The way I read the rules it will be difficult to take away an existing garden. The real problem is the statements that have been made by Adrian Benepe, the Parks Department Commissioner - listen to the Brian Lehrer show link above - that sound more like the city is looking for excuses to develop any gardens that may do anything deemed to break the rule. The city really should be rewarding the community gardeners for their stewardship of city land which has provided many community benefits at no cost to the city.
The commissioner refers to problems with the gardens or gardeners. With nearly 500 community gardens in NYC there will be issues from time to time with characters who do things that might jeopardize all of the good work done by the overwhelming majority of community gardeners. The point is that the land that the gardens sit on happens in most cases to be in areas where their is a lack of open space. Building on even one garden means that a neighborhood, usually one of color and low income will forever have less open space. There are several organizations that work with community gardeners like the Green Guerillas, GrowNYC, GreenThumb, Brooklyn Green Bridge, the New York City Community Garden Coalition and Bronx Green Up to strengthen the social sustainability of the gardeners that can help if and when these issues arise. The people who are the community gardeners change all of the time as people age, move away or pass away but there seems to always be newcomers to the city and the neighborhood or longtime residents to step in and continue the good work.
So lets find a way to protect our community garden land.