Big sagebrush may need to count on its soil seed bank for survival

Mar 27, 2012
The article by Wijayratne and Pyke is featured in the March 2012 issue of the American Journal of Botany. Credit: Cover image credit: Peter Wilf

Big sagebrush (Artemisia tridentata) is a key foundational species in an ecosystem that is threatened by invasion of cheatgrass and the subsequent increase in fire frequency. Critical to the conservation, reestablishment, and restoration of the sagebrush steppe ecosystem (which comprises 63 million hectares of the Great Basin of North America) is understanding the dynamics of A. tridentata seeds—how long do they remain viable and are they able to persist in the seed bank for any length of time?

Previously it was thought that A. tridentata did not persist in the seed bank, severely curtailing this species' ability to regenerate post-fire. Upekala Wijayratne and David Pyke (USGS and Oregon State University, Corvallis, OR) experimentally investigated whether A. tridentata seeds were able to form a short-term seed bank, a critical strategy that would enable this species to persist despite environmental conditions that have been altered by the invasive . They published their findings in a recent issue of the American Journal of Botany.

"Understanding seed bank dynamics of sagebrush, an ecologically and economically significant species, is important for its sustainable management," said Wijayratne.

"Many seed viability studies are conducted in greenhouse settings or within a very small field site," she added. "What makes this study valuable is that it was replicated at several different study sites throughout the ."

By sowing seeds of two different subspecies of A. tridentata at the soil's surface, under the leaf litter, and buried 3 cm below the soil at six different study sites across Oregon, Idaho, Utah, and Nevada, the authors determined that, contrary to previous assumptions, seeds were able to survive in the soil beyond a single growing season and as much as up to 2 years post-dispersal.

Interestingly, the authors found that very few seeds that were on the surface or under the leaf litter survived intact within the first year—they either decomposed or germinated right away. In contrast, 30%󈞔% of the seeds that were buried 3 cm below the soil surface remained viable up to and possibly beyond 24 months post-dispersal.

"Our study showed that burying sagebrush seeds in a few centimeters of soil allowed a proportion of seeds to remain alive for multiple years, whereas seeds on the soil surface or under plant litter died within 6 months," notes Wijayratne.

Previous research had indicated that A. tridentata seeds did not persist in the soil beyond the first season; however, when the authors looked at naturally dispersed seeds they did find some seeds in the soil seed bank, providing newly found hope that this species may be able to survive the frequent fires.

"Our results have the greatest implication for sagebrush restoration," comments Wijayratne. "Getting sagebrush plants established from seed is very difficult because environmental conditions have to be just right. If we can create a soil seed bank during restoration efforts, then we may see a payoff for those efforts in establishment for multiple years rather than potential failure."

"Identifying restoration practices that best promote seeds into entering the is the next step," she concludes.

Indeed, restoration efforts that involve aerial seeding may not be as effective as ones in which soil disturbance or mulch aid in moving seeds below the litter surface. Once under the , A. tridentata seeds may remain viable for a few years and may also escape incineration due to fires.

Explore further: Male monkey filmed caring for dying mate (w/ Video)

More information: Wijayratne, Upekala C. and David A. Pyke. 2012. Burial increases seed longevity of two Artemisia tridentata (Asteraceae) subspecies. American Journal of Botany 99(4): 438-447. DOI: 10.3732/ajb. 1000477

add to favorites email to friend print save as pdf

Related Stories

Short-lived seed of alpine plants

Sep 21, 2011

Scientists from the Millennium Seed Bank Partnership have found that the seeds of alpine plants are shorter lived than their lowland relatives. This will have implications for seed conservation strategies ...

Storing seeds for a rainy day -- or in this case, a fire

May 31, 2011

As mountain pine beetles march across the forests of western North America, these insects may kill millions of pine trees during a single outbreak. A rise in overall temperatures over the past several years has increased ...

Vehicles aid in weed seed dispersal

Jun 24, 2011

Noxious weeds are often found growing along roads and trails and vehicles have long been suspected of picking up weed seeds and dispersing them to new locations. A new Montana State University Extension publication describes ...

Recommended for you

Male monkey filmed caring for dying mate (w/ Video)

18 hours ago

( —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Orchid named after UC Riverside researcher

Apr 17, 2014

One day about eight years ago, Katia Silvera, a postdoctoral scholar at the University of California, Riverside, and her father were on a field trip in a mountainous area in central Panama when they stumbled ...

In sex-reversed cave insects, females have the penises

Apr 17, 2014

Researchers reporting in the Cell Press journal Current Biology on April 17 have discovered little-known cave insects with rather novel sex lives. The Brazilian insects, which represent four distinct but re ...

Fear of the cuckoo mafia

Apr 17, 2014

If a restaurant owner fails to pay the protection money demanded of him, he can expect his premises to be trashed. Warnings like these are seldom required, however, as fear of the consequences is enough to ...

User comments : 0

More news stories

Researchers successfully clone adult human stem cells

( —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Male monkey filmed caring for dying mate (w/ Video)

( —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Researchers develop new model of cellular movement

( —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

Impact glass stores biodata for millions of years

( —Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists ...