Biology

The Galápagos Archipelago is famous for evolution of species such as Darwin’s finches and giant tortoises. Underlying that unique diversity, however, are the geographic structure of the islands and the climatic environment that supports life. As a chronosequence of islands varying in size and isolation on a topographically complex submarine platform, the archipelago provides exceptional opportunities to explore research avenues connecting the disciplines of biology, climate science and geology to better understand island systems.

Much of what sets the Galápagos Archipelago apart is not the uniqueness of species occupying these isolated islands, but the simplicity of the system which makes it ideal for generating and testing hypotheses. Being so far from a mainland, colonization events are rare and thus radiations most often start from single founders that have diverged and speciated over time. With a moderate number of radiations of terrestrial and aquatic vertebrates and invertebrates on these small, desert islands in the middle of the ocean, it should be simple to reconstruct the past events leading to the diversity seen today, yet many questions remain due to uncertainty about the past environment that species evolved in.

With most islands now under the ocean or fully under the South American Tectonic Plate and a poor understanding of when climate events changed to support water-dependent life on these desert islands, biologists need to use multi-directional inference to create theories on the how, when, where, and why of species evolution in the Galápagos. Similarly, the geological template creates interactions between major currents and submarine topography producing upwelling that differentiates several biogeographic regions in the small geographic area of the islands and stimulates bottom up (nutrient driven) enrichment of marine populations and communities. This stimulated marine productivity likely transfers to terrestrial plant communities via sea bird and sea lion vectors, establishing potentially strong yet largely unstudied cross-ecosystem food webs. Considering that upwelling is reduced during El Niño and returns during La Niña, there is the potential to study how whole ecosystem shifts in the sea and on land are triggered by climate oscillations. Source-sink relationships, and dispersal mediated by wind and water transport can be predicted by climatological mechanisms, yet there is limited understanding of the connectivity that ensures linkages and the resilience of populations and communities across space. This contemporary metacommunity perspective is likely influenced by geological processes in Galápagos such as earthquakes and volcanism which create spatially complex habitats that may serve as biodiverse pockets for source populations and fragment the biotic and geological landscape.