scholarly journals Effect of trapping methods on the estimation of alpha diversity of a phlebotomine sandfly assemblage in southern Mexico

2017 ◽  
Vol 31 (4) ◽  
pp. 392-401 ◽  
Author(s):  
J. J. RODRÍGUEZ-ROJAS ◽  
E. A. REBOLLAR-TÉLLEZ
Keyword(s):  
Alpha Diversity ◽  
Southern Mexico ◽  
Phlebotomine Sandfly ◽  
Trapping Methods

Effects of habitat fragmentation on the diversity of epiphytic orchids from a montane forest of southern Mexico

2014 ◽  
Vol 31 (2) ◽  
pp. 103-115 ◽  
Author(s):  
Ezequiel Hernández-Pérez ◽  
Eloy Solano
Keyword(s):  
Species Turnover ◽  
Alpha Diversity ◽  
Montane Forest ◽  
Core Area ◽  
Edge Density ◽  
Southern Mexico ◽  
Epiphytic Orchids ◽  
Epiphytic Orchid ◽  
Tolerant Species ◽  
Shade Tolerant Species

Abstract:Epiphytic orchids are very diverse in montane forests, but fragmentation modifies this diversity. Twenty fragments were quantified to evaluate the effects of fragmentation on the alpha and beta diversities of epiphytic orchids in a montane forest located in southern Mexico. The following factors were evaluated: area, core area, shape, edge density, Euclidean nearest-neighbour distance fragment and contrast index. In each fragment, two transects of 2 × 50 m were drawn, and the trees with a diameter at breast height ≥ 20 cm were recorded. In each tree, the orchid species present were identified and quantified. Twenty-three species of epiphytic orchid in 234 phorophytes corresponding to 20 species were recorded. The epiphytic orchid richness per tree and species turnover was different between the phorophytes. The edge density and the contrast index had significant effects on the alpha diversity, while the isolation of the fragments significantly affected the beta diversity. The edge density positively affected the alpha diversity of the epiphytic orchids, likely through microclimatic changes caused by fragmentation. Drought-tolerant species were common on the edges of the fragments, and shade-tolerant species established on the core area of the fragments. This pattern most likely depends on the ecological range of the taxa, which is crucial to their development and persistence in fragmented habitats.

scholarly journals Diversity of epiphyte ferns along an elevational gradient in El Triunfo Biosphere Reserve, southern Mexico

2020 ◽  
Vol 153 (1) ◽  
pp. 12-21
Author(s):  
Derio A. Jiménez-López ◽  
Rubén Martínez-Camilo ◽  
Nayely Martínez-Meléndez ◽  
Michael Kessler
Keyword(s):  
Linear Regression ◽  
Beta Diversity ◽  
Species Turnover ◽  
Cloud Forest ◽  
Alpha Diversity ◽  
Elevational Gradient ◽  
Mountain Range ◽  
Southern Mexico ◽  
Diversity Patterns ◽  
Individual Trees

Background and aims – In the tropics, some studies have found that the richness of epiphytic ferns present a peak at mountain mid-elevations. However, it is not well understood how transitions from tropical to subtropical conditions affect this peak, and even less is known about beta diversity of epiphytic ferns. Thus, the objective is to understand the effect of climatic gradients on the variation of local richness of ferns and beta diversity patterns along an elevational gradient in a mountain system in southern Mexico.Methods – We sampled 32 trees, each in four elevational bands (100–2200 m). Alpha diversity patterns were analysed using linear regression models. We used the Morisita index to quantify species turnover between bands. An additive partitioning approach was used to analyse the degree to which individual trees, plots, and bands contributed to total species richness. We evaluated the influence of climatic variables on species composition via linear regression models.Key results – A total of 30 species in five families were recorded. Each family contributed in different magnitude to the elevational richness pattern, with Polypodiaceae dominating due to its richness and presence along the entire transect. Alpha diversity at the three scales (αtree, αplot, αband) increased with elevation and rainfall, and with decreasing temperature. Species turnover was high along the gradient, but was scale-dependent, with βtransect (65–75%) and βband (14%) with the greatest contributing to total diversity. Although the contribution of the individual trees was lower, it increased with elevation. Conclusions – We emphasize the importance of including different scale levels in analyses of diversity along elevational gradients. In the region, cloud forest on the mountain peaks harbours the highest diversity of epiphytic fern communities. Due to a limited extent of this mountain range, the epiphyte ferns are susceptible to the effects of climate change.

Overcoming Challenges of International Migration Research: A Case Study Approach in Southern Mexico

2016 ◽  
Vol 13 (1) ◽  
pp. 131-143
Author(s):  
Julie Boyles
Keyword(s):  
International Migration ◽  
Common Ground ◽  
Data Gathering ◽  
Ethnographic Case Study ◽  
Case Study Approach ◽  
Southern Mexico ◽  
Mixed Methods Approach ◽  
Study Approach ◽  
Migration Research

An ethnographic case study approach to understanding women’s actions and reactions to husbands’ emigration—or potential emigration—offers a distinct set of challenges to a U.S.-based researcher.  International migration research in a foreign context likely offers challenges in language, culture, lifestyle, as well as potential gender norm impediments. A mixed methods approach contributed to successfully overcoming barriers through an array of research methods, strategies, and tactics, as well as practicing flexibility in data gathering methods. Even this researcher’s influence on the research was minimized and alleviated, to a degree, through ascertaining common ground with many of the women. Research with the women of San Juan Guelavía, Oaxaca, Mexico offered numerous and constant challenges, each overcome with ensuing rewards.

The value, costs, and meaning of transnational migration in rural Oaxaca, Mexico

2006 ◽  
Vol 3 (1) ◽  
pp. 15-25 ◽  
Author(s):  
Jeffrey H. Cohen ◽  
Bernardo Rios ◽  
Lise Byars
Keyword(s):  
Social Networks ◽  
Sense Of Belonging ◽  
Southern California ◽  
Transnational Migration ◽  
Urban Centers ◽  
Cultural Economic ◽  
Southern Mexico ◽  
Shared Identity ◽  
The Social

Rural Oaxacan migrants are defined as quintessential transnational movers, people who access rich social networks as they move between rural hometowns in southern Mexico and the urban centers of southern California.  The social and cultural ties that characterize Oaxacan movers are critical to successful migrations, lead to jobs and create a sense of belonging and shared identity.  Nevertheless, migration has socio-cultural, economic and psychological costs.  To move the discussion away from a framework that emphasizes the positive transnational qualities of movement we focus on the costs of migration for Oaxacans from the state’s central valleys and Sierra regions.   

Redefined Nationalism in Building a Movement for Indigenous Autonomy in Southern Mexico

1997 ◽  
Vol 3 (1) ◽  
pp. 72-101 ◽  
Author(s):  
Lynn Stephen
Keyword(s):  
Southern Mexico ◽  
Indigenous Autonomy

Kyiv park "Nivki" and "Teremki" forests and ecological analysis of their habitats

2014 ◽  
Vol 25 (3-4) ◽  
pp. 53-68
Author(s):  
I. V. Goncharenko ◽  
H. M. Holyk
Keyword(s):  
Standard Deviation ◽  
Species Composition ◽  
Human Impact ◽  
Soil Nitrogen ◽  
Beta Diversity ◽  
Plant Cover ◽  
Alpha Diversity ◽  
Light Regime ◽  
Individual Species ◽  
Anthropogenic Pressure

Cenotic diversity and leading ecological factors of its floristic differentiation were studied on an example of two areas – Kyiv parks "Nivki" and "Teremki". It is shown that in megalopolis the Galeobdoloni-Carpinetum impatientosum parviflorae subassociation is formed under anthropogenic pressure on the typical ecotope of near-Dnieper hornbeam oak forests on fresh gray-forest soils. The degree of anthropogenic transformation of cenofloras can be estimated by the number of species of Robinietea and Galio-Urticetea classes, as well as neophytes and cultivars. Phytoindication for hemeroby index may be also used in calculation. We propose the modified index of biotic dispersion (normalized by alpha-diversity) for the estimation of ecophytocenotic range (beta-diversity) of releves series. We found that alpha-diversity initially increases (due to the invasion of antropophytes) at low level of antropogenic pressure, then it decreases (due to the loss of aboriginal species) secondarily with increasing of human impact. Also we found that beta-diversity (differential diversity) decreases, increasing homogeneity of plant cover, under the influence of anthropogenic factor. Vegetation classification was completed by a new original method of cluster analysis, designated as DRSA («distance-ranked sorting assembling»). The classification quality is suggested to be validated on the "seriation" diagram, which is а distance matrix between objects with gradient filling. Dark diagonal blocks confirm clusters’ density (intracluster compactness), uncolored off-diagonal blocks are evidence in favor of clusters’ isolation (intercluster distinctness). In addition, distinction of clusters (syntaxa) in ordination area suggests their independence. For phytoindication we propose to include only species with more than 10% constancy. Furthermore, for the description of syntaxonomic amplitude we suggest to use 25%-75% interquartile scope instead of mean and standard deviation. It is shown that comparative analysis of syntaxa for each ecofactor is convenient to carry out by using violin (bulb) plots. A new approach to the phytoindication of syntaxa, designated as R-phytoindication, was proposed for our study. In this case, the ecofactor values, calculated for individual releves, are not taken into account, however, the composition of cenoflora with species constancies is used that helps us to minimize for phytoindication the influence of non-typical species. We suggested a syntaxon’s amplitude to be described by more robust statistics: for the optimum of amplitude (central tendency) – by a median (instead of arithmetic mean), and for the range of tolerance – by an interquartile scope (instead of standard deviation). We assesses amplitudes of syntaxa by phytoindication method for moisture (Hd), acidity (Rc), soil nitrogen content (Nt), wetting variability (vHd), light regime (Lc), salt regime (Sl). We revealed no significant differences on these ecofactors among ecotopes of our syntaxa, that proved the variant syntaxonomic rank for all syntaxa. We found that the core of species composition of our phytocenoses consists of plants with moderate requirements for moisture, soil nitrogen, light and salt regime. We prove that the leading factor of syntaxonomic differentiation is hidden anthropogenic, which is not subject to direct measurement. But we detect that hidden factor of "human pressure" was correlated with phytoindication parameters (variables) that can be measured "directly" by species composition of plant communities. The most correlated factors were ecofactors of soil nitrogen, wetting variability, light regime and hemeroby. The last one is the most indicative empirically for the assessment of "human impact". We establish that there is a concept of «hemeroby of phytocenosis» (tolerance to human impact), which can be calculated approximately as the mean or the median of hemeroby scores of individual species which are present in it.

GEOCHRONOLOGY AND PETROGENESIS OF THE PUERTO ESCONDIDO-HUATULCO INTRUSIONS IN SOUTHERN MEXICO AND STRUCTURAL ANALYSIS OF THE WESTERN CHACALAPA FAULT SYSTEM

2019 ◽  
Author(s):  
Samantha Yahel García Hernández ◽  
◽  
Dante J. Morán-Zenteno ◽  
Barbara M. Martiny ◽  
Gustavo Tolson
Keyword(s):  
Structural Analysis ◽  
Fault System ◽  
Southern Mexico

GEOCHRONOLOGY AND PETROGENESIS OF THE JAMILTEPEC – PUERTO ESCONDIDO BATHOLITHS: NEW INSIGHTS ON SOUTHERN MEXICO CENOZOIC MAGMATISM

2019 ◽  
Author(s):  
Hermes Martín García Rodríguez ◽  
◽  
Dante J. Morán-Zenteno ◽  
Barbara M. Martiny
Keyword(s):  
Southern Mexico ◽  
Cenozoic Magmatism

Tongues of Fire

2018 ◽  
Author(s):  
Nancy Farriss
Keyword(s):  
Cultural Difference ◽  
Language Contact ◽  
Social Contexts ◽  
Culture Contact ◽  
Rhetorical Strategies ◽  
Southern Mexico ◽  
Fine Grained ◽  
Indigenous Church ◽  
Cultural Gaps

Language and translation governed the creation of Mexican Christianity during the first centuries of colonial rule. Spanish missionaries collaborated with indigenous intellectuals to communicate the gospel in dozens of local languages that had previously lacked grammars, dictionaries, or alphabetic script. The major challenge to translators, more serious than the absence of written aids or the great diversity of languages and their phonetic and syntactical complexity, was the vast cultural difference between the two worlds. The lexical gaps that frustrated the search for equivalence in conveying fundamental Christian doctrines derived from cultural gaps that separated European experiences and concepts from those of the Indians. This study focuses on the Otomangue languages of Oaxaca in southern Mexico, especially Zapotec, and relates their role in the Dominican evangelizing program to the larger frame of culture contact in postconquest Mesoamerica. Fine-grained analysis of translated texts is used to reveal the rhetorical strategies of missionary discourse and combines with an examination of language contact in different social contexts. A major aim is to spotlight the role of the native elites in shaping what emerged as a new form of Christianity. As translators, chief catechists, and parish administrators they made evangelization in many respects an indigenous enterprise and the Mexican church it created an indigenous church.

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