Warmer temperatures and longer dry spells have killed thousands of trees and shrubs in a Southern California mountain range, pushing the plants' habitat an average of 213 feet up the mountain over the past 30 years, a UC Irvine study has determined.
White fir and Jeffrey pine trees died at the lower altitudes of their growth range in the Santa Rosa Mountains, from 6,400 feet to as high as 7,200 feet in elevation, while California lilacs died between 4,000-4,800 feet. Almost all of the studied plants crept up the mountain a similar distance, countering the belief that slower-growing trees would move slower than faster-growing grasses and wildflowers.
This study is the first to show directly the impact of climate change on a mountainous ecosystem by physically studying the location of plants, and it shows what could occur globally if the Earth's temperature continues to rise. The finding also has implications for forest management, as it rules out air pollution and fire suppression as main causes of plant death.
"Plants are dying out at the bottom of their ranges, and at the tops of their ranges they seem to be growing in and doing much better," said Anne Kelly, lead author of the study and a graduate student in the Department of Earth System Science at UCI. "The only thing that could explain this happening across the entire face of the mountain would be a change in the local climate."
The study appears online the week of Aug. 11 in the Proceedings of the National Academy of Sciences.
Kelly and Michael Goulden, Earth system science professor, studied the north face of the Santa Rosa Mountains, just south of Palm Desert near Idyllwild, Calif. In the past 30 years, the average temperature there rose about 2 degrees Fahrenheit. While overall precipitation increased, the area experienced longer periods of drought, specifically in 1987-1990 and 1999-2002.
They decided to study the area after learning that people who live and work there were speculating that climate change was causing the plants to die.
Kelly and Goulden began with a 1977 plant survey by researcher Jan Zabriskie that cataloged all plants along a five-mile vertical stretch through the desert scrub, pinyon-juniper woodland, and chaparral shrubland and conifer forest.
The UCI scientists went back to the same spot in 2006-07 and did another plant survey, in which they stretched a measuring tape along the route and physically identified and measured plants that covered the tape. Then with a computer, they compared their results with those of the 1977 survey.
In the UCI study, 141 different species were identified along the tape, but the final analysis focused on 10 that were most abundant at different elevations. Those species included white fir and Jeffrey pine trees; golden cup oak trees; sugar bush, California lilac, Muller scrub oak, creosote bush, ragweed, and brittle bush shrubs; and agave plants.
The mean elevation of nine of the 10 species rose, with an average gain of 213 feet.
"I was surprised by how nice the data looked and how unambiguous the signal was," Goulden said. "It is clear that ecosystems can respond rather rapidly to climate change."
The scientists say air pollution did not kill the trees or cause the shift because the area does not have unusually high carbon dioxide levels, and they did not observe the characteristic speckling on plants caused by ozone damage. Also, if it was pollution, all of the plants would be suffering, not just the ones at the bottom of their range.
Fire suppression also is not a culprit, they say. The fire regime there is normal, with the last major fire occurring in the 1940s.
"The plants should still be in a recovery phase where they are growing back in," Kelly said. "But they have stopped recovering and now are dying, which these plants should not be doing."
A study published recently in the journal Science also found that plant growth ranges are moving upward in a French mountain range, but its conclusions were based on historic databases, not a systematic, repeated measurement of plant cover. The UCI study also found that all types of plants, from pine trees to ragweed, moved up a similar distance, not just small, short-lived plants as found by the French scientists.
Jennifer Fitzenberger | EurekAlert!
International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
World Water Day 2017: It doesn’t Always Have to Be Drinking Water – Using Wastewater as a Resource
17.03.2017 | ISOE - Institut für sozial-ökologische Forschung
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy