The Use of Contact Sampling in Studies of Association in Vegetation

(1) The contact sampling method has been used frequently in studies of between-species association in vegetation. An earlier paper presented a probability argument for determining completely random association and a parallel statistical approach. (2) It is shown to be preferable, however, to tabulate and analyse the data with an unfolded contingency table where the ordered 'contact pairs' (i, j) and (j, i) are distinguished,-rather than with the folded (triangular) table used previously. If these ordered pairs are distinguished, a more fluent and straightforward data analysis is possible. (3) This, together with considerations of the treatment of data in which there are events of within-species 'contact pairs' (i.e. when j = i), forms the basis for recommending an 'optimal' strategy for…