A dynamic bioeconomic model of ivory trade

Africa is divided into four regions because of differences in the size of their elephant populations, the institutional and biological challenges to protecting elephant stocks, the extent of poaching, and the importance of elephants in attracting tourists. [...] Another aspect not considered in the spatial price equilibrium model is the non-market component to ivory trade, namely, the elephant’s role as a flagship species for attracting tourists and the willingness of the international community to protect elephants in situ, which is one reason for the ban on ivory trade. [...] The model is modified to include poaching and then expanded to examine the failure of conservation payments, the potential of a quota regime, and the costs and benefits of an ivory trade ban. [...] The amounts coming from the other regions are indicated in Table 3. If we assume linear supply functions and guesstimates of the intercepts, it is then possible to determine the slopes of the supply curves based on the share of the total quantity of illegal ivory that each region contributes to the market. [...] That is, as one nears the end of the 200-year planning horizon, all animals will be harvested unless they have no value, or the (marginal) cost of harvesting the next animal is less than the marginal benefit.16 Given the richness of the model, it is possible to explore only a limited number of scenarios and variables.