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4 resultados encontrados para: AUTOR: Vásquez Morales, Suria Gisela
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1.
- Artículo con arbitraje
Seed germination and population structure of two endangered tree species: Magnolia perezfarrerae and Magnolia sharpii
Vásquez Morales, Suria Gisela (autora) ; Ramírez Marcial, Neptalí (autor) (1963-) ;
Disponible en línea
Contenido en: Botanical Sciences Vol. 97, no. 1 (January 2019), p. 2-12 ISSN: 2007-4476
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Resumen en: Español | Inglés |
Resumen en español

Antecedentes: Las especies de Magnolia en México se encuentran en riesgo de extinción debido a la fragmentación de su hábitat. Preguntas: ¿Qué tipos de estructura poblacional exhiben Magnolia perezfarrerae y M. sharpii, dos especies endémicas de Chiapas, México? ¿La extrema reducción de las poblaciones presentan alguna afectación en la capacidad reproductiva de las dos especies de Magnolia? ¿Cuál es el potencial de propagación en ambas especies de Magnolia? ¿Es necesario usar tratamientos pregerminativos para incrementar la propagación de ambas especies de Magnolia? Especies estudiadas: Magnolia perezfarrerae A. Vázquez & Gómez-Domínguez y Magnolia sharpii Miranda. Sitios y años de estudio: Los Altos y la Depresión Central de Chiapas, México, de 2015 a 2017. Métodos: En este estudio evaluamos la densidad y distribución de tamaños diamétricos de M. perezfarrerae y M. sharpii en dos poblaciones naturales. Se evaluó su capacidad reproductiva y la germinación ex situ. Resultados: La densidad poblacional de M. perezfarrerae fue de 40-53 ind. ha-1 y 24-83 ind. ha-1 en M. sharpii. La estructura de tamaños varía entre las poblaciones de cada especie: una aparentemente sin problemas de regeneración y otra con distribución discontinua en varias categorías de tamaños. Las semillas presentaron latencia física, química y mecánica. Los tratamientos pregerminativos aplicados fueron efectivos para M. sharpii con 73 % y 64 % para M. perezfarrerae. Conclusiones: La condición actual de las poblaciones de Magnolia es crítica, por lo que su persistencia está comprometida. Las opciones viables de conservación requieren de identificar sitios potenciales para la reintroducción de nuevas poblaciones.

Resumen en inglés

Background: Due to habitat fragmentation many Magnolia species are at risk of extinction in Mexico. Question: What type of population structure is exhibited by Magnolia perezfarrerae and M. sharpii, endemic species of Chiapas, Mexico? Does the extreme reduction in the population of both Magnolia affect their reproductive capacity? What is the propagation potential in both species of Magnolia? Is it necessary to use pregerminative treatments for Magnolia species propagation? Studied species: Magnolia perezfarrerae A. Vázquez & Gómez-Domínguez and Magnolia sharpii Miranda. Study sites and years of study: Highlands and Central Depression of Chiapas, Mexico, from 2015 to 2017. Methods: In this study, the density and distribution of diametric sizes of M. perezfarrerae and M. sharpii were assessed in natural populations. Their reproductive capacity and the ex-situ germination of both species was analyzed. Results: The population density in M. perezfarrerae was 40-53 ind. ha-1, and 24-83 ind. ha-1 in M. sharpii. Size structure varied between populations of each species: one apparently without problems of regeneration, and another with discontinuous distribution in several size categories. The seeds presented physical, chemical and mechanical dormancy. The pre-germination treatments applied proved mostly effective for M. sharpii by 73 % and by 64 % for M. perezfarrerae. Conclusions: The current condition of Magnolia species is critical and their persistence is compromised. Any viable conservation option would need to identify potential sites for the reintroduction of new populations.


2.
- Artículo con arbitraje
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Resumen en: Español | Inglés |
Resumen en español

Para entender la dinámica de la cobertura del suelo en el Parque Nacional Cofre de Perote, se hizo una comparación de las tasas de cambio de uso a dos escalas durante el periodo 1995-2004. A escala meso, se estudiaron estos patrones en toda la superficie del Parque Nacional Cofre de Perote, que es una de las 60 montañas prioritarias de México y también una importante área natural protegida del país ubicada en el estado de Veracruz. A escala micro el estudio se enfocó en el ejido El Conejo que se encuentra dentro de los límites de este parque nacional. Se utilizaron ortofotos digitales del gobierno federal para determinar el cambio en nueve categorías de uso del suelo. En ambas, meso y microescalas, se encontró que las categorías predominantes de cobertura son la agricultura y el bosque. Las probabilidades de cambio de cobertura del suelo en ambas escalas son bajas y tienen valores esencialmente iguales para la mayoría de las categorías de uso, reflejando tanto pequeñas ganancias en cobertura forestal en todo el parque como la efectividad del ejido en el manejo de recursos naturales dentro del parque. Se considera que los hallazgos de este estudio pueden ser aplicables a la situación prevaleciente en los restantes parques nacionales de México; al final se discute la importancia de integrar a los actores locales en el manejo de áreas naturales protegidas.

Resumen en inglés

To understand the dynamics of land cover at the Parque Nacional Cofre de Perote, the rates of change in land use were compared at two different scales during the period 1995-2004. At the meso scale, these patterns were studied throughout the entire Parque Nacional Cofre de Perote, which is one of the 60 priority mountains of Mexico, and an important natural protected area of the country located in the state of Veracruz. At a micro scale, the work was focused in ejido El Conejo, located within the boundaries of this national park. Federal government digital orthophotos were used to determine changes in nine categories of land use. In both, the meso- and micro-scale, it was found that the predominant land cover categories are agriculture and forest. The probabilities of land cover change at both scales are low and essentially the same for most land use categories, reflecting both small gains in forest cover park-wide as well as the effectiveness of the ejido in managing natural resources within the park. The authors consider that the findings of the study may be applicable to the broader situation of national parks in Mexico and, finally, the importance of integrating local stakeholders in the management of natural protected areas is discussed.


Resumen en: Inglés |
Resumen en inglés

Among the many Magnolia species that are endangered by anthropogenic disturbance, some are knownto have the capacity to produce new shoots. Demographic studies are an important tool to evaluate the impact of disturbances as well as the resilience and resistance of endangered species. Our study lookedat the demographic dynamics of two Magnolia schiedeana populations, with an aim to determine therole played by disturbances. The questions were: 1) what demographic trends characterize this species? 2) What differences are there between disturbed and undisturbed populations? 3) Is M. schiedeana adisturbance-resilient species in general? 4) How important is the contribution of the resprouting trait to λ in a population under anthropogenic disturbance? The demographic attributes evaluated were: elasticity, population growth rate (λ), and sensitivity to concrete disturbances (LTRE, Life Table Response Experiment). The results indicated that the λ of the two populations did not differ significantly. The transitions that contributed the most to λ and presented the largest variation were similar in both population sunder study. More than 90% of the contribution came from those individuals measuring ≤ 5 cm in diameter. Surprisingly, M. schiedeana is not sensitive to moderate anthropogenic disturbance. Resprouting contributed to with less than 0.2%.


4.
- Capítulo de libro con arbitraje
*Solicítelo con su bibliotecario/a
Ecology and conservation of endangered species: the case of Magnolias
Sánchez Velásquez, Lázaro Rafael ; Pineda López, María del Rosario (coaut.) ; Vásquez Morales, Suria Gisela (coaut.) ; Avendaño Yáñez, Ma. de la Luz (coaut.) ;
Contenido en: Endangered species: threats, conservation and future research [New York] : Nova Science Publishers, Incorporated, 2016 p. 63-84 ISBN:978-1-63484-404-8
Nota: Solicítelo con su bibliotecario/a
Resumen en: Inglés |
Resumen en inglés

One of the aims of conservation biology is to protect and maintain rare and endangered species in their natural habitats. With fossil remains dating back to between 50 and 65 million years, Magnoliaceae is an ancient family with approximately 330 species of trees and shrubs, half of them native to Asia and the other half to the American continent. The Magnolia genus comprises trees and shrubs from temperate to tropical environments, such as evergreen and deciduous species, distributed between 40 and 3,300 m above sea level. Magnolias have been used in traditional folk medicine in both continents. Many taxa of Magnolia can produce molecules with medical potential for the treatment of cancer, for example, as well as for the production of pesticides in agriculture. The great number of primary species in northern as well as in tropical ecosystems makes the study of this family an important endeavor from both ecologic and conservation perspectives. Genetic studies show that whereas some populations present a high diversity, diversity is low in others, and there are populations with very low density. The few existing demographic studies of magnolias show a population growth rate (λ) of over one.

The individuals whose contribution to λ is greater in M. dealbata are those measuring over 10 cm in diameter, and in M. schiedeana and M. mexicana, those with a diameter of less than 5 cm. It is possible to keep long-standing seed banks of magnolias, and the best pre-germinate treatments are: Stratification at 4-10oC for only 13 days, for some tropical magnolias, and cold stratification (0 to 8°C) for a period of 3 to 6 months for temperate-climate magnolias. Since, as the evidence shows, magnolias are plants of intermediate and late-successional status, successional reforestation seems to be the most appropriate reforestation strategy; i.e., to plat the magnolias where a previous cover of fastgrowing plants of different species at their early successional stages already exists. As a great deal of magnolias has a good sprouting capacity, and sprouts grow much faster than seedlings, they can quickly occupy the existing gaps. These entire traits are important to consider in any reintroduction, conservation or restoration programs.