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6 resultados encontrados para: TEMA: Sierra de Juárez (Oaxaca, México)
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1.
- Artículo con arbitraje
*Solicítelo con su bibliotecario/a
Land cover changes and fragmentation in mountain neotropical ecosystems of Oaxaca, Mexico under community forest management
Navarro Cerrillo, Rafael María ; Esteves Vieira, Dennis Junio (coaut.) ; Ochoa Gaona, Susana (coaut.) ; De Jong, Bernardus Hendricus Jozeph (coaut.) ; Delgado Serrano, María del Mar (coaut.) ;
Contenido en: Journal of Forestry Research Vol. 30, no. 1 (February 2019), p. 143-155 ISSN: 1993-0607
Nota: Solicítelo con su bibliotecario/a
Resumen en: Inglés |
Resumen en inglés

Changes in land cover have a direct impact on forest ecosystem goods and services. In this study, changes in land cover in Sierra de Juarez–Oaxaca ecosystems were estimated using a consistent processing of Landsat images and OBIA methodology. Additionally, landscape analyses using FRAGSTAT were conducted. In 2014, Sierra de Juarez–Oaxaca was covered by approximately 84% of forests, mainly pine-oak and cloud forests. After extensive deforestation until 2001, this trend was reversed and the forest cover surface area in 2014 was slightly higher than in 1979. The comparison of the landscape structure of the forested and agricultural lands suggests an increase in habitat heterogeneity. However, interspersion and juxtaposition indices, showing the patch shape by patch area and perimeter, were similar throughout the study period (1979–2014). Social and economic drivers can explain this situation: namely, community organization, forest enterprises, payment for ecosystem services programs, and changes of agricultural activity. Communities in the Sierra of Oaxaca have reforested degraded lands, created community forest enterprises, and preserved the forest under conservation schemes like those proposed by the Mexican payment for ecosystem services programs. However, their sustainable management faces internal challenges and has become highly dependent on political and institutional decisions beyond their control.


2.
- Artículo con arbitraje
*Solicítelo con su bibliotecario/a
Changes in butterfly distributions and species assemblages on a Neotropical mountain range in response to global warming and anthropogenic land use
Molina Martínez, Arcángel ; León Cortés, Jorge Leonel (coaut.) ; Regan, Helen M. (coaut.) ; Lewis, Owen T. (coaut.) ; Navarrete Gutiérrez, Darío Alejandro (coaut.) ; Caballero Pérez, Ubaldo (coaut.) ; Luis Martínez, Moisés Armando (coaut.) ;
Contenido en: Diversity and Distributions Vol. 22, no. 11 (November 2016), p. 1085–1098 ISSN: 1472-4642
Nota: Solicítelo con su bibliotecario/a
Resumen en: Inglés |
Resumen en inglés

Aim To assess the changes in the elevational distribution of 151 butterfly species over a period of 22 years (1988–2011) and investigate whether these changes are related to regional global warming and land use change. Location Sierra de Juarez, Oaxaca, Mexico. Methods Butterflies were surveyed at eight sites spanning elevations ranging from 117 m to 3000 m in 1988, and the same sites were resurveyed in 2010– 2011. Changes in the elevational distribution of species and the structure and composition of species assemblages were compared between surveys. The results were interpreted in the context of land use and climate change in the region. Results Butterfly species had shifted their distributions uphill by approximately 145 m on average. Significantly more species (78) showed an uphill shift in their distributions than a downhill shift (32 species). Species occurring above 1000 m elevation had shifted their distribution to an extent that matched the range shift expected under the recorded temperature changes. However, for species occurring below 1000 m elevation, and for all species combined, uphill range shifts were significantly less than expected based solely on the increase in temperature. Land use change over the study period was more pronounced at low elevations, and these butterfly assemblages are now dominated by generalist species. Main conclusions Our results represent the first concrete evidence of shifts in elevation distribution of a large Neotropical butterfly community, attributable to increased regional temperatures. At high elevations, land use change is minimal and climate change appears to be the main driver of changes to distributions and assemblages, and the main conservation threat. However, extensive land use change has been the main driver of changes to butterfly communities at lower elevations.


3.
- Artículo con arbitraje
Climatic and geometric constraints as driving factors of butterfly species richness along a Neotropical elevational gradient
Molina Martínez, Arcángel ; León Cortés, Jorge Leonel (coaut.) ; Regan, Helen M. (coaut.) ;
Contenido en: Journal of Insect Conservation Vol. 17, no. 6 (December 2013), p. 1169-1180 ISSN: 1366-638X
Resumen en: Inglés |
Resumen en inglés

We tested the effects of temperature, humidity and geographical constraints upon butterfly species richness along an elevational gradient covering an altitude ranging from 117 to 3,104 m above sea level (m. a.s.l.), in Southern Mexico. Ten transect sites were sampled 219 times from May 2010 to May 2011, along the elevational gradient to estimate range and population abundance of butterfly species. The effects of temperature, humidity and geometric constraints (mid-domain effects) on species richness along the study gradient were assessed using ordinary least squares regression. A total of 7,005 specimens representing 193 species were recorded. Species richness was relatively higher at elevations between 117 and 1,000 m. a.s.l. with an observed decline in richness values as elevation increased. Butterfly species richness along the study environmental gradient was predominantly determined by climatic constraints, rather than geometric constraints—a mid-domain model fit well only for largeranged Pieridae species. Temperature and humidity explained the variation species richness for the entire butterfly community and for the three families evaluated; however the effect of predictor variables varied according to the measure of species richness and taxonomic family.


4.
Artículo
*En hemeroteca, SIBE-San Cristóbal
Evaluación de la presencia del hongo Batrachochytrium dentrobatidis, en poblaciones de anfibios en área cero extinción (aze) en Oaxaca y Chiapas, México
Cabrera Hernández, Rodolfo ;
Contenido en: Lacandonia. Revista de ciencias de la UNICACH Año 6, Vol. 6, no. 1 (junio 2012), p. 7-16 ISSN: 2007-1000
Bibliotecas: San Cristóbal
Cerrar
SIBE San Cristóbal
51819-10 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-San Cristóbal

Resumen en: Inglés |
Resumen en inglés

A possible consequence of planting genetically modified organisms (GMOs) in centres of crop origin is unintended gene flow into traditional landraces. In 2001, a study reported the presence of the transgenic 35S promoter in maize landraces sampled in 2000 from the Sierra Juarez of Oaxaca, Mexico. Analysis of a large sample taken from the same region in 2003 and 2004 could not confirm the existence of transgenes, thereby casting doubt on the earlier results. These two studies were based on different sampling and analytical procedures and are thus hard to compare. Here, we present new molecular data for this region that confirm the presence of transgenes in three of 23 localities sampled in 2001. Transgene sequences were not detected in samples taken in 2002 from nine localities, while directed samples taken in 2004 from two of the positive 2001 localities were again found to contain transgenic sequences. These findings suggest the persistence or re-introduction of transgenes up until 2004 in this area. We address variability in recombinant sequence detection by analyzing the consistency of current molecular assays. We also present theoretical results on the limitations of estimating the probability of transgene detection in samples taken from landraces. The inclusion of a limited number of female gametes and, more importantly, aggregated transgene distributions may significantly lower detection probabilities. Our analytical and sampling considerations help explain discrepancies among different detection efforts, including the one presented here, and provide considerations for the establishment of monitoring protocols to detect the presence of transgenes among structured populations of landraces.


6.
- Artículo con arbitraje
*En hemeroteca, SIBE-Chetumal
Amphibian population declines in montane southern Mexico: resurveys of historical localities
Lips, Karen Rene (coaut.) ; Mendelson III, Joseph R. ; Muñoz Alonso, Luis Antonio (coaut.) ; Canseco Márquez, Luis (coaut.) ; Mulcahy, Daniel G. (coaut.) ;
Contenido en: Biological Conservation Vol. 119, no. 4 (October 2004), p. 555-564 ISSN: 0006-3207
Bibliotecas: Chetumal
Cerrar
SIBE Chetumal
49440-10 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-Chetumal
Resumen en: Inglés |
Resumen en inglés

Declines of amphibian populations have been well documented in the US, Canada, and Central America, but little is known regarding the status of amphibian populations in Mexico. In 2000, we surveyed 43 transects from 3 upland regions in Guerrero and Oaxaca, Mexico. We found 161 adult amphibians belonging to 39 species, representing only 19–48% of the anuran fauna known from these regions. We found one dead (Eleutherodactylus saltator) and one dying frog (Ptychohyla erythromma) from two different streams near Chilpancingo, Guerrero. Both frogs were infected with Batrachochytridium dendrobatidis, a pathogenic fungus involved in other declines of amphibian populations. We collected 368 tadpoles; 60 (19%) tadpoles from 9 different streams among the three regions were missing mouthparts, which is indicative of infection by chytrid fungus. We report additional data from the state of Chiapas, Mexico, that document declines, disease, and apparent extirpations from that region as well. Overall, we report 31 populations (representing 24 species) that appear to have been extirpated, including populations of as many as 11 endemic species that have been missing for 16–40 years and may be extinct.