Two dozen people attended a talk by Dr. Bruce Archibald in Ashcroft last week, in which the paleoentomologist discussed his work at the McAbee Fossil Beds site over the years, what he has discovered there, and what it can tell us: not only about our planet’s past, but its present and future.
The McAbee site dates back to the Eocene Epoch, and is some 53 million years old. At the time, the site was covered by a lake, and over time insects, leaves, feathers, pollen, and more sank to the lake bed, where they were covered by layers of fine silt and preserved as fossils.
“I tell kids that insects are much cooler than dinosaurs,” said Archibald (dinosaurs became extinct approximately 10 million years before McAbee). He explained that during the Eocene, the area from Smithers south to northern Washington State was uplifted, with faults on top where lakes formed. There are many fossil sites throughout the area, but Archibald said that what makes McAbee so special is the diversity found there.
He demonstrated this with the help of a slide which showed one piece of McAbee shale that contained seven orders and 10 species of insects, birds, and plants. “A whole museum exhibit could be made around this one rock,” he noted.
The diversity was caused by the fact that the area was much more temperate then than it is now. “The climate here then was very similar to the climate in Venezuela today. It was a temperate upland, with a very narrow summer to winter change in temperature, and probably no frost.”
Eocene means “dawn of the present”, and Archibald said that there is a reason why it is called that: “It’s where the world came back to life.” He did his Ph.D. thesis studies at McAbee, examining why there is so much more biodiversity (community diversity) in the tropics, and spoke first about biodiversity, saying that he felt climate was the issue.
“There is a lot more heat and light in the tropics, plus summer and winter don’t vary much. Which factor is associated with biodiversity? Low seasonality is the key. It’s the stability of the tropics, not heat and light. McAbee had low seasonality.”
Archibald then discussed the lineages that make up the diversity at McAbee. “Many insects associated with the tropics today are found here, such as a beetle that feeds only on palm trees. That establishes the important fact that palms were present here, and gives us the big picture of how things were distributed across the globe.
“And the response of insects to climate affects us all,” he added, citing the pine beetle infestation as a current demonstration of this. “You need cold winters to kill off the pine beetle, and temperatures have increased.”
He talked about understanding ecology interactions and how things changed. “Some people say we live in the age of mammals, but I say we live in the age of flowers. We see these really important partnerships, with bees, ants, and flowering plants all interacting at McAbee. And at McAbee we see the ends of some things, the beginnings of others, and some things that are only seen during the Eocene.
“There is a lot of potential for wonderful findings at McAbee, and the opportunity for some world-class science. The Eocene is the perfect time to try to model what is happening with climate now.”
Archibald’s thesis, as well as many other of his writings about McAbee, can be found at his website at www.brucearchibald.com.