Aggregation and regularity: an inclusive one-tailed nearest-neighbour analysis of small spatially patchy populations

When analysing spatial pattern, aggregation and regularity are normally regarded as being mutually exclusive and a two-tailed test is applied to check whether or not there is a deviation from random expectation towards one or the other. However any fine-scale regularity occurring in crowded patches is likely to be masked by the larger-scale aggregation using this approach. An associated problem is that edge effects are particularly severe for small patchy populations. An inclusive analysis utilising one-tailed nearest-neighbour tests to check for aggregation and regularity separately is described. In addition the technique resolves the edge-effect problem. The approach is illustrated using a synthetic patchy population, and is then applied to a population of granite tors showing both large-scale aggregation and fine-scale regularity. Regular spacing of buzzard territories is discussed briefly.