Landscape alterations connect to the evolution of biodiversity

A ‘Snowball Earth’ covered in ice may have had oases that harbored life much further north than once thought, according to new research – Copyright AFP/File Kerem Yücel

Scientists from the University of Sydney, ISTerre at the French state research organisation CNRS and the University of Grenoble Alpes in France proposed a unified theory that connects the evolution of life in the marine and terrestrial realms to sediment pulses controlled by past landscapes.

The resultant new scientific model reveals a striking correlation to how life evolved over 500 million years. In particular, the movement of rivers, mountains, oceans and sediment nutrients at different geological timescale acted as the central drivers of Earth’s biodiversity.

The research looks back over 500 million years of Earth’s history to the period just after the Cambrian explosion of life, which established the main species types of modern life.

The new research has been published in the journal Nature. Here, the research also shows that biodiversity evolves at similar rates to the pace of plate tectonics, the slow geological processes that drive the shape of continents, mountains and oceans.

“That is a rate incomparably slower than the current rates of extinction caused by human activity,” summarises lead author Dr Tristan Salles from the School of Geosciences.

Dr Salles adds: “Earth’s surface is the living skin of our planet. Over geological time, this surface evolves with rivers fragmenting the landscape into an environmentally diverse range of habitats. However, these rivers not only carve canyons and form valleys, but play the role of Earth’s circulatory system as the main conduits for nutrient and sediment transfer from sources (mountains) to sinks (oceans).”

Salles continues: “While modern science has a growing understanding of global biodiversity, we tend to view this through the prism of narrow expertise. This is like looking inside a house from just one window and thinking we understand its architecture.”

The model connects physical, chemical and biological systems over half a billion years in five-million-year chunks at a resolution of five kilometres.

Of significance is the discovery in 1994 of the ancient Wollemi pine species in a secluded valley in the Blue Mountains west of Sydney gives us a glimpse into the holistic role that time, geology, hydrology, climate and genetics play in biodiversity and species survival.

The idea that landscapes play a role in the trajectory of life on Earth can be traced back to German naturalist and polymath Alexander von Humboldt. His work inspired Charles Darwin and Alfred Wallace, who were the first to note that animal species boundaries correspond to landscape discontinuities and gradients.

Instead of considering isolated pieces of the environmental puzzle independently, the researchers developed a model that combines them and simulates at high resolution the compounding effect of these forces.

Dr. Tim Sandle is Digital Journal’s Editor-at-Large for science news.
Tim specializes in science, technology, environmental, business, and health journalism. He is additionally a practising microbiologist; and an author. He is also interested in history, politics and current affairs.