Practicing Palaeoecology

By David Arnold

Ever since California was confirmed as the destination for this year’s London NERC DTP field training course, I’ve been excitedly planning my teaching session. As a specialist in ice age mammals, I pushed the organising committee again and again to include the La Brea Tar Pits in Los Angeles in our itinerary. Here, the fossilised remains of more than 600 species of animals and plants have been found, providing a unique insight into life during the last Ice Age.

A sabre tooth cat and a dire wolf fight it out over a mammoth carcass that has become trapped in the tar pits in this illustration of what may have been a common scene 20,000 years ago in the Los Angeles basin.
Public domain image from Wikimedia commons.

Tar pits are concentrated areas of liquid asphalt (also known as tar, or Brea in Spanish), which has seeped up to the surface. Plants and animals easily become trapped in the thick, gloopy tar, their remains preserved over millennia. At La Brea, scientists have uncovered thousands of fossils, which can provide lots of information about what the climate, environment and wildlife of the Los Angeles basin was like 20,000 years ago.

We are a diverse cohort of PhD students, with interests ranging from genetics to geology and from conservation to climate science, so it can be tricky to design a field session that will cater for everyone. However, as the science of reconstructing past environments is multidisciplinary in itself, we have an advantage! In order to reconstruct past environments we must consider all parts of the Earth system, including the physical, chemical and biological. So everyone should have the opportunity to apply their specialised expertise to palaeoenvironmental questions. And what better way to convince the group of the importance of studying the past, than to visit one of the most important fossil sites in the World!

An impressive skeleton of a Columbian mammoth found in the tar pits. We will be interacting with the museum exhibits to try and piece together the past.
Image used under a creative commons licence from Wikimedia commons

La Brea mainly contains fossil mammals, so I volunteered to lead the session, as my PhD research is also in this field. With the assistance of my DTP colleagues in the fields of past climates (Rachel Devine), mammalian evolution (Andrew Knapp) and palaeoanthropology (Sarah Peacey), we have developed a field session that will turn the whole DTP cohort into budding palaeoecologists (at least for an afternoon!). We have tried to combine written exercises with interactive elements, which will require investigating the whole of the La Brea site, splitting into groups so that everyone can share expertise to complete the tasks. The leaders of the field session will be on hand to help interpret the fossil evidence and don’t worry… we have a health and safety representative who will be making sure we don’t wander off into the tar pits and become part of the fossil assemblage ourselves!

Further information:

• Information on the La Brea Museum and the Tar Pits themselves, including an interactive timeline of the tar pits.
• A (non-exhaustive) list of fossils founds at La Brea.