The Ecosystem

A savanna is “…a natural and stable ecosystem occurring under a tropical climate, having a relatively continuous layer of xeromorphic grasses and sedges, and often with a discontinuous layer of low trees and shrubs.” J.S. Beard (1953) cited in Kirchner, J. 1977. A Neotropical Companion: An introduction to the animals, plants, and ecosystems of the New World tropics. 2nd Ed. Princeton University Press. Princeton, N.J. P. 228.

At roughly 8 degrees 40 minutes north of the equator, we are firmly in the tropics. At 82 degrees 27 minutes west of Greenwich, England, we are in the New World tropics – the neotropics.

At an altitude of about 760 meters, we are just over a quarter of the way up the tallest mountain in Panama, Volcan Baru, which is 3,478 meters. When we look to the south, we see the Pacific Ocean, far in the distance. If we were to climb to the top of Volcan Baru and look north, we’d see the Caribbean Sea.

What we see here at 760 meters is decided by climate, by geology, and by plants.

Within the tropical climate, we have a rainy season (May – December) and a dry season (January – April). However, it is my impression (no data yet) that we have about 300 sunny mornings each year. When it rains, it usually rains in the afternoon and evening. When it’s dry, the wind usually blows in the afternoon and evening. Since we’ve been here, the lowest temperature that we have measured has been 62 degrees F and the highest has been 88 degrees F.

According to a geologist friend, the mountain at some time in its history spewed gazillions of rocks out its mouth, most of them landing, it sometimes seems, at the 760 meter elevation. He says they are sandstone rocks, lying close to the surface. The soil layer is relatively thin and the area has mostly been used as pastureland. Our property is on abandoned pastureland and cattle still graze on the land just north of us.

The plant life is a savanna ecosystem, having been disturbed by grazing and now disturbed by humans living within it. By Beard’s definition given at the start of this post, it is “… a natural and stable ecosystem occurring under a tropical climate….” Natural and stable tells us that is not expected to become a forest over time. It has “… a relatively continuous layer of xeromorphic grasses and sedges….” Xeromorphic tells us that the grasses and sedges tolerate a dry climate. The savanna often has “… a discontinuous layer of low trees and shrubs.” Discontinuous tells us the low trees and shrubs may appear in clumps or scattered but do not appear as a continuous forest.

This blog is about exploring the particular savanna that occurs at roughly 8 degrees 40 minutes north of the equator, 82 degrees 27 minutes west of Greenwich, England, and at an elevation of 760 meters.