Auburn University’s College of Science and Mathematics Leadership Council held their Distinguished Lecture Tuesday afternoon, inviting presenter Sean Carroll, author of “The Serengeti Rules: The Quest to Discover How Life Works and Why It Matters.”
Carroll, speaking to an audience full of COSAM faculty and a number of students, began his presentation by explaining his background as a molecular biologist.
A Howard Hughes research fellow, Carroll works in Washington, D.C. and admitted even though he had a deep interest in the Serengeti, he knew very little about the ecosystem there. He was determined to learn more and did so by applying some of his molecular biology knowledge to this ecosystem.
“To understand how life works, we need to know the 'rules' of regulation,” Carroll said before referencing breakthroughs in medicine and environmental studies.
Carroll explained the studies of Bernhard and Michael Grzimek in the 1960s.
The Grzimeks studied the numbers of animals such as buffalo and wildebeest in the Serengeti. These numbers were very low due to a disease called Rinderpest that spread to these populations from domesticated cattle.
After vaccinating the cattle, the buffalo and wildebeest numbers grew, which created a domino effect throughout the entire ecosystem.
Since these animals are grazers, there was less grass in the Serengeti, which led to fewer fires. Fewer fires led to more trees lasting longer, providing more food for mammals such as giraffes and nesting ground and protection for birds and other animals.
Carroll said the first Serengeti rule is some animals are
The second Serengeti rule is that some species have strong, indirect effects on other species through trophic cascades. The phrase “trophic cascades” referred to the food pyramid in these ecosystems and relates back to the domino effect mentioned previously.
“Everywhere is the Serengeti,” Carroll said to explain how other ecosystems deal with similar crises.
The third Serengeti rule discussed how the regulation of some species depends on their density. Carroll said that usually the populations of plants or animals isn’t noticed unless it is very large or small.
“For example, in Yellowstone during the late 1990s, a decline in young Aspen trees was noticed,” Carroll said.
He continued by sharing that a large elk population caused this deficit since elk weren't being hunted by wolves.
Wolves had been removed from Yellowstone in 1924 but were reintroduced in the mid-1990s to try and reverse this issue. The reintroduction of wolves caused a decline in the elk population but resulted in more Aspen and Willow trees, along with a larger beaver population.
Serengeti rule number four was based on this example and stated that nature is resilient. Carroll said how the protection of certain species near extinction, such as sea otters and bald eagles results in the population being able to surge back.
“When given a chance, populations can
Carroll’s final point focused on Gorongosa National Park and its rebound from near desolation. Located in Mozambique, Gorongosa, was a thriving park before the country’s civil war. All of the mammal populations decreased dramatically from the early 1970s to 2000.
A philanthropist and conservationist Greg Carr saw the issue and strived to fix it. The numbers of large mammals in the park in 2000 was less than 1,000, but by 2014, the number was over 71,000.
“In 2018, in a time in where all we hear is gloom and doom and terrible headlines, there is a plan for Gorongosa — to bring it back and make it one of the biggest wildlife conservation areas on the planet,” Carroll said.
Carroll then concluded by showing more footage of giraffes living in the Serengeti ecosystem.