Lakes Enriquillo and Azuei, the two largest lakes in Hispaniola and in the Caribbean, have risen 10 and 5 m respectively within the last 8 years. Higher lake levels have submerged towns, road systems, agricultural lan...Lakes Enriquillo and Azuei, the two largest lakes in Hispaniola and in the Caribbean, have risen 10 and 5 m respectively within the last 8 years. Higher lake levels have submerged towns, road systems, agricultural lands and utilities, and have threatened to submerge the major overland highway that connects the Dominican Republic and Haiti. In this study, we use CHIRP seismic data, satellite imagery, and regional meteorological data to quantify and assess controls on the recent lake level rises. Although data are limited, the analyses indicate that the lakes’ water level changes may be attributed to a combination of increased rainfall and natural or man-made changes to the hydraulic connectivity of the various water bodies within the drainage basin. We show that a weak correlation exists between changes in Lake Enriquillo’s and Azuei’s water levels and precipitation rates (0.2 and 0.08 respectively, 1984-2012) and that both lakes experience periods of anti-correlation where, for example, water level drops at Lake Azuei (~20 masl) coincide with water level rises at Lake Enriquillo (41 mbsl). From these observations, we propose that the lakes experience intermittent periods of hydraulic connectivity along reactivated or newly developed stratigraphic-controlled sub-surface transport pathways. We also note that moderately small earthquakes along the large active fault system that extends through both lakes may promote or limit hydraulic conductivity on decadal or shorter time scales. The extents to which recent earthquakes have triggered changes in groundwater flow at this site remain unclear but represent an important topic of future research.展开更多
This article presents a study of the cloud forest dominated by the Prestoea montana (R. Graham) Nichols. This is a hyperhumid forest located in ravines and shaded areas with cloud condensation, and at heights ranging ...This article presents a study of the cloud forest dominated by the Prestoea montana (R. Graham) Nichols. This is a hyperhumid forest located in ravines and shaded areas with cloud condensation, and at heights ranging from 350 - 1250 masl. This type of forest is always found in thermal and mesotropical belts, without ever reaching the supratropical belt. This study was based on works published by other authors and on our own field sampling. The article begins by describing the geological, bioclimatic, biogeographic and floristic aspects of the areas in the study, specifically the hyperhumid areas in the central and eastern mountains. Due to the scarcity of phytosociological works on this area, we apply a statistical treatment to compare our communities with other associations described in Cuba. This comparison reveals that these forest groups are floristically quite distant from each other, both with regard to alliance and association species. We therefore propose two new communities: Cyathea furfuracea Baker and Prestoea montana (Grah.) Nichol;Ormosia krugii Urb. and Prestoea montana (Grah.) Nichol.展开更多
文摘Lakes Enriquillo and Azuei, the two largest lakes in Hispaniola and in the Caribbean, have risen 10 and 5 m respectively within the last 8 years. Higher lake levels have submerged towns, road systems, agricultural lands and utilities, and have threatened to submerge the major overland highway that connects the Dominican Republic and Haiti. In this study, we use CHIRP seismic data, satellite imagery, and regional meteorological data to quantify and assess controls on the recent lake level rises. Although data are limited, the analyses indicate that the lakes’ water level changes may be attributed to a combination of increased rainfall and natural or man-made changes to the hydraulic connectivity of the various water bodies within the drainage basin. We show that a weak correlation exists between changes in Lake Enriquillo’s and Azuei’s water levels and precipitation rates (0.2 and 0.08 respectively, 1984-2012) and that both lakes experience periods of anti-correlation where, for example, water level drops at Lake Azuei (~20 masl) coincide with water level rises at Lake Enriquillo (41 mbsl). From these observations, we propose that the lakes experience intermittent periods of hydraulic connectivity along reactivated or newly developed stratigraphic-controlled sub-surface transport pathways. We also note that moderately small earthquakes along the large active fault system that extends through both lakes may promote or limit hydraulic conductivity on decadal or shorter time scales. The extents to which recent earthquakes have triggered changes in groundwater flow at this site remain unclear but represent an important topic of future research.
文摘This article presents a study of the cloud forest dominated by the Prestoea montana (R. Graham) Nichols. This is a hyperhumid forest located in ravines and shaded areas with cloud condensation, and at heights ranging from 350 - 1250 masl. This type of forest is always found in thermal and mesotropical belts, without ever reaching the supratropical belt. This study was based on works published by other authors and on our own field sampling. The article begins by describing the geological, bioclimatic, biogeographic and floristic aspects of the areas in the study, specifically the hyperhumid areas in the central and eastern mountains. Due to the scarcity of phytosociological works on this area, we apply a statistical treatment to compare our communities with other associations described in Cuba. This comparison reveals that these forest groups are floristically quite distant from each other, both with regard to alliance and association species. We therefore propose two new communities: Cyathea furfuracea Baker and Prestoea montana (Grah.) Nichol;Ormosia krugii Urb. and Prestoea montana (Grah.) Nichol.
