"The abundance of fruit-eating birds in the Happy Valley region is linked to the abundance of honeysuckle," Carlo explained. "Honeysuckle comprises more than half of all the fruits available in the landscape, and it benefits birds by providing them with a source of food in the fall. Meanwhile, birds benefit honeysuckle by dispersing the plant's seeds across a wider geographical area, helping the species to occupy more and more territory in areas already affected by human activities." Carlo explained that returning this particular ecosystem to its honeysuckle-free state could harm many species of native birds that now seem to rely on honeysuckle as a major food source in the fall.
The team also tested the honeysuckle's influence, not just on birds, but on other species of fruiting plants. First, they grew native fruiting plants known as American nightshades in pots in a greenhouse. When the fruits were ripe on each plant, they then placed them into both honeysuckle-dense areas and areas area without honeysuckle but dominated by other native and non-native fruiting species. "We chose the American nightshade because it is native and common in the Happy Valley region," Carlo said. "Also, it is easy to manipulate experimentally, and its fruits are eaten -- and thus dispersed -- by native birds."
In the area in which honeysuckle grew in abundance, the rate of fruit-removal of Carlo's American nightshades was 30-percent higher than in the areas without honeysuckle.
|Contact: Barbara Kennedy|