Randomization tests for time effects and heterogeneity in capture probabilities for closed populations

We propose the use of randomization tests to detect time effects and heterogeneity in capture probabilities of individuals in a closed-population mark-recapture study. The results of a simulation study show the randomization procedures can be implemented so that tests are robust to extraneous sources of variation, with good power to detect the desired effects. We apply the tests to two examples of real data, finding very strong evidence of heterogeneous capture probabilities in both data sets and highly significant time effects for one of the sets.