September 23, 2020

Speaker maps 400-year-old Manhattan ecosystem

Ecologist Eric Sanders presented ‘The Mannahatta Project,’ discussing the possible ecological descriptions of the island of Manhattan from 1609. (Tom O’Dell / Photo Editor)

Whales and dolphins swam in New York City’s harbor and beavers built dams in the middle of Manhattan. Wolves abounded and mountain lions prowled what are now the streets of Harlem.

This is not the plot of a fantastical children’s story. In fact, it could be a page right out of the city’s history book, describing 1609.

During a School of Science colloquium, held on Wednesday, Feb. 16, ecologist Eric Sanders presented research and information from “The Mannahatta Project,” which he directed and turned into a book, regarding probable ecological descriptions of what the island of Manhattan looked like 400 years ago.

Sanders works at the Wildlife Conservation Society (WCS) and focuses on the field of “landscape ecology,” where different terrains are analyzed, as well as the life forms residing in these habitats.

Throughout the presentation, he used an interactive map on the computer, which allowed him to show what Manhattan most likely looked like centuries ago.

Sanders described the map as “a picture of what the ecosystem may have looked like and what mammals may have lived there,” subsequently explaining that such information is determined by a system of analyzing historical data and considering habitats versus the probability of certain life forms surviving in such locations.

“(The system) can take otherwise separate habitat descriptions and connect them together to form networks,” he said.

This network structure was described by the ecologist as “quite general,” yet a necessary means for analyzing and organizing the ecosystems. Based on food, water and other characteristics, the system can determine what the ecosystem may have looked like hundreds of years before.

“This matrix is what Facebook does with you,” Sanders said. “Imagine you and your friends and how Facebook connects all of you.”

“There were up to 1000 different types of plants, 85 species of fish and up to 300 species of birds,” Sanders said, when explaining Manhattan’s inhabitants 400 years ago.

“Beavers on most of the streams in Manhattan,” he said. “They were important to the landscape. They build dams, which slows down water and creates other habitats.”

Sanders shared a quote from “one of his heroes,” John Muir, a naturalist in California, who once said, “When we try to pick out anything by itself, we find it hitched to everything else in the universe.”

“That’s what we do every day at WCS,” Sanders said. “There’s potential for biodiversity everywhere. It’s not something that only exists in rain forests or the coral reefs.”

Jamie Primeau can be reached at

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