Folks eager to learn about the good, the bad and the ugly in Pennsylvania's fields, streams and other green spaces can begin today, when the Urban EcoStewards program kicks off at Mount Washington's Grandview Scenic Byway Park.

It is the first of a dozen such events scheduled for city parks this year by the Nine Mile Run Watershed Association, Pittsburgh Parks Conservancy, Frick Environmental Center and Mount Washington Community Development Corporation, in an effort to build a network of environmental caretakers.

Much of the focus is on controlling invasive plants so native species can thrive, helping to ensure a healthy ecosystem.

"It's a little early in the season to be whacking weeds. That typically starts in May," said Nine Mile Run Watershed Association program director Jeffrey Bergman. "But we'll start educating people and bringing new volunteers together with returning stewards. Each of our programs has a learning, a social and a hands-on component."

City parks have dozens of invasive plants, including Japanese knotweed and mugwort.

"Non-natives were brought to the U.S. by immigrants who used them for cooking or medicines or for aesthetic garden plantings," said Bergman. "But they crowd out native plants, which means native songbirds and other animals lose habitat, too."

Bergman's association helps maintain Nine Mile Run in Frick Park. A $7.7 million restoration of the creek, which empties into the Monongahela River, was completed two years ago, and included the installation of $300,000 in native plants, shrubs and trees, such as wild blueberry, sycamore, dogwood and oak.

The Urban EcoStewards program features a wetlands walk in May to help people identify these natives, and a seed-gathering outing in Frick in October. Similar programs are scheduled for Highland, Schenley and Riverview parks.

Invasives are a statewide problem, and terrestrial plants aren't the only concern for the environment.

Pennsylvania fly-fishing shops in Central Pennsylvania are warning anglers about didymo, an algae that can blanket the bottom of lakes and streams and snuff out aquatic life.

Now documented in Pennsylvania in the east and west branches of the Delaware River, didymo -- often called "rock snot" -- can be spread by contaminated waders and other equipment. Shops are urging fishermen to keep their gear clean.

The Pennsylvania Fish and Boat Commission is stepping up plans to get the word out, too. It has put didymo on a list of invasive species being targeting in a new public information effort.

"Didymo, zebra mussels and viral hemorrhagic septisemia (VHS) are the three we're most worried about, although there are many more invasive plants and animals in our state," said Tim Schaeffer, the commission's director of policy, planning and communications. "They're easily spread, but they're also easy to contain."

Although VHS -- the Great Lakes virus that has killed walleyes, muskies and other species in recent years -- can be spread through infected water, the primary vectors are live fish and fresh fish eggs. Anglers are banned from taking either outside the Lake Erie watershed.

Zebra mussels and didymo expand their range by hitching rides on boats, tackle and other equipment.

"Didymo is the big, emerging concern," said biologist Eric Obert of Sea Grant, a coastal stewardship agency. "It was probably brought to Pennsylvania by folks traveling from other parts of the country or the world, and the best thing you can do to keep it from spreading is to clean your tackle when you come off the water."

Felt-soled waders are a particular culprit. At least one manufacturer has announced it will phase out felt-soled wader production by 2010. It is making Vibram soles instead because they are easier to keep clean. But because a single drop of water containing didymo organisms can doom a fishery, anglers are urged to be diligent about cleaning all their tackle.

The Governor's Invasive Species Council recommends soaking or spraying non-absorbent gear in a 5 percent dishwashing liquid solution or 2 percent bleach solution for at least a minute, and soaking absorbent gear in hot water for 40 minutes. Two to five days of drying time helps, too.

Eric Norman of TCO Fly Shop in State College, located about 100 yards from Spring Creek, encourages customers who travel to keep a separate set of gear for didymo-infected streams.

"Soaking in really hot water can be hard on waders," he said, "so that may be the most practical solution."

Anglers will begin seeing Clean Your Gear signs this summer at public access points across the state, and boaters will receive reminders to practice good tackle hygiene with their boat registration renewal letters, Schaeffer said.

Cleanings are the best prevention for zebra mussels, too.

"A small clump of vegetation can hold hundreds of zebra mussel larvae, so we're asking people to wash their boats, trailers and other gear of every piece of vegetation before launching in another waterway," said Obert.

According to the Zebra and Quagga Mussel Monitoring Network, the unwanted bivalves have spread from Lake Erie, where they probably first arrived in the ballast water of freighters, to Sandy and Edinboro lakes, the Allegheny River, the Susquehanna River, and several diving quarries.

Zebra mussels cause multiple headaches.

"They affect the lower food chain," said Obert. "Because they eat a lot of plankton, they take food away from larval fish. On Erie, more light penetration has caused heavier weed growth and algal bloom."

Zebra mussels also keep another invasive, Erie's round gobie, well-fed, making up 70 percent of the gobies' diet.

"Zebra mussels colonize on top of desirable mussels and suffocate them," said Obert. "And they clog up pipes affecting public water supplies."

Once they take hold, zebra mussels are hard to get rid of, although Ashley Walter, who heads the Governor's Invasive Species Council, said some states have had success removing zebra mussels from fisheries by hand.

"That's something we've talked about for Pennsylvania," she said. "For now, though, we're focused on preventing the spread."

TCO's Norman said anglers are mixed in their concern.

"Customers who travel know didymo's a real threat," he said. "Others figure, it's only a matter of time before it does, regardless of what we do."

But Schaeffer draws a parallel to the common cold.

"Sure, germs may be everywhere, but washing your hands can minimize your risk of infection. Not everyone gets sick."

For more, visit www.fishandboat.com and www.pittsburghparks.org.