Historic Range Map Sampling:

Random Sampling Method
The random sampling method uses an irregular grid of different sized cells over the area of interest (10, 100, 1,000, 10,000 km2). In this case, the “mammal province” boundary is used to establish the extent of the sampling grid. The benefit of this method is that the influence of heterogeneities over a region can be reduced.

Differences from one place to another within the “mammal province” can be smoothed out because the grid samples over the entire region. The species / area curve developed then reflects the mean situation for the mammal province.

Direct Sampling Method
Direct sampling takes the boundaries of current parks and reserves in a “mammal province” and overlays them on the species range maps. The species richness for these boundaries is determined. Species / area curves can then be determined using the area of the parks and the sampled species values. The results of this method are heavily dependant on the placement of the parks. The resultant species / area curves are affected by un-quantifiable social and political factors.