Where am I?

First impressions help define a moment and perhaps even set a perspective on what must lay ahead. Several days before venturing to El Eden Ecological Reserve last October, Hurricane Roxanne slowly meandered across the Yucatan, setting the stage for our fieldwork in a landscape that is defined by disturbances. Yet it is the very nature of these disturbances over time that may have allowed for the resulting adaptive capabilities of the species found in this region to speciate and define a landscape with perhaps the greatest assemblage of endemic species found in all of Mexico.

Located 38 kilometers WNW of Cancun (21?3' N, 87?11' W), El Eden Ecological Reserve is four hours driving and a world away from the tourist mecca. It is a rich and complicated habitat comprised of at least three distinct plant communities that will be discussed later on in this report.

Geologically, the area is characterized by Karstic sinkholes of varying sizes. Locally, the sinkholes are called "cenotes" and are defined as either a microcenote (.1-2.0 m in diameter) or as a macrocenote (which may be several 10's to 100's of meters in diameter).

The bedrock is primarily an uplifted Cretaceous limestone reef with many well preserved corals and mollusca evident. The dip is slight and trends from south to north which defines the flow of groundwater. Additionaly, the Holbox Fracture Zone is a north-south trending fault zone that is 80 km by 65 km wide just north of El Eden Ecological Reserve and defines the "Cenote Belt".

The area receives 1.4-2.0 meters of rainfall annually which translates to a consistently high water table supporting a diverse group of freshwater aquatic species in the Karstic environment. The microcenotes are interconnected and offer limnologists an interesting study in algae and freshwater fish species (to be studied in April-July, 1997).