What is Biodiversity?

As you stroll through Central Park, how many different living things do you see? Take note of the waterfowl, squirrels, humans, flowers, trees, grasses, dogs, and insects you find. Observe the vast variations in characteristics from one to the next. Now, consider what you can’t see: the microorganisms beneath the soil, the aquatic life under the surface of the water bodies, or the fungi on the woodland floor.

Biodiversity refers to the variety across all living organisms within a particular ecosystem, like here in Central Park or on the planet as a whole. It is the foundation for many of the earth’s systems, including the food and water that humans and other living creatures need to survive. As the earth faces a significant reduction in global biodiversity how do we protect and foster an abundance of species in New York City’s backyard?

Creating Space to Grow

When you hear the term “biodiversity,” perhaps lush rainforests, colorful oceanic life, or other wild landscapes come to mind. But even so-called concrete jungles like New York City have their own degree of biodiversity. In fact, urban biodiversity is essential to the health and resilience of highly developed areas. The greater the variation among organisms in our cities, the more likely it is that all the life they contain—human and otherwise—can adapt to changing environmental conditions and continue to thrive.

Gabriel Sanders is the Natural Areas Volunteer Coordinator at the Central Park Conservancy, where he manages teams of passionate volunteers doing ecological restoration work in the Park. And what does that entail? “It's not as glamorous or cool as it sounds,” Gabriel jokes. “80% of it is pulling weeds. But that’s fundamental to the project of trying to enhance biodiversity!”

The “weeds” that Gabriel and his team remove are called invasive species, and they pose a direct threat to the biodiversity of the area in which they’re growing. In a healthy ecosystem, many different native plants, animals, and other organisms live symbiotically and harmoniously. Because natural environments consist of complex, interwoven networks of interdependent relationships between organisms, a larger variety of native plants within an ecosystem leads to more plentiful food, habitat, and resources for other living creatures to flourish. Specific types of non-native plants can spread aggressively and compete with native plants. If they’re not managed properly, invasive species can displace the native plants within a landscape entirely—along with the other organisms that depend on them.

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The Conservancy’s Natural Areas team and volunteers work to remove invasive species and minimize ecosystem disturbances to foster Central Park’s biodiversity.

Native plants have adapted to their local environment over a long period of time, meaning they’re excellent at supporting native wildlife and promoting a balanced and diverse community of organisms. But when these plants are dominated and crowded out by an invasive species, it has a ripple effect on the ecosystem’s potential to succeed as its overall biodiversity declines. When you remove human-imposed challenges like the presence of invasive species, natural ecosystems intuitively know how to flourish. Gabriel remembers seeing this firsthand when he began working at the Conservancy.

“When I started here two and a half years ago, I didn't know how native plants impacted biodiversity. I had an out-of-date vision of what horticulture meant: I thought it meant tidy landscapes and healthy, robust flowers, but I didn't know why it mattered that the plants be native,” Gabriel says. Prior to working at the Conservancy, Gabriel was a chef with a passion for plants and gardening. He remembers learning about biodiversity from his Conservancy colleagues as they worked on a project to reduce an infestation of mugwort, one of Central Park’s major invasive species. “I was blown away by what came up when I gave it the space to grow. Just in the first year, an incredibly rich collection of goldenrods, asters, and other native wildflowers popped up. That experience of getting this incredible display of native life—and not just the flowers but all the different insects that were visiting the flowers—it felt like I had really helped something. I had supported something beautiful happening. And that was when I fell in love with the work we do.”

Understanding the Layers of Biodiversity

Biodiversity can be conceptualized across scopes that range from microscopic to global, so it’s helpful to understand and categorize its different scales. Gabriel recommends thinking about biodiversity as existing on three levels: the diversity of species within an ecosystem, the diversity of genetics within a species, and the diversity across different ecosystems. The work of the Conservancy’s Natural Areas team and their volunteers impacts all three of these levels of diversity.

There are endless examples in Central Park. The different species of wildflowers and insects Gabriel saw among the native plants where mugwort once grew? That’s an example of species diversity in an ecosystem. But what if we narrowed in on a dozen brown-belted bumblebees pollinating the goldenrod? Though they all might look similar as members of the same species, they each have their own unique genetic makeup. This genetic biodiversity is important to the strength and resilience of any given species.

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In 2017, the Conservancy transformed an eroded hillside on the Park’s south end into a 1.25-acre native meadow. The Dene, as it’s now known, is home to a variety of native flowers, grasses, and the organisms that they sustain.

“We don't really know what the future holds environmentally or how conditions are going to change.” Gabriel elaborates. The higher degree of genetic diversity a species has, the more likely they are to be able to survive a broader range of possible future environmental changes. “The way that we promote genetic diversity within a species is by encouraging them to reproduce spontaneously and wildly in the Park. In relation to biodiversity, that’s what our team is most passionately striving for: populations of native plants that are successfully reproducing on their own without us doing anything.”

The ecological composition of the Park and the variation within it is an example of the last level of biodiversity: diversity across ecosystems. Though it is human-made, Central Park is a microcosm of naturally occurring, wild landscapes. Across its 843 acres, there are many unique landscapes—waterbodies, woodlands, meadows, and more. The Dene Slope, for example, was once an eroded hillside spanning 1.25 acres. In 2017, the Conservancy transformed the landscape into a flourishing native meadow. In our restoration efforts and care of the Park, our knowledgeable staff considers the overall makeup of the Park and how it’s fostering rich ecological systems.

“The Conservancy’s work on the new Harlem Meer Center and its surrounding landscape is a great example of an effort to promote biodiversity across different ecosystems.” Gabriel says. A major objective of this project is to establish a wetland habitat that closely resembles natural conditions, enhancing ecosystem diversity within the Park.

“Wetland is the least represented type of ecosystem in Central Park. A lot of the Park’s water bodies are artificial water bodies with unnaturally hard edges. This means that there isn’t a natural transition from ground to water, with intermediate zones and water levels that rise and fall seasonally.”

How Park-Goers Can Promote Biodiversity

In Central Park and around the world, all three levels of biodiversity are increasingly essential as we plan for the current and impending impact of climate change. Initiatives aimed at habitat conservation, native species promotion, tree health and diversity, light pollution mitigation, and other sustainable urban practices emerge as core strategies for protecting the ecological integrity of urban greenspaces like Central Park. If we work to foster a greater diversity of species in an ecosystem, it is better able to withstand the threats posed by the climate crisis. In resilient landscapes that are abundant with variation, an attack on a single species is less likely to cause damage to the entire system. As climate change continues to ask increasingly challenging questions of life on earth, an increase in biodiversity will maximize our potential answers.

While Conservancy staff works diligently against the effects of the climate crisis, the Park’s 42 million annual visitors also play a vital role in fostering the health of our urban ecosystem. One of the best ways to encourage spontaneous and wild reproduction of native species in Central Park is to minimize disturbances—another key priority for the Natural Areas team and volunteers. Disturbances to the ecosystem include someone walking through a landscape or a dog running within an area that’s been fenced off to protect the landscape. By staying on designated walking paths and leashing their dogs, Park-goers give organisms the best possible chance at survival—even the microscopic creatures visitors can’t see—and help promote adaptable landscapes in the Park.

As we confront the mounting challenges of climate change, resilience is key, and biodiversity stands as a potent defense mechanism. Together, we can work to ensure Central Park will serve as a beacon of hope and model for fostering the beauty and potential of biodiverse landscapes amid a shifting environment.

Amileah Sutliff is the Senior Marketing Writer & Editor at the Central Park Conservancy.