Sierra De Los Tuxtlas Research Articles

Presence of Anti-T. cruzi Antibodies in Inhabitants and Dogs of Two Rural Settlements in the Sierra de Los Tuxtlas, Veracruz, Mexico.

The aim of this study was to identify the risk factors associated with house infestation by Triatoma dimidiata as well as with Trypanosoma cruzi infection in humans and owned dogs in two rural communities from the municipality of Catemaco, Veracruz, Mexico. One hundred and 16 human blood samples and 34 dog blood samples were collected. The presence of anti-T. cruzi antibodies was determined using four different ELISA assays. Moreover, reactive ELISA sera from humans and dogs were processed by indirect immunofluorescence (IFI) to confirm the presence of anti-T. cruzi antibodies. Serologic tests for T. cruzi infection showed a prevalence of 5.1% (6/116) in humans and of 50% (17/34) in owned dogs. The presence of animals (dogs, chickens and wild animals), as well as some characteristics of house construction were identified as risk factors for infestation and infection. Complementary studies must be carried out to allow a better understanding of the transmission dynamics in the state of Veracruz, Mexico, and the implementation of adequate control programs.

Distinct Patterns of Genetic Connectivity Found for Two Frugivorous Bat Species in Mesoamerica

Sturnira parvidens and Sturnira hondurensis are two frugivorous bat species distributed throughout the Mesoamerican region. Sturnira parvidens inhabits tropical lowland forests and S. hondurensis montane cloud forests. Their populations are respectively separated by the intervening highlands or lowlands. We used mitochondrial DNA control region sequences to compare genetic structure among the populations of these two species in the region of the Gulf of Mexico. We also measured genetic connectivity among their populations and assessed the distribution model for each species. We found high genetic diversity in both species: the FST comparisons values were low to high in S. hondurensis and low in S. parvidens. For S. hondurensis, we found isolation by landscape resistance (IBR) where the highland habitat heterogeneity may have restricted gene flow among the populations of the Sierra Madre Oriental, Sierra de Los Tuxtlas, Chiapas and Guatemala. For S. parvidens, the isolation is explained by geographic distance rather than by landscape heterogeneity.

Impact of the Thermal Load for a Library Model in a Rural Region of Tropical Climate in Mexico

The evaluation and results of a thermal balance is presented for a building located at latitude 18° N, in an intercultural university community in the “Sierra de los Tuxtlas” (Tuxtlas Mountains), southeast of Mexico. The case study corresponds to the main building of the Intercultural University of Veracruz Las Selvas which is able to house the library, a center for learning native languages ​​and a computing. In order to maintain thermal comfort conditions in this space, the use of an air conditioning system is required, which works at its maximum capacity, implying high consumption of electrical energy, as well as important maintenance expenses. The objective of this work was to evaluate the thermal load of the building considering the American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE) methodology in order to reduce the consumption of the electric energy required for the use of air conditioning, which is of vital importance in this tropical zone. In the first stage of evaluation, the following assumptions were considered: (a) the loads related to the glazed enclosures (radiation, conduction and infiltration of air), (b) the effect of the surface of the windows of the different orientations of the building and, (c) the use of solar control films to decrease heat gains. Special care was taken not to make alterations on the infrastructure of the physical space and to not compromise the external environment. In the building that was under evaluation it was found that by reducing the enveloped area of the north and south sections, heat can be minimized and the transmitted visible light required for the development of the occupants’ activities is not affected. However, if the enveloped area on the west side is modified, visible light would be compromised. The use of solar control films provides significant benefits because the heat gained by radiation can be minimized by more than 60 %, this is achieved without obstruction the view to the outside nor the visible light required by the occupants to maintain an adequate performance in the development of their activities. If these strategies are implemented, the consumption of electrical energy can be reduced considerably.

Arqueología y medio ambiente en Los Tuxtlas ¿hacia dónde se inclina la balanza?

This study presents the problematic case of the Sierra de Los Tuxtlas with regard to the different forms of management, dissemination, and attention dedicated to the environment and archaeological remains by the authorities, the tourism sector, and the population of the region, who favor ecology over archaeology. Through a comparison between two museums and one tourist attraction, which claims to promote the ecology and cultural history of the region, this study exposes disinformation about the archaeological past which causes confusion related to culture and identity among local inhabitants by promoting non-local ethnic manifestations to attract the attention and interest of tourists. This study proposes that archaeology and ecology be considered together to strengthen the society’s bonds with its past.

Impacto de las unidades de selva manejada tradicionalmente en la conectividad del paisaje de la Sierra de Los Tuxtlas, México

The ever-increasing establishment of landscape mosaics is expressed as a surrounding matrix of agricultural activities, which frames patches or remnants of the original vegetation cover. Conservation actions should be aimed to establish or to increase those interactive systems, which help to maintain the land- scape flow through linkages. Spaces occupied by traditional management systems retain and support this func- tion. In this paper, we used Geographic Information Systems to evaluate the importance of traditionally managed forest units ('acahuales'-coffee plantations) and to assess landscape connectivity in the indigenous Popoluca area of Sierra de los Tuxtlas, Mexico. The cartographic material used to establish the types of vegetation and their coverture included the period 1991-2008. At landscape level, four indices were used to assess the general situation of the habitat network, and to identify the patches of high priority. Individually, indices evaluated if patches were important for their area, their potential flow or their connecting function. Results showed that the landscape is functioning as a single system, but having low connectivity. Values improved when traditionally managed forest patches were considered as viable habitat. We detected 367 patches of very high priority, 80% belonging to forests managed traditionally. Patches were important for their potential flow (size and topologi- cal relationships). Only 70 patches were significant for their function as biological corridors between largest forests located at the top of the volcanoes, and are mostly managed forest (75%). We concluded that the units of traditionally managed forest play a significant role in landscape connectivity maintenance.

Dos especies nuevas de la familia Rubiaceae de la sierra de los Tuxtlas, Veracruz, México

Two new species of Rubiaceae are described from Sierra de los Tuxtlas in southern Veracruz, Mexico: Arachnotrhyx pumae (Guettardeae) and Hoffmannia altipetens (Hamelieae). Arachnotrhyx pumae is similar to A. buddleioides and A. villosa, but it differs by the triangular stipules, 2.0 to 3.0mm long, lax inflorescence, floral bracts of 3.0mm long and 1.0mm width, 10-ribbed fruit and the folded seed. Hoffmannia altipetens is characterized by cystoliths on the leaf veins, inflorescences with 2 to 6 axis per node and white fruits.

Decadal changes and delayed avian species losses due to deforestation in the northern Neotropics

How avifauna respond to the long-term loss and fragmentation of tropical forests is a critical issue in biodiversity management. We use data from over 30 years to gain insights into such changes in the northernmost Neotropical rainforest in the Sierra de Los Tuxtlas of southern Veracruz, Mexico. This region has been extensively deforested over the past half-century. The Estación de Biología Tropical Los Tuxtlas, of the Universidad Nacional Autónoma de México (UNAM), protects a 640 ha tract of lowland forest. It became relatively isolated from other forested tracts between 1975 and 1985, but it retains a corridor of forest to more extensive forests at higher elevations on Volcán San Martín. Most deforestation in this area occurred during the 1970s and early 1980s. Forest birds were sampled on the station and surrounding areas using mist nets during eight non-breeding seasons from 1973 to 2004 (though in some seasons netting extended into the local breeding season for some species). Our data suggested extirpations or declines in 12 species of birds subject to capture in mist nets. Six of the eight species no longer present were captured in 1992–95, but not in 2003–2004. Presence/absence data from netting and observational data suggested that another four low-density species also disappeared since sampling began. This indicates a substantial time lag between the loss of habitat and the apparent extirpation of these species. Delayed species loss and the heterogeneous nature of the species affected will be important factors in tropical forest management and conservation.

Spring Stopover and Refueling Among Migrant Passerines in the Sierra De Los Tuxtlas, Veracruz, Mexico

The narrowing of the North American continent at the Isthmus of Tehuantepec creates an important geographic bottleneck for songbirds on their northward spring migrations. The Sierra de Los Tuxtlas, in the northwestern portion of the Isthmus, provide an ideal location from which to address questions of resource use and fuel acquisition during migration. We operated mist nets during morning and evening to capture passerines during spring migration in 2003 and 2004. Seven of 13 taxa had significant diurnal increases in body condition (an index of size-adjusted mass): Swainson's Thrush (Catharus ustulatus), Wood Thrush (Hylocichla mustelina), Magnolia Warbler (Dendroica magnolia), Kentucky Warbler (Oporornis formosus), Hooded Warbler (Wilsonia citrina), Worm-eating Warbler (Helmitheros vermivorum), and Ovenbird (Seiurus aurocapilla). All of these species, except Ovenbird, also had a significant increase in fat score. Indigo Buntings (Passerina cyanea) had a significant increase in fat score but not in condition index. A comparison with autumn migration at this site showed overall similarities in percentage of species gaining mass and in the amount gained, but there were seasonal differences within species. There was no relationship between increase in body condition and a mainland versus trans-gulf migratory strategy.

Late Holocene palaeoecology of Lago Verde: evidence of human impact and climate change in the northern limit of the neotropics during the late formative and classic periods

Multiproxy analysis (pollen, diatom, charcoal) on a 6 m core from Lago Verde (Sierra de Los Tuxtlas), shows evidences of environmental changes and human impact on the evergreen rainforest on the tropical lowlands of eastern Mexico during the last ca. 2,800 years. Prehistoric human occupation is recorded since the late Formative throughout the middle Classic (250 b.c.–ca. a.d. 800) by the presence of maize pollen, a low abundance of tropical arboreal taxa and a high abundance of herbaceous pollen and charcoal particles. This occurred under a scenario of very low lake levels from which dry conditions are inferred based on the dominance of aerophilous and periphytic diatom taxa. After ca. a.d. 800 the site was abandoned and forest regeneration started, at the same time higher lake levels, an indication of more humid conditions, were established. In the absence of human disturbance, tropical forest regeneration was rapid (ca. 200 years). Fluctuations in pollen composition during times of low human population at the site are related to climate variability, with the highest tropical forest diversity and lake levels recorded during the Little Ice Age. Modern human impact is also recorded and compared with the prehistoric deforestation event. Comparison with palaeoecological records from Yucatan and the highlands of central Mexico offers a Mesoamerican perspective of climatic variability giving evidence that the late Formative and early to middle Classic demographic expansion occurred under a scenario of climates dryer than present, with the Postclassic characterized by moister conditions. The end of the Classic (ca. a.d. 800–1000) is identified as a period of rapid climate change which marks one of the most important cultural transitions in Mesoamerica.

Farming and Catastrophe at La Joya: A Consideration of Agricultural Intensification and Risk in the Formative Sierra de los Tuxtlas

espanolEste estudio examina el proceso de sedentarizacion, intensificacion agricola y desarrollo de una jerarquia politica regional durante el periodo Formativo (1400 a. C.-300 d. C.) a lo largo de la costa meridional del Golfo de Mexico, en la zona olmeca de la Sierra de los Tuxtlas. Los resultados obtenidos analizando los datos de animales y plantas provenientes del sitio de La Joya, un pueblo agricola ubicado en el sur de Veracruz (Mexico) que abarca todo el Formativo, indican que la intensificacion del maiz fue un proceso largo y gradual que se inicio en la fase media de esta etapa, cientos de anos antes del establecimiento de un centro regional. A finales del Formativo Tardio, despues de su consolidacion politica, una severa erupcion volcanica cubrio con ceniza la region. Los aldeanos de La Joya respondieron a esta catastrofe incrementando la produccion de maiz en las inmediaciones y ampliando sus territorios de caza y pesca para explotar una gama mas amplia de animales. EnglishThis paper examines the process of agricultural intensification as it occurred during the Formative period (1400 BC-AD 300) along the southern Gulf Coast of Mexico. Over the course of two millennia, rural villagers living in the Olmec hinterland of the Sierra de los Tuxtlas invested more time and labor into farming activities as they became increasingly sedentary and dealt with episodic volcanic eruptions and ash fall. This period of time witnessed the development of a regional political hierarchy in the Tuxtlas, which also had consequences for village-level subsistence. In examining agricultural intensification in the context of volcanic catastrophe and political development, I analyze archaeological plant and animal data from the site of La Joya, a farming village located in southern Veracruz, Mexico spanning the Formative period. The subsistence data indicate that maize intensification was a long, incremental process that began in the Middle Formative period, hundreds of years before political development and the establishment of a regional center. At the close of the Late Formative period, after the region’s political consolidation, a severe volcanic eruption blanketed the region with ash, leading to significant, if temporary, environmental circumscription. La Joya villagers responded to this catastrophe by intensifying maize production on infields and expanding their hunting and fishing territories to exploit a wider range of animal prey.

Geophysical Investigations at Teotepec, Mexico (1000 B.C.–A.D. 1000)

Recent investigations at the site of Teotepec in the Sierra de los Tuxtlas in southern Veracruz, Mexico explored Middle Formative through Late Classic (1000 B.C.–A.D. 1000) socioeconomic conditions. A central focus was the form and function of the site's distinctive architectural configuration, the Long Plaza Group. During the 2007 and 2008 field seasons, a systematic geophysical survey of Teotepec obtained initial information on the layout, orientation, and possible function of the site's central architectural core. Results from the survey allow for a clear definition of the site's Long Plaza Group in addition to the identification of a possible ball court along its eastern edge. It is also clear that Teotepecans incorporated natural features into their architectural core by placing a pyramid atop a volcanic landform and modifying a natural basalt flow in order to create a level plaza. Finally, the geophysical data indicate significant time depth in architectural construction by suggesting diffirent mound construction techniques, thus underscoring the importance of Teotepec as a persistent place in a region marked by significant population fluctuations in the Formative and Classic periods.

Cultivating, Farming, and Food Containers: Reflections on Formative Subsistence and Intensification in the Southern Gulf Coast Lowlands

Robert S. Santley was known for his studies of obsidian exchange and Teotihaucan influence in Mesoamerica. He also was a student of tropical agriculture and a practitioner of innovative survey methods. In 1992 Santley published a study of Formative period (1500-500 BC) agriculture and settlement in the Sierra de los Tuxtlas, Veracruz, Mexico. His model linked land use and food preparation practices to ceramic vessel use. He compared the food production model to the distribution of Early and Middle Formative ceramics from village contexts in the central Tuxtlas. Today, the study suggests amplification of Boserup's (1965) scheme of agricultural intensification anda reassessment of the terms horticulture and agriculture in tropical lowland contexts. Santley's work resonates well with recent research on agriculture and settlement in southern Veracruz and the variable role of wild and cultivated food resources among Olmec and pre-Olmec societies of the Gulf Coast lowlands.

Exchange of Coarse Orange pottery in the Middle Classic Tuxtla Mountains, Southern Veracruz, Mexico

This research seeks to elucidate the role of large and intensive ceramic production industries located at the Classic period center of Matacapan in the Tuxtla Mountains, Southern Veracruz, Mexico. Arnold et al. [Arnold III, P.J., Kneebone, R.R., Santley, R.S., Pool, C.A., 1993. Intensive ceramic production and Classic-period political economy in the Sierra de los Tuxtlas, Veracruz, Mexico. Ancient Mesoamerica 4(2), 175–191] have suggested that the specialized pottery production at Comoapan, the largest production locality at Matacapan, supplied the region with ceramics. This production locality overwhelmingly specialized in manufacturing Coarse Orange jars, which are found in many parts of the region. The current authors employed instrumental neutron activation analysis (INAA) and petrographic point-counting analysis on Coarse Orange sherds sampled from 44 localities in the southwestern Tuxtlas to examine the distribution of this important ware. The use of these techniques partitioned the sample into two major compositional groups. These groups formed eastern and western zones of production and exchange that partly overlapped. Three minor Coarse Orange paste recipes were also identified, these are considered to be locally produced variants of the ware. From the compositional data, and supplementary evidence of ceramic production from survey and excavation, we argue that Comoapan traded some ceramics of the CO1 composition to sites along the Catemaco River and into the southern Tuxtlas foothills. These jars were exchanged to all levels of the settlement hierarchy, which may indicate market exchange. Furthermore, the other paste recipes (CO1a, CO2, CO2a, and CO3) were not produced at Matacapan. Group COP6 was a special recipe made only at an attached production locality in the administrative district of Matacapan. We conclude the paper with a methodological consideration that advocates the use of both point mineralogical and bulk chemical techniques to more accurately interrogate compositional data.

Phylogeography of the Buarremon brush-finch complex (Aves, Emberizidae) in Mesoamerica

The Buarremon brush-finches represent a complex suite of populations distributed in the montane New World Tropics from Mexico south to South America. Traditional taxonomic arrangements have separated populations of this genus into three species, based on plumage variation, although plumage patterns are well known to exhibit homoplasy. We present a first detailed phylogeographic and phylogenetic study, focused on Mesoamerican populations, and signal the existence of strong differentiation among populations with a clear geographic structure. We find well differentiated clades for (1) the Sierra Madre Oriental and Sierra Madre del Sur in Oaxaca, (2) western Mexican populations, including the B. brunneinucha populations in the Sierra Madre del Sur and B. virenticeps, (3) Sierra Madre Oriental and Sierra de los Tuxtlas, (4) northern Central America, (5) southern Central America, (6) middle Central America, and (7) South America. We demonstrate a lack of concordance with plumage patterns, and argue for several additional species to be recognized in the complex.

210Pb chronology and trace metal geochemistry at Los Tuxtlas, Mexico, as evidenced by a sedimentary record from the Lago Verde crater lake

Lago Verde is a fresh-water maar found on the lower slopes of San Martin volcano, at the Sierra de Los Tuxtlas, Mexico, currently the northernmost remnant of the tropical rain forest in America. 210Pb and 137Cs analyzed in a sediment core were used to reconstruct the historical fluxes of Ag, Cd, Cu, Pb, Hg and Zn to the site during the last ∼ 150 yr. The 210Pb xs-derived sediment accumulation rates, the magnetic susceptibility, C/N ratios and δ 13C data evidenced background conditions at the lake until 1960s, when enhanced erosion related to the clearing of large forested areas at Los Tuxtlas promoted higher accumulation rates of a heavier and more magnetic sedimentary material. Recent sediments from Lago Verde were found enriched by Pb (26-fold natural concentration level [NCLs]) and moderately enriched by Cd > Cu > Zn and Hg (6-, 5-, 4- and 4-fold corresponding NCLs, respectively). The fluxes of Cu, Hg, Pb and Zn have significantly increased since 1940s, with peak ratios of total modern to pre-industrial fluxes of 11, 11, 19 and 49, respectively. The lake occupies a relatively pristine, non-industrialized basin, and therefore the increased metal fluxes might be related to long-distance aeolian transport of trace metals.

Present Limnological Conditions and Recent (ca. 340 yr) Palaeolimnology of a Tropical Lake in the Sierra de Los Tuxtlas, Eastern Mexico

The Sierra de Los Tuxtlas is a recently active volcanic field, with eruptions in 1664 and 1792. It holds one of the reserves of tropical evergreen forest in Mexico, as well as several maar lakes. One of them, Lago Verde, was chosen for a three-fold study (1) on its present limnological conditions, (2) on the algal community living in the water column and preserved in the surface sediments; and (3) on its recent history (ca. 340 yr). The palaeolimnological study was based on multiproxy analyses on core material dated by 210 Pb, 137 Cs and 14 C. Lago Verde is a small, shallow lake with dilute, slightly alkaline water (CO3 2 +H CO 3 >C l >S O 4 2 , Na + +K + >C a 2+ >M g 2+ ). It is turbid, eutrophic, with high phosphorus levels. It is a warm polymictic lake, with thermal and oxygen stratification establishing by midday during the warm months. The lake does not stratify in winter. Diatoms dominate the phytoplankton community in the cold ‘nortes’ season, Cyanobacteria in summer, and Chlorophyta in autumn. Cyanobacteria (Chroococcales) are not well preserved in the surface sediments while Chlorophyta are better preserved. Sedimentary diatoms are well preserved, dominated by the three most abundant species in the water column: Achnanthidium minutissimum, Fragilaria capucina and Aulacoseira granulata. The base of the studied sequences is constrained by the historic eruption of 1664. The period from 1664 to 1963 is characterised by a meso-eutrophic lake. Tropical Forest vegetation reaches maximum values between ca. 1800 and 1963. Between ca. 1785 and 1885 the lake was slightly shallower than in the rest of the 1664–1963 period, probably recording climatic variability. An early pulse of anthropogenic disturbance was recorded by ca. 1921 and after ca. 1963 intense forest clearance and high erosion rates led to a more turbid, more productive, nutrient-rich lake. The highest anthropogenic impact was reached by ca. 1988; afterwards the lake and its basin reached a new balance, with the establishment of the present modern conditions.

NEW LIZARD OF THE GENUS DIPLOGLOSSUS (ANGUIDAE: DIPLOGLOSSINAE) FROM THE TUXTLAN FAUNAL REGION, VERACRUZ, MEXICO

Abstract A new species of Diploglossus is described from the Sierra de Los Tuxtlas in southern Veracruz, Mexico. Individuals of this species are among the largest in the genus in Mexico (up to 105 mm snoutvent length). Similar to D. enneagrammus and D. legnotus, this new species has the suboculars and postoculars arranged in a single continuous series, in contrast to suboculars and postoculars in juxtaposed series. The new species differs from D. enneagrammus in having more scales around the midbody and a redorange throat and anterior flanks marked with broad dark bars; it differs from D. legnotus in possessing more scales around the midbody and more scales along the dorsal midline.

TAXONOMIC REVISION OF THE MEXICAN PLETHODONTID SALAMANDERS OF THE GENUS LINEATRITON, WITH THE DESCRIPTION OF TWO NEW SPECIES

We describe two new species of salamanders of the genus Lineatriton, which occur as allopatric populations in the Sierra de Juarez, Oaxaca, and the Sierra de Los Tuxtlas, Veracruz, Mexico. The name Lineatriton lineolus (Cope) is restricted to populations in the Sierra Madre Oriental of Veracruz. The population in the Sierra de Los Tuxtlas, previously allocated to L. lineolus, is here described as Lineatriton orchimelas. The population from the Sierra de Juarez is reported here for the first time and is described as yet another new species of Lineatriton. These new species differ from L. lineolus in aspects of body size, body proportions, and pigmentation of the male reproductive organs.

Comments On ‘Technological Choices in Ceramic Production’, Archaeometry, 42(1), 1–76, 2000

Sillar, B., and Tite, M. S., 2000, The challenge of ‘technological choices for materials science approaches in archaeology, Archaeometry42, 2–20. Livingstone Smith, A., 2000, Processing clay for pottery in northern Cameroon: social and technical requirements, Archaeometry42, 21–42. Sillar, B., 2000, Dung by preference: the choice of fuel as an example of how Andean pottery production is embedded within wider technical, social, and economic practices, Archaeometry42, 43–60. Pool, C. A., 2000, Why a kiln? Firing technology in the Sierra de los Tuxtlas, Veracruz (Mexico), Archaeometry42, 61–76.

A Ceramic Perspective on the Formative to Classic Transition in Southern Veracruz, Mexico

For any particular historical circumstance, explanations of ceramic evolution should consider the performance characteristics of pottery vessels in their behavioral contexts, as well as the varying effects of evolutionary processes operating at different social, spatial, and temporal scales. The replacement of tempered black and differentially fired serving vessels by fine-paste wares during the Formative to Classic transition in the Sierra de los Tuxtlas, Veracruz, Mexico illustrates these points. New radiocarbon assays from the Bezuapan site document the rapidity of this transition. Evaluation of visual performance characteristics and contextual associations suggest that the Tuxtlas fine-paste tradition began as a Late Formative prestige technology. Adoption of updraft kilns in the Terminal Formative period lowered the risk of firing losses and allowed savings in paste preparation and resource procurement costs to be realized. As a result, the fine-paste tradition spread to wider segments of society, ultimately replacing earlier traditions. A volcanic eruption at the close of the Formative period and subsequent immigration of Central Mexican settlers constituted evolutionary sorting mechanisms, which perturbed general trends in ceramic evolution within a restricted area of the central Tuxtlas.