How climate change could rob Pennsylvania of 2 state symbols

Central Pennsylvania is known for its beautiful mountains, plentiful rivers and bountiful wildlife. In 2016, Centre County was treated to an unusually mild and pleasant winter, and many look forward to returning outdoors in the springtime.

However, the warm winter Pennsylvanians enjoyed could be a harbinger of a serious risk to wildlife.

According to the National Wildlife Federation, climate change is the single biggest threat to wildlife this century. For Pennsylvanians, the changing climate could strip away two of its state symbols: the eastern hemlock tree and the brook trout.

Pennsylvania's forests are under threat: Coniferous eastern hemlock trees all across the state are suffering from an infestation of the parasitic woolly adelgid.

Native to Asia, the hemlock woolly adelgid is a small insect that threatens the health and sustainability of eastern hemlock in the eastern U.S. It sucks sap from the young branches, which results in premature needle drop and branch dieback.

Ed Perry, of Boalsburg, was a biologist with U.S. Fish and Wildlife service for 30 years. Now retired, he works for the National Wildlife Federation's global warming campaign to educate people about the effects of climate change on Pennsylvania's fish and wildlife.

Perry said hemlocks were thriving up until a couple years ago, but mild winters have allowed the woolly adelgid to survive and continue its slow killing of hemlocks.

The parasitic insect was first reported in the eastern U.S. in 1951 near Richmond, Va., according to Pennsylvania Department of Conservation and Natural Resources. By 2005, it was established in portions of 16 states from Maine to Georgia, where infestations covered about half of the range of hemlock.

The effect has been most severe in areas of Virginia, New Jersey, Pennsylvania and Connecticut. As of fall 2015, only eight counties in Pennsylvania remain free of infestation.

Outdoorsman Ed Zygmunt, of Susquehanna County, said he has noticed the hemlock mortality in the past five years.

"In river corridors with steep hillsides, the mortality from adelgid is often very visible from the river or from where highways follow the river corridors," he said.

If the hemlock population is decimated, it could have disastrous effects on the ecosystems it lives in and drastically disrupt the carbon cycle of the forests, according to a study conducted by the U.S. Forest Service.

"Hemlocks are what we call a 'Keystone species' - a species upon which a lot of other life forms depend," Perry said.

Providing protection from erosion along stream banks, food for deer and wildlife, and shelter for deer in the winter, hemlock is also valued both as an ornamental tree and as an important source of lumber.

Unfortunately, Zygmunt said it's economically unfeasible to treat a whole forest for woolly adelgid infestation.

"You can treat individual trees, but most private landowners couldn't afford to do that," Zygmunt said.

According to the DCNR, commercial spray and injection treatments are expensive and have varied results. For forest landowners with dozens or hundreds of infested hemlocks, there are few options: treat, harvest or wait and see.

The DCNR reported most Pennsylvania landowners with infected hemlocks are watching and hoping that their trees survive, while others are selling their commercial hemlock timber.

While obviously a problem for forest-dwelling animals and landowners, the dying trees also cause problems for rivers and streams, said Tyler Wagner, adjunct professor of fisheries ecology at Penn State.

Forest cover can reduce solar radiation to waterways. Without it, the water temperatures will increase to lethal levels.

All fish require oxygen and a particular temperature of water to thrive, said Wagner, who is also assistant unit leader of the Pennsylvania Cooperative Fish and Wildlife Research Unit. High temperatures and oxygen depletion can be a surreptitious killer.

If water temperatures stay above the average for too long, a river or stream may become an unsuitable habitat for the fish that live there.

Without the shelter of the hemlock trees, one species in particular will be in grave danger: the brook trout.

These trout were once so synonymous with hemlock trees that they were called the hemlock brook trout.

An important recreational species throughout the northeastern U.S., brook trout are also a top predator in a lot of headwater streams, spring-fed ponds and fast-flowing rivers, and require cold, clear water to survive.

"They require cold water below 23 degrees Celsius (73.4 degrees Fahrenheit) to survive," Wagner said. "Anything that happens to increase solar radiation on streams has a negative effect on them."

When coldwater habitats warm, brook trout can become more susceptible to toxins, parasites and disease, according to the National Wildlife Federation. Warm water also holds less oxygen and allows the growth of harmful algae.

These high temperatures, combined with oxygen depletion, can lead to a higher mortality rate and massive die-offs.

However, warming water temperatures aren't the only danger to brook trout.

Wagner said it's been predicted that there will be changes in precipitation patterns along with the warming temperatures. Extra precipitation can cause changing river patterns and more rushing water.

This can lead to issues for brook trout eggs, Wagner said, which are spawned and incubated during the winter in cold, still water.

"It's predicted that there will be more rain instead of snow," he said. "That could scour out their nests and cause mortality to their eggs."

The Environmental Protection Agency predicted that brook trout habitats from 2050-2100 could suffer 50 to 100 percent potential loss due to global climate change.

"It's important to understand that climate change isn't going to have just direct effect on air temperature," Wagner said. It will also affect water temperatures, precipitation patterns and ultimately entire ecosystems.

"To people like myself and the thousands of other anglers in Pennsylvania and millions across the country, to lose that fishery would just break our hearts," Zygmunt said. "It is such a precious and irreplaceable resource."

The hemlock-brook trout ecosystem is likely to disappear without intervention.

"The forecast is for trout and salmon to be largely gone from the eastern U.S. by 2100," Perry said. "The brook trout population has already declined by one-third due to development."

In the past 100 years, the temperature has gone up by 1 degree, Perry said. With only this marginal increase, the Earth has had massive changes: Glaciers are melting and disappearing, weather is getting more extreme and Arctic sea ice is at an all-time low.

According to the NWF, the planet is projected to warm 7 to 11 degrees by the end of the century without significant steps to reduce carbon pollution, leading to severe consequences for wildlife.

Perry said the projected increase for the coming century is undeniably significant when you average the temperature of the whole planet.

"It's not like going from 60 degrees to 67, and that's the hardest thing for people to understand," Perry said.

"It's like the proverbial frog in boiling water. . The change is so slow and imperceptible, it's hard for anyone to really see it until it's too late."

Cate Hansberry: 814-235-3933, @catehans216

2016 the Centre Daily Times (State College, Pa.)



 

Last edited by Goose (6/05/2016 9:30 am)