Are fluvial islands “real” islands for arboreal mammals? Uncovering the effect of patch size under the species-area relationship

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Large islands contain more species than small ones, right? Based on this information, would you say that the size of a given island affects the number of species that it harbours? We bet that you said "yes". Now, imagine a continuous forest, in which you survey species in a large area and in a smaller one. It is very likely that you’ll find more species in the large area simply because you surveyed a larger area, isn’t it? This is the sample area effect. In this paper, we showed that the number of mammal species found in fluvial islands in Central Amazon is higher in large islands than in smaller ones, but this pattern only happens due to the sample area effect. Besides, we also found that the amount of suitable habitat in the landscape surrounding an island is more important than island size per se for predicting its number of species. The higher the habitat amount in the landscape, the higher the number of species!

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