Fig. 1.

Environmental factors related to spinescence of African tree species. (A) Variation partitioning of the proportion of spiny species explained by the biomass of different herbivore functional types, environmental variables, and vegetation type. (B) Relationships between environmental factors and proportion of spiny species. Black arrows indicate a positive relationship; gray arrows indicate a negative relationship. The position on the arrow indicates the strength of the relationship. Names of functional types of mammals follow the work in ref. 23. LBr, large browser; MSMix, medium-sized social mixed feeders; NRum, nonruminant; SNSBr, small nonsocial browser; Total, total biomass of mammalian herbivores; WDBr, water-dependent grazer.