Instituto Geográfico Universitario (IGU)

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    Clusters of high abundance of plans detected from local indicators of spatial association (LISA) in a semi-deciduous tropical forest
    (2018-12-13) José Ramón Martínez Batlle
    Plants are rarely randomly distributed across communities, and patchiness is a common spatial pattern in most tropical forests. Clusters of high density of plant individuals are related to internal and external forces, as well as to historical events. The detection of aggregated patterns of plant individuals allows for a better understanding of the internal and external factors that guide the distribution of species. The aim of this research was to detect and characterize clusters of high abundance of plants and species richness in semi-deciduous forests in the Dominican Republic. For this, we collected vegetation data from 575 quadrats in 23 transects (2300 m2 in total) within the Ocoa river basin. Using local Moran’s I statistics, we isolated 18 quadrats of high density of individuals. We show that density of individuals can be 2.5 times larger on average than in non-aggregated quadrats, and can reach higher values for shrubs species as well as for palms and vines species. In addition, we found that shrub species are the most abundant group in aggregated quadrats, and density of tree species is significantly smaller than that of shrub species. High density quadrats are predominantly occupied by shrubs, palms and vines, following patterns of species composition and lithology. Detecting clusters of high density of individuals could help in the efficient assessment of richness in semi-deciduous tropical forests, and may support new conservation practices for this valuable but threatened ecosystem.
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    Desarrollo de competencias geográficas a través de la participación voluntaria en investigaciones de campo reales: un enfoque interdisciplinario
    (2024-04-20) Estrella del Mar Tena
    Este artículo aborda el impacto de la participación de estudiantes universitarios como voluntarios en un proyecto de investigación socioambiental, específicamente en viajes de campo. Se destaca cómo esta experiencia fortalece competencias geográficas e interdisciplinarias, promoviendo una mayor comprensión de la relación entre la actividad humana y el medio ambiente, así como una conciencia ambiental más profunda. Se evidenció que los aspectos que se tengan en cuenta o no desde el diseño de la investigación repercuten en las interpretaciones que hacen los estudiantes en el territorio. Se sugiere una mayor integración de estudiantes en proyectos de investigación universitarios interdisciplinarios para mejorar la formación geográfica de futuros profesionales teniendo en cuenta un abordaje interdisciplinario desde el diseño de la investigación. Asimismo, se enfatiza la importancia de la enseñanza de la geografía en contextos más allá de las asignaturas específicas como un elemento clave para el desarrollo de competencias geográficas en la formación ciudadana y profesional de los estudiantes.
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    Impacts of Acid Mine Drainage Remediation in the largest gold mine of Latin America on natural water bodies in the Dominican Republic
    (2024-12-26) Martín Rapilly
    Impacts of the acid mine drainage (AMD) remediation are investigated on the largest gold mine in Latin America, located in the Dominican Republic. Geochemical analysis of suspended matter in water performed in 2022 on water bodies located downstream to the mine, namely, the Margajita River and Lake Hatillo, are compared with analyses made in 2007, before the AMD remediation. The results for the Margajita River show a strong decrease in heavy metal and metalloid concentrations in the dissolved phase for Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, Sb, and Pb (between 89.1 and 99.9%) which is correlated with a pH neutralization (from a pH of 2 to 7.5). However, the concentrations of Cd and sulfate in the dissolved fraction remain higher than their environmental standard values, and a high concentration of K is also observed. High contributions in terms of mass are identified for Cs, Tl, Cd, and Li in the Margajita River. Concentrations of Al, Fe, Ni, Zn, and As in suspended sediments are higher than the environmental standard values in 2022. Modeling of the chemical speciation shows that the higher pH leads to the formation of suspended particles in the form of hydroxides and sulfates. The concentrations in suspended sediments are highly correlated between Margajita River and Lake Hatillo in 2022 for Fe, Cd, Li, and Ca (R2 between 0.9 and 0.99 with p ≤ 0.05). In Lake Hatillo, principal component analysis shows that invariant elements Fe, P, Ti, Zr, and Al are correlated, as they precipitate between the inlet and outlet of the lake.
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    Projetcted Hydroclimate changes on Hispaniola Island through the 21st century in CMIP6 Models
    (2020-12-23) Dimitri Herrera; Ramón Delanoy
    Climate change might increase the frequency and severity of longer-lasting drought in the Caribbean, including in Hispaniola Island. Nevertheless, the hydroclimate changes projected by the state-of-the-art earth system models across the island remain unknown. Here, we assess 21st-century changes in hydroclimate over Hispaniola Island using precipitation, temperature, and surface soil moisture data from the 6th Phase of the Coupled Model Intercomparison Project (CMIP6). The resulting analysis indicates, as with the previous 5th Phase of CMIP (CMIP5) models, that Hispaniola Island might see a significant drying through the 21st century. The aridity appears to be robust in most of the island following the Shared Socioeconomic Pathways (SSP) 5–8.6, which assumes the “worst case” greenhouse gas emissions into the atmosphere. We find a significant reduction in both annual mean precipitation and surface soil moisture (soil’s upper 10 cm), although it appears to be more pronounced for precipitation (up to 26% and 11% for precipitation and surface soil moisture, respectively). Even though we provide insights into future hydroclimate changes on Hispaniola Island, CMIP6’s intrinsic uncertainties and native horizontal resolution precludes us to better assess these changes at local scales. As such, we consider future dynamical downscaling efforts that might help us to better inform policy-makers and stakeholders in terms of drought risk.