Biome evolution and biogeographical change through time

Christine Bacon

doi:10.21425/f5fbg19101

Abstract

Keystone plant groups can be used to infer the evolution of biomes and biogeographical change of communities and taxa. In this thesis I investigated whether lineages in Trachycarpeae palms could be used to track different forest types through time and whether change in biome or biogeographic region had an effect on species diversification. These questions were approached using genetic data integrated with fossil record, species distribution, and speciation models. Although the three chapters of my thesis had additional foci outside of the main goal of inferring biogeographic change and diversification through time, they come together to paint a clear picture of how fine-scale and interdisciplinary studies can lead to more robust hypothesis testing and conclusions. I found that outside of tracking tropical forests through time, palms are useful for understanding island biogeography and the formation of other types of biomes.

Highlights

The inference of biogeography and diversification is an integral window into the past that enables the investigation of how geographic regions, bi‐ omes, and communities are assembled through time and how they may evolve in the future
Results from species delimitation showed that long‐distance dispersal and rapid island radiation were fundamental in the biogeography of species and corresponded to the geological age of each of the island groups (Bacon et al 2012b)
We showed that open‐forest, savanna endemic palm lineages evolved in North America in open, tropical grass‐ lands, and dispersed through the Isthmus of Pa‐ nama region, into savannas in northern South America (Bacon et al 2013b)

Summary

Introduction

The inference of biogeography and diversification is an integral window into the past that enables the investigation of how geographic regions, bi‐ omes, and communities are assembled through time and how they may evolve in the future. For example from geology, genet‐ ics, fossils, species distribution and abundance, and morphology, we can reach a more compre‐ hensive framework for the understanding of bio‐ geographical evolution (Figure 1). The importance of these types of studies reaches beyond basic biodiversity science and the discovery of impor‐ tant evolutionary processes, and underscores cut‐ ting edge conservation research (Rolland et al 2011). Understanding how biodiversity evolved can inform modeling of the past, present and fu‐ ture of that biodiversity and can aid in, for exam‐ ple, the design of protected areas that take into account diverse evolutionary processes (Sarker et al 2006), or the definition of how climate change may affect the future availability of resources (Piao et al 2010). Focusing on the Hawaiian radiation, species delimitation meth‐ ods were compared to robustly infer spe‐ cies diversity and biogeography, and to under‐

Methods

Results

Conclusion