At least two general approaches can be taken in designing and conducting research into the questions of distribution, abundance and diversity. This duality is an underlying feature of ecological research and interpretation, but it tends to be downplayed or avoided in most ecological writings. The issue is frequently circumvented with statements about ecology comprising different subject areas, such as population ecology, spatial ecology, behavioral ecology, the explanation of local diversity, applied and theoretical ecology, and so on. Similarly, reference is made to the different aims of ecologists, such as the prediction of population trends, the explanation of local diversity, the generation of general models of ecological processes, the conservation of rare species, or the reduction of pest populations.