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Furbish lousewort Listed: 4/26/1978 Status since listing: Stable The furbish lousewort (Pedicularis furbishiae), discovered in 1880, was declared extinct in 1975 (it had not been collected since 1943) [1]. This member of the snapdragon family that occurs only along the St. John River in Maine and adjacent New Brunswick was rediscovered in 1976 during surveys of a stretch of the St. John River where a hydroelectric project was proposed [1]. This led to the furbish louseworts’ listing under the endangered species act and the deauthorization of the proposed hydroelectric project (the Dickey-Lincoln School Lakes Hydroelectric Project) that would have resulted in the loss of 40% of the known plants [1]. Along the 140-mile stretch of the St. John River where furbish louseworts occur, they are largely confined to a narrow shrub-dominated transition zone on north-facing riverbanks below undisturbed boreal forest and above a sparsely vegetated, flooded cobble zone [2]. Because these plants are restricted to a narrow zone that is frequently disturbed by ice scour and flooding, populations tend to disappear unpredictably from one location and turn up in others [3]. Considering this variability, populations of furbish lousewort have been relatively stable since their rediscovery. Extensive censuses were conducted in 1980, 1984 and 1989 [1]. For census purposes, the river was divided into 48 river segments, of which 28 were known to support furbish lousewort populations. The number of flowering plants counted in 1980 was 5,114 [1]. This number rose to 6,889 in 1989 [1]. In looking at the percent change in numbers of flowering stems over these time periods, researchers determined that there was an overall increase of 29% in flowering stems within 23 river segments [1]. These surveys also revealed dramatic fluctuations over time in the distribution of individuals within particular river segments [1]. In 1991, the furbish lousewort population was reduced by more then 50% by a particularly formidable ice scouring event that reshaped large portions of the riverbank [4]. Following this event, 3,065 flowering stems were counted [4]. By 2003, populations had increased to 5,647 flowering stems, but they still have not returned to 1989 levels [4]. The dynamism of the St. John River is both a benefit and a problem for furbish lousewort populations [2]. The lousewort requires disturbances to create habitat by removing competing vegetation [2]. These same disturbance events, however, can cause catastrophic lousewort mortality [2]. No furbish lousewort populations occur on federal land, making protection of this species difficult [1]. There are no prohibitions on the future construction of dams on a long stretch of the St. John River from Big Rapids to Hamlin [1]. Damming the river would not only inundate some populations, but would prevent the ice scour and floods that now shape riverbank vegetation [1]. New Brunswick Power is still considering possible modifications of an existing dam at Grand Falls, as well as the creation of an additional hydropower facility near Morrill, New Brunswick [1]. In addition, records suggest that the spring flows of the St. John River have been increasing since the 1940s [1]. This could result in more severe disturbance events [1]. Increasing flows could be due to accelerated timber harvesting within the watershed leading to increased runoff [1]. [1] U.S. Fish and Wildlife Service. 1991. Revised Furbish Lousewort Recovery Plan. Newton Corner, Massachusetts, 62 pp. |
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