Tests for Similarity and Convergence of Finch Communities

Convergence at the community level occurs when whole groups of organisms become more similar than their ancestors in a similar environment. I suggest a method for indirectly assessing community convergence, and apply it to several characteristics of finch communities in different habitats worldwide. The method is based on the analysis of variance, and has several advantages over other indirect tests for convergence. Advantages include: (a) convergence is tested by comparing the variance between replicate communities within habitats to the variance between habitats, using a large and representative sample of habitat types; (b) the method estimates degree of convergence, a useful index for contrasting convergence of different community traits; (c) historical constraint on community convergence may be viewed as an additional component of total variation in the community character, and its importance can be estimated and compared with the effect of habitat type. The method revealed significant convergence of ...