Recently in Native plants Category

Plant Releases Toxic Chemicals Into Soil

A team led by Harsh Bais has determined that Phragmites employs a strategy known as allelopathy, in which plants release toxic chemicals into the soil to deter other plants from growing close to them.

Phragmites australis, ranks as one of the world's most invasive plants.

The invasive strain, which hails from Eurasia, overtakes its "native" cousin, which has lived in North America for the past 10,000 years, ironically by provoking the native plant to "take itself out," through a combination of microbial and enzymatic activity in the soil.

Phragmites Reeds in Wetlands

In soil studies at the Delaware Biotechnology Institute, a center for life sciences research at UD, scientists discovered that invasive Phragmites produces elevated levels of a benign compound, a precursor of gallic acid known as gallotannin, relative to its native cousin.

However, when this gallotannin, a polymeric phenol, is attacked by tannase produced through enzymatic activity by native plants and rhizospheric microbes, toxic gallic acid is produced and released in the root zone, exacerbating the invasive Phragmites' noxiousness.

"The tannins are like partners in crime in the process," Bais said.

He noted that Hanson and Kumar collected microbes present on the root surface of the plants and revealed that the "bugs" cleave the polymer (gallotannin) to release the monomer (gallic acid) because the microbes are using the tannins as a carbon source.

"It's like a two-way highway," Bais said, "the plant is working with bacteria to secrete gallic acid into the soil."

Bais says that the microbial population is the same in the native versus the invasive Phragmites. The invasive variety simply secretes more gallotannins into the soil than its native cousin, putting the native plant at a disadvantage in turf battles between the two strains.

Phragmites has overtaken millions of acres of wetlands in the United States, thanks to the aggressive, invasive strain of the plant that came on the scene some 200 years ago from Eurasia.

The exotic species has displaced the non-aggressive native variety of the plant, relegating the native strain to isolated patches and wetland margins along the Atlantic coast.

"Now we have a way to remedy the sick soil," Bais said. "After years of research, we have identified a mechanism that may lead to a solution to the Phragmites invasion."

The research was supported by the University of Delaware Research Foundation (UDRF). Gurdeep Bains's involvement in the study was made possibly by a BOYSCAST Fellowship from the Department of Science and Technology, India.

SOURCE: Newswise

Farmscaping is the management of vegetation on and around the farm, to include plantings on roadways, field margins, waterways, natural areas and generally non-cropped areas. The term "farmscaping" can cover a wide range of practices, such as grassed waterways, buffers, filter strips and cover crops, as well as hedgerows and windbreaks.

Hedgerows are defined as lines or groups of trees, shrubs, perennial forbs, and grasses that are planted along roadways, fences, field edges or other non-cropped areas. The word "hedge," from the Old English word "hegg," referred to an enclosure or boundary formed by closely growing bushes or by dead plant material.

Windbreaks are barriers usually consisting of trees or shrubs that are used to reduce and redirect wind, resulting in microclimate changes in the sheltered zone.

Filter strips are planted areas that use vegetation to control soil erosion, slow water runoff, and capture and prevent sediments and nutrients from entering waterways.

Hedgerows can have multiple functions 

• They can serve as habitat for beneficial insects, pollinators and other wildlife;
• provide erosion protection and weed control;
• serve as windbreaks;
• stabilize waterways;
• reduce non-point source water pollution and groundwater pollution;
• increase surface water infiltration;
• buffer pesticide drift, noise, odors and dust;
• act as living fences and boundary lines;
• increase biodiversity;
• and provide an aesthetic resource.

Diversity in hedgerow species, especially when using natives, assures a range of attributes, such as multiple kinds of insects and wildlife attracted, positive effects to soil and water resources, and success of individual plants under site-specific climatic and other environmental conditions.

Find more info about farmsacping at the Community Alliance with Family Farmers

Birds are some of the most difficult animals to study because the fly so far and so fast.  It's no wonder that biologists are still making astounding discoveries about these light-weight wonders.  They grace our landscapes with color, song and acrobatics...but they do far more than that.  They help pollinate key plant species.  They turn seeds into protein.  They plant seeds along their journeys...and they give so many other animals pleasure and food.

Bird populations matter.

Biologists for the first time have documented a second breeding season during the annual cycle of five songbird species that spend summers in temperate North America and winters in tropical Central and South America
.

It was known that these species, which migrate at night when there are fewer predators and the stars can guide their journey, breed during their stay in temperate regions of the United States and Canada.

But it turns out that they squeeze in a second breeding season during a stopover in western Mexico on their southward migration, said Sievert Rohwer a University of Washington professor emeritus of biology and curator emeritus of birds at the Burke Museum of Natural History and Culture at the UW.

"It's pretty much unheard of to have a nocturnal migrant with a second breeding season. It's a pretty special observation," Rohwer said. "We saw these birds breeding and we were completely surprised."

Migratory double-breeding has been observed in two Old World bird species on their northward migration, but this is the first documented observation of "migratory double breeders" in the New World, and the first anywhere for the southward migration, Rohwer said.

The scientists traveled to the lowland thorn forests of coastal western Mexico to survey and collect songbirds that had raised their young in the United States and Canada and then immediately migrated to Mexico to molt, or shed and replace their feathers.

Yellow-billed cuckoos, orchard orioles, hooded orioles, yellow-breasted chats and Cassin's vireos

But during July and August in three consecutive summers, 2005-2007, the researchers found individuals from five species - yellow-billed cuckoos, orchard orioles, hooded orioles, yellow-breasted chats and Cassin's vireos - that were breeding rather than molting.

They found evidence that the birds had, in fact, bred earlier that year. Females of all five species examined in July had dry and featherless brood patches, indicating they had bred earlier that summer. (To more efficiently transfer heat to eggs, the abdominal brood patch becomes featherless and thickened with fluid when females are incubating, but as the young mature it dries out and remains featherless.). In the Mexican breeding ground, there was a complete absence of young birds, indicating the females had not bred in the area of the thorn forests.

Active nests were found for two species and males of all five species were singing and defending territories or guarding females, behaviors associated with breeding. In addition, isotopic analysis of the birds' tissues showed that many had recently arrived in west Mexico from temperate areas farther north.

The observation is much more than an oddity in bird behavior, Sievert Rohwer said. He noted that orchard orioles might raise a first brood in the Midwestern and south-central U.S. and a second on Mexico's western coast, yet both sets of offspring find the same wintering area in Central America.

The question is how both groups find the right place, since they must travel in different directions.

Then there is the yellow-billed cuckoo, once commonly seen throughout the western United States and as far north as the Seattle area but now seldom seen along the West Coast. Disappearing habitat in the U.S. is usually cited as the reason.

But Rohwer believes the real problem could be the transformation of thorn forests of southern Sonora and Sinaloa, states in northwestern Mexico, into irrigated industrial farms. That loss of habitat, he said, could mean not enough young are produced in the second breeding season to sustain the populations previously seen on the U.S. West Coast.

"It turns out that many of those migrants, both molt migrants and the newly discovered migratory double breeders, are dependent on the low-altitude thorn forests that become very productive during the monsoon," Rohwer said.

The thorn forests lie in an arid and forbidding scrubland that springs to life with the monsoon lasting from June through August. The monsoon brings virtually all of the area's annual rainfall. The small trees leaf out and insects become abundant, making an ideal stopover for migrating songbirds.

However, with plenty of biting insects, temperatures often at 100 degrees Fahrenheit and humidity hovering near 100 percent, it is a difficult place for researchers to work, so there has been little previous documentation of life in the thorn forest. The new findings could spur more work there.

"For western North America, the conservation implications are pretty serious," Rohwer said. "Biologists know theoretically that they should pay attention to these migration stopover sites, but they've been largely ignored for their conservation implications."