Featured Research

from universities, journals, and other organizations

International Trade Imperils U.S. Plants, Animals And Crops

Date:
February 25, 2000
Source:
University Of California, Berkeley
Summary:
While the booming global economy promises greater prosperity in the next century, it poses a real threat to the country's native plants and animals as well as to its productive croplands, says an ecologist from the University of California, Berkeley.

Washington, D.C. -- While the booming global economy promises greater prosperity in the next century, it poses a real threat to the country's native plants and animals as well as to its productive croplands, says an ecologist from the University of California, Berkeley.

"International trade has a really big cost associated with it," said Carla M. D'Antonio, associate professor of integrative biology and an expert on invasive plants. "Most harmful non-indigenous insect pests and plant pathogens arrive in the U.S. as stowaways on nursery stock, raw logs or cargo containers. And many invasive exotic plants are purposely introduced through the horticultural market."

Alien invaders already cost the country $136 billion every year in lost and damaged products and the expense of controlling them, according to a January article in the journal Bioscience. With a predicted exponential rise in international trade, D'Antonio predicts at least a 50 percent rise in this cost in the next 20 years, not including any increased costs from battling invaders already established in this country.

"We obviously can't get rid of trade, but we have to make a commitment to inspection, quarantine and control to accompany the rise -- and that is just to maintain things as they are today," she said. "The first place to stop these exotic species is at the dock, or even better, before they leave their native country."

D'Antonio will lay out her predictions in a talk on Sunday, Feb. 20, at this week's meeting of the American Association for the Advancement of Science in Washington, D.C., at a session on "Ecological Forecasting: How Will Human Domination Impact Ecosystems This Century?"

She estimates that some 1,500 new insects and 50 new pathogens -- fungi or bacteria -- will make their way into the United States in the next 20 years, with perhaps 15 percent causing serious ecological and/or economic harm.

The economic effects come primarily from invaders, like the Russian wheat aphid, that attack crops; parasitic plants like witch weed, which now affect corn farmers; or weeds, such as thistles, that invade cropland. Alien weeds like spotted knapweed, star thistle and cheat grass reduce the quality of rangeland for grazing cattle, while fungi and insects plague both croplands and forest trees. A recent arrival is the Asian long-horned beetle, first detected only in the past three years, now feasting on hardwood trees in the Northeast.

"This beetle came over from China in wood packaging material and is destroying street trees in several cities in the East," she said. "It has a very wide host range and, while it is currently feasting on a variety of maple species, it has the potential to expand to many other types of trees."

Crop weeds accounted for $26 billion in loss and control last year, while agricultural pests cost the country $14.4 billion, according to the report in Bioscience. Forest pests, on the other hand, cost $2.1 billion, counting control costs and lost production. Fire ants alone accounted for a billion dollars last year in control costs and the loss of rangeland in the Southeast and Texas.

Apart from economic damage, however, these invaders upset the ecosystem, preying on native species, outcompeting them and spreading disease. They also can alter ecosystem processes to the point that the systems can no longer support native species. Non-indigenous species are second only to land use change in causing species extinction, D'Antonio said.

"I don't think any native communities are entirely resistant to invasion," she said. "With repeated introduction of new propagules, you increase the probability that a few of them will establish themselves, and eventually some will cause the extinction of native species."

Propagules are larvae, seeds or pieces of plants or fungi capable of developing into mature adults.

One of the major sources of alien pathogens such as fungi are nursery plants imported for the horticultural market. These come into the country carrying foreign contaminants in the soil around their roots or in the roots themselves. Though all nursery stock must be quarantined and irradiated, this is not sufficient to prevent the entry of many harmful pathogens, D'Antonio said.

"Nursery stock has really been bad news for U.S. forests," she said.

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS) is responsible for inspecting all imports for hitchhiking invaders, but huge container ships are difficult to inspect thoroughly. And some imports, such as seeds, are immune from inspection. More than 100,000 different seeds are involved in the uncontrolled seed trade today, with at least 59,000 species available in U.S. seed catalogs alone, she said.

In addition, many species introduced as ornamentals have become highly invasive and ecologically damaging plants. These range from kudzu and the tree melaleuca in the South to giant reed grass and saltcedar in the West and Japanese honeysuckle in the East.

Though the USDA is now studying its future needs, partly as a result of President Clinton's decree several years ago to do everything possible to control the introduction of new species, it is unclear whether APHIS can keep up with the increase in imports.

"Our inspection and quarantine and eradication efforts must be commensurate with the increase in trade," D'Antonio said.

D'Antonio's specialty is invasive plants in the Western U.S. and Hawaii. Among the plants she has studied are ice plant, a South African succulent that invades dune and shrub communities in coastal areas; French broom, an abundant invasive shrub along the Pacific coast; African pasture grasses that have invaded Hawaiian dry forests and caused their almost complete demise; and grasses introduced long ago, such as velvet grass, canary grass and tall fescue, that force out native bunch grasses in the continental U.S. Of primary interest are the ways through which exotic plants outcompete native plants.

One of her current new concerns is African buffel grass, planted by Mexican cattle ranchers and now invading desert areas in southern Arizona.

"The plant has the potential to enhance the occurrence of fire -- a disturbance to which the native species are not adapted," she said.


Story Source:

The above story is based on materials provided by University Of California, Berkeley. Note: Materials may be edited for content and length.


Cite This Page:

University Of California, Berkeley. "International Trade Imperils U.S. Plants, Animals And Crops." ScienceDaily. ScienceDaily, 25 February 2000. <www.sciencedaily.com/releases/2000/02/000225080409.htm>.
University Of California, Berkeley. (2000, February 25). International Trade Imperils U.S. Plants, Animals And Crops. ScienceDaily. Retrieved August 21, 2014 from www.sciencedaily.com/releases/2000/02/000225080409.htm
University Of California, Berkeley. "International Trade Imperils U.S. Plants, Animals And Crops." ScienceDaily. www.sciencedaily.com/releases/2000/02/000225080409.htm (accessed August 21, 2014).

Share This




More Earth & Climate News

Thursday, August 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

California Drought Stings Honeybees, Beekeepers

California Drought Stings Honeybees, Beekeepers

AP (Aug. 21, 2014) California's record drought is hurting honey supplies and raising prices for consumers. The lack of rainfall means fewer crops and wildflowers that provide the nectar bees need to make honey. (Aug. 21) Video provided by AP
Powered by NewsLook.com
Thousands Of Species Found In Lake Under Antarctic Ice

Thousands Of Species Found In Lake Under Antarctic Ice

Newsy (Aug. 20, 2014) A U.S. team found nearly 4,000 species in a subglacial lake that hasn't seen sunlight in millennia, showing life can thrive even under the ice. Video provided by Newsy
Powered by NewsLook.com
Unsustainable Elephant Poaching Killed 100K In 3 Years

Unsustainable Elephant Poaching Killed 100K In 3 Years

Newsy (Aug. 20, 2014) Poachers have killed 100,000 elephants between 2010 and 2012, as the booming ivory trade takes its toll on the animals in Africa. Video provided by Newsy
Powered by NewsLook.com
Charter Schools Alter Post-Katrina Landscape

Charter Schools Alter Post-Katrina Landscape

AP (Aug. 20, 2014) Nine years after Hurricane Katrina, charter schools are the new reality of public education in New Orleans. The state of Louisiana took over most of the city's public schools after the killer storm in 2005. (Aug. 20) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins