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40 resultados encontrados para: TEMA: Distribución espacial
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1.
Artículo
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Resumen en: Español | Inglés |
Resumen en español

Objetivo. Determinar la abundancia y la distribución geográfica de los principales vectores de la malaria, las cuales están influenciadas por las características del hábitat y los factores ecológicos que afectan directamente la densidad de los adultos y la dinámica de la transmisión de la malaria en México. Material y métodos. Se obtuvieron muestras de larvas de 19 estados de México. Cada hábitat larvario se caracterizó in situ determinando los siguientes parámetros: profundidad del agua, turbidez, porcentaje de cobertura vegetal, cantidad de detritus, presencia de algas, intensidad de luz, tipo de vegetación, cantidad de depredadores, estabilidad del hábitat, altitud y tipo hidrológico. Resultados. Se identificaron un total de 21 687 larvas pertenecientes a 13 especies de anofelinos, de 149 hábitats acuáticos. Las tres especies más abundantes fueron Anopheles pseudopunctipennis (52.91%), An. albimanus (39.14%) y An. franciscanus (5.29%). El análisis de regresión logística múltiple mostró una asociación negativa para An. pseudopunctipennis y la turbidez del agua (ß=-1.342; Wald= 6.122; p=0.013) y la cantidad de detritus (ß=-2.206; Wald= 3.642; p=0.050). Para An. albimanus se encontró una asociación positiva significativa con la turbidez del agua (ß=1.344; Wald= 4.256; p=0.039) y una correlación negativa con la altitud (ß=-3.445; Wald=5.407; p=0.020). El índice de diversidad más alto se encontró en Chiapas (α de Fisher=1.20) y la diversidad más baja en Chihuahua (α de Fisher=0.26). La mayor riqueza se encontró en los arroyos (n=11). Conclusiones. Las dos especies más abundantes fueron An. albimanus y An. pseudopunctipennis. El conocimiento detallado de la distribución y características de sus hábitats larvales será útil para la implementación efectiva de las estrategias de control en México.

Resumen en inglés

Objective. To determine the abundance and geographic distribution of the main malaria vectors, which are influenced by habitat characteristics and ecological factors that directly impact adult density and the dynamics of malaria transmission in Mexico. Materials and methods. Samples of larvae were collected from 19 states in Mexico. Each larval habitat was characterized in situ determining the following parameters: water depth, turbidity, percentage of vegetation cover, amount of detritus, presence of algae, light intensity, type of vegetation, amount of predators, habitat stability, altitude, and hydrologic type. Results. A total of 21 687 larvae corresponding to 13 anopheline species were obtained from 149 aquatic habitats. The most abundant species were Anopheles pseudopunctipennis (52.91%), An. albimanus (39.14%) and An. franciscanus (5.29%). The multiple logistic regression analysis showed a negative association between An. pseudopunctipennis and water turbidity (ß=-1.342; Wald=6.122; p=0.013) and the amount of detritus (ß=-2.206; Wald=3.642; p=0.050). While in An. albimanus, there was a significant positive association with water turbidity (ß=1.344; Wald=4.256; p=0.039), a negative correlation was found with the altitude (ß=-3.445; Wald=5.407; p =0.020). The highest mosquito species diversity index was found in Chiapas (Fisher’s α=1.20) and the lowest diversity in Chihuahua (Fisher’s α=0.26). The greatest richness was found in streams (n=11). Conclusions. The two most abundant species were: An. albimanus and An. pseudopunctipennis. Detailed knowledge of the distribution and characteristics of their larval habitats will be useful for the effective implementation of control strategies in Mexico.


2.
Artículo
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Resumen en: Inglés |
Resumen en inglés

Background: Reliable information about the spatial distribution of aboveground biomass (AGB) in tropical forests is fundamental for climate change mitigation and for maintaining carbon stocks. Recent AGB maps at continental and national scales have shown large uncertainties, particularly in tropical areas with high AGB values. Errors in AGB maps are linked to the quality of plot data used to calibrate remote sensing products, and the ability of radar data to map high AGB forest. Here we suggest an approach to improve the accuracy of AGB maps and test this approach with a case study of the tropical forests of the Yucatan peninsula, where the accuracy of AGB mapping is lower than other forest types in Mexico. To reduce the errors in field data, National Forest Inventory (NFI) plots were corrected to consider small trees. Temporal differences between NFI plots and imagery acquisition were addressed by considering biomass changes over time. To overcome issues related to saturation of radar backscatter, we incorporate radar texture metrics and climate data to improve the accuracy of AGB maps. Finally, we increased the number of sampling plots using biomass estimates derived from LiDAR data to assess if increasing sample size could improve the accuracy of AGB estimates.

Results: Correcting NFI plot data for both small trees and temporal differences between field and remotely sensed measurements reduced the relative error of biomass estimates by 12.2%. Using a machine learning algorithm, Random Forest, with corrected field plot data, backscatter and surface texture from the L‑band synthetic aperture radar (PALSAR) installed on the on the Advanced Land Observing Satellite‑1 (ALOS), and climatic water deficit data improved the accuracy of the maps obtained in this study as compared to previous studies (R²=0.44 vs R²= 0.32). However, using sample plots derived from LiDAR data to increase sample size did not improve accuracy of AGB maps (R²= 0.26). Conclusions: This study reveals that the suggested approach has the potential to improve AGB maps of tropical dry forests and shows predictors of AGB that should be considered in future studies. Our results highlight the importance of using ecological knowledge to correct errors associated with both the plot‑level biomass estimates and the mis‑match between field and remotely sensed data.


3.
Artículo
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Population status, connectivity, and conservation action for the endangered Baird's tapir
Schank, Cody J. (autor) ; Cove, Michael V. (autor) ; Arima, Eugenio Y. (autor) ; Brandt, Laroy S. E. (autor) ; Brenes Mora, Esteban (autor) ; Carver, Andrew (autor) ; Diaz Pulido, Angelica (autora) ; Estrada, Nereyda (autora) ; Foster, Rebecca J. (autora) ; Godínez Gómez, Oscar (autor) ; Harmsen, Bart J. (autor) ; Jordan, Christopher A. (autor) ; Keitt, Timothy H. (autor) ; Kelly, Marcella J. (autora) ; Sáenz Méndez, Joel (autor) ; Mendoza Ramírez, Eduardo (autor) ; Meyer, Ninon France Victoire (autora) ; Pozo Montuy, Gilberto (autor) ; Naranjo Piñera, Eduardo Jorge (autor) (1963-) ; Nielsen, Clayton K. (autor) ; O´Farril Cruz, Elsa Georgina (autora) ; Reyna Hurtado, Rafael Ángel (autor) ; Rivero Hernández, Crysia Marina (autora) ; Carvajal Sánchez, José Pablo (autor) ; Singleton, Maggie (autora) ; Torre, J. Antonio de la (autor) ; Wood, Margot A. (autora) ; Young, Kenneth R. (autor) ; Miller, Jennifer A. (autora) ;
Disponible en línea
Contenido en: Biological Conservation Volumen 245, número 108501 (May 2020), p. 1-12 ISSN: 0006-3207
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Resumen en: Inglés |
Resumen en inglés

Although many large mammals currently face significant threats that could lead to their extinction, resources for conservation are often scarce, resulting in the need to develop efficient plans to prioritize conservation actions. We combined several methods in spatial ecology to identify the distribution of the endangered Baird's tapir across its range from southern Mexico to northern Colombia. Twenty-eight habitat patches covering 23% of the study area were identified, harboring potentially 62% or more of the total population for this flagship species. Roughly half of the total area is under some form of protection, while most of the remaining habitat (~70%) occurs in indigenous/local communities. The network with maximum connectivity created from these patches contains at least one complete break (in Mexico between Selva El Ocote and Selva Lacandona) even when considering the most generous dispersal scenario. The connectivity analysis also highlighted a probable break at the Panama Canal and high habitat fragmentation in Honduras. In light of these findings, we recommend the following actions to facilitate the conservation of Baird's tapir: 1) protect existing habitat by strengthening enforcement in areas already under protection, 2) work with indigenous territories to preserve and enforce their land rights, and help local communities maintain traditional practices; 3) re-establish connections between habitat patches that will allow for connectivity across the species' distribution; 4) conduct additional noninvasive surveys in patches with little or no species data; and 5) collect more telemetry and genetic data on the species to estimate home range size, dispersal capabilities, and meta-population structure.


4.
Tesis - Maestría
Almacenamiento de carbono en áreas verdes urbanas de San Cristóbal de Las Casas, Chiapas / Angélica Uribe-Villavicencio
Uribe Villavicencio, Angélica (autora) ; Vázquez Hernández, Luis Bernardo (director) ; Castillo Santiago, Miguel Ángel (asesor) ; Aryal, Deb Raj (asesor) ;
San Cristóbal de Las Casas, Chiapas : El Colegio de la Frontera Sur , 2019
Clasificación: TE/333.751609727 / U7
Bibliotecas: San Cristóbal
Cerrar
SIBE San Cristóbal
ECO010019916 (Disponible)
Disponibles para prestamo: 1
Índice

Capítulo I. Introducción General
Almacenamiento de carbono en árboles urbanos
Almacenamiento de carbono y ciclo del carbono
Objetivo general
Hipótesis
Objetivos específicos
Capítulo II. Urban Trees in a Neotropical City in Southern Mexico: Diversity, Abundance, and Composition
Abstract
Key words
Introduction
Methods
Field surveys and tree identification
Data analysis
Results
Discussion
Acknowlegment
References
Figures and tables
Capítulo III. Almacenamiento de Carbono en Áreas Verdes Urbanas: El Caso de Estudio de San Cristóbal de Las Casas, Chiapas
Resumen
Palabras Clave
Introducción
Materiales y métodos
Área de Estudio
Selección y características generales de los sitios de muestreo
Análisis de datos
Resultados
Discusión
Conclusiones
Literatura Citada
Tablas y Figuras
Capítulo IV. Conclusiones y recomendaciones generales de la tesis
Literatura citada


5.
Artículo
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Resumen en: Inglés |
Resumen en inglés

Background: Ticks are a problem for cattle production mainly in tropical and subtropical regions, because they generate great economic losses. Acaricides and vaccines have been used to try to keep tick populations under control. This has been proven difficult given the resistance to acaricides and vaccines observed in ticks. Resistance to protein rBm86-based vaccines has been associated with the genetic diversity of Bm86 among the ectoparasite’spopulations. So far, neither genetic diversity, nor spatial distribution of circulating Bm86 haplotypes, have been studied within the Mexican territory. Here, we explored the genetic diversity of 125 Bm86 cDNA gene sequences from R. microplusfrom 10 endemic areas of Mexico by analyzing haplotype distribution patterns to help in understanding the population genetic structure of Mexican ticks. Results: Our results showed an average nucleotide identity among the Mexican isolates of 98.3%, ranging from 91.1 to 100%. Divergence between the Mexican and Yeerongpilly (the Bm86 reference vaccine antigen) sequences ranged from 3.1 to 7.4%. Based on the geographic distribution of Bm86 haplotypes in Mexico, our results suggest gene flow occurrence within different regions of the Mexican territory, and even the USA. Conclusions: The polymorphism of Bm86 found in the populations included in this study, could account for thepoor efficacy of the current Bm86 antigen based commercial vaccine in many regions of Mexico. Our data may contribute towards designing new, highly-specific, Bm86 antigen vaccine candidates against R. microplus circulatingin Mexico.


6.
- Artículo con arbitraje
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Across-shore distribution of Ocypode quadrata burrows in relation to beach features and human disturbance
Ocaña Borrego, Frank Alberto (autor) ; De Jesús Navarrete, Alberto (autor) ; Hernández Arana, Héctor Abuid (autor) ;
Disponible en línea
Contenido en: Journal of Natural History Vol. 52, no. 33-34 (2018), p. 2185–2196 ISSN: 0022-2933
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Resumen en: Inglés |
Resumen en inglés

Spatial distribution patterns of the ghost crab Ocypode quadrata were analysed using different approaches at one disturbed and two preserved reflective sandy beaches of the Mexican Caribbean. We used spatial correlation analysis to describe the across-shore distribution of O. quadrata and their patch dynamics by beach and sampling time. In addition, we analysed the across-shore variability of habitat extent of O. quadrata (habitat envelope) and its relation to human disturbance and beach features. The spatial structure of burrow density was consistent through time, showing a bimodal distribution with very low abundance in the mid distribution range and a discrete increment of burrows to landward. Nonetheless, the size of patches varied temporally for the three beaches. Burrow size increased from seaward to landward. The location of the first burrow and the habitat envelope varied among sampling times and beaches. The location of the first burrow is mostly mediated by the swash climate, while the habitat envelope is mainly controlled by the level of human disturbance. Despite the low number of disturbed and control beaches, our results suggest that the habitat envelope could be included in future studies when using ghost crabs as indicators of human disturbance. Polynomial models and variographic analysis proved to be useful tools to describe the across-shore distribution and patch dynamics of the ghost crab.


7.
Tesis - Doctorado
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Resumen en: Español |
Resumen en español

La presente investigación describe la diversidad y distribución espacio-temporal de la comunidad de anfípodos bentónicos de la plataforma continental de Yucatán, así como su relación biogeográfica con el Atlántico occidental tropical. Se revisó material biológico de cuatro campañas de muestreo (2009–2012), obteniendo información sobre la riqueza, abundancia, y composición de especies; también se obtuvo información de literatura y bases de datos en línea. El análisis de datos de 2009, de un ecosistema de arrecife (Alacranes), demostró que la comunidad de anfípodos se estructura en tres ensamblajes de especies en función del tipo de fondo (blando, duro y artificial), con valores altos de riqueza y abundancia de especies en hábitats de fondo duro y artificiales, respectivamente. El análisis de datos de 2010–2012, de hábitats de sustratos blandos en la plataforma continental, reveló tres ensamblajes de especies, Caribe Oeste, Yucatán Medio y Golfo Sureste, en dos escenarios hidrográficos (surgencia en 2010–2011 y no surgencia en 2012), siendo la temperatura, textura del sedimento, productividad primaria, y materia orgánica las características que mayor explicaron la variabilidad espacio-temporal en la estructura de la comunidad de anfípodos en la plataforma interior (<60 m). Finalmente, el análisis de la composición de especies del material revisado, literatura, y bases de datos permitió reconocer una elevada riqueza de anfípodos (201 spp.) respecto a otras regiones del Atlántico, y una distribución geográfica por provincia biogeográfica Caribeña y Caroliniana, confirmando que la diversidad de anfípodos de la plataforma de Yucatán está más relacionada con la Caribeña.

La evidencia generada demostró que los hábitats bentónicos de la plataforma de Yucatán permiten al grupo de los anfípodos ser muy diversos, con especies recientemente descubiertas para la ciencia, como Gammaropsis elvirae (descrita en la tesis) y otras potencialmente nuevas (en proceso de descripción), así como una fauna con afinidad tropical hacia la provincia Caribeña. La distribución de la composición de especies reflejó la influencia de factores ambientales temporalmente dominantes en la plataforma de Yucatán interior asociados con procesos hidrográficos de la surgencia, y espacialmente a los tipos de fondo y a las características de los sedimentos carbonatados en el gradiente geográfico longitudinal.


8.
Artículo
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Gammaropsis elvirae sp. nov., a widely distributed amphipod (Amphipoda: Photidae) in the Yucatan Shelf, with ecological comments and a key for the genus in tropical America
Paz Ríos, Carlos Enrique (autor) ; Pech Pool, Daniel Guadalupe (autor) ;
Contenido en: Zootaxa Vol. 4555, no. 3 (Feb. 2019), p. 359–371 ISSN: 1175-5326
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Resumen en: Inglés |
Resumen en inglés

Gammaropsis elvirae sp. nov. is described and illustrated here, as a new species of the family Photidae Boeck, 1871, occurring on sites widely distributed in the soft-sediment habitats from the Yucatan shelf, southern Gulf of Mexico. This new species differs from all other congeners by a unique set of characteristics: lateral cephalic lobes rounded; outer lobes of lower lip with one cone on each lobe; gnathopod 1 propodus longer than carpus; gnathopod 2 propodus enlarged with small convoluted processes on posterior margin and palmar angle undefined; gnathopod 2 dactylus short, less than one half in length of propodus; dense setation on basis, carpus, and propodus of gnathopod 2; epimeral plates 1–3 rounded; inner ramus of uropods 1–3 longer than outer ramus; and telson emarginated. Ecological comments on spatial distribution and associated environmental variables are included, as well an identification key to the genus in tropical America.


9.
- Artículo con arbitraje
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The symbolic violence of tolerance zones: constructing the spatial marginalization of female Central American migrant sex workers in Mexico
Pintín Pérez, Margarita Julia ; Rojas Wiesner, Martha (coaut.) ; Bhuyan, Rupaleem (coaut.) ;
Contenido en: Women's Studies International Forum Vol. 68 (May–June 2018), p. 75-84 ISSN: 1364-8152
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Resumen en: Inglés |
Resumen en inglés

In this paper, we explore how the spatial ordering of sex-work in southern Mexico naturalizes the presence of migrant women in designated “tolerance zones”. Drawing on a feminist approach to ethnographic research in the city of Dominguez, Chiapas, we critically analyze the symbolic powers concealed and enacted through the official discourse of “tolerance” in public health regulations on commercial sex and embodied everyday life of migrant women from Central America. We engage with feminist debates regarding geographies of sex work and oppression to illustrate how tolerance zones mediate and maintain the marginal status of female sex workers who, despite their irregular migration status, are constructed (and view themselves) as bodies in “need of tolerance”. Our analysis of spatial practices that govern tolerance zones illustrates how the discourse of tolerance becomes a vehicle for symbolic violence, naturalizing unequal social relations of power in the lives of migrant Central American women.


10.
Artículo
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Resumen en: Español | Inglés |
Resumen en español

El flamenco caribeño (Phoenicopterus ruber) en México se distribuye en todo el complejo de lagunas dentro de los humedales costeros de la Península de Yucatán y se ha observado una cierta tendencia a un uso diferencial de las áreas entre los juveniles y adultos en las diferentes etapas de su ciclo de vida, según las estaciones del año. El objetivo de este estudio fue determinar las áreas más importantes donde se distribuyen espacialmente los flamencos en los humedales de Yucatán, México y sus variaciones temporales según la edad y las diferentes etapas de su ciclo de vida. Se utilizaron registros de individuos anillados que se han avistado durante el período 2010-2015. Se identificaron las áreas con el mayor número de individuos según la estación y la temporada. Se registraron flamencos en 39 áreas diferentes, de 43 muestreadas. En general, los sitios con el mayor número de registros fueron: La Angostura y Punta Mecoh. Tanto para los juveniles como para los adultos, las áreas con mayores porcentajes de ocupación fueron diferentes por edades entre las diferentes etapas del ciclo de vida y las estaciones del año. Charca Salinera Chel e Isla La Angostura fueron áreas en las que se registraron flamencos anillados de casi todas las edades. Aunque se siguen destacando como zonas importantes para la especie, ya descritas con anterioridad (Celestún, Ría Lagartos), aparecen nuevos sitios que albergan un número considerable de la población en algún momento de su ciclo de vida (e. g. Humedal Progreso. Salamandra, Laguna Rosada; Xcambo). A estos nuevos sitios se les debe prestar más atención y se recomiendan medidas de seguridad y protección importantes para todos ellos. Es necesario buscar nuevas fuentes de apoyo para realizar estudios que determinen el estado de las poblaciones de flamencos en áreas de difícil acceso de las que se tiene muy poca información.

Resumen en inglés

The Caribbean Flamingo (Phoenicopterus ruber) in Mexico is distributed throughout the complex of lagoons in coastal wetlands of the Yucatan Peninsula. The species shows a tendency toward differential use of areas between juveniles and adults at different stages of their life cycle, and in different seasons. The aim of this study was to determine the most important areas where flamingos are distributed in Yucatan wetlands, and to describe temporal variations according to age and stages of their life cycle. For this, we used the records of ringed individuals sighted during the period 2010-2015. The areas with the largest numbers of individuals, by stage and season, were identified. Flamingos were recorded in 39 different areas of 43 sampled. In general, the sites with the largest number of records were Isla La Angostura and Punta Mecoh. To both juveniles and adults, areas with higher occupancy rates differed by age between the different stages of the life cycle and seasons. In the Charca Salinera Chel and Isla La Angostura ringed flamingos of almost all ages were recorded. Although already described areas (Celestún, Ría Lagartos) are certainly important, new sites hosting considerable populations at some stage of this species life cycle were detected (e.g. Humedal Progreso; Salamandra, Laguna Rosada; Xcambo). These new sites should be given more attention and important security measures and protection are recommended to all of them. It is necessary to seek new support sources for studies that determine the flamingo population’s status in difficult access areas for which little information is available.