How Lithology Impacts Global Topography, Vegetation, and Animal Biodiversity: A Global-Scale Analysis of Mountainous Regions

Abstract

Chemical and mechanical properties of lithology exert a first-order control on landscape evolution and biological colonization of substrate. To quantify the influence of lithology on topography, vegetation density, and animal biodiversity, I compile lithologic, topographic, climatic, and biological data sets for mountainous regions globally. I find significant variations in the topographic steepness of regions underlain by different lithologies that, accounting for tectonic uplift, likely reflect lithologic differences in erosional resistance. These relative differences in erodibility are similar across different climate zones. To isolate the effect of lithology on vegetation and animal biodiversity, I account for the heterogeneous lithologic distribution among climate zones. I show that siliciclastic, plutonic, and, for some biological variables, metamorphic rocks exhibit elevated values of Normalized Difference Vegetation Index and tetrapod and amphibian species richness relative to carbonate rocks. These results likely reflect lithology-related variation in soil nutrients and hydrology that promote or inhibit habitat suitability.