Green Triangle

By SHEILA READ

Triangle residents have been grumbling for months about the unprecedented heat and drought of the summer of 2007, which has driven people indoors to air conditioned rooms and led to increasing restrictions on use of water.

Suffering more quietly, but noticeably, are the animals, trees and plants of the Piedmont woodlands and the aquatic life in the drying-up rivers and streams.

The drought, still labeled extreme in the Triangle area despite Friday’s rainfall, is having a “profound effect” on the Eno River, said Dave Cook, superintendent of Eno River State Park.

Across North Carolina, streams currently have less than 25 percent of their normal water levels. In the Eno River, the water level on Saturday was slightly over 1 foot, according to U.S. Geological Survey data. Just to keep water at that minimal level, state officials daily are releasing water into the river from Lake Orange “so the life in the river doesn’t die,” Cook said.

Trees in the Piedmont are also suffering. “I’ve never seen as much wilting and dead branches, leaves, and trees as I have this year,” said Peter White, director of the North Carolina Botanical Garden. “There seems to be more damage and in a wider range of species than I’ve seen before,” he said.

Dogwoods are perhaps the hardest hit of local trees. Dead and dying dogwoods can be seen throughout the Triangle along road edges and in open berms.

One sign of the drought’s severity is that native trees that usually are considered to be drought-tolerant–such as redbud and post oak–are having widespread problems and even dying, White said.

Exotic Plants Threaten Fish
In the Eno River, the low water level is resulting in profuse blooms of plants such as algae and hydrilla that can endanger aquatic life, Cook said.

Hydrilla, an exotic plant thought to have entered the wild through the aquarium trade, is “taking over the river,” Cook said, as it quickly colonizes newly bare shoreline. The blooms of vegetation in the Eno River may lead to fish kills in the winter, as the decaying of dead plants robs the water of oxygen, Cook said.

At Falls Lake, biologists are concerned about another exotic plant, water primrose, that has taken advantage of the drought by taking over a dry beach, said Emily Parisher, Piedmont regional biologist for State Parks. In smaller bodies of water, the aggressive water primrose is capable of becoming thick enough that boats can’t move through the water.

Meanwhile, as smaller tributaries and streams have dried up, exposed freshwater mussels are falling victim to raccoons, Parisher said. “It’s a bust for mussels but a boom for raccoons,” she said.

White-tailed deer may be under stress too, as dead and wilting plants limit their food supply. Keith Nealson, park ranger at William B. Umstead Park in Raleigh, has observed deer out and about in the middle of the day nearly every day, despite the hot sun. That usually indicates the deer are having to spend more time foraging, he said.

Leaves Fall Early
The widespread browning and dropping of leaves gives the Triangle the feel of autumn, more than a month ahead of schedule. At William B. Umstead Park, “maintenance crews have pretty much given up lawn mowing and moved to leaf blowing,” Nealson said. The woods are so dry that the risk of fire is very high.

Biologist Parisher points out that leaf dropping, while unattractive in the landscape, is an adaptation that trees have developed to cope with drought. Leaves lose water through microscopic openings, and dropping leaves therefore helps trees to conserve water.

In the long-term, no one knows how this year’s severe drought will affect North Carolina ecosystems. Most native plants can withstand one year of drought, but cumulative stresses can be fatal. If rainfall next year is normal, most trees and other plants should recover, but aquatic life could take longer to rebound, Cook said.