Hierarchic classifications can differ with respect to tree balance—the degree to which branches divide the subtended taxa into subsets of equal size. Several indices, sensitive to different aspects of tree balance, are compared. Extensions of these indices to multifurcating trees and to trees with varying numbers of OTUs are proposed, and suggestions for employing these indices are furnished. Different tree-forming algorithms may result in trees with differing degrees of balance no matter which index is computed. Tree balance is an important consideration for phylogenetic systematics, because balance of the true phylogeny will affect the accuracy of its estimates.

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Several coral reefs of Nanwan Bay, Taiwan have recently undergone shifts to macroalgal or sea anemone dominance. Thus, a mass-balance trophic model was constructed to analyze the structure and functioning of the food web. The fringing reef model was comprised of 18 compartments, with the highest trophic level of 3.45 for piscivorous fish. Comparative analyses with other reef models demonstrated that Nanwan Bay was similar to reefs with high fishery catches. While coral biomass was not lower, fish biomass was lower than those of reefs with high catches. Consequently, the sums of consumption and respiratory flows and total system throughput were also decreased. The Nanwan Bay model potentially suggests an overfished status in which the mean trophic level of the catch, matter cycling, and trophic transfer efficiency are extremely reduced.

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