Known for its striking rosette, the silversword grows for 20-90 years before the single reproductive event at the end of its life, at which time it produces a large (up to six feet tall) inflorescence with as many as 600 flower heads.
This is a Haleakala silversword (Argyroxyphium sandwicense subsp. macrocephalum) in bloom, with Haleakala Volcano crater in background. It is the west rim of Haleakala; crater, Maui, Hawaii, 2007.
Credit: Paul Krushelnycky, University of Hawaii at Manoa
The plant was in jeopardy in the early 1900s due to animals eating the plants and visitors gathering them. With successful management, including legal protection and the physical exclusion of hoofed animals, the species made a strong recovery, but since the mid-1990s it has entered a period of substantial decline.
A strong association of annual population growth rates with patterns of precipitation suggests the plants are 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 example foreshadows trouble for diversity in other biological hotspots," said Dr. Paul Krushelnycky, a biologist with the University of Hawaiʻi at Mânoa, 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 Haleakalâ 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."
The Haleakalâ silversword (Argyroxyphium sandwicense macrocephalum) grows only on a single volcano summit in Hawaiʻi, yet it is viewed by 1 million visitors annually at Haleakalâ National Park. 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 Mânoa, 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, and they are hoping to increase this understanding.
This report is the first publication to result from a collaborative effort between research scientists and land managers at Haleakalâ 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.
The full report, "Climate-Associated Population Declines Reverse Recovery and Threaten Future of an Iconic High-Elevation Plant," published in the scientific journal Global Change Biology, is available on request from the above contacts.
Paul Krushelnycky | EurekAlert!
Novel method for investigating pore geometry in rocks
17.06.2018 | Kyushu University, I2CNER
Decades of satellite monitoring reveal Antarctic ice loss
14.06.2018 | University of Maryland
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
Light detection and control lies at the heart of many modern device applications, such as smartphone cameras. Using graphene as a light-sensitive material for...
Water molecules exist in two different forms with almost identical physical properties. For the first time, researchers have succeeded in separating the two forms to show that they can exhibit different chemical reactivities. These results were reported by researchers from the University of Basel and their colleagues in Hamburg in the scientific journal Nature Communications.
From a chemical perspective, water is a molecule in which a single oxygen atom is linked to two hydrogen atoms. It is less well known that water exists in two...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
15.06.2018 | Materials Sciences
15.06.2018 | Ecology, The Environment and Conservation
15.06.2018 | Power and Electrical Engineering