Where every great city stands today, a natural ecosystem once thrived. London was built on a floodplain of the River Thames; New York was set up on great tracts of oak woodland; and Tokyo, the most populous metropolis in the world, once supported a lush and verdant subtropical forest. These ambitious cities have sacrificed natural diversity to become the cultural, artistic and economic centers they are today. The very definition of the word urban excludes notions of nature and rurality, instead conjuring images of industry and skyscrapers. But in an increasingly green-minded world, many cities are working to reverse their reputations and are redefining the concept of urbanity altogether.
The Big Apple is home to more than eight million people and covers 305 square miles. Not only does it boast the highest levels of public transportation use, but its citizens consume less than half the energy of the national per capita average.Compared to San Francisco, where plastic bags are illegal and municipal composting is the norm, New York far out-ranks the ecologically conscious California city, contributing almost 30 percent less per capita in annual greenhouse gas emissions.
Despite having grown to become the most populous city in the United States, a quarter of New York’s area is dedicated to open space. Most visitors to New York make a trip to see the city’s most famous undeveloped area, the iconic Central Park. Opened in 1857 in response to the city’s growing population and an increased need for recreational green space, the park has long been a favorite destination of birders who come to see, among other species, the famous peregrine falcons (Falco peregrinus) that nest on the buildings along the park’s perimeter. For botanists, Central Park is home to one of the largest remaining stands of American elm (Ulmus americanus), a species that has almost been extinguished since the introduction of Dutch elm disease in the 1920s.
More than 2,100 plant species can be found within New York City — more than in the entire country of Great Britain — and some of these species are exceedingly rare. Staten Island, the fastest growing borough in the city, is home to the globally vulnerable Torrey’s mountain-mint(Pycnanthemum torrei), a plant found in fewer than twenty locations worldwide. The American chestnut (Castanea dentata), a once-abundant tree in northeastern forests, can still be found in several locations in New York City, as well.
These accolades must be appreciated but also checked by the realities of the relationships between urban centers and biodiversity loss. Preserving the habitat wherein biological diversity occurs requires preserving large amounts of often contiguous green space, a commodity that is in high demand for development in New York City. In 2000, a 3.4-acre property in the center of Manhattan famously sold for $345 million, or approximately $2,300 per square foot. As vacant land disappears and suitable habitat is lost to development, plant populations shrink and become geographically isolated. Reproductive isolation causes the critical gene flow between populations to weaken or even stop, increasing the incidence of inbreeding. In a study by Dr. Robert DeCandido, New York City was found to have lost 43 percent of its native flora since 1925. Of the original 1,357 native species found in the city, only 779 remain.
The tireless spread of foreign invaders another problem effective ecological management must remedy. The overall degradation of native soils due to pollution and compaction is one of the biggest, and most difficult to mitigate, threats to native flora in New York City. Because of the city’s high population density, natural wildfire cycles are no longer permitted to occur. Fast-growing invasive species fill tree-fall gaps that create similar forest openings suitable for light-loving species, such as huckleberry(Gaylussacia baccata) and lowbush blueberry (Vaccinium pallidum), before natives have a chance to become established. Invasive species also alter soil nutrient and pH levels, thus inviting late-successional species into the forest and encouraging growth of non-native types of woodland vegetation.
However, native plants and ecosystems reclaim lost ground quickly and have been found exploiting new and surprising niches only available in urban environments. The nutrient poor, thin soils on landfills are underlain with a clay lens used to cap the mound. This mixture of substrate inadvertently creates perfect habitat for, among other things, members of the threatened blueberry family. Fresh Kills landfill on Staten Island, one of the largest piles of garbage on the planet, is slated to be the site of an equally large native plant restoration project in the newly created Freshkills Park. In only a handful of years, a meadow of native grasses will sway over the landfill’s hump, preventing erosion, providing habitat for ground-nesting birds and sowing ecologically appropriate seed for miles around. New Yorkers will be free to wander the park, run on its trails, and admire its flora and fauna. Perhaps there is no better symbol of the unification of nature and urbanity — and the rewriting of their relationship — than this budding partnership. Instead of mutual exclusion and antagonism, the two entities nurture each other: New growth is literally sprouting from city detritus, and the city, in turn, is richer, greener, healthier and happier because of it.
Read the entire article, written by Molly Marquand, at the Izilwane website. We are constantly on the lookout for new content; please be in touch if you are interested in becoming a “citizen eco-reporter” for the progressive knowledge-sharing platform Izilwane. Find out more here.