141 

 (Andrews, 1960, 1965; Deevey et al., 1979). At the height of the Maya civilization, roads, villages, 

 large ceremonial centers, and extensive agricultural fields supplied with water by canals occurred 

 throughout the Yucatan Peninsula to Guatemala and Honduras (Hammond, 1982a, 1982b, 1986; 

 Turner, 1974, 1990; Turner and Harrison, 1983). The impact of these activities on plants and animals 

 in Mesoamerica can only be surmised. Likewise, the impact of the fall of the Maya civilization about 

 900 A.D. on plants and animals and the resulting decrease in human activities has yet to be determined. 

 Change persists, however, as humans now exploit lumber, chicle, and other nontimber forest products 

 in Quintana Roo and the southern portion of the peninsula (Edwards, 1986; Konrad, 1988). 



Two additional factors affecting animal populations in other areas may also be affecting animal 

 populations at Ejido X-Hazil y Anexos; human hunters and large predators. In a study of tapir 

 (Japirus bairdii) abundance in Belize, Fragoso (1991, 1992) determined that among such factors as 

 logging, disease, habitat destruction, and shifting cultivation, the most parsimonious explanation for the 

 low number of tapirs was human hunting. Similarly, Glanz (1991) compared mammal abundances at 

 protected and unprotected areas in central Panama and compared them with Barro Colorado Island, 

 which is a protected area, but also lacks large predators such as jaguars (Panthera onca) and pumas 

 {Felis concolor). Glanz (1991) noted dramatic differences in mammal densities among sites and 

 attributed these differences to the impacts of hunting by humans rather than due to the absence of large 

 predators, as had been noted by Emmons (1987) at other Neotropical forested sites. 



Forest Successional Stages and Relative Abundance of Birds and Mammals 



The study area had three forest successional stages that differed with respect to degree of 



human disturbance, the abundance of gardens, and the number and kinds of crops planted in the 



gardens. Birds and mammals were expected to select for or against the different stages according to 



their individual requirements. Few clear patterns, however, were noted. 



At the species level, a significant difference in sighting frequency between forest successional 



stages was observed only for the plain chachalaca (P = 0.0143; Table 4-1). No significant differences 



