Humboldt, Biogeography, and the Dimension of Time

Abstract

In the nineteenth century, Alexander von Humboldt and Alfred Russel Wallace laid out the basis for the field of biogeography, the discipline that studies the relation between organisms and their geographic distribution. Almost in parallel with the birth of biogeography, the foundations of geology were laid out, providing a dimension of time to spatial changes of the landscape. In this paper, we review the historical context of the early biogeographers and explore what the lasting significance of the nineteenth-century holistic research approach is in present research. We also discuss the historical context in which biogeography and geology developed, and how the concept of deep time, plate tectonics, and mountain building provided a broader perspective to biogeography. To illustrate the benefits of integrating geological and biological methods, we focus on the genesis and chronology of the elevational gradient, core to Humboldt’s work. In particular, we use as example the evolution of two mountain systems, the Andes in South America, and the Tibet-Himalaya-Hengduan region in Asia. We conclude that in the nineteenth century, an interdisciplinary approach and progress in the different scientific fields led to a paradigm shift in the understanding of drivers of biogeography. Implementing such integrative vision today, and aided by advances in molecular phylogenetics and geology, has enabled biogeographers to form new, and more accurate, models of mountain building, climate, and species evolution. These models are particularly relevant in view of present scenarios of climate change and conservation strategies.