Nav: Home

ASU study finds weather extremes harmful to grasslands

September 28, 2015

Tempe, Ariz. -- Fluctuations in extreme weather events, such as heavy rains and droughts, are affecting ecosystems in unexpected ways -- creating "winners and losers" among plant species that humans depend upon for food.

Arizona State University investigators conducted a six-year experiment on the effects of climatic variability on desert grassland. The study revealed that when unpredictable weather patterns create alternating wet and dry years, ecosystem productivity declines -- mostly because grasses diminish, which allows shrubs to flourish.

"We found that not all species could respond effectively to extreme weather events including both dry and wet conditions," said Osvaldo Sala, senior sustainability scientist and professor with ASU School of Life Sciences. "Grasses don't fare as well as shrubs, which is really important to know because cattle ranchers depend on grasslands to graze their herds. Humans could see a reduction in the production of food -- mostly cattle for meat -- as the provision of ecosystem services like this one change."

The findings were published today in the online early edition of the journal Proceedings of the National Academy of Sciences.

"Interestingly, the effect of precipitation variability was amplified over the six years the experiment lasted and we still don't know its end point," said Laureano Gherardi, a School of Life Sciences postdoctoral research associate and co-author of the paper. "Therefore, the effect of the expected climatic variance may be even larger and the ecosystem may shift into a different state," he added.

The researchers created 50 study plots in the Chihuahuan desert in New Mexico, at the Jornada Long Term Ecological Research site. They increased precipitation variability on each plot to mimic the projected increased in the frequency of weather extremes such as drought and unusually wet conditions. Over a six-year period, the plots were alternately irrigated or subjected to dry conditions.

"Shrubs did rather well under these conditions because of their growing response to annual precipitation, but the grasses declined as a result of their limited response to wet years," said Sala. "A desert grassland ecosystem could fairly quickly change into a different state, such as shrubland. This would have serious consequences for humans, considering that a large portion of land around the world is grassland."

Sala added that some of the more dramatic changes to the grasslands did not occur until later in the study, proving how important long-term studies are, as well as the difficulty of making long-term predictions based on short-term experimentation.
-end-


Arizona State University

Related Plant Species Articles:

Newly established, a national park in Australia unveils a new plant species
A new species of bush tomato discovered in a recently established national park in Australia provides a compelling argument for the importance of federal investment in science and conservation.
Climate change is already causing widespread local extinction in plant and animal species
Extinctions related to climate change have already happened in hundreds of plant and animal species around the world.
Plant-species hotspot maps identify priority conservation areas of tropical Africa
New research led by the University of Oxford has created plant-species hotspot maps for tropical Africa, making use of 3.1 million global distribution records of more than 40,000 African plant species to map the areas that are home to the world's rarest plants.
Plant-species hotspot maps identify priority conservation areas of tropical Africa
A research team led by the University of Oxford, and including Jan Wieringa of Naturalis Biodiversity Center, has mapped areas in tropical Africa containing relatively many rare plant species.
Toyota supports Kew's vital research into threatened plant species
Toyota is supporting vital research into the world's most threatened plant species at a dedicated research unit just opened at the Royal Botanic Gardens, Kew, UK.
A nonet of new plant species from Africa emphasizes the importance of herbaria in botany
Some collected 40 years ago, some as far back as a 100, nine new plant species from the custard apple genus Monanthotaxis have been recently discovered on dusty shelves and described in PhytoKeys to showcase the importance of herbaria in botany.
New plant species discovered on Yakushima
Suetsugu Kenji, a project associate professor at the Kobe University Graduate School of Science, has discovered a new species of plant on the subtropical Japanese island of Yakushima (located off the southern coast of Kyushu in Kagoshima prefecture) and named it Sciaphila yakushimensis.
Trapped in amber: Flower identified by Rutgers plant biologist as new species
A Rutgers scientist has identified a flower trapped in ancient amber as belonging to a species completely new to science.
Land plant became key marine species
The genome of eelgrass (Zostera marina) has now been unveiled.
Botanical big data helping to predict how plant species will react to environmental change
Scientists are using a 'botanical big data' approach to predict how different plant species will respond to human-induced disturbances and environmental change in different ecosystems spanning the world's continents.

Related Plant Species Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Jumpstarting Creativity
Our greatest breakthroughs and triumphs have one thing in common: creativity. But how do you ignite it? And how do you rekindle it? This hour, TED speakers explore ideas on jumpstarting creativity. Guests include economist Tim Harford, producer Helen Marriage, artificial intelligence researcher Steve Engels, and behavioral scientist Marily Oppezzo.
Now Playing: Science for the People

#524 The Human Network
What does a network of humans look like and how does it work? How does information spread? How do decisions and opinions spread? What gets distorted as it moves through the network and why? This week we dig into the ins and outs of human networks with Matthew Jackson, Professor of Economics at Stanford University and author of the book "The Human Network: How Your Social Position Determines Your Power, Beliefs, and Behaviours".