Swamp pink: measuring the few inches around a plant

Protection preceded a detailed hydrologic test

The Fish and Wildlife Service published its final determination listing swamp pink as threatened on September 9, 1988. The earlier proposal identified filling, drainage and private collecting among the threats and placed many known populations in New Jersey. These are dated conservation records, not a present-day count of every surviving colony. USFWS final listing, September 9, 1988; USFWS proposed listing, February 25, 1988.

Plants occupied particular parts of the hummocks

Kim Laidig, Robert Zampella and Carlo Popolizio studied two streamside colonies and published their results in 2009. They measured water levels over two years and related them to 958 clusters, usually growing on exposed portions of hummocks. The plants were not spread uniformly across all available wet ground. Laidig, Zampella and Popolizio, Journal of the Torrey Botanical Society (2009).

When the researchers simulated a fifteen-centimeter drawdown, more than thirty percent of existing cluster area at both sites fell into unusually dry conditions by their study’s definition. A thirty-centimeter reduction affected all or nearly all cluster area. These were modeled exposures, not observed deaths caused by experimental pumping. Laidig, Zampella and Popolizio, Journal of the Torrey Botanical Society (2009).

Newly exposed ground was not an automatic replacement

Lower water could also expose ground that had previously been submerged. The authors stressed that its value as replacement habitat depended on whether swamp pink could colonize it. That unresolved step matters: a map of apparently suitable substrate does not prove that a slow-moving plant population will occupy it in time. Laidig, Zampella and Popolizio, Journal of the Torrey Botanical Society (2009).