Seasonal change in the shoot flora diversity of hardwood forest stands on Mont St. Hilaire, Quebec

Diversity, in the various senses in which the term is used by plant ecologists, is shown to vary with time of year in each of four stands in the northern hardwood forest region of southern Quebec. The lowest values were obtained in winter and the highest in summer. Much of the variation in diversity over the year can be explained by changes in the numbers of plant species, present as shoots, in a stand: this is particularly the case in the late spring and summer months, but rather less so in the fall. Analysis of the simply collected, and reliable, presence/absence sample data gives as satisfactory an account of seasonal trends in shoot flora diversity as does analysis of the more usually consulted abundance data. It is concluded that many of the formal notions of succession studies may apply to the more restricted case of seasonal change in vegetation composition and structure.