Central Ecuador Research Articles

La biodiversidad de Colombia: significado y distribución regional

Based on the geographical pattern of natural regions of Colombia, namely Pacific coast - biogeographical Choco-region, Caribbean coast, llanos (Orinoco), Amazon and Andean, results of inventories of biodiversity are presented. Flora includes flowering plants, ferns, mosses and lichens. Fauna include reptiles, birds, amphibians and mammals. Plant vegetation includes the terrestrial and aquatic plant communities. The climatic analysis was made from an ecological perspective with detailed analysis of precipitation; ecosystems were defined based on characterizations of biotic components (species, communities) and the complementary aspects related to geology, climate and soils. At the level of the world, Colombia is one of two countries with the highest expression of this renewable natural capital (biodiversity). In flora, it means around 26,500 species of flowering plants. There are 1,600 species of ferns, 976 mosses and 1,700 lichens, these values placed the country as the richest in each of these groups of neotropical countries. The diversity and richness of forests and other vegetation types as shrublands, grasslands, rosette-plants, Colombia reaches about 1,200 different types, which give unique feature as one of the countries with the greatest variety worldwide. The Andean region has the largest concentration of biodiversity; about 11,500 species of flowering plants, 914 mosses, 756 liverworts, lichens 1,396 and 1,050 of ferns, serve as testimony to the enormous concentration of plant richness; in faunal groups, the values of 974 bird species, 484 amphibians, 274 reptiles and 349 mammals, also show this natural region in the first place. The Choco region of Colombia is richer than the areas of the same biogeographical region in Central America and Ecuador. The Colombian paramo region represented 85% of the richness of flowering plants the entire biogeographical region and about 41% of the species are restricted in distribution to Colombia. In terms of fauna richness Colombia is the richest country in birds (1,834 species) and amphibians (700 species) and reached very important values in other groups like reptiles (512 species) and mammals (492 species).

Ebola Virus Epidemic in West Africa and Beyond

Is there a reason to fear that an Ebola outbreak may strike Latin America? The fear may not be unreasonable taking into account the history of epidemics that have affected the American continent since colonization times in 1492. Old World small pox epidemics spread and killed millions of Native Americans north and south from the equator. Imported West Nile virus infections reported in New York in 1999 dramatically spread East to West of the United States. Most recently, Chikungunya virus arrived to Central America in 2013 and has already infected close to 1 million people in Mexico, Central American countries, Brazil, Colombia, Ecuador, Guyanas, Paraguay, and Venezuela.

Prevalence of metabolic syndrome and associated risk factors in ecuadorian university students

Overweight and obesity in in young people especially in children and adolescents is considered as public health problem in the world. Obesity could be the most important cause of insulin resistance. For this reason obese children and adolescents become in a risky group for developing metabolic syndrome (MS). In Ecuador is shocking the low following that is given to the diagnosis of MS for predicting the risk of cardio and cerebral vascular disease and diabetes mellitus. To determine the prevalence of metabolic syndrome and its risk factors in a sample of students from the "Universidad Central del Ecuador" (UCE) in Quito. Students form first, second and third semester of Medicine College in UCE were included in the study. The age range was between 17 and 25 years old. All students were measured weight, height, body mass index (BMI, blood pressure, waist circumference and serum levels of total cholesterol, HDL, LDL, triglycerides and glucose. The study shows that the prevalence of MS was 7.58% (IDF). It means that 1 of 13 students had MS. 22.24% has pre obesity and 3.14% has obesity. We found that waist circumference was mainly higher in women than men (33.67% vs. 9.55) of the 31.79% of low values of HDLc, the 24.50% occurred among women and 7.29% among men. , the values of total cholesterol, LDL cholesterol and glucose were normal. In the tested sample was found that 1 out of 13 students had MS and 1 out of 2 had at least one risk factor for MS. According with the pre-obesity and obesity result, 1 out of 4 students shows one of these symptoms. In addition, these results show the direct relationship between risk factors and TA. Finally, Healthy lifestyles promotion (includes non-pharmacological treatments such diet and exercise) could be the first goal to prevent metabolic disease, because the large amount of persons with at least one risk factor for MS.

A new and previously misidentified Cyrtochilum (Orchidaceae: Oncidiinae) from the high plains of central Ecuador

A new and previously misidentified, small-flowered Cyrtochilum (Orchidaceae: Oncidiinae) from central Ecuador is described, illustrated with a line drawing and photographs, and compared with the species that it has previously been taxonomically mixed-up with by the author. The new species is readily distinguished by the dark yellow, gibbous and carnose lip callus, versus more elongate, longitudinally furrowed and bilobed calli for similar species.

Distribution of Promops davisoni Thomas, 1921 (Chiroptera: Molossidae) in Peru with a new record and southward range extension

Promops davisoni is a poorly known insectivorous bat represented by fewer than two dozen specimens in collections. These species are endemic from the Andean western slopes of Ecuador and Peru where it is known from the Mongoya River, province of Manabí, central Ecuador to the Santuario Nacional Lagunas de Mejia, Arequipa department, southwestern Peru. We report a new record of P. davisoni from Pampa Alta, Tacna department, Peru. This new specimen documents a 125 km range extension and the southernmost record of P. davisoni from Peru.

Atraumatic restorative treatment - glass ionomer sealants survival after a postgraduate training program in Ecuador: 2-year follow-up

This study aimed to evaluate the survival of atraum atic restorative treatment high-viscosity glass ion omer sealants (ART-hvGIS) and its relationship with carious lesio ns incidence in underserved communities of Ecuador. A total of 483 first permanent molars with ART-hvGIS were incl uded after treatment, in which fifteen students of the First Preventive Dentistry Post Graduate Program of Unive rsidad Central del Ecuador assisted 176 schoolchild ren, from 5 to 12 year-old. All the students had previously p articipated in a training course in ART approach. A fter one and two years follow-up, schoolchildren were reevaluate d in relation to sealants retention and new carious lesions development. After first year of evaluation ART-hvG IS retention rate was about 30% and after second ye ar 20%. Incidence of carious lesions was 4.0 and 3.4% after first and second periods, respectively. Although twas an extensive ART-hvGIS loss, carious lesions incidence was low in both the periods of evaluation. ART-hvG IS might be an important key to prevent tooth decay in underser ved communities.

Admixture and genetic relationships of Mexican Mestizos regarding Latin American and Caribbean populations based on 13 CODIS-STRs

Short tandem repeats (STRs) of the combined DNA index system (CODIS) are probably the most employed markers for human identification purposes. STR databases generated to interpret DNA profiles are also helpful for anthropological purposes. In this work, we report admixture, population structure, and genetic relationships of Mexican Mestizos with respect to Latin American and Caribbean populations based on 13 CODIS-STRs. In addition, new STR population data were included from Tijuana, Baja California (Northwest, Mexico), which represents an interesting case of elevated genetic flow as a bordering city with the USA. Inter-population analyses included CODIS-STR data from 11 Mexican Mestizo, 12 Latin American and four Caribbean populations, in addition to European, Amerindian, and African genetic pools as ancestral references. We report allele frequencies and statistical parameters of forensic interest (PD, PE, Het, PIC, typical PI), for 15 STRs in Tijuana, Baja California. This Mexican border city was peculiar by the increase of African ancestry, and by presenting three STRs in Hardy–Weinberg disequilibrium, probably explained by recurrent gene flow. The Amerindian ancestry in Central and Southeast of Mexico was the greatest in Latin America (50.9–68.6%), only comparable with the North of Central America and Ecuador (48.8–56.4%), whereas the European ancestry was prevalent in South America (66.7–75%). The African ancestry in Mexico was the smallest (2.2–6.3%) in Latin America (≥2.6%), particularly regarding Brazil (21%), Honduras (62%), and the Caribbean (43.2–65.2%). CODIS-STRs allowed detecting significant population structure in Latin America based on greater presence of European, Amerindian, and African ancestries in Central/South America, Mexican Mestizos, and the Caribbean, respectively.

Spiders (Araneae) Found in Bananas and Other International Cargo Submitted to North American Arachnologists for Identification.

Spiders found in international cargo brought into North America are sometimes submitted to arachnologists for identification. Often, these spiders are presumed to be of medical importance because of size or a submitter's familiarity with a toxic spider genus from the continent of origin. Starting in 2006, requests were made for spiders found in international cargo brought into North America, in addition to the specimens from similar cargo shipments already in our museum collections. This was an ad hoc study that allowed us to focus on spiders of concern to the discoverer. We identified 135 spiders found in international cargo. A key for the most common species is provided. The most frequently submitted spiders were the pantropical huntsman spider, Heteropoda venatoria (L.) (Sparassidae), and the redfaced banana spider, Cupiennius chiapanensis Medina Soriano (Ctenidae). Spiders of medical importance were rare. The most common cargo from which spiders were submitted was bananas with most specimens coming from Central America, Ecuador, or Colombia. Lack of experience with nonnative fauna caused several experienced American arachnologists to misidentify harmless ctenid spiders (C. chiapanensis, spotlegged banana spider, Cupiennius getazi Simon) as highly toxic Phoneutria spiders. These misidentifications could have led to costly, unwarranted prophylactic eradication measures, unnecessary employee health education, heightened employee anxiety and spoilage when perishable goods are left unloaded due to safety concerns.

Food Justice, Nervios, and the Unequal Burden of Misery

INTRODUCTIONThe focus of this article is the unwelcome consequences of the global labor market for sending regions. I have been teaching a sociology course focused on globalization in Ecuador every year since 1998. Travels throughout Ecuador have provided many opportunities to speak with Ecuadorians from all walks of life. I have had extemporaneous conversations with bus drivers, wait staff, close friends, town mayors, college students, farmers, and many others during the past sixteen years. The many conversations that I shared with Ecuadorians over this long period of time reflect the experiences of thousands of others living in the southern Andes region of Ecuador. This essay is a personal reflection on some of the insights gained through those many encounters. The majority of the conversations took place in and around Cuenca, Ecuador in Azuay Province. Azuay Province is located in the Andes Mountains of south central Ecuador. Circumstances in this region reflect the causes and consequences of significant immigration to the United States and to Spain. The limited arable land, the high levels of unemployment and poverty, the increasing inability of parents to secure a future in agriculture for their children, and the significant inflation in prices for basic necessities, including land, all serve to limit the options open to Ecuadorians from this region, particularly among young adults. Ecuadorians must create an alternative path in order to meet socially negotiated expectations of adult status. This is one dimension of the intersection of migration occasioned by transnational labor markets and broad issues of food justice.The global labor surplus under neoliberal globalization drives down wages and working conditions, especially for those at the bottom of the market. Combined with their illegal status in receiving countries, undocumented migrant laborers occupy the most marginal circumstances. The consequences of these fragile and exposed living conditions accrue not only to the worker, but their families in the sending regions as well. The central focus of this paper is the way in which persons in sending regions experience a variety of negative consequences of the transnational agricultural labor market, particularly the depressionlike disorder of nervios. Little precise data exist regarding the employment status of Ecuadorians in the United States, but the seminal work of Pribilisky (2007) suggests that working in the food industry is a frequent source of employment for these migrants. These positions range from working in a restaurant, farm work, and distributing restaurant menus in parking lots. The psychic, social, financial, and medical consequences of these particular forms of labor-tied to the tenuous circumstances of migration, most often as undocumented workers-are largely unknown and unacknowledged in the receiving nations. North Americans pay little attention to the problems of sending regions due to distance, ignorance, and prejudice.Capitalism is a global enterprise and will become even more so due to the increasing trade in commodities, persons, and ideas. Notions of food justice will necessarily expand in recognition of the fact that food production, distribution, and consumption touch every region of the world and connect these regions through our globalized food systems. The consequences of these global dynamics produce winners and losers although these categories are not strictly drawn dichotomies. Ecuadorians materially benefit in many cases from remittances but pay a deep and bitter price for the new found income. Offsetting the remittances is often a significant debt to the coyotes for leading the migrant to the United States. More than one person told of losing their homes and farms in order to finance their children's journey north. The typical charge for bringing an Ecuadorian into the United States was reported to be $15,000 with interest accruing immediately if the fees were not paid in full. …

Paracoccidioides species complex: ecology, phylogeny, sexual reproduction, and virulence.

Paracoccidioidomycosis (PCM) is a deep systemic mycosis caused by human fungal pathogens of the Paracoccidioides genus. The disease is geographically restricted to subtropical areas of Latin America (from south of Mexico to north of Argentina) with a high prevalence in Brazil, Colombia, Venezuela, and Argentina [1]. The annual incidence rate in Brazil is 10–30 infections per million inhabitants, and the mean mortality rate is 1.4 per million inhabitants per year, making this disease the highest cause of mortality among systemic mycoses [2]. PCM is endemic in rural populations and mainly affects individuals engaged in agricultural activities, who inhale aerosols containing fungal material during manipulation of the soil. Molecular evolutionary studies place the genus Paracoccidioides in the thermodimorphic fungal pathogen clade related to the family Ajellomycetaceae (Ascomycetes), which includes the Blastomyces, Histoplasma, and Emmonsia genera, and with which it shares a common ancestor, Lacazia loboi. PCM can be caused by two species Paracoccidioides brasiliensis and P. lutzii [3]. P. brasiliensis has been considered a single species since its discovery, although several studies including molecular and morphological data support the split of P. brasiliensis into two species [3,4]. P. lutzii is composed of a single monophyletic and recombining population so far found in central, southwest, and north Brazil and Ecuador [3–5]. On the other hand, P. brasiliensis contains a complex of at least four different cryptic species (S1, PS2, PS3 and PS4; Figure 1A [6]). P. brasiliensis S1 represents a monophyletic and recombining population widely distributed in South America and has been associated with the majority of cases of PCM detected up until the present time. Strains belonging to P. brasiliensis S1 have previously been recovered from armadillos, soil, and penguin feces [6]. P. brasiliensis PS2 is a paraphyletic and recombining population identified so far only in Brazil and Venezuela [6]. P. brasiliensis PS3 is comprised of a monophyletic and clonal population that has been recovered in humans and armadillos in endemic regions of Colombia [6]. P. brasiliensis PS4 was recently identified and is composed of a monophyletic population of clinical isolates from Venezuela [5,7]. Besides the typical bicorn cocked hat– and barrel-shaped conidia produced by both species, P. lutzii frequently produces elongated rod-shaped conidia, a characteristic feature that may be used for species identification [3]. Because of the difficulties of conidia production in the laboratory and slight morphological differences among species, molecular identification of Paracoccidioides species has become the most common tool of choice. Several molecular markers have already been applied in population studies of the Pararacoccidioides genus, and for multilocus sequencing typing, gp43, arf, b-tub, and hsp70 loci are the best choices for species delineation [4,6].

Building evidence on HRH programme implementation: assessment in 15 Latin American and Caribbean countries

The health systems in the Americas region are characterized by fragmentation and segmentation that constitute an important barrier for expanding coverage, achieving integrated primary health care, and reducing the inefficiency and discontinuity of care. An assessment of the HRH programmes that have been implemented at country level was developed as part of the measurement of the 20 Human Resources for Health (HRH regional goals 2007-2015 adopted in 2007 the Pan-American Sanitary Conference (CSPA)). The exercise was a combination of academic research and the development/application of an advocacy tool, involving policy makers and stakeholders to influence decision-making on the development, implementation or change the HRH programmes, while building evidence through a structured approach based on qualitative and quantitative information, and exchange and dissemination of best practices. The presentation will cover the methodological challenges, as well as a summary of the main findings of the study that included 15 countries: El Salvador, Costa Rica, Guatemala, Honduras, Nicaragua, Panama, Dominican Republic and Belize in Central America, Ecuador, Colombia, Chile and Peru in the Andean region and Argentina, Paraguay and Uruguay in the Mercosur.

Projected impact of twenty-first century ENSO changes on rainfall over Central America and northwest South America from CMIP5 AOGCMs

Due to the importance that the El Nino-Southern Oscillation (ENSO) has on rainfall over the tropical Americas, future changes in ENSO characteristics and teleconnections are important for regional hydroclimate. Projected changes to the ENSO mean state and characteristics, and the resulting impacts on rainfall anomalies over Central America, Colombia, and Ecuador during the twenty-first century are explored for several forcing scenarios using a suite of coupled atmosphere–ocean global climate models (AOGCMs) from the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Mean-state warming of eastern tropical Pacific sea surface temperatures, drying of Central America and northern Colombia, and wetting of southwest Colombia and Ecuador are consistent with previous studies that used earlier versions of the AOGCMs. Current and projected future characteristics of ENSO (frequency, duration, amplitude) show a wide range of values across the various AOGCMs. The magnitude of ENSO-related rainfall anomalies are currently underestimated by most of the models, but the model ensembles generally simulate the correct sign of the anomalies across the seasons around the peak ENSO effects. While the models capture the broad present-day ENSO-related rainfall anomalies, there is not a clear sense of projected future changes in the precipitation anomalies.

Paleoseismology and tectonic geomorphology of the Pallatanga fault (Central Ecuador), a major structure of the South-American crust

The Pallatanga fault (PF) is a prominent NNE-SSW strike–slip fault crossing Central Ecuador. This structure is suspected to have hosted large earthquakes, including the 1797 Riobamba event which caused severe destructions to buildings and a heavy death toll (more than 12,000 people), as well as widespread secondary effects like landsliding, liquefaction and surface cracking. The scope of this study is to evaluate the seismic history of the fault through a paleoseismological approach. This work also aims at improving the seismotectonic map of this part of the Andes through a new mapping campaign and, finally, aims at improving the seismic hazard assessment.We show that the PF continues to the north of the previously mapped fault portion in the Western Cordillera (Rumipamba–Pallatanga portion) into the Inter-Andean Valley (Riobamba basin). Field evidences of faulting are numerous, ranging from a clear geomorphological signature to fault plane outcrops. Along the western side of the Riobamba basin, the strike–slip component seems predominant along several fault portions, with a typical landscape assemblage (dextral offsets of valleys, fluvial terrace risers and generation of linear pressure ridges). In the core of the inter-Andean valley, the main fault portion exhibits a vertical component along the c. 100m-high cumulative scarp. The presence of such an active fault bounding the western suburbs of Riobamba drastically increases the seismic risk for this densely inhabited and vulnerable city. To the east (Peltetec Massif, Cordillera Real), the continuation of the Pallatanga fault is suspected, but not definitely proved yet.Based on the analysis of three trenches, we state that the Rumipamba–Pallatanga section of the PF experienced 4 (maybe 5) Holocene to Historical strong events (Mw>7). The coseismic behavior of the fault is deduced from the occurrence of several colluvial wedges and layers associated with the fault activity and interbedded within the organic black soil sequence. According to a series of 14C datings, we document that these events occurred during the last 6500years. The clear deformation of the shallowest layer (14C: 1633AD) is most likely associated with the 1797 Riobamba earthquake. After retrodeforming one of the 3 trenches, we estimate coseismic vertical throws (0.70 to 0.90m). Because of bad outcrop conditions, we could not determine the horizontal component of slip and we used the slip vector determined in a previous work with a tectonic geomorphology study.Assuming this slip vector, we obtain total coseismic offsets between 3.5 and 4.5m, indicative of earthquake magnitudes around c. Mw 7.5. The estimated recurrence time intervals range between 1300 and 3000years, indicating an average slip rate of c. 2.5mm/a for the Rumipamba–Pallatanga section of the fault.

Do richness and rarity hotspots really matter for orchid conservation in light of anticipated habitat loss?

AbstractAimThe aim of this analysis was to identify strategies that will maximize efficiency and effectiveness in conservation planning. As many orchids are threatened with extinction for various reasons, our primary objective was to combine hotspots analyses with stochastic extinction modelling to highlight possible conservation priorities for Lepanthes spp. (Orchidaceae) based on patterns of richness, rarity and threat. Our subsequent objective was to identify potential conservation surrogates and variables that are the best predictors of extinction probabilities. The ultimate goal was to determine which factors should be emphasized in conservation planning to prevent species extinctions.LocationLatin America; the Caribbean.MethodsWe used herbarium records and ArcGIS to map the distribution of Lepanthes spp. and to identify hotspots of richness and rarity. We forecasted extinction patterns with Koopowitz's stochastic extinction model and calculated extinction probabilities in each country. We used a randomForest regression model in R to assess the importance of richness, rarity and threat for explaining extinction probabilities.ResultsHotspots of Lepanthes richness and rarity occurred in north‐western South America and southern Central America and largely overlapped with each other. The highest extinction probabilities occurred in northern Central America, Haiti and Ecuador, and generally, hotspots of richness and rarity did not correspond with patterns of threat. Habitat loss was the most important variable for explaining extinction probabilities, followed by measures of rarity.Main conclusionsConservation efforts will be most efficient in richness and rarity hotspots, and because they overlap, rarity hotspots could act as surrogates for protecting overall Lepanthes diversity. Hotspots rarely occurred in the most threatened areas, and therefore, conservation efforts are more urgent in non‐hotspot areas. Conservation efforts will be most effective if they combine ex situ strategies in locations with high habitat conversion rates with reservation strategies in rarity and richness hotspots, particularly where they overlap.

Systematics of treefrogs of the Hypsiboas calcaratus and Hypsiboas fasciatus species complex (Anura, Hylidae) with the description of four new species

We review the systematics of the Hypsiboas calcaratus species complex, a group of widely distributed Amazonian hylid frogs. A comprehensive analysis of genetic, morphological, and bioacoustic datasets uncovered the existence of eleven candidate species, six of which are confirmed. Two of them correspond to Hypsiboas fasciatus and Hypsiboas calcaratus and the remaining four are new species that we describe here. Hypsiboas fasciatus sensu stricto has a geographic range restricted to the eastern Andean foothills of southern Ecuador while Hypsiboas calcaratus sensu stricto has a wide distribution in the Amazon basin. Hypsiboas almendarizae sp. n. occurs at elevations between 500 and 1950 m in central and northern Ecuador; the other new species (H. maculateralis sp. n., H. alfaroi sp. n., and H. tetete sp. n.) occur at elevations below 500 m in Amazonian Ecuador and Peru. The new species differ from H. calcaratus and H. fasciatus in morphology, advertisement calls, and mitochondrial and nuclear DNA sequences. Five candidate species from the Guianan region, Peru, and Bolivia are left as unconfirmed. Examination of the type material of Hyla steinbachi, from Bolivia, shows that it is not conspecific with H. fasciatus and thus is removed from its synonymy.

High local genetic diversity of canine parvovirus from Ecuador

Canine parvovirus (CPV) comprises three antigenic variants (2a, 2b, and 2c) that are distributed globally with different frequencies and levels of genetic variability. CPVs from central Ecuador were herein analyzed to characterize the strains and to provide new insights into local viral diversity, evolution, and pathogenicity. Variant prevalence was analyzed by PCR and partial sequencing for 53 CPV-positive samples collected during 2011 and 2012. The full-length VP2 gene was sequenced in 24 selected strains and a maximum-likelihood phylogenetic tree was constructed using both Ecuadorian and worldwide strains. Ecuadorian CPVs have a remarkable genetic diversity that includes the circulation of all three variants and the existence of different evolutionary groups or lineages. CPV-2c was the most prevalent variant (54.7%), confirming the spread of this variant in America. Ecuadorian CPV-2c strains clustered in two lineages, which represent the first evidence of polyphyletic CPV-2c circulating in South America. CPV-2a strains constituted 41.5% of the samples and clustered in a single lineage. The two detected CPV-2b strains (3.8%) were clearly polyphyletic and appeared related to Ecuadorian CPV-2a or foreign CPV-2b strains. Besides the substitution at residue 426 that is used to identify the variants, two amino acid changes occurred in Ecuadorian strains: Val139Iso and Thr440Ser. Ser(440) occurred in a biologically relevant domain of VP2 and is here described for the first time in CPV. The associations of Ecuadorian CPV-2c and CPV-2a with clinical symptoms indicate that dull mentation, hemorrhagic gastroenteritis and hypothermia occurred more frequently in infection with CPV-2c than with CPV-2a.

Intense interface seismicity triggered by a shallow slow slip event in the Central Ecuador subduction zone

AbstractWe document a 1 week long slow slip event (SSE) with an equivalent moment magnitude of 6.0–6.3 which occurred in August 2010 below La Plata Island (Ecuador), south of the rupture area of the 1906 Mw = 8.8 megathrust earthquake. GPS data reveal that the SSE occurred at a depth of about 10 km, within the downdip part of a shallow (<15 km), isolated, locked patch along the subduction interface. The availability of both broadband seismometer and continuous geodetic station located at the La Plata Island, 10 km above the SSE, enables a careful analysis of the relationships between slow and rapid processes of stress release along the subduction interface. During the slow slip sequence, the seismic data show a sharp increase of the local seismicity, with more than 650 earthquakes detected, among which 50 have a moment magnitude between 1.8 and 4.1. However, the cumulative moment released through earthquakes accounts, at most, for 0.2% of the total moment release estimated from GPS displacements. Most of the largest earthquakes are located along or very close to the subduction interface with focal mechanism consistent with the relative plate motion. While the earthquake sizes show a classical distribution (Gutenberg‐Richter law with a b‐value close to 1), the space‐time occurrence presents a specific pattern. First, the largest earthquakes appear to occur randomly during the slow slip sequence, which further evidence that the seismicity is driven by the stress fluctuations related to aseismic slip. Moreover, the seismicity observed during the SSE consists in individual events and families of repeating earthquakes. These observations indicate that the stress increment induced by the episodic aseismic slip may lead both to sudden seismic moment release and to progressive rupture within small locked patches. This study offers an a posteriori interpretation of the seismogenesis in the Central Ecuador subduction zone, where intense seismic swarms have been regularly observed (1977, 1998, 2002, and 2005). These swarms have likely been triggered by large‐magnitude slow slip events.

A Devastating Plinian Eruption at Tungurahua Volcano Reveals Formative Occupation at ~1100 cal BC in Central Ecuador

Based on archaeological and radiometric constraints, previous studies have divided pre-Columbian times of Ecuador into a succession of cultural periods. The Paleoindian and Preceramic periods encompass the time from the first Amerindian occupation to about 4000 BC. The Formative period extends from ∼4000 to ∼300 BC, while the Regional Development (∼300 BC to ∼AD 700) and Integration periods predate the Columbian period, which starts in AD 1533 in Ecuador. The Formative cultural period is poorly known from earlier studies. Here, we bring the first documentation of Formative age occupation around Tungurahua Volcano, 120 km SW of Quito, and show that local settlements were devastated by a violent eruption around 1100 cal BC. Recent volcanological works combining lithostratigraphic, petrologic, and geochronologic analyses reveal that the steep-sloped Tungurahua edifice suffered a major Late Holocene flank failure. We show that the failure event resulted from a major explosive eruption triggered by massive magma intrusion inside the volcano. Decompression of the magma due to a flank collapse resulted in a violent, high-velocity directed blast explosion, which deposited charcoaland sherd-rich ash layers upon and near the volcano. Our 14C results range from 2225 ± 30 to 5195 ± 45 BP, but most cluster between 2640 ± 45 and 3195 ± 45 BP. A calibration analysis indicates that the event took place at ∼1100 cal BC, in the Formative period. We gathered 38 pottery sherds from 3 localities. The sherds show a diversity of size, shape, color, and ornamentation. Examination of pastes, surface finish, and firing indicates that our material shares many common features from site to site. The material from Tungurahua shares affinities with the Cotocollao tradition, which developed in the Quito region between 1500 and 500 BC, and with the Machalilla tradition (coastal region of Ecuador), with the occurrence of carinated bowls with punctuate decorations at 1500–1000 BC. Our study reveals that the ∼1100 cal BC Plinian eruption of Tungurahua Volcano is among the oldest known volcanic disasters in the Andes.

A Devastating Plinian Eruption at Tungurahua Volcano Reveals Formative Occupation at ∼1100 cal BC in Central Ecuador

Based on archaeological and radiometric constraints, previous studies have divided pre-Columbian times of Ecuador into a succession of cultural periods. The Paleoindian and Preceramic periods encompass the time from the first Amerindian occupation to about 4000 BC. The Formative period extends from ∼4000 to ∼300 BC, while the Regional Development (∼300 BC to ∼AD 700) and Integration periods predate the Columbian period, which starts in AD 1533 in Ecuador. The Formative cultural period is poorly known from earlier studies. Here, we bring the first documentation of Formative age occupation around Tungurahua Volcano, 120 km SW of Quito, and show that local settlements were devastated by a violent eruption around 1100 cal BC. Recent volcanological works combining lithostratigraphic, petrologic, and geochronologic analyses reveal that the steep-sloped Tungurahua edifice suffered a major Late Holocene flank failure. We show that the failure event resulted from a major explosive eruption triggered by massive magma intrusion inside the volcano. Decompression of the magma due to a flank collapse resulted in a violent, high-velocity directed blast explosion, which deposited charcoaland sherd-rich ash layers upon and near the volcano. Our 14C results range from 2225 ± 30 to 5195 ± 45 BP, but most cluster between 2640 ± 45 and 3195 ± 45 BP. A calibration analysis indicates that the event took place at ∼1100 cal BC, in the Formative period. We gathered 38 pottery sherds from 3 localities. The sherds show a diversity of size, shape, color, and ornamentation. Examination of pastes, surface finish, and firing indicates that our material shares many common features from site to site. The material from Tungurahua shares affinities with the Cotocollao tradition, which developed in the Quito region between 1500 and 500 BC, and with the Machalilla tradition (coastal region of Ecuador), with the occurrence of carinated bowls with punctuate decorations at 1500–1000 BC. Our study reveals that the ∼1100 cal BC Plinian eruption of Tungurahua Volcano is among the oldest known volcanic disasters in the Andes.

FARM-LEVEL ECONOMIC IMPACTS OF CONSERVATION AGRICULTURE IN ECUADOR

SUMMARYFarm households in the Andean region of South America face serious livelihood challenges, including a poor natural resource base and declining agricultural yields. Conservation agriculture has been identified as a potential solution to environmental degradation and the associated poverty and food insecurity in the region. This study analyses the potential economic impact of conservation agriculture in two sub-watersheds in central Ecuador utilizing a linear programming model and data from experiments in farmer fields. The model found that specific cover crops, crop rotations and reduced tillage designed to reduce soil erosion and increase soil organic matter can lead to increased incomes for farm households in a time period of as short as two years. It appears that conservation agriculture practices have the potential to improve the livelihoods of the rural poor in Ecuador because conservation agriculture activities entered the revenue-maximizing model solution for both sub-watersheds.