868 resultados para Indian art -- Central America
Resumo:
The coyote (Canis latrans) is among the most studied animals in North America. Because of its adaptability and success as a predator, the coyote has flourished and is still expanding its range. Coyotes can now be found throughout most of North America and south into Central America (Voight and Berg 1987). Studies in recent years have been extensive to understand the interrelationships of prey and coyotes (Shelton and Klindt 1974, Beckoff and Wells 1981), as well as demographic relationships (Davis et al. 1975, Knowlton and Stoddart 1978, Mitchell 1979, Bowen 1981) and feeding strategies (Todd and Keith 1976, Andelt et al. 1987, MacCracken and Hansen 1987, Gese et al. 1988a). With the advance of radio telemetry, researchers have investigated lifestyle characteristics spatially with home ranges or temporally with movements in relation to habitat requirements. Researchers have studied home ranges of coyotes in various regions of the United States (Livaitis and Shaw 1980, Andelt 1981, Springer 1982, Pyrah 1984, Gese et al. 1988a) and Canada (Bowen 1982). Some studies of home range were separated by season (Ozoga and Harger 1966) or relation to nearby food sources (Danner and Smith 1980). Home range analysis in relation to social interactions of coyotes has been either neglected, overlooked, or avoided. Gese et al. (1988a) recognized a transient class of coyote by home range size. Coyote social systems are very complex and can vary by season or locality in addition to some reports of group or pack systems (Hamlin and Schweitzer 1979, Beckoff and Wells 1981, Bowen 1981, Gese et al. 1988b). Coyotes maintain communication with conspecifics through vocal and olfactory signals (Lehner 1987, Bowen and McTaggert Cowan 1980). Social interactions may be by far the most complex and least understood aspect related to coyote ecology. Coyote movements can be related to many factors including food, water, cover, and social interactions. Movements in relation to food sources are well documented (Fitch 1948, Todd and Keith 1976, Danner and Smith 1980) although reports on movements in relation to water have not been reported, probably because of limited research in desert situations. There has been some mention of coyotes' movements in relation to cover (Wells and Beckoff 1982). The objectives of this study were to delineate annual and seasonal home ranges, movements, and habitat use of coyotes in the northern Chihuahuan desert.
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The Neotropical genus Neodischistus Painter has a distribution restricted to South (Brazil and Argentina) and Central America (Panama). The genus is composed of two previously described species that are herein revised: N. currani Painter and N. collaris Painter. One new Brazilian species is described: N. marstoni sp. nov. Illustrations of the external morphology of adults and male and female terminalia are also included. An identification key to the species is presented and a short discussion about species distributions is added.
Resumo:
Based on the hypothesis that reproduction is a continuous process in tropical habitats, we analysed reproductive periodicity and egg production in the callianassid ghost shrimp Lepidophthalmus bocourti, one of the most common species in mangrove systems along the Pacific coast of Central America. During one year (May 2008 to April 2009), individuals of L. bocourti (N = 499) were collected nearshore Gulf of Nicoya, Pacific coast of Costa Rica. Observations were made on presence or absence of incubated embryos, and gonad activity of females was analysed as gonadosomatic index (GSI). Our results revealed that L. bocourti has a marked seasonal breeding period, which contradicts previous reports regarding coastal marine decapods from the tropics. Ovigerous females were found only from June to August, while high GSI values were obtained from March to July. The increase of GSI and appearance of ovigerous females were associated with a concomitant decrease of salinity, but not with temperature. We assume that reproduction of L. bocourti is adapted to local changes of environmental conditions, and that a decrease in salinity during rainy season may serve as a triggering factor for ovarian development. Compared to other ghost shrimps, L. bocourti produced on average more (2002 +/- 1365) and smaller (0.87 +/- 0.109 mm) eggs, which seems to suggest that this species does not have an abbreviated larval development as reported for other species of genus. The deviation from the generalization of constant reproduction in the tropics for shallow water marine invertebrates and its probable cause are adequately discussed.
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A phylogenetic analysis of a fragment of the mitochondrial gene 16S was used to test the monophyletic status of Potimirim. Existing doubts on the taxonomic status of brasiliana (once P glabra) and P potimirim (once P mexicana) were clarified. Potimirim mexicana and P potimirim are distinct species according to molecular data and appendix masculina morphology. A new species (Potimirim sp. 1) from Puerto Rico was revealed with molecular data, and it is evolutionarily related to P potimirim and P mexicana according to our analysis. We found out three distinct species under the name P glabra. Then, we recommend the application of the name P glabra for the populations of the Pacific slope of Central America and revalidation of P brasiliana for the Brazilian ones. The need for a new name to those "P glabra" of the Caribbean is highlighted, and it was provisionally referred as Potimirim sp. 2. The ontogenetic (juveniles to adults) development of the appendix masculina of P brasiliana was observed and compared to the other species of Potimirim (adults). In the light of our phylogenetic hypothesis, we postulate a pattern of character addition for the evolution of the appendix masculina of Potimirim. This hypothesis is plausible for two key reasons. First. Potimirim is a monophyletic group according to our hypothesis. Second, the shape of appendix masculina found in adults of P. americana is similar and comparable to those found in the earliest juvenile stages of P brasiliana, a derived species according to our phylogeny (P americana, ((P mexicana, Potimirim sp. 1. P potimirim), (P glabra, (brasiliana, Potimirim sp. 2)))). As so, the basal P americana retain the ancestral morphological state of the appendix masculina when compared to the other species of Potimirim. In our interpretation the ontogeny of the appendix masculina recapitulated the proposed phylogeny, giving further support to it.
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Hippolyte obliquimanus is a marine shrimp reported from the Caribbean Sea and Brazil. The literature provides indications for morphological variation between populations from those regions and the species has a troubled taxonomic history. The aims of this study were to analyse morphological and genetic variation in the populations of H. obliquimanus from Brazil and the Caribbean Sea and to verify if those might support separation of H. obliquimanus into two or more species. This hypothesis was tested with the analysis of morphological and genetic data (mitochondrial gene 16S and the barcode region Cytochrome Oxidase I). The material analysed was obtained from samples and from loans of zoological collections. The rostrum as well as pereiopods 3, 4, and 5 were the adult morphological characters that showed variation, but this occurred in samples from both regions, Brazil and the Caribbean Sea. The sequences of the 16S gene were identical among all specimens analysed. There was, however, variation among the sequences of the barcoding gene COI (<2.0%); this divergence separated the specimens into two groups (Brazil versus the Caribbean) and these groups did not share haplotypes. In conclusion, specimens from the regions analysed showed both morphological and genetic variation, but these did not support the separation of H. obliquimanus into two or more species.
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The endemic stingless honey-making bee Melipona (Melikerria) insularissp.n. on Coiba and Rancheria Islands in Pacific Panama is described, together with the proposed sister species, M. ambigua sp.n. from northeast Colombia. The Coiba Island group and Panama mainland were surveyed, yielding one meliponine endemic (M. insularissp.n.) and six meliponine genera and species. The poor Coiba fauna of amphibians and birds corresponds to the poor social bee fauna and suggests habitat barriers generally precluded recolonization from the mainland during glacial periods. Many animals became extinct, yet some remain as relicts. Melipona insularissp.n. was isolated on accreted terranes of Coiba rainforest in the Panama microplate. Morphology suggests that M. insularissp.n. is not a direct descendant of the San Blas-E. Panama endemic Melikerria, M. triplaridis. A phylogenetic hypothesis corroborates disjunct distributions. Rainforest endemics such as Peltogyne purpurea (Fabaceae) and Ptilotrigona occidentalis (Apidae, Meliponini) also occur as relictual, disjunct populations in Central and South America. These may have been isolated before accelerated biotic exchange began 2.4 Ma. Our work supports the geological findings of both a volcanic arc and the San Blas massif providing a substantial bridge for Melikerria from Colombia and Panama in Eocene to Miocene times. We suggest there have been taxon cycles permitting recolonization during glaciations, whereby colonies of M. insularissp.n. were able to recolonize Rancheria, a 250 ha island, 2 km from Coiba. However, rafting colonies nesting in trees, carried on vegetation mats, may have produced founding populations of Melipona in Central America and on oceanic islands such as Coiba.
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Four Amblyomma sabanerae ticks collected from a turtle (Kinosternon sp.) in San Miguel, El Salvador, were found by molecular analysis to be infected by Rickettsia bellii. We provide the first report of Rickettsia bellii in Central America, and the first report of a Rickettsia species in El Salvador.
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Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) è una specie esotica invasiva di origine centro americana e introdotta in Europa agli inizi degli anni ’90, in Italia nel 1998. Considerata negli Stati Uniti la principale avversità del mais (Zea mais L.), è oggi presente in quasi tutti i Paesi europei dove è presente tale coltura. Poiché il mais risulta l’ospite prioritario di Diabrotica, attualmente il principale metodo di contenimento consiste nella rotazione con una coltura non ospite. L’obiettivo del lavoro è stato quello di indagare sulle piante ospiti alternative al mais nel nostro ambiente, accertando il ruolo che possono avere le infestanti o altre Poaceae coltivate nella biologia della Diabrotica. Tali essenze sono state scelte tra specie mai sottoposte a sperimentazione e tra quelli già oggetto di indagini, ma su cui si sono ottenuti esiti discordi o non soddisfacenti. Sono state allestite prove con infestazione artificiale in ambiente controllato e prove in campo per valutare la sopravvivenza larvale e il completamento del ciclo, nonché le prestazioni biologiche degli individui ottenuti. Le ricerche hanno permesso di osservare sopravvivenza di Diabrotica su numerose graminacee, in particolare cereali. Tale capacità è confermata dalla presenza di larve di diversa età e in alcuni casi di pupe sulle specie ospiti alternative, sia con infestazione artificiale che in campo. Tuttavia crescita e sviluppo su queste piante sono stati più lenti del mais e gli stadi giovanili trovati hanno mostrato caratteristiche morfometriche inferiori rispetto a quelli del mais. Adulti non sono mai stati raccolti in campo, mentre questo si è verificato in condizioni controllate. Le specie che meritano maggior attenzione sono i cereali Triticum spelta e Panicum miliaceum e l’infestante Sorghum halepense. Si potrebbe dunque ipotizzare che alcune specie vegetali possano fungere da ospite secondario quando non è presente il mais riducendo l’efficacia dell’avvicendamento.
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Background Men who have sex with men (MSM) remain the group most at risk of acquiring HIV infection in Britain. HIV prevalence appears to vary widely between MSM from different ethnic minority groups in this country for reasons that are not fully understood. The aim of the MESH project was to examine in detail the sexual health of ethnic minority MSM living in Britain. Methods/Design The main objectives of the MESH project were to explore among ethnic minority MSM living in Britain: (i) sexual risk behaviour and HIV prevalence; (ii) their experience of stigma and discrimination; (iii) disclosure of sexuality; (iv) use of, and satisfaction with sexual health services; (v) the extent to which sexual health services (for treatment and prevention) are aware of the needs of ethnic minority MSM. The research was conducted between 2006 and 2008 in four national samples: (i) ethnic minority MSM living in Britain; (ii) a comparison group of white British MSM living in Britain; (iii) NHS sexual health clinic staff in 15 British towns and cities with significant ethnic minority communities and; (iv) sexual health promotion/HIV prevention service providers. We also recruited men from two "key migrant" groups living in Britain: MSM born in Central or Eastern Europe and MSM born in Central or South America. Internet-based quantitative and qualitative research methods were used. Ethnic minority MSM were recruited through advertisements on websites, in community venues, via informal networks and in sexual health clinics. White and "key migrant" MSM were recruited mostly through Gaydar, one of the most popular dating sites used by gay men in Britain. MSM who agreed to take part completed a questionnaire online. Ethnic minority MSM who completed the online questionnaire were asked if they would be willing to take part in an online qualitative interview using email. Service providers were identified through the British Association of Sexual Health and HIV (BASHH) and the Terrence Higgins Trust (THT) CHAPS partnerships. Staff who agreed to take part were asked to complete a questionnaire online. The online survey was completed by 1241 ethnic minority MSM, 416 men born in South and Central America or Central and Eastern Europe, and 13,717 white British MSM; 67 ethnic minority MSM took part in the online qualitative interview. In addition 364 people working in sexual health clinics and 124 health promotion workers from around Britain completed an online questionnaire. Discussion The findings from this study will improve our understanding of the sexual health and needs of ethnic minority MSM in Britain.
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Under President Ronald Reagan, the White House pursued a complex foreign policy towards the Contras, rebels in trying to overthrow the Sandinista regime in Nicaragua, in Nicaragua. In 1979, the leftist Sandinista government seized power in Nicaragua. The loss of the previous pro-United States Somoza military dictatorship deeply troubled the conservatives, for whom eradication of communism internationally was a top foreign policy goal. Consequently, the Reagan Administration sought to redress the policy of his predecessor, Jimmy Carter, and assume a hard line stance against leftist regimes in Central America. Reagan and the conservatives within his administration, therefore, supported the Contra through military arms, humanitarian aid, and financial contributions. This intervention in Nicaragua, however, failed to garner popular support from American citizens and Democrats. Consequently, between 1982 and 1984 Congress prohibited further funding to the Contras in a series of legislation called the Boland Amendments. These Amendments barred any military aid from reaching the Contras, including through intelligence agencies. Shortly after their passage, Central Intelligence Agency Director William Casey and influential members of Reagan¿s National Security Council (NSC) including National Security Advisor Robert McFarlane, NSC Aide Oliver North, and Deputy National Security Advisor John Poindexter cooperated to identify and exploit loopholes in the legislation. By recognizing the NSC as a non-intelligence body, these masterminds orchestrated a scheme in which third parties, including foreign countries and private donors, contributed both financially and through arms donations to sustain the Contras independently of Congressional oversight. This thesis explores the mechanism and process of soliciting donations from private individuals, recognizing the forces and actors that created a situation for covert action to continue without detection. Oliver North, the main actor of the state, worked within his role as an NSC bureaucrat to network with influential politicians and private individuals to execute the orders of his superiors and shape foreign policy. Although Reagan articulated his desire for the Contras to remain a military presence in Nicaragua, he delegated the details of policy to his subordinates, which allowed this scheme to flourish. Second, this thesis explores the individual donors, analyzing their role as private citizens in sustaining and encouraging the policy of the Reagan Administration. The Contra movement found non-state support from followers of the New Right, demonstrated through financial and organizational assistance, that allowed the Reagan Administration¿s statistically unpopular policy in Nicaragua to continue. I interpret these donors as politically involved, but politically philanthropic, individuals, donating to their charity of choice to further the principles of American freedom internationally in a Cold War environment. The thesis then proceeds to assess the balance of power between the executive and other political actors in shaping policy, concluding that the executive cannot act alone in the formulation and implementation of foreign policy.
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It is a globally important challenge to meet increasing demands for resources and, at the same time, protect biodiversity and ecosystem services. Farming is usually regarded as a major threat to biodiversity due to its expansion into natural areas. We compared biodiversity of bees and wasps between heterogeneous small-scale farming areas and protected forest in northern coastal Belize, Central America. Malaise traps operated for three months during the transition from wet to dry season. Farming areas consisted of a mosaic of mixed crop types, open habitat, secondary forest, and agroforestry. Mean species richness per site (alpha diversity), as well as spatial and temporal community variation (beta diversity) of bees and wasps were equal or higher in farming areas compared to protected forest. The higher species richness and community variation in farmland was due to additional species that did not occur in the forest, whereas most species trapped in forest were also found in farming areas. The overall regional species richness (gamma diversity) increased by 70% with the inclusion of farming areas. Our results suggest that small-scale farming systems adjacent to protected forest may not only conserve, but even favour, biodiversity of some taxonomic groups. We can, however, not exclude possible declines of bee and wasp diversity in more intensified farmland or in landscapes completely covered by heterogeneous farming systems.
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International migration has increased rapidly in the Czech Republic, with more than 150,000 legally registered foreign residents at the end of 1996. A large proportion of these are in Prague - 35% of the total in December 1996. The aim of this project was to enrich the fund of information concerning the "environment", reasons and "mechanisms" behind immigration to the Czech Republic. Mr. Drbohlav looked first at the empirical situation and on this basis set out to test certain well-known migration theories. He focused on four main areas: 1) a detailed description and explanation of the stock of foreign citizens legally settled in Czech territory, concentrating particularly on "economic" migrants; 2) a questionnaire survey targeting a total of 192 Ukrainian workers (98 in the fall 1995 and 94 in the fall 1996) working in Prague or its vicinity; 3) a second questionnaire survey of 40 "western" firms (20 in 1996 and 20 in 1997) operating out of Prague; 4) an opinion poll on how the Czech population reacts to foreign workers in the CR. Over 80% of economic immigrants at the end of 1996 were from European countries, 16% from Asia and under 2% from North America. The largest single nationalities were Ukrainians, Slovaks, Vietnamese and Poles. There has been a huge increase in the Ukrainian immigrant community over both space (by region) and time (a ten-fold increase since 1993), and at 40,000 persons this represents one third of all legal immigrants. Indications are that many more live and work there illegally. Young males with low educational/skills levels predominate, in contrast with the more heterogeneous immigration from the "West". The primary reason for this migration is the higher wages in the Czech Republic. In 1994 the relative figures of GDP adjusted for parity of purchasing power were US$ 8,095 for the Czech Republic versus US$ 3,330 for the Ukraine as a whole and US$ 1,600 for the Zakarpatye region from which 49% of the respondents in the survey came. On an individual level, the average Czech wage is about US$ 330 per month, while 50% of the Ukrainian respondents put their last monthly wage before leaving for the Czech Republic at under US$ 27. The very low level of unemployment in the latter country (fluctuating around 4%) was also mentioned as an important factor. Migration was seen as a way of diversifying the family's source of income and 49% of the respondents had made their plans together with partners or close relatives, while 45% regularly send remittances to Ukraine (94% do so through friends or relatives). Looking at Ukrainian migration from the point of view of the dual market theory, these migrants' type and conditions of work, work load and earnings were all significantly worse than in the primary sector, which employs well educated people and offers them good earnings, job security and benefits. 53% of respondents were working and/or staying in the Czech Republic illegally at the time of the research, 73% worked as unqualified, unskilled workers or auxiliary workers, 62% worked more than 12 hours a day, and 40% evaluated their working conditions as hard. 51% had no days off, earnings were low in relation to the number of hours worked. and 85% said that their earnings did not increase over time. Nearly half the workers were recruited in Ukraine and only 4% expressed a desire to stay in the Czech Republic. Network theories were also borne out to some extent as 33% of immigrants came together with friends from the same village, town or region in Ukraine. The number who have relatives working in the Czech Republic is rising, and many wish to invite relatives or children to visit them. The presence of organisations which organised cross-border migration, including some which resort to organising illegal documents, also gives some support for the institutional theory. Mr. Drbohlav found that all the migration theories considered offered some insights on the situation, but that none was sufficient to explain it all. He also points out parallels with many other regions of the world, including Central America, South and North America, Melanesia, Indonesia, East Africa, India, the Middle East and Russia. For the survey of foreign and international firms, those chosen were largely from countries represented by more than one company and were mainly active in market services such as financial and trade services, marketing and consulting. While 48% of the firms had more than 10,000 employees spread through many countries, more than two thirds had fewer than 50 employees in the Czech Republic. Czechs formed 80% plus of general staff in these firms although not more than 50% of senior management, and very few other "easterners" were employed. All companies absolutely denied employing people illegally. The average monthly wage of Czech staff was US$ 850, with that of top managers from the firm's "mother country" being US$ 6,350 and that of other western managers US$ 3,410. The foreign staff were generally highly mobile and were rarely accompanied by their families. Most saw their time in the Czech Republic as positive for their careers but very few had any intention of remaining there. Factors in the local situation which were evaluated positively included market opportunities, the economic and political environment, the quality of technical and managerial staff, and cheap labour and low production costs. In contrast, the level of appropriate business ethics and conduct, the attitude of local and regional authorities, environmental production conditions, the legal environment and financial markets and fiscal policy were rated very low. In the final section of his work Mr. Drbohlav looked at the opinions expressed by the local Czech population in a poll carried out at the beginning of 1997. This confirmed that international labour migration has become visible in this country, with 43% of respondents knowing at least one foreigner employed by a Czech firm in this country. Perception differ according to the region from which the workers come and those from "the West" are preferred to those coming from further east. 49% saw their attitude towards the former as friendly but only 20% felt thus towards the latter. Overall, attitudes towards migrant workers is neutral, although 38% said that such workers should not have the same rights as Czech citizens. Sympathy towards foreign workers tends to increase with education and the standard of living, and the relatively positive attitudes towards foreigners in the South Bohemia region contradicted the frequent belief that a lack of experience of international migration lowers positive perceptions of it.
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The global population of the Neotropical migrant Golden-winged Warbler (Vermivora chrysoptera) has declined steadily over the past fifty years. While factors influencing this decline have been well researched on the breeding grounds, little is known about the distribution and habitat requirements of this warbler on its stationary non-breeding range. Recent efforts to quantify the non-breeding habitat requirements of this warbler have focused on Colombia and Costa Rica, though the species ranges as far north as the Yucatan Peninsula, Mexico. To address the gap in knowledge from the northern portion of the non-breeding range, I conducted 80 serial point-count surveys targeting Goldenwinged Warblers at eight field sites in Honduras, Central America. I found that Goldenwinged Warblers occupy a greater variety of habitats than previously recognized, including pine-oak forest and semi-deciduous broadleaf forest. I also documented habitat associations that have not been observed in other parts of the non-breeding range with respect to elevation, rainfall, and spatial segregation by sex. These results demonstrate the need to consider the entire non-breeding range in conservation planning, as Goldenwinged Warbler habitat associations appear to vary regionally.
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The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) has been used to quantify SO2 emissions from passively degassing volcanoes. This dissertation explores ASTER’s capability to detect SO2 with satellite validation, enhancement techniques and extensive processing of images at a variety of volcanoes. ASTER is compared to the Mini UV Spectrometer (MUSe), a ground based instrument, to determine if reasonable SO2 fluxes can be quantified from a plume emitted from Lascar, Chile. The two sensors were in good agreement with ASTER proving to be a reliable detector of SO2. ASTER illustrated the advantages of imaging a plume in 2D, with better temporal resolution than the MUSe. SO2 plumes in ASTER imagery are not always discernible in the raw TIR data. Principal Component Analysis (PCA) and Decorrelation Stretch (DCS) enhancement techniques were compared to determine how well they highlight a variety of volcanic plumes. DCS produced a consistent output and the composition of the plumes was easy to identify from explosive eruptions. As the plumes became smaller and lower in altitude they became harder to distinguish using DCS. PCA proved to be better at identifying smaller low altitude plumes. ASTER was used to investigate SO2 emissions at Lascar, Chile. Activity at Lascar has been characterized by cyclic behavior and persistent degassing (Matthews et al. 1997). Previous studies at Lascar have primarily focused on changes in thermal infrared anomalies, neglecting gas emissions. Using the SO2 data along with changes in thermal anomalies and visual observations it is evident that Lascar is at the end an eruptive cycle that began in 1993. Declining gas emissions and crater temperatures suggest that the conduit is sealing. ASTER and the Ozone Monitoring Instrument (OMI) were used to determine the annual contribution of SO2 to the troposphere from the Central and South American volcanic arcs between 2000 and 2011. Fluxes of 3.4 Tg/a for Central America and 3.7 Tg/a for South America were calculated. The detection limits of ASTER were explored. The results a proved to be interesting, with plumes from many of the high emitting volcanoes, such as Villarrica, Chile, not being detected by ASTER.
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Water springs are the principal source of water for many localities in Central America, including the municipality of Concepción Chiquirichapa in the Western Highlands of Guatemala. Long-term monitoring records are critical for informed water management as well as resource forecasting, though data are scarce and monitoring in low-resource settings presents special challenges. Spring discharge was monitored monthly in six municipal springs during the author’s Peace Corps assignment, from May 2011 to March 2012, and water level height was monitored in two spring boxes over the same time period using automated water-level loggers. The intention of this approach was to circumvent the need for frequent and time-intensive manual measurement by identifying a fixed relationship between discharge and water level. No such relationship was identified, but the water level record reveals that spring yield increased for four months following Tropical Depression 12E in October 2011. This suggests that the relationship between extreme precipitation events and long-term water spring yields in Concepción should be examined further. These limited discharge data also indicate that aquifer baseflow recession and catchment water balance could be successfully characterized if a long-term discharge record were established. This study also presents technical and social considerations for selecting a methodology for spring discharge measurement and highlights the importance of local interest in conducting successful community-based research in intercultural low-resource settings.