U-PB AND 40AR/39AR GEOCHRONOLOGY OF RHYOLITIC TUFFS AND LAVAS OF THE SIERRA MADRE OCCIDENTAL SILICIC LARGE IGNEOUS PROVINCE, CHIHUAHUA AND DURANGO BORDER REGION, NORTHERN MEXICO

Arceuthobium blumeri A. Nelson (Blumer's dwarf mistletoe, Viscaceae) is a parasite of Pinus ayacahuite Ehrenberg ex Schlechtendahl (Mexican white pine) and P. strobiformis Engelm. (southwestern white pine) in the Sierra Madre Occidental of northern Mexico (3). It is widely distributed in Chihuahua and Durango and is known from one location in Sonora (3,4). A. globosum Hawksworth & Wiens subsp. globosum (rounded dwarf mistletoe) parasitizes several pine species in the same areas of Mexico, but extends as far south as northern Jalisco (3). In July 2005, S. Quiñonez Barraza observed both of these dwarf mistletoes in Ejido San José del Barranco, Municipio de Badiraguato, Sinaloa, Mexico. A. blumeri was observed parasitizing P. ayacahuite at two locations: Paraje Faldeo Rancho del Oso (25°39′18″N, 107°01′27″W, elevation 2,600 m) and Paraje La Tableta (25°40′14″N, 107°01′33″W, elevation 2,520 m). The host at these two locations was identified by cone and needle morphology (1). Because the mistletoe plants were gray to straw in color and larger than 6 cm, they were clearly A. blumeri and not A. apachecum Hawksworth & Wiens, another dwarf mistletoe that parasitizes P. strobiformis in Arizona, New Mexico, and Coahuila, Mexico (3). A. globosum subsp. globosum was observed parasitizing P. durangensis Martínez at Paraje Puerto del Alacrán (25°39′52″N, 107°00′57″W, elevation 2,650 m). Infection of the pine hosts was severe at all three locations in Sinaloa and many trees were rated as class 5 and 6 by the 6-class dwarf mistletoe rating system (2). Large witches' brooms were formed on P. ayacahuite infected with A. blumeri, but no witches' brooms were formed on infected P. durangensis. Typically, A. globosum does not induce witches' brooms on infected pines (3). Specimens of A. blumeri and A. globosum subsp. globosum were collected and deposited at the Herbario CIIDIR, Instituto Politecnico Nacional, Durango, Dgo., 34220 Mexico. To our knowledge, this is the first report of A. blumeri and A. globosum subsp. globosum from Sinaloa, Mexico. References: (1) A. Farjon and B. T. Styles. Flora Neotrop. Monogr. 75. 1997. (2) F. G. Hawksworth. USDA For. Serv. Gen. Tech. Rep. RM-78, 1977. (3) F. G. Hawksworth and D. Wiens. USDA For. Serv. Agric. Handb. 709, 1996. (4) R. Mathiasen et al. Madroño 55:161, 2008.

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Hydroclimatic variations reveal differences in carbon capture in two sympatric conifers in northern Mexico

PeerJ ◽

10.7717/peerj.7085 ◽

2019 ◽

Vol 7 ◽

pp. e7085 ◽

Cited By ~ 2

Author(s):

Marcos González-Cásares ◽

Marín Pompa-García ◽

Alejandro Venegas-González ◽

Pedro Domínguez-Calleros ◽

José Hernández-Díaz ◽

...

Keyword(s):

Wood Density ◽

Carbon Capture ◽

Ring Width ◽

Terrestrial Ecosystems ◽

Carbon Accumulation ◽

Cupressus Lusitanica ◽

Sierra Madre Occidental ◽

Northern Mexico ◽

Sierra Madre ◽

Annual Carbon

Background Forest ecosystems are considered among the largest terrestrial carbon sinks. The dynamics of forest carbon depend on where the carbon is stored and its responses to environmental factors, as well as the physiology of the trees. Thus, threatened forest regions with high biodiversity have great scientific importance, such as the Sierra Madre Occidental in Mexico. A comparative analysis of tree species can expand the knowledge of the carbon cycle dynamics and ecological processes in this region. Here, we examined the growth, wood density, and carbon accumulation of two threatened species (Pseudotsuga menziesii and Cupressus lusitanica) to evaluate their hydroclimatic responsiveness. Methods The temporal variations in the carbon accumulation patterns of two co-occurring species (P. menziesii and C. lusitanica) and their sensitivity to the local climate were studied using dendroecological techniques, X-ray densitometry, and allometric equations. Results The results show that the annual carbon accumulation in C. lusitanica is positively associated with the temperature during the current fall, while the carbon accumulation in P. menziesii is correlated with the rainfall during the winter of the previous year. The climatic responses are associated with the intra-annual variations of wood density and ring widths for each species. The ring width was strongly correlated with carbon accumulation in C. lusitanica, while the mean wood density was linked to carbon accumulation in P. menziesii. Discussion This study has implications for the carbon accumulation rates of both species, revealing differences in the carbon capture patterns in response to climatic variations. Although the species coexist, there are variation in the hydroclimatic sensitivity of the annual carbon sequestered by trunks of trees, which would be associated with tree-ring width and/or wood density, i.e., directly by anatomical features. The results are relevant to analyze the response to the variability of climatic conditions expected in the near future of the tree communities of Sierra Madre Occidental. Therefore, this study provides a basis for modeling the long-term carbon budget projections in terrestrial ecosystems in northern Mexico.

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New records of ectoparasites for Mexico and their prevalence in the montane shrew Sorex monticolus (Eulipotyphla: Soricidae) at Cerro del Mohinora, Sierra Madre Occidental of Chihuahua, Mexico

Zootaxa ◽

10.11646/zootaxa.4809.2.11 ◽

2020 ◽

Vol 4809 (2) ◽

pp. 393-396

Author(s):

ROXANA ACOSTA ◽

CARMEN GUZMÁN-CORNEJO ◽

FLOR ANGÉLICA QUIÑONEZ CISNEROS ◽

ANGÉLICA ANNAY TORRES QUIÑONEZ ◽

JESÚS A. FERNÁNDEZ

Keyword(s):

New Records ◽

High Elevation ◽

The State ◽

High Altitudes ◽

Southwestern Part ◽

Sierra Madre Occidental ◽

Northern Mexico ◽

Sierra Madre ◽

Protection Area

The Flora and Fauna Protection Area (Área de Protección de Flora y Fauna—ÁPFF) Cerro del Mohinora, is the highest mountain in northern Mexico, reaching an elevation of 3,300 meters. It constitutes one of the last high-elevation islands of alpine and subalpine vegetation known in the Sierra Madre Occidental, in the extreme southwestern part of Chihuahua. The ÁPFF Cerro del Mohinora is located near the state border and limits with Durango and Sinaloa. This type of ecosystem located at high altitudes is in danger of disappearing since only 1% or less of its original extension remains; it is considered a refuge for species with boreal affinities (McDonald et al. 2011).

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