‘The silversword example foreshadows trouble for diversity in other biological hotspots’
By Summit Voice
SUMMIT COUNTY — An all-out effort to protect a rare Hawaiian plan from extinction may not be enough in the face of climate change.
The Haleakalā silversword made a strong recovery from early 20th-century threats, but researchers with the U.S. Geological Survey and the University of Hawaiʻi at Mānoa say it has been hit hard by climate change, undergoing increasingly frequent and lethal water stress. Local climate data confirm trends towards warmer and drier conditions on the mountain, which the researchers warn will create a bleak outlook for the threatened silverswords if climate trends continue.
The silversword grows for 20-90 years before producing a large flowering spike large with as many as 600 flower heads. The plant grows only in Haleakalā National Park on the slopes of a single volcano. Under protective measures, including the exclusion of hoofed animals, the species made a strong recovery, but the new research shows a decline since the 1990s.
“The silversword example foreshadows trouble for diversity in other biological hotspots,” said Dr. Paul Krushelnycky, a biologist with the University of Hawaiʻi at Mānoa, College of Tropical Agriculture and Human Resources, and principal investigator for the project, “and it also illustrates how even well-protected and relatively abundant species may succumb to climate-induced stresses.”
“The silversword is an amazing story of selective biological adaptation of this distant cousin of the daisy to the high winds and sometimes freezing temperatures on the high slopes and thin soils of Haleakalā volcano,” said USGS director Marcia McNutt. “Despite the successful efforts of the National Park Service to protect this very special plant from local disturbance from humans and introduced species, we now fear that these actions alone may be insufficient to secure this plant’s future. No part of our planet is immune from the impacts of climate change.”
Although the decline and extinction of other rare species with small ranges (and the accompanying loss of biodiversity) can easily go unobserved and unappreciated, the silversword’s high profile makes it a good example with which to educate the public about global climate change.
Krushelnycky co-authored the paper along with Lloyd Loope, scientist emeritus with the U.S. Geological Survey, and others at the University of Hawai‘i at Mānoa, and University of Arizona.They explain that, although climate change is predicted to place mountaintop and other narrowly endemic species such as the silversword at severe risk of extinction, the ecological processes involved in such extinctions are still poorly understood.
This report is the first publication to result from a collaborative effort between research scientists and land managers at Haleakalā National Park seeking to understand worrying trends for this popular federally threatened plant. The work was facilitated and funded by the National Park Service, along with U.S. Geological Survey and U.S. Fish and Wildlife Service. Dr. Krushelnycky and his collaborators were also awarded a grant by the newly established U.S. Department of the Interior Pacific Islands Climate Science Center, one of eight such centers throughout the country, to continue the work.