Research finds mangroves being fed to death

May 19, 2009
Research finds mangroves being fed to death

(PhysOrg.com) -- New UQ Science research has found the increase in nutrients coming out of our river systems is putting pressure on our mangrove forests and making them far more susceptible to environmental variability and climate change.

Originally thought to benefit growth, Associate Professor Catherine Lovelock's research shows the man-made rise in available nutrients from runoff or urban and industrial processes, actually decreases their resilience.

Dr Lovelock, from the Centre for Marine Studies, said this increase in nutrients could be responsible for the death of formerly healthy mangroves.

“While this increase in available nutrients initially favours mangrove growth, you get an increase in the growth of shoots relative to roots, and that's the wrong kind of growth,” Dr Lovelock said.

“This higher ratio of shoots to roots means the mangroves are much more susceptible to high salinity and drought.”

She said under such conditions, the plant needs to have as many roots as possible so that it can provide water for its shoots, however nutrient enrichment causes the exact opposite.

“Our results show that mangroves exposed to high nutrient availability suffer greater mortality during , and that nutrient-induced mortality is greater in sites subject to periods of low rainfall, low humidity and high salinity,” she said.

“It's particularly important in terms of because droughts may become more extreme, or at least more frequent, and we could see mangrove populations collapse.

“This paints nutrient enrichment as one of the greatest threats to near shore coastal ecosystems, bringing increased mangrove mortality on top of , coral reef degradation and loss of biodiversity and ecosystem resilience.”

Dr Lovelock and her team added either nitrogen or phosphorous based fertilisers to mangrove trees at 12 study sites around the world including Australia, New Zealand, Florida and the Caribbean.

The team then measured the growth and mortality rates for the mangroves at these sites over a period of more than three years.

The study showed a marked difference in tree mortality between sea fringing mangroves - that are flushed out by the tide - and further inland ‘scrub' mangroves.

Dr Lovelock said while the increase in nutrients had little effect on the sea fringing mangroves, there was a massive increase in mortality for the ‘scrub' mangrove forests.

“Scrub forests are less frequently inundated by tides, so in times of low rainfall the surrounding soil can become extremely saline and the plant cannot survive,” Dr Lovelock said.

“So nutrient enrichment could have a particularly disastrous impact on ecosystem function in drier areas where scrub forests account for the majority of mangrove forest cover.”

The new research, titled Nutrient enrichment increases of mangroves, was published in the international journal PLoS ONE.

Provided by University of Queensland (news : web)

Explore further: Call for alternative identification methods for endangered species

add to favorites email to friend print save as pdf

Related Stories

Mangroves importance and decline studied

Feb 27, 2006

Scientists say mangroves, the backbone of tropical ocean coastlines, are far more important to the global ocean's biosphere than previously thought.

Mangroves key to saving lives

Jul 21, 2008

The replanting of mangroves on the coasts of the Philippines could help save many of the lives lost in the 20-30 typhoons that hit the islands annually. This is one of the numerous reasons for the 'urgent need for immediate ...

Mangroves Save Lives In Storms

Apr 14, 2009

(PhysOrg.com) -- A new study of storm-related deaths from a super cyclone that hit the eastern coast of India in 1999 finds that villages shielded from the storm surge by mangrove forests experienced significantly ...

Killifish can adapt to life in a tree

Oct 19, 2007

Biologists in Belize and Florida have discovered that the mangrove killifish lives in trees when the water they usually live in has disappeared.

Recommended for you

Plants with dormant seeds give rise to more species

3 hours ago

Seeds that sprout as soon as they're planted may be good news for a garden. But wild plants need to be more careful. In the wild, a plant whose seeds sprouted at the first warm spell or rainy day would risk disaster. More ...

Scientists tether lionfish to Cayman reefs

13 hours ago

Research done by U.S. scientists in the Cayman Islands suggests that native predators can be trained to gobble up invasive lionfish that colonize regional reefs and voraciously prey on juvenile marine creatures.

User comments : 0

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —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 ...

Researchers develop new model of cellular movement

(Phys.org) —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 ...

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

(Phys.org) —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 ...

Plants with dormant seeds give rise to more species

Seeds that sprout as soon as they're planted may be good news for a garden. But wild plants need to be more careful. In the wild, a plant whose seeds sprouted at the first warm spell or rainy day would risk disaster. More ...