Ecological patterns in the trophic-size structure of large mammal communities: a ‘taxon-free’ characterization

Abstract

Questions: Are different types of terrestrial mammalian-dominated ecosystems characterized by specific taxon-free patterns in the trophic structure of the mammalian community? If so, are these patterns an intrinsic property of the ecosystems? If this is indeed true, the trophic structure of present-day mammalian communities can be used for the synecological reconstruction of past terrestrial mammalian-dominated communities. Data: 110 Recent large mammal communities, 86 from Africa and 24 from Asia, and one large mammal assemblage from the early Pleistocene locality at Venta Micena (Guadix-Baza Basin, southeast Spain). Search method: Stepwise discriminant analysis generated mathematical algorithms that characterize definite patterns in the trophic structure of the mammalian communities from each type of ecosystem. Algorithms adjusted with African communities were applied to the Asian and Pleistocene ones, whose species are completely different from those of Africa, to test if these patterns are independent of specific historical circumstances and taxonomic composition. Conclusions: Terrestrial mammalian-dominated ecosystems are characterized by definite taxon-free patterns in the trophic structure of the mammalian community. These patterns are an intrinsic property of the ecosystems, independent of their specific historical circumstances and taxonomic composition. Therefore, the trophic structure of present-day mammalian communities can be used for the synecological reconstruction of past ones. The sedimentologic and taphonomic information for the early Pleistocene community of Venta Micena is indicative of a wooded savanna; this type of ecosystem is also indicated by the trophic structure of the mammalian community. This congruence supports the hypothesis that the ecological patterns identified here are an intrinsic property of past ecosystems, at least as far as Pleistocene land mammal-dominated communities are concerned.