21 



estimated to be high. Species richness of Quintana Roo is enhanced by the fact that 79% of the natural 

 habitat is categorized as unaltered and has not been significantly perturbed by recent human activity. 



Flora 



Several attempts have been made to characterize the vegetation of Quintana Roo. In describing 

 and classifying the Yucatan Peninsula, Standley (1930), Lundell (1934, 1937), Leopold (1950), Paynter 

 (1955a), Cabrera Cano et al. (1982), and Rzedowski (1986) generally recognized from three to six 

 vegetation types. Tropical semi-evergreen forest is the dominant type in the Quintana Roo, occurring 

 in the south and east, while tropical semi-deciduous forest is less dominant and occurs in the north and 

 west (Rzedowski and Calder6n de Rzedowski, 1989; Figure 2-1). Phytogeographically, the Yucatin 

 Peninsula is more similar to northern Central America than to southern Mexico (Estrada-Loera, 1991). 



The flora of central Quintana Roo is characterized by a medium-height forest that is 7-25 m 

 tall (Cabrera Cano et al., 1982). The forest floor has boUi woody and herbaceous plants but little soil 

 or organic matter. Lianas and epiphytes are abundant and are supported by a large number of trees. 

 The dominant trees include the following; Brosimum alicastrum, Bursera simaruba, Manilkara zapota, 

 Metopium brownei, Psidium sartorianum, and Vitex gaumeri. 



The State of Quintana Roo has a long history of logging and shifting cultivation (Edwards, 

 1986). Although litde information about deforestation rates is available for the state, Flores-Villela and 

 Gerez Fernandez (1989) determined that only 21% of the natural habitat had been significantly 

 perturbed or was in the process of being transformed. Since 1957, commercial logging has been 

 managed through cooperative agreements between the ejidos and the State Forestry Program (see 

 Snook, 1993). 



Fauna 



Mexico is among the richest countries in the world in terms of the number of autochthonous 

 animal species (Ramamoorthy et al., 1992). Within Mexico, however, Uie fauna of the Yucatan 



