Jul 192011
 

The Fish and Wildlife Service has determined that whitebark pine (Pinus albicaulis) should be listed as threatened or endangered, but that “[w]ork on a proposed listing determination . . . is precluded by work on higher priority listing actions with absolute statutory, court-ordered, or court-approved deadlines and final listing determinations.”

The pine, which is found in seven Western states, faces “high-magnitude, imminent threats,” but the service said it can’t continue to work on it without the money.

Whitebark mortality in Yellowstone ecosystem (from NRDC_Media)

Dead and dying whitebark pines near Goodwin Lake, Gros Ventre Range, Wyoming (Photo by Whitney Leonard for NRDC)

The Natural Resources Defense Council, which petitioned the service and then sued to force a response, said the pine “is the first broadly dispersed tree that the federal government has clearly pegged as a climate casualty.” NRDC added that “A recent study shows 80 percent of the whitebark pine forests in the Greater Yellowstone Ecosystem are already dead or dying.”

Whitebark pine is an important food source for grizzly bears.

“The rapid decline of whitebark pine is one of the most dramatic signs of how quickly our mountain ecosystems are warming,” NRDC’s Sylvia Fallon, lead author of the petition, said. “There are things we can do to buoy these trees and the ecosystems that depend on them for a while–but we have to get to the hard work of dealing with the underlying climate issue before a host of other species join whitebark on the long, hot march to extinction.”

Mildly edited excerpts from 12-month finding:

Climate change is expected to significantly decrease the probability of rangewide persistence of Pinus albicaulis. Projections from an empirically based bioclimatic model . . .  showed a rangewide distribution decline of 70 percent and an average elevation loss of 333 m (1,093 ft) for the decade beginning in 2030 (Warwell et al. 2007, p. 2). At the end of the century, less than 3 percent of currently suitable habitat is expected to remain (Warwell et al. 2007, p. 2). Similarly, climate envelope modeling on P. albicaulis distribution in British Columbia estimated a potential decrease of 70 percent of currently suitable habitat by the year 2055 (Hamman and Wang 2006, p. 2783). The area occupied by P. albicaulis in the Greater Yellowstone Ecosystem also is predicted to be significantly reduced with increasing temperature under various climate change scenarios (Schrag et al. 2007, p. 6). Pinus albicaulis is predicted to be nearly extirpated under a scenario of warming only and warming with a concomitant increase in precipitation (Schrag et al. 2007, p. 7). Fire suppression has had unintended negative impacts on Pinus albicaulis populations (Keane 2001a, entire), due to this shift from a natural fire regime to a managed fire regime. Stands once dominated by P. albicaulis have undergone succession to more shade-tolerant conifers (Arno et al. 1993 in Keane et al. 1994, p. 225; Flanagan et al. 1998, p. 307). Once shade-tolerant conifer species become firmly established, the habitat is effectively lost to P. albicaulis until a disturbance like fire once again opens the area for P. albicaulis regeneration.

Direct habitat loss from climate change is anticipated to occur with current habitats becoming unsuitable for P. albicaulis as temperatures increase and soil moisture availability decreases (Hamman and Wang 2006, p. 2783; Schrag et al. 2007, p. 8; Aitken et al. 2008, p. 103). Habitat loss is expected because (1) temperatures become so warm that they exceed the thermal tolerance of P. albicaulis and the species is unable to survive or (2) warmer temperatures favor other species of conifer that currently cannot compete with P. albicaulis in cold high-elevation habitats. Pinus albicaulis is widely distributed and thus likely has a wide range of tolerance to varying temperatures (Keane 2011c, pers.comm.). Therefore, increasing competition from other species that cannot normally persist in current P. albicaulis habitats is possibly the more probable climate-driven mechanism for habitat loss. Historical (paleoecological) evidence indicates that plant species have generally responded to past climate change through migration, and that adaptation to changing climate conditions is less likely to occur (Bradshaw and McNeilly 1991, p. 12; Huntley 1991, p. 19). Adaptation to a change in habitat conditions as a result of a changing climate is even more unlikely for P. albicaulis, given its very long generation time of approximately 60 years (Bradshaw and McNeilly 1991, p. 10). The rate of latitudinal plant migration during past warming and cooling events is estimated to have been on the order of 100 m (328 ft) per year (Aitken et al. 2008, p. 96). Given the current and anticipated rates of global climate change, migration rates will potentially need to be substantially higher than those measured in historic pollen records to sustain the species over time. A migration rate of at least a magnitude higher (1,000 m (3,280 ft)) per year is estimated to be necessary in order for tree species to be capable of tracking suitable habitats under projected warming trends

[W]arming temperatures are expected to result in direct habitat loss and are also currently causing an increase in populations of the predatory mountain pine beetle resulting in significant mortality rangewide.

Distribution

Pinus albicaulis occurs in scattered areas of the warm and dry Great Basin but it typically occurs on cold and windy high-elevation or high-latitude sites in western North America. As a result, many stands are geographically isolated (Arno and Hoff 1989, p. 1; Keane et al. 2010, p. 13). Its range extends longitudinally between 107 and 128 degrees west and latitudinally between 27 and 55 degrees north (McCaughey and Schmidt 2001, p. 33). The distribution of P. albicaulis includes coastal and Rocky Mountain ranges that are connected by scattered populations in northeastern Washington and southeastern British Columbia (Arno and Hoff 1990, p. 268; Keane et al. 2010, p. 13). The coastal distribution of P. albicaulis extends from the Bulkley Mountains in British Columbia to the northeastern Olympic Mountains and Cascade Range of Washington and Oregon, to the Kern River of the Sierra Nevada Range of east-central California (Arno and Hoff 1990, p. 268). Isolated stands of P. albicaulis are known from the Blue and Wallowa Mountains in northeastern Oregon and the subalpine and montane zones of mountains in northeastern California, south-central Oregon, and northern Nevada (Arno and Hoff 1990, p. 268; Keane et al. 2010, p. 13). The Rocky Mountain distribution of P. albicaulis ranges from northern British Columbia and Alberta to Idaho, Montana, Wyoming, and Nevada (Arno and Hoff 1990, p. 268; Keane et al. 2010, p. 13), with extensive stands occurring in the Yellowstone ecosystem (McCaughey and Schmidt 2001, p. 33). The Wind River Range in Wyoming is the eastern most distribution of the species (Arno and Hoff 1990, p. 268; McCaughey and Schmidt 2001, p. 33) (Figure 1).

Links

Photo of dead and dying whitebark pines near Goodwin Lake (Wyo.)

Whitebark pine info from NRDC’s page (result of search for “whitebark”)

Petition filed by NRDC

Matt Skoglund (NRDC) blog post

Coverage in Washington Post