A Brief Biogeoclimatic History of the Arenal Observatory Lodge & Spa

Arenal Observatory Lodge & Spa

By Austin Gess

                The Arenal Observatory Lodge & Spa is located in the Caribbean foothills of the Tilaran Cordillera, in the premontane rainforest of Costa Rica. Occupying an elevational range between 600 and 1100 meters above sea level and nestled in-between the Rio Agua Calliente and the Rio Danta, the 350-hectare property encompasses a diverse array of ecosystems and micro-habitats.

                Arenal Observatory Lodge and Spa is enclosed by the Arenal Volcano National Park, one of the most important areas of conservation in the country. It has been calculated that 43% of the endangered birds and 51% of the endangered mammals of Costa Rica inhabit this area. Furthermore, this area contains 47% of the amphibian and reptiles, 51% of the birds, and 48% of the mammals of Costa Rica. Temperatures range from lows of 17oC to highs of 30oC with an average temperature of 23oC. The lodge receives approximately 4000 mm of rain every year.

                The nearest notable geographical landmarks include, Arenal Volcano, Cerro Chato, and Lake Arenal. Arenal Volcano was one of the most active volcanos in the world until 2010, when it entered its current dormant state. At approximately 7000 years old, it is the youngest volcano in Costa Rica. Arenal Volcano and the foothills that surround it make up the watershed for the important Lake Arenal. Lake Arenal is the largest body of freshwater in Costa Rica, at 85 km2. This large size is a result of the hydroelectricity project which tripled the size of the lake in 1979. This project initially generated 70% of the country’s electricity and still provides 17% of the country’s electricity today. Cerro Chato, literally “flat hill” in Spanish, is actually an inactive volcano which lies southeast of the nearby Arenal Volcano. It is believed that it first erupted 38,000 years ago, and last erupted 3,500 years ago. Now, its dormant crater has filled with water creating a small green lagoon.

                This diversity of geographical characteristics coupled with variable climatic conditions creates an incredible number of ecological niches for flora and fauna to occupy. Riparian ecosystems, primary rainforests, secondary rainforests, premontane rainforests, and agricultural pasturelands all exist within the boundaries of the Arenal Observatory Lodge & Spa. Different plants and animals can be found within every step of this spatial-temporal distribution of habitats. From the forest floor to the emergent layer and from the recently disturbed pastureland to the ancient rainforest, life at the Arenal Observatory Lodge & Spa flourishes.