The flora on the High Line, New York City, New York: A 17-year comparison

This study compares the lichen, moss, and vascular plant species found on the abandoned High Line rail line in 2002 with those found on a three-block remnant of the High Line between 30th and 33rd Streets and 12th Avenue in 2019. One hundred fifty-five species were identified in 125 genera belonging to 47 families in the 2002 study. The 2019 study identified 79 species within 68 genera belonging to 32 families. Ten lichens were identified in 2019; four were identified in 2002. The number of mosses found in 2019 remained the same (six species); four species were new to the study area, and four species found in 2002 were not relocated. The loss of vascular plant species on the old High Line in 2019 is a function of its reduced size, a three-block remnant of the original site. The increase in lichen diversity might reflect improved air quality and continued lack of disturbance to suitable substrates at the remnant site.