Last summer, I received a master’s degree in environmental science and policy administration from Columbia (MPA-ESP) participated in the program and conducted a field trip to urban ecology. Matthew PalmerHe is a senior lecturer in the Department of Ecology, Evolution, and Environmental Biology at Columbia University. The cohort visited three major locations in New York City: Randall’s Island, River Park, and Bronx Park East. Each location served as a living laboratory where students explored the intersection of natural ecosystems and urban environments. Through hands-on learning and direct observation, students deepened their understanding of the important role urban ecology plays in fostering sustainable and resilient communities.
First stop: Randall’s Island
The trip began at Randall’s Island, where the students met Anne Wilson, Chief Planning Officer for the Randall’s Island Park Alliance (RIPA). Wilson explained how RIPA, a nonprofit public-private partnership founded in 1998, manages the park by securing both private and public funding. This approach allows RIPA to efficiently improve the park by supporting features such as waterfront trails, courts, and playgrounds that attract approximately 4 million visitors each year.
Next, RIPA biologist Olivia Smith discussed Little Hell Gate Salt Marsh, one of the first restored salt marshes in New York County. Named for the treacherous waters that once caused shipwrecks, wetlands are important breeding grounds for fish because they have higher plant and animal growth rates per square foot than tropical rainforests. Tall spartina grass filters sediment and “sweat” salts, and mussels contribute to nutrient cycling. However, wetlands require additional restoration efforts because their small size and limited space for movement make them vulnerable to frequent hurricanes. On the island, restoration work primarily focuses on vegetation management as animals naturally migrate to new habitats.
Palmer provided students with an overview of Randall’s Island’s hydrological issues and restoration efforts. Originally two small islands surrounded by salt marshes, Randall’s Island has experienced significant changes due to urbanization, which has altered stream flows and created shallow groundwater discharge problems. To address this, nature-based solutions such as building wetlands to help manage stormwater and improve water quality have been implemented. Most of the island’s rainwater is now collected in pipes designed to filter out waste and slow the deposition of sediment, and the island’s topography and soil microbes play an important role in processing the rainwater. Heavy metals do not decompose but are fixed in the soil and absorbed by plants, while hydrocarbons are broken down by microorganisms.
Second stop: River Park
At River Park in the Bronx, the group learned about wetland restoration efforts led by a team from NYC Parks’ Natural Resources Group. The tidal-influenced Bronx River at its southern end supports a dynamic ecosystem, including oysters that filter water and create habitat for marine life. However, poor water quality and excessive sediment hinder the growth of oyster reefs. The Billion Oyster project solves this problem by collecting oyster shells from restaurants and placing them in the river to provide a solid substrate for reef formation.
Students also explored the role of anadromous fish, such as river herring, which swim upstream to reproduce. First built in the 1600s, dams blocked herring migration for centuries. But the construction of fish ladders and the introduction of shad from other areas into the upper Bronx River have helped restore breeding patterns. Herring are imprinted on the chemical composition of the river during their early life stages, allowing them to recognize this and return to the same location to spawn as adults.
The discussion then shifted to green infrastructure in the Bronx. Students learned how rooftops and impervious surfaces allow water to quickly drain into sewers, causing pollution and fines for New York City. The city is currently investing in green infrastructure solutions such as green roofs, bioswales and rain gardens to absorb stormwater, reduce sewer overflows and promote groundwater recharge.
Final destination: Bronx Park East
The final stop was Bronx Park East, where Urban Ecology Assistant Ayanna Butler discussed the relationship between stream and forest health. She explained how hurricanes can cause significant nitrate losses in forests, affecting the nitrogen cycle, an important process for both plants and animals. Butler detailed the processes of mineralization, nitrification, and nitrogen fixation, particularly emphasizing the role of locust trees in converting atmospheric nitrogen into a form usable by plants.
At Bronx Park East, students also learned about the challenges of managing invasive species, focusing on knotweed. Originally introduced as an ornamental plant, knotweed has become one of the most aggressive invasive species in urban environments. Their rapid growth causes them to form dense thickets that outgrow native plants, reducing biodiversity and threatening local wildlife. These dense underbrush can also be a concern for law enforcement agencies as they can impede visibility and create secluded areas that can attract undesirable activities. Knotweed is particularly difficult to control because it thrives in disturbed soils, which are common in urban environments. Their shallow roots make them less effective at stabilizing the soil, which can worsen erosion in floodplain areas. However, natural shade from tall trees and plants has proven to be an effective way to inhibit growth. By reducing the amount of sunlight that reaches the ground, native tree cover can help limit the spread of knotweed, providing a more sustainable approach to managing this persistent invader.
These three stops provided valuable hands-on experience for Columbia’s MPA-ESP students, demonstrating the complex balance required to maintain and restore natural environments within a dynamic urban environment. From salt marsh restoration efforts on Randall’s Island, to the role of oysters and green infrastructure along the Bronx River, to the critical connection between forest health and urban streams in Bronx Park East, students were able to connect the knowledge they learned in the classroom directly to the real world. environmental issues.
