Sequence matters in droughts and floods

January 8, 2009

When extremes of drought and flood come in rapid succession, the extent of damage to vegetation may depend in part on the sequence of those events, according to a new study published in The American Naturalist.

The study, which focused on tree species common to the Everglades in Florida, found that seedlings maintained higher growth rates and were less likely to die when subjected to drought first then flood, rather than vice versa. The findings could have significant implications for predicting how vegetation responds to climate extremes—especially amid forecasts of increasingly severe droughts and floods associated with climate change, say authors ShiLi Miao (South Florida Water Management), Chris B. Zou and David D. Breshears (both University of Arizona).

According to Dr. Miao, most previous studies on how vegetation responds to hydrological events have been based largely on responses to a single hydrological condition. Few studies have investigated multiple events in succession.

"Our research suggests that you can't really predict how the plants will respond to combinations of drought and flood by studies that look just at a single drought or a single flood," Dr. Miao said. "We found that plants respond very differently depending on the sequence of flood and drought."

In a greenhouse, Dr. Miao's team subjected seedlings to sequences of conditions that simulated drought and flood, with each phase lasting four months.

The three species chosen for the experiments have varying tolerances to hydrological events. The pond-apple tree (annona glabra) tends to be flood tolerant. The gumbo-limbo (bursera simaruba, also known as West Indian birch) tends to be drought tolerant. The red maple (acer rabrum, also known as swamp maple) has intermediate tolerances to drought and flood.

Each species tested showed higher mortality and lower growth rate when flood was first in the sequence, compared to when drought came first.

The study has implications for the restoration and management of the Everglades and other aquatic systems, Dr. Miao says. The results suggest that "the challenge ahead includes evaluating different sequences of extreme events."

Dr. Miao and her team plan to conduct additional research on various wetland plants related to their nutrient removal function under extreme hydrological conditions.

Source: University of Chicago

Explore further: Meteorologist lifts the fog surrounding El Niño

Related Stories

Meteorologist lifts the fog surrounding El Niño

November 24, 2015

Based on the latest information from a San Francisco State University meteorologist, now may be a good time to stock up on rain ponchos, rubber boots and umbrellas. The overall consensus among scientists, forecasters and ...

With El Nino, be careful what you wish for

November 17, 2015

A few weeks ago in the hills north of Los Angeles, heavy rain set off widespread mudslides that blocked roads and covered highways, burying hundreds of vehicles and bringing much of Los Angeles' infamous traffic to a standstill.

Global warming: What if we do nothing?

November 17, 2015

If mankind fails to curtail global warming, we will have to deal with fallout ranging from massive refugee crises and submerged cities to scorching heatwaves and drought, scientists say.

Recommended for you

'Material universe' yields surprising new particle

November 25, 2015

An international team of researchers has predicted the existence of a new type of particle called the type-II Weyl fermion in metallic materials. When subjected to a magnetic field, the materials containing the particle act ...

New gene map reveals cancer's Achilles heel

November 25, 2015

Scientists have mapped out the genes that keep our cells alive, creating a long-awaited foothold for understanding how our genome works and which genes are crucial in disease like cancer.

CERN collides heavy nuclei at new record high energy

November 25, 2015

The world's most powerful accelerator, the 27 km long Large Hadron Collider (LHC) operating at CERN in Geneva established collisions between lead nuclei, this morning, at the highest energies ever. The LHC has been colliding ...

A blue, neptune-size exoplanet around a red dwarf star

November 25, 2015

A team of astronomers have used the LCOGT network to detect light scattered by tiny particles (called Rayleigh scattering), through the atmosphere of a Neptune-size transiting exoplanet. This suggests a blue sky on this world ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.