) of Central America and Mexico. We combine measurements of morphology and plumage patterning with thousands of nuclear loci derived from ultraconserved elements (UCEs) and mitochondrial DNA to evaluate population differentiation. We find deep levels of molecular divergence between two S. torqueola lineages that are phenotypically diagnosable: One corresponds to S. t. torqueola along the Pacific coast of Mexico, and the other includes S. t. morelleti and S. t. sharpei from the Gulf Coast of Mexico and Central America. Surprisingly, these two lineages are strongly differentiated in both nuclear and mitochondrial markers, and each is more closely related to other Sporophila species than to one another. We infer low levels of gene flow between these two groups based on demographic models, suggesting multiple independent evolutionary lineages within S. torqueola have been obscured by coarse-scale similarity in plumage patterning. These findings improve our understanding of the biogeographic history of this lineage, which includes multiple dispersal events out of South America and across the Isthmus of Tehuantepec into Mesoamerica. Finally, the phenotypic and genetic distinctiveness of the range-restricted S. t. torqueola highlights the Pacific Coast of Mexico as an important region of endemism and conservation priority

Determinación de la actividad del radón(222Rn) en fuentes termales de áreas geotérmicas

Se presenta una metodología para determinar la presencia y medición de radón (222Rn) en aguas termales, fumarolas y un pozo geotérmico como un aporte a la matriz de medición en exploración. Se hizo uso del Método ASTM D5072-09, que fue seleccionado ya que se contaba con los materiales, reactivos, el equipo de centelleo líquido y el uso del laboratorio del Centro de Investigaciones y Aplicaciones Nucleares de la Facultad de Ingeniería y Arquitectura de la Universidad de El Salvador (CIAN-FIA-UES). Para la recolección de muestras se seleccionaron 3 zonas; Berlín, San Vicente y Ahuachapán, solamente en la zona de Ahuachapán se pudieron repetir algunos sitios de medición esto debido a la disponibilidad de tiempo. Además, se determinó de manera cualitativa y cuantitativa la presencia de radón en las tres zonas muestreadas, en una fumarola y en un pozo geotérmico. Dentro de los resultados que se obtuvieron se encontraron concentraciones en el rango entre 0.03 ± 1.27 a 20.72 ± 0.67 Bq/L. Siendo la concentración más alta de 20.72 ± 0.67 Bq/L encontrada en las aguas termales de Santa Teresa con una T=69 °C en la zona de Ahuachapán, en esta misma zona se muestreó la fuente El Playón donde se tuvo la oportunidad de fijar tres puntos de recolección de muestra para tomarlas periódicamente en los 3 días que se visitó ese campo geotérmico, a partir de estos resultados se aprecia la dinámica de este gas, ya que la concentración varía respecto al tiempo de medición y el sitio que se ha fijado para la toma de muestra. Sin embargo, es la misma fuente, lo que indica que las concentraciones no se pueden predecir, es de monitorearlas periódicamente, esta variación en la concentración del radón se debe a la litología de la zona, los flujos de agua, permeabilidad del suelo, fallas activas, y las condiciones termodinámicas: presión, temperatura. Asimismo, se determinó la presencia de Radón (222Rn) en la fuente termal El Playón, en la fumarola y en un pozo geotérmico; ubicado estos 3 sitios en la misma zona de Ahuachapán y también se pudo estimar a través de una relación entre parámetros fisicoquímicos y actividad de radón (222Rn), de dónde proviene este gas presente en las fuentes. Los resultados que se obtuvieron de la fuente El Playón en un punto de medición fijado fueron: temperaturas altas, pH ácido, TDS bajos, lo que indica que esta fuente recibe el aporte de radón (222Rn) por parte de la fumarola. A partir de los resultados obtenidos en la investigación se puede concluir que la presencia y medición de radón (222Rn) en aguas termales, fumarolas y un pozo geotérmico puede ser utilizada como técnica de medición en exploración. Sin embargo, con los resultados que se obtuvieron podría afectar en la calidad de agua que las personas utilizan para diferentes usos, por tal motivo se recomienda realizar un estudio para evaluar periódicamente la concentración de radón (222Rn) como en las fuentes: El Salitre, Agua Shuca, El playón, Aguas termales Santa Teresa y la fuente Aponí