Karst zone from Ventana cave in Arecibo

Karst zone from Ventana cave in Arecibo

In the karst region of northern Puerto Rico there are five public forests: Cambalache, Guajataca, Vega, Río Abajo (the largest) and Piñones (the largest coastal mangrove forest in Puerto Rico). These forests are home to flora that is unique and that varies from the tops and sides of the haystack hills, or mogotes, to the valleys, because of the characteristics of the zone.

The biodiversity of the island’s vegetation has been studied by various researchers (Danserau, Chinea, Holdridge). The most recent studies have been done by J.C. Figueroa, who confirmed that the karst region of Puerto Rico is home to the greatest diversity of vegetation on the island.

Figueroa used the U.S. Geological Survey’s geological substrata data and the Holdridge Life Zones System as the basis for his studies. The researcher classified the geo-climactic zones, considering climactic aspects and the nature and condition of the soils and relating those factors to the plants. The study revealed that the greatest diversity of native trees (49%) was found in the humid karst region. The next two regions with the most biodiversity in Puerto Rico also had calcareous soils (humid calcareous and dry calcareous).

Not only is there greater biodiversity among the vegetation in the northern karst zone, but there also exists, within the same zone, an interesting variety of climactic and soil conditions, in micro-environmental terms, that lead to even greater variety in the distribution of forest vegetation in the northern limestone region.

Without getting into details about the types of vegetation found there, the study determined that humidity is the most important environmental factor in these variations in vegetation, along with climactic factors such as solar radiation and atmospheric events that occur on the island, such as hurricanes. Variations in flora are affected by rain, by the geological materials in the zone and by the soil. The types of plants that develop on a site are also influenced by exposure to climactic factors (temperature, rain, evaporation and transpiration) and the micro-topography. Each mogote can be seen as a complex ecosystem that is influenced by a variety of environmental factors.


Chinea, J. D. (1980). The forest vegetation of the limestone hills of northern Puerto Rico. Tesis Universidad de Cornell, Ithaca, New York. 70 p.

Figueroa Colón, J.C.; Gómez, G.; Ortíz, P.; Lapin, B. (1984). Informe de progreso (julio 1 -31 diciembre de 1983). Departamento de Recursos Naturales. San Juan, Puerto Rico.

Author: María A. Juncos Gautier
Published: August 27, 2014.

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