Too much water, fertilizer bad for plant diversity

Mar 26, 2007

Too much of multiple good things -- water or nutrients, for example -- may decrease the diversity of plant life in an ecosystem while increasing the productivity of a few species, a UC Irvine scientist has discovered.

This finding provides a new explanation for why grasslands, lakes and rivers polluted with nitrogen and phosphorus, usually from agriculture, contain a limited number of plant species. For example, where the Mississippi River empties into the Gulf of Mexico, the water contains low levels of oxygen and high levels of nitrogen and phosphorus used in fertilizers resulting in reduced plant diversity.

"Our results show nutrient pollution can cause loss of plant species from a habitat that can persist for more than 100 years," said W. Stanley Harpole, postdoctoral researcher in ecology and evolutionary biology at UCI and first author of the study. "This means human actions that simplify habitats can lead to long-term loss of biodiversity."

This study appeared March 25 in the online edition of the journal Nature.

The findings are based on experiments conducted at the University of California's Sedgwick Reserve in the Santa Ynez Valley. Researchers applied combinations of water and nutrients -- including nitrogen, phosphorus and cations -- to plots of grassland and found that areas treated with all of the resources had the fewest number of species but the highest productivity of a select few plant types.

When the many resources that plants compete for become overly abundant, the environment simplifies, and an emphasis is placed on a single environmental factor such as space or sunlight. Only a few species best adapted to the new environmental conditions will thrive, Harpole said.

The experiment, combined with an analysis of a similar 150-year-old study, supports the scientists' theory that plant diversity is directly related to the number of limiting factors such as levels of nitrogen, phosphorus, potassium and water.

Source: University of California - Irvine

Explore further: Adventurous bacteria

add to favorites email to friend print save as pdf

Related Stories

Sharks contain more pollutants than polar bears

Apr 15, 2014

The polar bear is known for having alarmingly high concentrations of PCB and other pollutants. But researchers have discovered that Greenland sharks store even more of these contaminants in their bodies.

Making dams safer for fish around the world

Apr 14, 2014

Think of the pressure change you feel when an elevator zips you up multiple floors in a tall building. Imagine how you'd feel if that elevator carried you all the way up to the top of Mt. Everest – in the ...

Icy research drills down on summer algae blooms

Apr 10, 2014

We've walked a mile out on the frozen skin of Missisquoi Bay. Clouds, snow and ice blend into an abstract collage of white shapes. To the west, a thin grey line, the New York shore, cuts the world in two. ...

Recommended for you

Chimpanzees prefer firm, stable beds

4 hours ago

Chimpanzees may select a certain type of wood, Ugandan Ironwood, over other options for its firm, stable, and resilient properties to make their bed, according to a study published April 16, 2014 in the open-access ...

For cells, internal stress leads to unique shapes

5 hours ago

From far away, the top of a leaf looks like one seamless surface; however, up close, that smooth exterior is actually made up of a patchwork of cells in a variety of shapes and sizes. Interested in how these ...

Adventurous bacteria

6 hours ago

To reproduce or to conquer the world? Surprisingly, bacteria also face this problem. Theoretical biophysicists at Ludwig-Maximilians-Universitaet (LMU) in Munich have now shown how these organisms should ...

User comments : 0

More news stories

Chimpanzees prefer firm, stable beds

Chimpanzees may select a certain type of wood, Ugandan Ironwood, over other options for its firm, stable, and resilient properties to make their bed, according to a study published April 16, 2014 in the open-access ...

Revealing camouflaged bacteria

A research team at the Biozentrum of the University of Basel has discovered an protein family that plays a central role in the fight against the bacterial pathogen Salmonella within the cells. The so cal ...

Down's chromosome cause genome-wide disruption

The extra copy of Chromosome 21 that causes Down's syndrome throws a spanner into the workings of all the other chromosomes as well, said a study published Wednesday that surprised its authors.