The size and age of plants have more of an impact on their productivity than temperature and precipitation, according to a landmark study by University of Arizona researchers.
UA professor Brian Enquist and postdoctoral researcher Sean Michaletz, along with collaborators Dongliang Cheng from Fujian Normal University in China and Drew Kerkhoff from Kenyon College in Gambier, Ohio, have combined a new mathematical theory with data from more than 1,000 forests across the world to show that climate has a relatively minor direct effect on net primary productivity, or the amount of biomass – wood or any other plant materials – that plants produce by harvesting sunlight, water and carbon dioxide.
The findings were made available as an advance online publication by the journal Nature on Sunday.
"A fundamental assumption of our models for understanding how climate influences the functioning of ecosystems is that temperature and precipitation directly influence how fast plants can take up and use carbon dioxide," said Enquist, a professor in the UA Department of Ecology and Evolutionary Biology, whose research lab led the study.
"Essentially, warm and wet environments are thought to allow plant metabolism to run fast, while cold and drier environments slow down metabolism and hence lower biomass production in ecosystems," he said. "This assumption makes sense, as we know from countless experiments that temperature and water control how fast plants can grow. However, when applied to the scale of entire ecosystems, this assumption appears to not be correct."
To test the assumption on the scale of ecosystems, the team developed a new mathematical theory that assesses the relative importance of several hypothesized drivers of net primary productivity. That theory was then evaluated using a massive new data set assembled from more than 1,000 forest locations across the world.
The analysis revealed a new and general mathematical relationship that governs worldwide variation in terrestrial ecosystem net primary productivity. The team found that plant size and plant age control most of the variation in plant productivity, not temperature and precipitation as traditionally thought.
"This general relationship shows that climate doesn't influence productivity by changing the metabolic reaction rates underlying plant growth, but instead by determining how large plants can get and how long they can live for," said Sean Michaletz, lead author of the study and a postdoctoral researcher in the UA Department of Ecology and Evolutionary Biology. "This means that plants in warm, wet environments can grow more because their larger size and longer growing season enable them to capture more resources, not because climate increases the speed of their metabolism."
The finding does not, however, mean that climate is unimportant for plant productivity, the researchers noted.
"Climate is still an important factor, but our understanding of how it influences ecosystem functioning has now changed," Michaletz said.
The team's findings suggest that mathematical models used for predicting the effects of global climate change can be improved by accounting for the effects of plant size and plant age on net primary productivity.
"Understanding exactly how climate controls net primary production is important for understanding the plant-atmosphere feedbacks that control climate change," Michaletz said.
Enquist added: "In other words, to better predict how ecosystems will change with climate, we need to understand what influences the amount of plant biomass in a given area as well as its age."
UA Department of Ecology and Evolutionary Biology
UA Department of Ecology and Evolutionary Biology
University Relations, Communications
Shelley Littin | University of Arizona
Shark Tagged by NSU’s Guy Harvey Research Institute Is Apparently Enjoying Time in Warm, Tropical Waters
30.03.2015 | Nova Southeastern University
Misuse of Sustainability Concept May Lead to Even More Toxic Chemical Materials
30.03.2015 | Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences
In an experiment at the Department of Energy's SLAC National Accelerator Laboratory, scientists precisely measured the temperature and structure of aluminum as...
The IPH presents a solution at HANNOVER MESSE 2015 to make ship traffic more reliable while decreasing the maintenance costs at the same time. In cooperation with project partners, the research institute from Hannover, Germany, has developed a sensor system which continuously monitors the condition of the marine gearbox, thus preventing breakdowns. Special feature: the monitoring system works wirelessly and energy-autonomously. The required electrical power is generated where it is needed – directly at the sensor.
As well as cars need to be certified regularly (in Germany by the TÜV – Technical Inspection Association), ships need to be inspected – if the powertrain stops...
When an earthquake hits, the faster first responders can get to an impacted area, the more likely infrastructure--and lives--can be saved.
The Atlantic overturning is one of Earth’s most important heat transport systems, pumping warm water northwards and cold water southwards. Also known as the Gulf Stream system, it is responsible for the mild climate in northwestern Europe.
Scientists now found evidence for a slowdown of the overturning – multiple lines of observation suggest that in recent decades, the current system has been...
Because they are regularly subjected to heavy vehicle traffic, emissions, moisture and salt, above- and underground parking garages, as well as bridges, frequently experience large areas of corrosion. Most inspection systems to date have only been capable of inspecting smaller surface areas.
From April 13 to April 17 at the Hannover Messe (hall 2, exhibit booth C16), engineers from the Fraunhofer Institute for Nondestructive Testing IZFP will be...
25.03.2015 | Event News
19.03.2015 | Event News
17.03.2015 | Event News
30.03.2015 | Press release
30.03.2015 | Life Sciences
30.03.2015 | Earth Sciences