Urban Biodiversity Nature in the City
Suummer 2000
By Robert DeCandido
Although people may think that biodiversity exists only in the rainforest or some other far away place, we New Yorkers know better. New York City is biodiversity. The diversity of wild plant and animal life in our parks is as important to us as our unique mixture of people, with their varied cultures and languages. By visiting a park in New York City it is possible to enjoy many different species of flowers, trees, fish, insects and birds that spend part or all of their lives here. But maintaining that level of biodiversity has been a challenge. To meet that challenge, the Urban Park Rangers have been studying changes in the city's biodiversity through time, and are taking steps to improve conditions in our natural ecosystems.
Why do so many animal and plant species make their homes in New York City? There are many different habitats here, from the forests of Staten Island and the Bronx, to the wetlands of Queens and Brooklyn, to the buildings of Manhattan. These habitats provide a home to a variety of species of plants and animals. Of the birds, for example, we have owls that nest in our forests, herons that breed near our rivers and bays, and falcons that nest on buildings.
We are studying the changes in species diversity of New York City. First, we turn to the historical records held in places like the American Museum of Natural History and the New York Botanical Garden. These records, dating back as far as 150 years for some areas, give us a baseline idea of what plants and animals we might expect to see in a given habitat. Then, we visit parks to see if the plant or animal can still be found.
Through our studies, we have discovered some interesting things. For example, we recently completed an analysis of existing native plant species diversity in all five boroughs. Staten Island, with 619 native plant species, is the most diverse borough in the city, although the Bronx (481) and Queens (337) are close behind. Manhattan (76) and Brooklyn (61) both have far fewer species of extant native plants. We also examined which species were the most common in New York City. Not surprisingly, the Aster family (goldenrod, sunflowers, and their allies) is most diverse with 225 total species living in our city. The grasses (199) are also a very large group. On the other hand, certain groups of plants have declined during the last century. For example, of the 30 species of orchids known from New York City in the past, 27 have become extinct in our parks during the last century. In all, non-woody species, like wildflowers and grasses, have been lost in our parks at a significantly greater rate than species of trees and shrubs.
The Rangers are working to stop this decline. We patrol sensitive areas rich in native species. As a part of our "Project X," we reestablish rare species in our parks, like the nodding trillium, a wildflower, and the American chestnut tree. And we teach people about the value of even the least numerous of our living organisms.
Why do we study biodiversity in a city? For one thing, higher levels of biodiversity result in a healthier and more resilient ecosystem. Also, by 2025 it is expected that almost two thirds of the world's people will live in an urban metropolis. Decisions that we urban dwellers make in terms of what we purchase, what laws we make, and how we live will eventually effect all the species and natural areas on Earth. Here at home, we need to learn from the past in order to preserve our biodiversity for the future.