Table 1. Variables hypothesized to influence compliance with protected area (PA) policies and categorized into four key types of factors

Factor
 		 Variable
 		 Source
 
PA characteristics
 		 Age
Area
Existence of buffer zones
IUCN category
 		 WDPA 2009
published studies identified in systematic review
 
Social characteristics
 		 Population density
Country adult literacy rates
 		 CIESIN and CIAT 2005
International Monetary Fund (IMF) 2011
 
Availability of resources
 		 GDP PPP (purchasing power parity) per capita
PA budget per country
PA staff number per km2 per country
 		 IMF 2011
James et al. 1999
James et al. 1999
 
PA management approach
 		 Level of local community participation in PA management
 		 Published studies identified in systematic review