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Central Park Plant Census

Central Park Plant Census | New York

It’s a seemingly impossible task: cataloguing every wild plant species in Central Park. But that’s exactly what two botanists are doing, and they’re making some surprising discoveries along the way.

As they have done hundreds of times in the past three years, botanists Regina Alvarez and Daniel Atha work feverishly to gather plant specimens for the Central Park Flora Project.

Extending a long fruit picker toward a towering hickory tree, Atha smiles patiently as a handful of nuts finally falls to the forest floor. The nuts, along with branches and flowers, are then pressed and transported to the herbarium at the New York Botanical Garden, where the specimen is catalogued, mounted, and preserved indefinitely.

Alvarez and Atha met during a 24-hour bio-blitz held in the 843-acre park in 2013. Alvarez and Atha realized that many of the plant species they were locating were not on a 2007 Central Park Conservancy plant list.

Atha suggested that the list should be redone from scratch, and the Central Park Flora Project was born. The main goal of the project, which is a collaboration between the Conservancy, the Botanical Garden, and the New York City Department of Parks and Recreation, is to document all of the naturally occurring plant species in Central Park.

Alvarez and Atha meet weekly and pick an area of the park to comb through for tree and plant species. Three years into their research, Alvarez and Atha have documented close to 400 naturally regenerating species in Central Park, including more than 40 species of grasses. All data from the species they find is entered into an online database and map that is accessible to the public.

The vast grounds of Central Park occupy 843 acres of prime Manhattan real estate in New York City. / Jet Lowe, Wikimedia Commons

While it may seem odd to discover new plant species in a manmade park located in a major metropolis, Alvarez and Atha are finding new species on a weekly basis, including the recent discovery of the pumpkin ash tree—a rare ash tree species that botanists had not found in New York since the mid-1930s. Several native species, including white wood aster, snakeroot, and black cherry, likely existed on the site before Central Park was created in 1853. Other lush, non-native plant species, including tree of heaven, were planted during the park’s construction.

Soon after Central Park officially opened, a list of Central Park’s plant and tree species was created in 1857. Alvarez and Atha have been tediously cross-referencing this list against their own findings, to see whether those species are still regenerating.

What has been most surprising in their research are the native species that were not on the list that have somehow made a comeback, including the round leaf shadbush that Alvarez and Atha discovered in the North Woods in 2015. Last spotted in Queens in 1967, the round leaf shadbush is an extremely rare find in New York City and had never been documented in Manhattan prior to the pair’s discovery.

While plant seeds can commonly travel through the air or with animals, how these native species made it into the park remains a mystery.

There is also the native leafy pondweed, never before documented in Central Park, which Alvarez and Atha found submerged in a body of swampy water known as the Pool. The native aquatic species is growing side-by-side with its non-native, invasive counterpart, curly-leaf pondweed. When Alvarez and Atha uncover an invasive species, they inform the Conservancy immediately. If invasives are not managed, they can spread uncontrollably throughout the park and take over native habitats.

A DNA sample is also collected with every herbarium specimen that can be used to track any changes in the species’ genetic composition. By documenting Central Park’s vegetation, Alvarez and Atha are providing physical, scientific evidence of what is growing where in one of the most dense metropolitan regions in the world.

“What’s going on biologically in Central Park is a very interesting question that has relevance for other urban areas throughout the world,” Atha said. “And we’re working to document its diversity and promote its conservation because we want to maintain a healthy ecosystem in New York City for wildlife habitat and for ecosystem services, and also to leave this legacy of biodiversity to our descendants. And in order to be able to do that responsibly, we need to know what’s growing there. And this Central Park Flora Project is a microcosm of what’s going on in the wider picture in New York City.”

The Central Park Flora Project has catalogued nearly 400 species of naturally regenerating species in the lush forests and wetlands of Central Park. / Jean-Christophe BENOIST, Wikimedia Commons

— Sean Keenehan

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