Login

GPC Members Login
If you have any problems or have forgotten your login please contact [email protected]


Incomplete drought recovery may be the new normal

The amount of time it takes for an ecosystem to recover from a drought is an important measure of a drought's severity. During the 20th century, the total area of land affected by drought increased, and longer recovery times became more common, according to new research published by Nature by a group of scientists including Carnegie's Anna Michalak and Yuanyuan Fang.

Scientists predict that more-severe droughts will occur with greater frequency in the 21st century, so understanding how ecosystems return to normal again will be crucial to preparing for the future. However, the factors that influence drought recovery have been largely unknown until now.

"Research has usually focused on the amount of rain and other precipitation that ends the deficit of water that causes a drought, but assessments of drought-recovery need to account for the restoration of normal plant function," explained Michalak.

The team -- including three other alumni of Carnegie Global Ecology research groups William Anderegg (University of Utah), Adam Wolf (Arable Labs Inc.), and Deborah Huntzinger (Northern Arizona University) -- used measures of photosynthetic activity to assess drought recovery. Quantifying how long it took for plant productivity to return to normal gave the researchers a better understanding of the longevity of a drought's effects.

"If another drought arrives before trees and other plants have recovered from the last one, the ecosystem can reach a 'tipping point' where the plants' ability to function normally is permanently affected," Fang said.

The conditions most-strongly contributing to drought recovery time were precipitation and temperature, they found. Unsurprisingly, better conditions shortened recovery. Temperature extremes, both hot and cold, lengthened it.

Recovery took the longest in the tropics, particularly the Amazon and Indonesia, and in the far north, especially Alaska and the far east of Russia.

Other factors influencing drought recovery included pre-drought photosynthetic activity, carbon dioxide concentrations, and biodiversity.

The team found that drought impacts increased over the 20th century. Given anticipated 21st century changes in temperature and projected increases in drought frequency and severity due to climate change, their findings suggest that recovery times will be slower in the future. A chronic state of incomplete drought recovery may be the new normal for the remainder of the 21st century and the risk of reaching "tipping points" that result in widespread tree deaths may be greater going forward, they say.

Read the paper: Global patterns of drought recovery.

Article source: Carnegie Institution for Science.

Image credit: William and Leander Anderegg

News

Shallow soils promote savannas in South America

New research suggests that the boundary between South American tropical rainforests and savannas is influenced by the depth to which plants can root. Shallow rooting depth promotes the establishment of savannas. Previous research has shown that precipitation and fire mediate tropical forest and savanna distributions. The study shows that below ground conditions need to be considered to understand the distribution of terrestrial vegetation both historically and in the face of future climate change. The study by researchers of the Senckenberg Biodiversity and Climate Research Centre and Goethe University is based on computer vegetation models and was published in the Journal of Biogeography.


Living mulch builds profits and soil

Living mulch functions like mulch on any farm or garden except -- it's alive. No, it's not out of the latest horror movie; living mulch is a system farmers can use to benefit both profits and the soil. While the system has been around for a while, scientists at the University of Georgia are making it more efficient and sustainable.


Sequencing of stevia plant genome revealed for first time by Purecircle Stevia Institute

For the first time, scientists have completed the sequencing of the stevia plant genome. Lead scientists from PureCircle Stevia Institute and KeyGene have unveiled this major breakthrough in research showing the annotated, high-quality genome sequences of three stevia cultivars.